Differential interchanges
Differential interchanges
I'm learning the ropes of my 300TD's. I plan to travel a lot, and would like to change the diff. ratio let my engine run as slow as possible at highway speeds. From what I've heard, 2.88 was only offered on the '85 W123 and the W126 platform also offered a 2.88 as well as a 2.47. Could W126 differentials be directly interchanged or are they different units that share the same ratios? Thanks!
Greetings everyone!
I'm learning the ropes of my 300TD's. I plan to travel a lot, and would like to change the diff. ratio let my engine run as slow as possible at highway speeds. From what I've heard, 2.88 was only offered on the '85 W123 and the W126 platform also offered a 2.88 as well as a 2.47. Could W126 differentials be directly interchanged or are they different units that share the same ratios? Thanks!
(05-19-2009, 11:11 PM)IsaacDW Could W126 differentials be directly interchanged or are they different units that share the same ratios? Thanks!
Early 126 diffs (1985 and earlier) should be a direct swap... i have one each of 123 and 126(early) and they appear to mount the same... some people say they have had to shim it a bit to get the driveshaft angle perfect... the 126 diffs are 210mm vice 185mm and are substantially heavier. my plan is to tear down both units and measure the internals to determine if any of the Quaiffe LSDs will fit and throw one of those in. I have a 2.47 out of an early 420SEL ('82 I think), which I hope to upgrade with an LSD and a 2.65:1 from a later model with 210mm diff... that way, the engine will turn at a lower RPM and have less noise and hopefully a little less wear on the engine... the fuel economy is not really going to change much if at all, but this is still something Im working on...
W123 Mods: 4 speed ** manual climate control ** '85 Kalitucky intake ** manual windows & full tint ** Euro headlights retrofit w/bixenon projectors ** 4 brake light mod ** Vogtland 50mm drop front & Lesjofors S600 drop rear springs ** 16" rims ** late w126 brake spindles, rotors & calipers ** full suspension rehab ** Bilstein HDs ** AL129X alternator & 1/0 starter and charging cables ** 300GD clutch/flywheel ** AFCO 80103N radiator & Earl's 41610 oil cooler ** custom block-off plate, remote oil filter & t-stat ** MW IP w/ tomnik's 6.5mm 'Holly' elements **
S124 Mods: 400E Rear subframe ** SL600 Brakes ** Late 300E 210mm diff ** SLK230 6 speed ** 17" CLK rims ** Vented RF Fender ** Facelift Hood, Headlights, and Lower Cladding **
OBK# 62
SurfRodder
05-20-2009, 12:10 AM #2(05-19-2009, 11:11 PM)IsaacDW Could W126 differentials be directly interchanged or are they different units that share the same ratios? Thanks!
Early 126 diffs (1985 and earlier) should be a direct swap... i have one each of 123 and 126(early) and they appear to mount the same... some people say they have had to shim it a bit to get the driveshaft angle perfect... the 126 diffs are 210mm vice 185mm and are substantially heavier. my plan is to tear down both units and measure the internals to determine if any of the Quaiffe LSDs will fit and throw one of those in. I have a 2.47 out of an early 420SEL ('82 I think), which I hope to upgrade with an LSD and a 2.65:1 from a later model with 210mm diff... that way, the engine will turn at a lower RPM and have less noise and hopefully a little less wear on the engine... the fuel economy is not really going to change much if at all, but this is still something Im working on...
W123 Mods: 4 speed ** manual climate control ** '85 Kalitucky intake ** manual windows & full tint ** Euro headlights retrofit w/bixenon projectors ** 4 brake light mod ** Vogtland 50mm drop front & Lesjofors S600 drop rear springs ** 16" rims ** late w126 brake spindles, rotors & calipers ** full suspension rehab ** Bilstein HDs ** AL129X alternator & 1/0 starter and charging cables ** 300GD clutch/flywheel ** AFCO 80103N radiator & Earl's 41610 oil cooler ** custom block-off plate, remote oil filter & t-stat ** MW IP w/ tomnik's 6.5mm 'Holly' elements **
S124 Mods: 400E Rear subframe ** SL600 Brakes ** Late 300E 210mm diff ** SLK230 6 speed ** 17" CLK rims ** Vented RF Fender ** Facelift Hood, Headlights, and Lower Cladding **
OBK# 62
If your going with a 1st generation w126 gasser 2.47 differential, you will need address the different yoke/flange size. The gassers uses a bigger flex disk then the diesels. So you will either have to change out flange to accept the smaller flex disk, or you can retain the beefiness of the bigger flex disk by modifying the driveshaft. In your application, it would be better just change out the flange.
(05-20-2009, 12:56 AM)IsaacDW Thank you! I hope to go to a parts yard Thursday to hopefully acquire an early 2.47. What did you mean by the 210 mm vice and 185 mm? Where are those measurements taken?
210 mm and 185 mm represent the physical size of the gear. The 2.47 has a taller case to accept the bigger gear then your stock 3.07 which has 185 mm gear.
On a side note, that Quaiffe carrier surfrodder is referring to are very expensive.
.
The other item to note is if you are going with the 2.47. Your speedometer will be off and will have to be corrected.
Unfortunately each speedometer is calibrated for the specific differential ratio, not through gears in the transmission like the old domestic vehicle makes. If you were going to a 2.88 it would have been easy because you will just use a 1985 300D speedo head. If you had a 1981 300TD, it would of been theoretically doable with a little modification from parts out of a w126 gasser 2.47 speedo head because they are both electronic.
But since your either working on the '82 or '83 TD, they are both mechanical and there are no 2.47 speedo heads to match it. So to make my long winded statement have a solution, you'll need to get a speedometer ratio adapter made. Here is a site that could probably help you. http://www.speedometershop.com/ratio.html#ADAPT
Gota love Mercedes Diesels!
.
DeliveryValve
05-20-2009, 01:03 AM #4No difference in the 1985 2.88 differential from either the w123 or w126 diesel. They have the same 185mm gear and same housing.
If your going with a 1st generation w126 gasser 2.47 differential, you will need address the different yoke/flange size. The gassers uses a bigger flex disk then the diesels. So you will either have to change out flange to accept the smaller flex disk, or you can retain the beefiness of the bigger flex disk by modifying the driveshaft. In your application, it would be better just change out the flange.
(05-20-2009, 12:56 AM)IsaacDW Thank you! I hope to go to a parts yard Thursday to hopefully acquire an early 2.47. What did you mean by the 210 mm vice and 185 mm? Where are those measurements taken?
210 mm and 185 mm represent the physical size of the gear. The 2.47 has a taller case to accept the bigger gear then your stock 3.07 which has 185 mm gear.
On a side note, that Quaiffe carrier surfrodder is referring to are very expensive.
.
The other item to note is if you are going with the 2.47. Your speedometer will be off and will have to be corrected.
Unfortunately each speedometer is calibrated for the specific differential ratio, not through gears in the transmission like the old domestic vehicle makes. If you were going to a 2.88 it would have been easy because you will just use a 1985 300D speedo head. If you had a 1981 300TD, it would of been theoretically doable with a little modification from parts out of a w126 gasser 2.47 speedo head because they are both electronic.
But since your either working on the '82 or '83 TD, they are both mechanical and there are no 2.47 speedo heads to match it. So to make my long winded statement have a solution, you'll need to get a speedometer ratio adapter made. Here is a site that could probably help you. http://www.speedometershop.com/ratio.html#ADAPT
Gota love Mercedes Diesels!
.
basically,
40 indicated = 50 actual
50 indicated = 60 actual
60 indicated = 70 actual
70 indicated = 80 actual
80 indicated = 90 actual
and you won't have enough power to go much faster than that.
GREASY_BEAST
05-20-2009, 10:47 AM #5You don't have to do a damn thing to the speedo with a 2.47 swap! At speeds between 15 and 30mph it is more or less right on, and between about 40-80 the speedo reads 10mph slower than what you are driving (I verified this with GPS).
basically,
40 indicated = 50 actual
50 indicated = 60 actual
60 indicated = 70 actual
70 indicated = 80 actual
80 indicated = 90 actual
and you won't have enough power to go much faster than that.
(05-20-2009, 10:47 AM)GREASY_BEAST You don't have to do a damn thing ....
Sarcasm?!? You should correct it for the obvious and for the odometer sake. If you happen to sell the vehicle later on and the mileage is less than actual, that would be an injustice.
Gota love Mercedes Diesels!
.
DeliveryValve
05-20-2009, 12:51 PM #6(05-20-2009, 10:47 AM)GREASY_BEAST You don't have to do a damn thing ....
Sarcasm?!? You should correct it for the obvious and for the odometer sake. If you happen to sell the vehicle later on and the mileage is less than actual, that would be an injustice.
Gota love Mercedes Diesels!
.
(05-20-2009, 12:51 PM)DeliveryValve(05-20-2009, 10:47 AM)GREASY_BEAST You don't have to do a damn thing ....
Sarcasm?!? You should correct it for the obvious and for the odometer sake. If you happen to sell the vehicle later on and the mileage is less than actual, that would be an injustice.
No sarcasm. My odometer has read the same number for about 3 years now.
GREASY_BEAST
05-20-2009, 01:18 PM #7(05-20-2009, 12:51 PM)DeliveryValve(05-20-2009, 10:47 AM)GREASY_BEAST You don't have to do a damn thing ....
Sarcasm?!? You should correct it for the obvious and for the odometer sake. If you happen to sell the vehicle later on and the mileage is less than actual, that would be an injustice.
No sarcasm. My odometer has read the same number for about 3 years now.
(05-20-2009, 01:24 PM)winmutt Are you saying the 2.47 diff case is bigger than the 2.88/3.07?
Yes.
(05-20-2009, 01:24 PM)winmutt Is it big enough to fit the innards from a W201 LSD?
No it is too big. The W201 3.27 LSD differential has a 185 mm gear. But you can fit the carrier in the case of a 2.88/3.07/3.46/3.69 with some custom spacers.
Gota love Mercedes Diesels!
.
DeliveryValve
05-20-2009, 02:42 PM #9(05-20-2009, 01:24 PM)winmutt Are you saying the 2.47 diff case is bigger than the 2.88/3.07?
Yes.
(05-20-2009, 01:24 PM)winmutt Is it big enough to fit the innards from a W201 LSD?
No it is too big. The W201 3.27 LSD differential has a 185 mm gear. But you can fit the carrier in the case of a 2.88/3.07/3.46/3.69 with some custom spacers.
Gota love Mercedes Diesels!
.
(05-20-2009, 01:03 AM)DeliveryValve So to make my long winded statement have a solution, you'll need to get a speedometer ratio adapter made. Here is a site that could probably help you. http://www.speedometershop.com/ratio.html#ADAPT
another option would be to take the tail cone off of an electronic speedo drive tranny, i.e. the auto in the 300SD and bolt that to the ass end of your tranny in place of the manual gear driven setup... then it's be a matter of swapping over the electronic speedo from the donor of the diff... prolly be a little cheaper, if not a bit more of a PITA, but def. still doable...
the Quaife LSDs are around 1200 bux, maybe cheaper if you know someone, but to do a stock LSD 'right' youre looking at ~500 anyway, neither of those prices include a shop setting it up for you, figure another 2-3 hundo for that...unless you have all the pricey tools to do that as well
yeah, when you go to the part yard, look for an early 126 gasser with a V-8 if you want the 2.47. There's a flat spot on the diff around the perimeter of the access cover that should have the ratio stamped into it, I'd check that just to be sure, buf if its a v-8, it should be a 2.47.
i forgot about the larger input flange on the bigger diff, if you have a 30mm 12 pt deep socket (like the one used to take off the trans output noted above), you could prolly swap it out while you're at the yard for another one from a 123 and be done with it... that part really should be adjusted by a shop prior to installing it on your car though.
(05-20-2009, 01:24 PM)winmutt Is it big enough to fit the innards from a W201 LSD?
what delivery valve said...
plus theres several 124s that have ASD and they also have a decent selection of ratios...in the 185mm ring size... I want to go with the 2.65 so my only option for a factory setup in 185mm size would be from a 90-93 300D 2.5T with the ASD option (at least according to gsxrs spreadsheet). I'd also rather not deal with ever having to replace the friction discs in the factory diff so that's another reason Im looking into the quaife setup with a 2.65 from any number of cars that had that in the 210mm size.
W123 Mods: 4 speed ** manual climate control ** '85 Kalitucky intake ** manual windows & full tint ** Euro headlights retrofit w/bixenon projectors ** 4 brake light mod ** Vogtland 50mm drop front & Lesjofors S600 drop rear springs ** 16" rims ** late w126 brake spindles, rotors & calipers ** full suspension rehab ** Bilstein HDs ** AL129X alternator & 1/0 starter and charging cables ** 300GD clutch/flywheel ** AFCO 80103N radiator & Earl's 41610 oil cooler ** custom block-off plate, remote oil filter & t-stat ** MW IP w/ tomnik's 6.5mm 'Holly' elements **
S124 Mods: 400E Rear subframe ** SL600 Brakes ** Late 300E 210mm diff ** SLK230 6 speed ** 17" CLK rims ** Vented RF Fender ** Facelift Hood, Headlights, and Lower Cladding **
OBK# 62
SurfRodder
05-20-2009, 08:52 PM #10(05-20-2009, 01:03 AM)DeliveryValve So to make my long winded statement have a solution, you'll need to get a speedometer ratio adapter made. Here is a site that could probably help you. http://www.speedometershop.com/ratio.html#ADAPT
another option would be to take the tail cone off of an electronic speedo drive tranny, i.e. the auto in the 300SD and bolt that to the ass end of your tranny in place of the manual gear driven setup... then it's be a matter of swapping over the electronic speedo from the donor of the diff... prolly be a little cheaper, if not a bit more of a PITA, but def. still doable...
the Quaife LSDs are around 1200 bux, maybe cheaper if you know someone, but to do a stock LSD 'right' youre looking at ~500 anyway, neither of those prices include a shop setting it up for you, figure another 2-3 hundo for that...unless you have all the pricey tools to do that as well
yeah, when you go to the part yard, look for an early 126 gasser with a V-8 if you want the 2.47. There's a flat spot on the diff around the perimeter of the access cover that should have the ratio stamped into it, I'd check that just to be sure, buf if its a v-8, it should be a 2.47.
i forgot about the larger input flange on the bigger diff, if you have a 30mm 12 pt deep socket (like the one used to take off the trans output noted above), you could prolly swap it out while you're at the yard for another one from a 123 and be done with it... that part really should be adjusted by a shop prior to installing it on your car though.
(05-20-2009, 01:24 PM)winmutt Is it big enough to fit the innards from a W201 LSD?
what delivery valve said...
plus theres several 124s that have ASD and they also have a decent selection of ratios...in the 185mm ring size... I want to go with the 2.65 so my only option for a factory setup in 185mm size would be from a 90-93 300D 2.5T with the ASD option (at least according to gsxrs spreadsheet). I'd also rather not deal with ever having to replace the friction discs in the factory diff so that's another reason Im looking into the quaife setup with a 2.65 from any number of cars that had that in the 210mm size.
W123 Mods: 4 speed ** manual climate control ** '85 Kalitucky intake ** manual windows & full tint ** Euro headlights retrofit w/bixenon projectors ** 4 brake light mod ** Vogtland 50mm drop front & Lesjofors S600 drop rear springs ** 16" rims ** late w126 brake spindles, rotors & calipers ** full suspension rehab ** Bilstein HDs ** AL129X alternator & 1/0 starter and charging cables ** 300GD clutch/flywheel ** AFCO 80103N radiator & Earl's 41610 oil cooler ** custom block-off plate, remote oil filter & t-stat ** MW IP w/ tomnik's 6.5mm 'Holly' elements **
S124 Mods: 400E Rear subframe ** SL600 Brakes ** Late 300E 210mm diff ** SLK230 6 speed ** 17" CLK rims ** Vented RF Fender ** Facelift Hood, Headlights, and Lower Cladding **
OBK# 62
I also want to add that when your swapping over the flanges, you want to make sure you have the same preload on the new flange as on the old. So you won't destroy the pinion bearing. (It would be better if you actually have the factory spec, But I can't seem to find it so you keep it the same as original) Before taking off the original flange, you have to measure the rotational torque the flange gives when you turn it. You do this with an inch pound torque wrench. Then when you install the new flange on the diff, you tighten a "new" nut down until you get the same rotational inch pound torque as before for the correct preload. You will then stake the nut to lock it in place.
Here is a youtube video of setting the preload on a Ford Differential. Same principle would be used for the Mercedes diff at 2:00 (two minutes) into the video.
http://www.youtube.com/watch?v=8APYO2sZy...re=related
.
Gota love Mercedes Diesels!
.
DeliveryValve
05-21-2009, 01:57 AM #11Good point SurfRodder made on the 30mm 12pt socket to remove the flange.
I also want to add that when your swapping over the flanges, you want to make sure you have the same preload on the new flange as on the old. So you won't destroy the pinion bearing. (It would be better if you actually have the factory spec, But I can't seem to find it so you keep it the same as original) Before taking off the original flange, you have to measure the rotational torque the flange gives when you turn it. You do this with an inch pound torque wrench. Then when you install the new flange on the diff, you tighten a "new" nut down until you get the same rotational inch pound torque as before for the correct preload. You will then stake the nut to lock it in place.
Here is a youtube video of setting the preload on a Ford Differential. Same principle would be used for the Mercedes diff at 2:00 (two minutes) into the video.
http://www.youtube.com/watch?v=8APYO2sZy...re=related
.
Gota love Mercedes Diesels!
.
W123 Mods: 4 speed ** manual climate control ** '85 Kalitucky intake ** manual windows & full tint ** Euro headlights retrofit w/bixenon projectors ** 4 brake light mod ** Vogtland 50mm drop front & Lesjofors S600 drop rear springs ** 16" rims ** late w126 brake spindles, rotors & calipers ** full suspension rehab ** Bilstein HDs ** AL129X alternator & 1/0 starter and charging cables ** 300GD clutch/flywheel ** AFCO 80103N radiator & Earl's 41610 oil cooler ** custom block-off plate, remote oil filter & t-stat ** MW IP w/ tomnik's 6.5mm 'Holly' elements **
S124 Mods: 400E Rear subframe ** SL600 Brakes ** Late 300E 210mm diff ** SLK230 6 speed ** 17" CLK rims ** Vented RF Fender ** Facelift Hood, Headlights, and Lower Cladding **
OBK# 62
SurfRodder
05-21-2009, 11:18 PM #12yeah, good call... you can def. pull the flange off of an old 123 diff and pay the 5 bux or so theyll prolly charge and then set it up proper on the larger one when you get it home...
W123 Mods: 4 speed ** manual climate control ** '85 Kalitucky intake ** manual windows & full tint ** Euro headlights retrofit w/bixenon projectors ** 4 brake light mod ** Vogtland 50mm drop front & Lesjofors S600 drop rear springs ** 16" rims ** late w126 brake spindles, rotors & calipers ** full suspension rehab ** Bilstein HDs ** AL129X alternator & 1/0 starter and charging cables ** 300GD clutch/flywheel ** AFCO 80103N radiator & Earl's 41610 oil cooler ** custom block-off plate, remote oil filter & t-stat ** MW IP w/ tomnik's 6.5mm 'Holly' elements **
S124 Mods: 400E Rear subframe ** SL600 Brakes ** Late 300E 210mm diff ** SLK230 6 speed ** 17" CLK rims ** Vented RF Fender ** Facelift Hood, Headlights, and Lower Cladding **
OBK# 62
GREASY_BEAST
05-22-2009, 11:23 AM #13Does anyone know the proper input shaft torque specs (pre-load) for the 3.69/3.46/3.07/2.88 diffs as well as those for the 2.47?
Gasoline Fumes
06-09-2009, 12:57 AM #14What can I do with a 1987 2.47 W126 LSD? Any way to make it work with my 2.88 W123 gears?
(06-09-2009, 12:57 AM)Gasoline Fumes What can I do with a 1987 2.47 W126 LSD? Any way to make it work with my 2.88 W123 gears?
no the 126 housing is bigger... and the case wont even bolt up 'casue its a later model... early (1985 and earlier) w126 diffs will bolt right in to the 123 chassis...but 1986 and newer mount up differently...
anyway, your 2.88 gears will swap into any w123 housing (185mm ring gear) but not any of the 126 housings (210mm ring gear).
If you wanted to swap out the 2.47 LSD into an earlier 126 housing you could have 2.47 LSD under your car...that would probably be a good option, if you dont mind loosing a little off the line performance for a little quiter operation at highway speeds.
W123 Mods: 4 speed ** manual climate control ** '85 Kalitucky intake ** manual windows & full tint ** Euro headlights retrofit w/bixenon projectors ** 4 brake light mod ** Vogtland 50mm drop front & Lesjofors S600 drop rear springs ** 16" rims ** late w126 brake spindles, rotors & calipers ** full suspension rehab ** Bilstein HDs ** AL129X alternator & 1/0 starter and charging cables ** 300GD clutch/flywheel ** AFCO 80103N radiator & Earl's 41610 oil cooler ** custom block-off plate, remote oil filter & t-stat ** MW IP w/ tomnik's 6.5mm 'Holly' elements **
S124 Mods: 400E Rear subframe ** SL600 Brakes ** Late 300E 210mm diff ** SLK230 6 speed ** 17" CLK rims ** Vented RF Fender ** Facelift Hood, Headlights, and Lower Cladding **
OBK# 62
SurfRodder
06-09-2009, 12:46 PM #15(06-09-2009, 12:57 AM)Gasoline Fumes What can I do with a 1987 2.47 W126 LSD? Any way to make it work with my 2.88 W123 gears?
no the 126 housing is bigger... and the case wont even bolt up 'casue its a later model... early (1985 and earlier) w126 diffs will bolt right in to the 123 chassis...but 1986 and newer mount up differently...
anyway, your 2.88 gears will swap into any w123 housing (185mm ring gear) but not any of the 126 housings (210mm ring gear).
If you wanted to swap out the 2.47 LSD into an earlier 126 housing you could have 2.47 LSD under your car...that would probably be a good option, if you dont mind loosing a little off the line performance for a little quiter operation at highway speeds.
W123 Mods: 4 speed ** manual climate control ** '85 Kalitucky intake ** manual windows & full tint ** Euro headlights retrofit w/bixenon projectors ** 4 brake light mod ** Vogtland 50mm drop front & Lesjofors S600 drop rear springs ** 16" rims ** late w126 brake spindles, rotors & calipers ** full suspension rehab ** Bilstein HDs ** AL129X alternator & 1/0 starter and charging cables ** 300GD clutch/flywheel ** AFCO 80103N radiator & Earl's 41610 oil cooler ** custom block-off plate, remote oil filter & t-stat ** MW IP w/ tomnik's 6.5mm 'Holly' elements **
S124 Mods: 400E Rear subframe ** SL600 Brakes ** Late 300E 210mm diff ** SLK230 6 speed ** 17" CLK rims ** Vented RF Fender ** Facelift Hood, Headlights, and Lower Cladding **
OBK# 62
(06-09-2009, 12:57 AM)Gasoline Fumes What can I do with a 1987 2.47 W126 LSD? Any way to make it work with my 2.88 W123 gears?
The other option besides swapping diff housings, is to surgically graph (weld) in the center part of the sub-frame of a 2nd Generation W126 into the w123 sub-frame so you can use the later differentials.
(06-09-2009, 12:46 PM)SurfRodder .....
anyway, your 2.88 gears will swap into any w123 housing (185mm ring gear) but not any of the 126 housings (210mm ring gear).....
Actually not all w126 had the 210mm housing, only the GAS version of the 126 had the 210mm Gear. The DIESEL 126 (300SD) had the 3.07/2.88 185mm housing.
Gota love Mercedes Diesels!
.
DeliveryValve
06-09-2009, 01:25 PM #16(06-09-2009, 12:57 AM)Gasoline Fumes What can I do with a 1987 2.47 W126 LSD? Any way to make it work with my 2.88 W123 gears?
The other option besides swapping diff housings, is to surgically graph (weld) in the center part of the sub-frame of a 2nd Generation W126 into the w123 sub-frame so you can use the later differentials.
(06-09-2009, 12:46 PM)SurfRodder .....
anyway, your 2.88 gears will swap into any w123 housing (185mm ring gear) but not any of the 126 housings (210mm ring gear).....
Actually not all w126 had the 210mm housing, only the GAS version of the 126 had the 210mm Gear. The DIESEL 126 (300SD) had the 3.07/2.88 185mm housing.
Gota love Mercedes Diesels!
.
(06-09-2009, 01:25 PM)DeliveryValve Actually not all w126 had the 210mm housing, only the GAS version of the 126 had the 210mm Gear. The DIESEL 126 (300SD) had the 3.07/2.88 185mm housing.
I think its more 2nd gen w126 than gasser vs diesel. I could be wrong I have *never* seen a 2nd gen diesel SD in the yards....
1987 300D Sturmmachine
1991 300D Nearly Perfect
1985 300D Weekend/Camping/Dog car
1974 L508D Motoroam Monarch "NightMare"
OBK #42
(06-09-2009, 01:25 PM)DeliveryValve Actually not all w126 had the 210mm housing, only the GAS version of the 126 had the 210mm Gear. The DIESEL 126 (300SD) had the 3.07/2.88 185mm housing.
I think its more 2nd gen w126 than gasser vs diesel. I could be wrong I have *never* seen a 2nd gen diesel SD in the yards....
1987 300D Sturmmachine
1991 300D Nearly Perfect
1985 300D Weekend/Camping/Dog car
1974 L508D Motoroam Monarch "NightMare"
OBK #42
(06-09-2009, 04:37 PM)winmutt(06-09-2009, 01:25 PM)DeliveryValve Actually not all w126 had the 210mm housing, only the GAS version of the 126 had the 210mm Gear. The DIESEL 126 (300SD) had the 3.07/2.88 185mm housing.
I think its more 2nd gen w126 than gasser vs diesel. I could be wrong I have *never* seen a 2nd gen diesel SD in the yards....
The first Generation W126 had both 1.1 liter 185mm (300SD - 2.88/3.07 same part number for w123 300D) and 1.3 liter 210mm (500SEC - 2.24, 380,500SE 2.47) casings.
The second generation had both sizes as well. The 1.1 liter 185mm was in 2.88 (300SDL) and a 1 liter 185mm 3.46 (300SE,SEL). The 1.3 liter 210mm case was offered in a 2.47 (380,420,500,560SEL) and a 2.82 ratio (350SD,350SDL).
.
Here is the difference between the two style of mounts.
Image provided by peachparts.com member Johnhef
Gota love Mercedes Diesels!
.
DeliveryValve
06-09-2009, 06:07 PM #18(06-09-2009, 04:37 PM)winmutt(06-09-2009, 01:25 PM)DeliveryValve Actually not all w126 had the 210mm housing, only the GAS version of the 126 had the 210mm Gear. The DIESEL 126 (300SD) had the 3.07/2.88 185mm housing.
I think its more 2nd gen w126 than gasser vs diesel. I could be wrong I have *never* seen a 2nd gen diesel SD in the yards....
The first Generation W126 had both 1.1 liter 185mm (300SD - 2.88/3.07 same part number for w123 300D) and 1.3 liter 210mm (500SEC - 2.24, 380,500SE 2.47) casings.
The second generation had both sizes as well. The 1.1 liter 185mm was in 2.88 (300SDL) and a 1 liter 185mm 3.46 (300SE,SEL). The 1.3 liter 210mm case was offered in a 2.47 (380,420,500,560SEL) and a 2.82 ratio (350SD,350SDL).
.
Here is the difference between the two style of mounts.
Image provided by peachparts.com member Johnhef
Gota love Mercedes Diesels!
.
(06-09-2009, 01:25 PM)DeliveryValve Actually not all w126 had the 210mm housing, only the GAS version of the 126 had the 210mm Gear. The DIESEL 126 (300SD) had the 3.07/2.88 185mm housing.
doh! i knew as I was writing that this morning that something didnt look right...
W123 Mods: 4 speed ** manual climate control ** '85 Kalitucky intake ** manual windows & full tint ** Euro headlights retrofit w/bixenon projectors ** 4 brake light mod ** Vogtland 50mm drop front & Lesjofors S600 drop rear springs ** 16" rims ** late w126 brake spindles, rotors & calipers ** full suspension rehab ** Bilstein HDs ** AL129X alternator & 1/0 starter and charging cables ** 300GD clutch/flywheel ** AFCO 80103N radiator & Earl's 41610 oil cooler ** custom block-off plate, remote oil filter & t-stat ** MW IP w/ tomnik's 6.5mm 'Holly' elements **
S124 Mods: 400E Rear subframe ** SL600 Brakes ** Late 300E 210mm diff ** SLK230 6 speed ** 17" CLK rims ** Vented RF Fender ** Facelift Hood, Headlights, and Lower Cladding **
OBK# 62
SurfRodder
06-09-2009, 11:00 PM #19(06-09-2009, 01:25 PM)DeliveryValve Actually not all w126 had the 210mm housing, only the GAS version of the 126 had the 210mm Gear. The DIESEL 126 (300SD) had the 3.07/2.88 185mm housing.
doh! i knew as I was writing that this morning that something didnt look right...
W123 Mods: 4 speed ** manual climate control ** '85 Kalitucky intake ** manual windows & full tint ** Euro headlights retrofit w/bixenon projectors ** 4 brake light mod ** Vogtland 50mm drop front & Lesjofors S600 drop rear springs ** 16" rims ** late w126 brake spindles, rotors & calipers ** full suspension rehab ** Bilstein HDs ** AL129X alternator & 1/0 starter and charging cables ** 300GD clutch/flywheel ** AFCO 80103N radiator & Earl's 41610 oil cooler ** custom block-off plate, remote oil filter & t-stat ** MW IP w/ tomnik's 6.5mm 'Holly' elements **
S124 Mods: 400E Rear subframe ** SL600 Brakes ** Late 300E 210mm diff ** SLK230 6 speed ** 17" CLK rims ** Vented RF Fender ** Facelift Hood, Headlights, and Lower Cladding **
OBK# 62
If you're concerned about engine wear you're not helping it out by running ultra high (numerically lower) gear ratios. You're making the engine work harder to move the car at the same speed - gears are mechanical leverage and you're giving it a shorter lever arm. The only way you might not be is if you live in Saskatchewan or Kansas - Flatland, in other words. If you have hills and grades to traverse you'll likely hate it.
Granted this is Mr - I - wanna - 350 - V8 - in - my - W123, Mr Hot Rod speaking, but the original engineers aren't often far, far off the mark on this kind of thing. With the 616 I go up the long 14 grade no problem with my whole 72 hp (hp is a concern when climbing hills as is torque), why? Because the MB engineers chose very good gear ratios for this engine. 240Ds run 3.46s, and remember folks, if fuel efficiency was as simple as running the worst dog gears you can find, all of the manufacturers would be doing it. 240Ds get better mileage than 300Ds and they have that extra .46 in the ratio. Find the most efficient gas motors (I'm not sure on the TDI, which is probably the most efficient motor I'm aware of) and they're not running dog gears, they're four-cylinders with 3.90 and higher ratios. Keeping your engine at a constant speed is more important than going for the lowest RPM (in other words, you'd be better off leaving the diff where it is and adjusting your driving technique, or take the money and get an extra gear in your transmission).
Granted the 5th gen and later Corvette and Gen IV F Bodies get about the same mileage as W123 with a 617a, and that is due to their ability to use their prodigious low end torque to loaf at highway speeds. (Their city mileage is quite a bit off of our cars, but our cars are quite a bit slower, so there's a trade-off). They do this with a six speed trans with a steep overdrive in 6th, though - the Vette comes with 3.55s and 3.73s as an option. And we're talking V8 gas motors of double the displacement of a 617, American, not Euro or Jap.. The gear ratios for these cars remained relatively unchanged from their 60's forebears, and the motors are the same displacement, having a tighter gear spread with a dedicated overdrive was what bumped them up from 8mpg to the upper 20s.
I think you'll essentially end up turning the 617a into an NA 617, a step backwards in performance with little to show for it except 'lower highway noise'. Differentials are difficult and expensive, Dynamat is easy and relatively cheap. Your mileage will likely be the same with either, the car will be faster with less engine wear with the latter. Diesels are the wrong tree to be barking up for NVH levels, especially ones of this vintage.
Working your engine harder to eke out maybe 2mpg, increasing it's wear, and paying $$$ to do so, isn't the very definition of false economy, but perhaps it should be. Gas is cheap, engines are expensive. Rebuilding an engine has it's own environmental impact to be considered.
If it's fuel efficiency you're after, go SVO and get your fuel for free. I knew a guy in Ohio who used to run his 300D on a 50/50 mix of filtered WVO and pump diesel - the regular diesel fuel chemically cut the thicker WVO and it ran fine in hot weather, he just ran straight diesel in the winter, and the big price to pay was about two fuel filters over the course of the warm months. Costs nothing to implement (there are easy ways to filter this stuff for cheap - about 40 bucks for enough filter bags to filter 1000 gallons of oil down to double digit microns, or there are other ways for free), and cuts your use of foreign oil and the money used to buy it in half. Run a real SVO system and you'll be filling up your diesel tank (used to start and shut down the engine) hardly ever, instead getting rid of a waste product and putting no money in the pocket of King Hussein or Exxon.
If you want a real hi-miler, get an A2 Golf or Jetta and swap a TDI with a six speed in. The later A4 chassis cars weigh almost a half a ton more and still (again, six speed, not dog gears) are capable of embarrassing a Prius in the mileage department while being an entertaining ride - taking essentially the same chassis with 800 to 1k lbs less to carry and 50+ mpg would be the norm, with 60+ easily possible with gear-skipping and a prudent right foot. The heavy versions can do this already, I'm being conservative with the estimates of the fly-weight. Despite the FWD handicap a car so configured would trump our likely best efforts with a 617a in power/weight, mileage, handling, and availability of tuning parts, not to mention being a known quantity. For an 80s compact, not bad looking either when done up right (think GLI with the round lights, BBS wheels and Recaro seats).
Granted, it's not my car, do what you will with yours, but I'm keeping my 3.46 LSD right where it is, awaiting it's future 617a heart. The 240D is probably running over 3k RPM at around 70 or so and the noise isn't that bad, and I only have a resonator, no muffler. Noise doesn't bother me, though - I love the sound of piston slap, it sounds like....Victory.
- CID
CID Vicious
06-09-2009, 11:12 PM #20This has to be the only forum in the couple dozen I've belonged to, German, Swedish, American, or Japanese manufacturer, where people are actually trying to go through the trouble to slow their car down by installing ludicrously tall gearing.
If you're concerned about engine wear you're not helping it out by running ultra high (numerically lower) gear ratios. You're making the engine work harder to move the car at the same speed - gears are mechanical leverage and you're giving it a shorter lever arm. The only way you might not be is if you live in Saskatchewan or Kansas - Flatland, in other words. If you have hills and grades to traverse you'll likely hate it.
Granted this is Mr - I - wanna - 350 - V8 - in - my - W123, Mr Hot Rod speaking, but the original engineers aren't often far, far off the mark on this kind of thing. With the 616 I go up the long 14 grade no problem with my whole 72 hp (hp is a concern when climbing hills as is torque), why? Because the MB engineers chose very good gear ratios for this engine. 240Ds run 3.46s, and remember folks, if fuel efficiency was as simple as running the worst dog gears you can find, all of the manufacturers would be doing it. 240Ds get better mileage than 300Ds and they have that extra .46 in the ratio. Find the most efficient gas motors (I'm not sure on the TDI, which is probably the most efficient motor I'm aware of) and they're not running dog gears, they're four-cylinders with 3.90 and higher ratios. Keeping your engine at a constant speed is more important than going for the lowest RPM (in other words, you'd be better off leaving the diff where it is and adjusting your driving technique, or take the money and get an extra gear in your transmission).
Granted the 5th gen and later Corvette and Gen IV F Bodies get about the same mileage as W123 with a 617a, and that is due to their ability to use their prodigious low end torque to loaf at highway speeds. (Their city mileage is quite a bit off of our cars, but our cars are quite a bit slower, so there's a trade-off). They do this with a six speed trans with a steep overdrive in 6th, though - the Vette comes with 3.55s and 3.73s as an option. And we're talking V8 gas motors of double the displacement of a 617, American, not Euro or Jap.. The gear ratios for these cars remained relatively unchanged from their 60's forebears, and the motors are the same displacement, having a tighter gear spread with a dedicated overdrive was what bumped them up from 8mpg to the upper 20s.
I think you'll essentially end up turning the 617a into an NA 617, a step backwards in performance with little to show for it except 'lower highway noise'. Differentials are difficult and expensive, Dynamat is easy and relatively cheap. Your mileage will likely be the same with either, the car will be faster with less engine wear with the latter. Diesels are the wrong tree to be barking up for NVH levels, especially ones of this vintage.
Working your engine harder to eke out maybe 2mpg, increasing it's wear, and paying $$$ to do so, isn't the very definition of false economy, but perhaps it should be. Gas is cheap, engines are expensive. Rebuilding an engine has it's own environmental impact to be considered.
If it's fuel efficiency you're after, go SVO and get your fuel for free. I knew a guy in Ohio who used to run his 300D on a 50/50 mix of filtered WVO and pump diesel - the regular diesel fuel chemically cut the thicker WVO and it ran fine in hot weather, he just ran straight diesel in the winter, and the big price to pay was about two fuel filters over the course of the warm months. Costs nothing to implement (there are easy ways to filter this stuff for cheap - about 40 bucks for enough filter bags to filter 1000 gallons of oil down to double digit microns, or there are other ways for free), and cuts your use of foreign oil and the money used to buy it in half. Run a real SVO system and you'll be filling up your diesel tank (used to start and shut down the engine) hardly ever, instead getting rid of a waste product and putting no money in the pocket of King Hussein or Exxon.
If you want a real hi-miler, get an A2 Golf or Jetta and swap a TDI with a six speed in. The later A4 chassis cars weigh almost a half a ton more and still (again, six speed, not dog gears) are capable of embarrassing a Prius in the mileage department while being an entertaining ride - taking essentially the same chassis with 800 to 1k lbs less to carry and 50+ mpg would be the norm, with 60+ easily possible with gear-skipping and a prudent right foot. The heavy versions can do this already, I'm being conservative with the estimates of the fly-weight. Despite the FWD handicap a car so configured would trump our likely best efforts with a 617a in power/weight, mileage, handling, and availability of tuning parts, not to mention being a known quantity. For an 80s compact, not bad looking either when done up right (think GLI with the round lights, BBS wheels and Recaro seats).
Granted, it's not my car, do what you will with yours, but I'm keeping my 3.46 LSD right where it is, awaiting it's future 617a heart. The 240D is probably running over 3k RPM at around 70 or so and the noise isn't that bad, and I only have a resonator, no muffler. Noise doesn't bother me, though - I love the sound of piston slap, it sounds like....Victory.
- CID
(06-09-2009, 11:12 PM)CID Vicious slow their car down by installing ludicrously tall gearing.were not talking a big jump here... 3.07 to 2.47 is nothing... if it were more like 4.56 compared to 2.08 or something crazy like that it would be ludicrous
(06-09-2009, 11:12 PM)CID Vicious If you're concerned about engine wear you're not helping it out by running ultra high (numerically lower) gear ratios. You're making the engine work harder to move the car at the same speed - gears are mechanical leverage and you're giving it a shorter lever arm.true, the drop in RPM will be countered by an increase in fuel necessary to maintain the increased load 'felt' by the engine at lower RPM, but wear would probably not really change one way or another...engines are made to take a load... plus in my experience, most engines also tend to run best when they are just a tad over peak torque, which for a 617 turbo is 2400RPM...sooo if I wanted to cruise in that range to maintain my staple 80 miles-per, I dont see a problem with that...
(06-09-2009, 11:12 PM)CID Vicious 240Ds get better mileage than 300Ds and they have that extra .46 in the ratio.and a whole cylinder less... 600cc's is a pretty decent decrease in displacement and associated hunger...
(06-09-2009, 11:12 PM)CID Vicious Find the most efficient gas motors (I'm not sure on the TDI, which is probably the most efficient motor I'm aware of) and they're not running dog gears, they're four-cylinders with 3.90 and higher ratios.they run shorter gears because the engines dont produce the torque necessary to run anything taller... MB put the taller 2.47 behind the v8s for the converse reason...
(06-09-2009, 11:12 PM)CID Vicious Keeping your engine at a constant speed is more important than going for the lowest RPM (in other words, you'd be better off leaving the diff where it is and adjusting your driving technique, or take the money and get an extra gear in your transmission).true, as long as that constant speed is the 'sweet spot' of the engine, usually just above peak torque as mentioned above... as for the extra cost involved, I spent ~$75 for a complete pumpkin from an early 126 with 2.47...I couldnt touch a 5 speed for anywhere near that little...I dont intend to run the 2.47 either, my plan is to swap out to a 2.65 with LSD and split the difference... I strongly believe there was good reason MB went with the 2.88 in '85 and it had to do with the characteristics of the 617...I want a little more than 2.88, but not as far as 2.47... that being said, Ill try the 2.47 if it comes down to it, more of my driving is on the top end and this is not my 'exhilarating' car, this is my DD...
(06-09-2009, 11:12 PM)CID Vicious Granted the 5th gen and later Corvette and Gen IV F Bodies get about the same mileage as W123 with a 617a, and that is due to their ability to use their prodigious low end torque to loaf at highway speeds. (Their city mileage is quite a bit off of our cars, but our cars are quite a bit slower, so there's a trade-off). They do this with a six speed trans with a steep overdrive in 6th, though - the Vette comes with 3.55s and 3.73s as an option. And we're talking V8 gas motors of double the displacement of a 617, American, not Euro or Jap..it all boils down to final drive ratio, which includes the rear end gearing and the diameter(or more correctly circumference) of the wheels... once the car is up to speed, it doesnt take gobs of torque to maintain the speed...even with really tall gears, I think that a numerically lower rear end gear would greatly enhance the overall drive-ability of my car, at least the way I currently have it set up...
(06-09-2009, 11:12 PM)CID Vicious The gear ratios for these cars remained relatively unchanged from their 60's forebears, and the motors are the same displacement, having a tighter gear spread with a dedicated overdrive was what bumped them up from 8mpg to the upper 20s.that and fuel injection, computer controls, lighter materials, etc...
(06-09-2009, 11:12 PM)CID Vicious I think you'll essentially end up turning the 617a into an NA 617, a step backwards in performance with little to show for it except 'lower highway noise'.again, were not talking a huge jump in ratios here, but there will be a performance loss on the bottom end...and if you can make the power a performance gain on the top (prolly take a bit of $$ to accomplish that tho..)
(06-09-2009, 11:12 PM)CID Vicious Differentials are difficult and expensive, Dynamat is easy and relatively cheap.Diffs changes are not that difficult...even changing the internals isnt that hard...just time consuming... paying someone else to do it can get expensive tho... A bit of dynamat would be a good idea in pretty much any car...especially these old tanks
(06-09-2009, 11:12 PM)CID Vicious Your mileage will likely be the same with either, the car will be faster with less engine wear with the latter. Diesels are the wrong tree to be barking up for NVH levels, especially ones of this vintage.again, the wear will likely be the same as the difference in mileage, higher RPMs vs. more resistance on the motor...total crapshoot... agreed, these are always going to be noisy cars, but there is a significant difference between 25-2600 RPM and 3000+ noise levels
(06-09-2009, 11:12 PM)CID Vicious (everything else)bio is a good option for those with a place to setup a rig... I live on a boat... personally, I could care less about mileage as long as it is in an acceptable range... I usually only pull down about 23 mpg, but I do most of my traveling upwards of 80mph... those engine swaps are great ideas, but $$$
(06-09-2009, 11:12 PM)CID Vicious Granted, it's not my car, do what you will with yours, but I'm keeping my 3.46 LSD right where it isand thats the beauty of it... if everyone did the same old shite to their autos, a much more boring ride it would be!
W123 Mods: 4 speed ** manual climate control ** '85 Kalitucky intake ** manual windows & full tint ** Euro headlights retrofit w/bixenon projectors ** 4 brake light mod ** Vogtland 50mm drop front & Lesjofors S600 drop rear springs ** 16" rims ** late w126 brake spindles, rotors & calipers ** full suspension rehab ** Bilstein HDs ** AL129X alternator & 1/0 starter and charging cables ** 300GD clutch/flywheel ** AFCO 80103N radiator & Earl's 41610 oil cooler ** custom block-off plate, remote oil filter & t-stat ** MW IP w/ tomnik's 6.5mm 'Holly' elements **
S124 Mods: 400E Rear subframe ** SL600 Brakes ** Late 300E 210mm diff ** SLK230 6 speed ** 17" CLK rims ** Vented RF Fender ** Facelift Hood, Headlights, and Lower Cladding **
OBK# 62
SurfRodder
06-11-2009, 03:10 AM #21(06-09-2009, 11:12 PM)CID Vicious slow their car down by installing ludicrously tall gearing.were not talking a big jump here... 3.07 to 2.47 is nothing... if it were more like 4.56 compared to 2.08 or something crazy like that it would be ludicrous
(06-09-2009, 11:12 PM)CID Vicious If you're concerned about engine wear you're not helping it out by running ultra high (numerically lower) gear ratios. You're making the engine work harder to move the car at the same speed - gears are mechanical leverage and you're giving it a shorter lever arm.true, the drop in RPM will be countered by an increase in fuel necessary to maintain the increased load 'felt' by the engine at lower RPM, but wear would probably not really change one way or another...engines are made to take a load... plus in my experience, most engines also tend to run best when they are just a tad over peak torque, which for a 617 turbo is 2400RPM...sooo if I wanted to cruise in that range to maintain my staple 80 miles-per, I dont see a problem with that...
(06-09-2009, 11:12 PM)CID Vicious 240Ds get better mileage than 300Ds and they have that extra .46 in the ratio.and a whole cylinder less... 600cc's is a pretty decent decrease in displacement and associated hunger...
(06-09-2009, 11:12 PM)CID Vicious Find the most efficient gas motors (I'm not sure on the TDI, which is probably the most efficient motor I'm aware of) and they're not running dog gears, they're four-cylinders with 3.90 and higher ratios.they run shorter gears because the engines dont produce the torque necessary to run anything taller... MB put the taller 2.47 behind the v8s for the converse reason...
(06-09-2009, 11:12 PM)CID Vicious Keeping your engine at a constant speed is more important than going for the lowest RPM (in other words, you'd be better off leaving the diff where it is and adjusting your driving technique, or take the money and get an extra gear in your transmission).true, as long as that constant speed is the 'sweet spot' of the engine, usually just above peak torque as mentioned above... as for the extra cost involved, I spent ~$75 for a complete pumpkin from an early 126 with 2.47...I couldnt touch a 5 speed for anywhere near that little...I dont intend to run the 2.47 either, my plan is to swap out to a 2.65 with LSD and split the difference... I strongly believe there was good reason MB went with the 2.88 in '85 and it had to do with the characteristics of the 617...I want a little more than 2.88, but not as far as 2.47... that being said, Ill try the 2.47 if it comes down to it, more of my driving is on the top end and this is not my 'exhilarating' car, this is my DD...
(06-09-2009, 11:12 PM)CID Vicious Granted the 5th gen and later Corvette and Gen IV F Bodies get about the same mileage as W123 with a 617a, and that is due to their ability to use their prodigious low end torque to loaf at highway speeds. (Their city mileage is quite a bit off of our cars, but our cars are quite a bit slower, so there's a trade-off). They do this with a six speed trans with a steep overdrive in 6th, though - the Vette comes with 3.55s and 3.73s as an option. And we're talking V8 gas motors of double the displacement of a 617, American, not Euro or Jap..it all boils down to final drive ratio, which includes the rear end gearing and the diameter(or more correctly circumference) of the wheels... once the car is up to speed, it doesnt take gobs of torque to maintain the speed...even with really tall gears, I think that a numerically lower rear end gear would greatly enhance the overall drive-ability of my car, at least the way I currently have it set up...
(06-09-2009, 11:12 PM)CID Vicious The gear ratios for these cars remained relatively unchanged from their 60's forebears, and the motors are the same displacement, having a tighter gear spread with a dedicated overdrive was what bumped them up from 8mpg to the upper 20s.that and fuel injection, computer controls, lighter materials, etc...
(06-09-2009, 11:12 PM)CID Vicious I think you'll essentially end up turning the 617a into an NA 617, a step backwards in performance with little to show for it except 'lower highway noise'.again, were not talking a huge jump in ratios here, but there will be a performance loss on the bottom end...and if you can make the power a performance gain on the top (prolly take a bit of $$ to accomplish that tho..)
(06-09-2009, 11:12 PM)CID Vicious Differentials are difficult and expensive, Dynamat is easy and relatively cheap.Diffs changes are not that difficult...even changing the internals isnt that hard...just time consuming... paying someone else to do it can get expensive tho... A bit of dynamat would be a good idea in pretty much any car...especially these old tanks
(06-09-2009, 11:12 PM)CID Vicious Your mileage will likely be the same with either, the car will be faster with less engine wear with the latter. Diesels are the wrong tree to be barking up for NVH levels, especially ones of this vintage.again, the wear will likely be the same as the difference in mileage, higher RPMs vs. more resistance on the motor...total crapshoot... agreed, these are always going to be noisy cars, but there is a significant difference between 25-2600 RPM and 3000+ noise levels
(06-09-2009, 11:12 PM)CID Vicious (everything else)bio is a good option for those with a place to setup a rig... I live on a boat... personally, I could care less about mileage as long as it is in an acceptable range... I usually only pull down about 23 mpg, but I do most of my traveling upwards of 80mph... those engine swaps are great ideas, but $$$
(06-09-2009, 11:12 PM)CID Vicious Granted, it's not my car, do what you will with yours, but I'm keeping my 3.46 LSD right where it isand thats the beauty of it... if everyone did the same old shite to their autos, a much more boring ride it would be!
W123 Mods: 4 speed ** manual climate control ** '85 Kalitucky intake ** manual windows & full tint ** Euro headlights retrofit w/bixenon projectors ** 4 brake light mod ** Vogtland 50mm drop front & Lesjofors S600 drop rear springs ** 16" rims ** late w126 brake spindles, rotors & calipers ** full suspension rehab ** Bilstein HDs ** AL129X alternator & 1/0 starter and charging cables ** 300GD clutch/flywheel ** AFCO 80103N radiator & Earl's 41610 oil cooler ** custom block-off plate, remote oil filter & t-stat ** MW IP w/ tomnik's 6.5mm 'Holly' elements **
S124 Mods: 400E Rear subframe ** SL600 Brakes ** Late 300E 210mm diff ** SLK230 6 speed ** 17" CLK rims ** Vented RF Fender ** Facelift Hood, Headlights, and Lower Cladding **
OBK# 62
2.46 may be the lowest ratio I've heard of yet in a car that wasn't headed to Bonneville for a speed run. Even the quick-change diffs used in old salt-flat cars were used to have steeper gears for the street, and the long, long legs for the top speed, but at the time, you were a lucky dog to have four speeds to choose from.
Most of the old V8 American boats had a 2.80-3.08 ring gear for use on the highway with a three speed auto, and those motors practically define low-end torque until you get to pickup diesels. Mercedes geared these things for extended runs on the autobahn - if most of your traveling is indeed around 80 on the highway, then it might not be a bad thing as far as RPMs go. You'll be dragging ass off of the line though. Going from a 3.08 to a 3.55 is quite an improvement in acceleration and is usually the gear ratio of choice for those looking for the performance/efficiency/streetability sweet spot in the domestic V8 scene.
The mileage, trust me, has more to do with the OD gear than the EFI. People have been able to get 20mpg highway out of a big block chevy with a carb using a Richmond 5-speed - a rear end ratio of 3.55. 7 liters plus and a carb. Check the mileage figures for a Mustang GT and a Camaro Z28 from the nineties and the 4.6l SOHC Mustang gets worse mileage than the OHV 5.7l Camaro - five speeds to six. (Also V6 like torque vs true V8 torque, not inconsequential.) 1.1l is not an insignificant amount of displacement, either. Put a C4 or a TH350 behind either of those motors and watch the dismal mileage return.
Those MB V8 cars are geared like that because otherwise the fuel consumption at 80+ highway speeds (as the cars were designed to be used for) would be out of hand with a 5+ liter V8. Ever heard of a guzzler tax? Well, in Germany, they're not going to just stop doing flat out on the autobahn, so the ultra long gears were the compromise that was reached. In America you're not going to be doing 85+ most of the time, at least not the average driver.
Also, consider this - you know how the Impala SS/9C1 Caprice can have it's speed upped from 140mph at the top to 155 or higher? A simple ring gear change - from 3.23 to 3.73. The motor can't get into the powerband necessary to attain higher speeds with the taller gears, but with the same horsepower and torque can get 15-20 mph on the top end - from increasing the size of it's lever arm, with a shorter/numerically higher gear ratio.
If you're modding the car for better acceleration, then taller gears are going to be counterproductive, is all I'm saying. If you go with the 2.46s and pull up to the same car with the same power with stock gears, the stock geared car will leave you behind, and both would be beaten by a car running the 3.46 set, all other things being equal, off the line. So it depends on what you want to spend your money on and what you're after, you seem to have thought this out more than I may have given you credit for. Let me know if you indeed see an appreciable mileage increase. I'm looking into this Toyota 5 speed thing to do at the same time as the 617a - no sense in reconfiguring it twice. Better shifting box than the MB and has a fifth gear for highway cruising, so you can keep your acceleration and have the reduced highway rpms. I could probably sell the 4 speed to a forum member and recoup the conversion cost.
One of the things people have to realize is that until the turbo system is upgraded this engine may have good low end torque, but it's still not a huge amount. It is relative to the size of the displacement, but the displacement is modest. If you're running a VGT then I could see, then, comparing to the V8 cars for ideas, as a VGT'd 617a puts out a comparable amount of power.
CID Vicious
06-11-2009, 07:40 PM #22Well, I would say it's a bit more of a jump than what it looks like on paper.
2.46 may be the lowest ratio I've heard of yet in a car that wasn't headed to Bonneville for a speed run. Even the quick-change diffs used in old salt-flat cars were used to have steeper gears for the street, and the long, long legs for the top speed, but at the time, you were a lucky dog to have four speeds to choose from.
Most of the old V8 American boats had a 2.80-3.08 ring gear for use on the highway with a three speed auto, and those motors practically define low-end torque until you get to pickup diesels. Mercedes geared these things for extended runs on the autobahn - if most of your traveling is indeed around 80 on the highway, then it might not be a bad thing as far as RPMs go. You'll be dragging ass off of the line though. Going from a 3.08 to a 3.55 is quite an improvement in acceleration and is usually the gear ratio of choice for those looking for the performance/efficiency/streetability sweet spot in the domestic V8 scene.
The mileage, trust me, has more to do with the OD gear than the EFI. People have been able to get 20mpg highway out of a big block chevy with a carb using a Richmond 5-speed - a rear end ratio of 3.55. 7 liters plus and a carb. Check the mileage figures for a Mustang GT and a Camaro Z28 from the nineties and the 4.6l SOHC Mustang gets worse mileage than the OHV 5.7l Camaro - five speeds to six. (Also V6 like torque vs true V8 torque, not inconsequential.) 1.1l is not an insignificant amount of displacement, either. Put a C4 or a TH350 behind either of those motors and watch the dismal mileage return.
Those MB V8 cars are geared like that because otherwise the fuel consumption at 80+ highway speeds (as the cars were designed to be used for) would be out of hand with a 5+ liter V8. Ever heard of a guzzler tax? Well, in Germany, they're not going to just stop doing flat out on the autobahn, so the ultra long gears were the compromise that was reached. In America you're not going to be doing 85+ most of the time, at least not the average driver.
Also, consider this - you know how the Impala SS/9C1 Caprice can have it's speed upped from 140mph at the top to 155 or higher? A simple ring gear change - from 3.23 to 3.73. The motor can't get into the powerband necessary to attain higher speeds with the taller gears, but with the same horsepower and torque can get 15-20 mph on the top end - from increasing the size of it's lever arm, with a shorter/numerically higher gear ratio.
If you're modding the car for better acceleration, then taller gears are going to be counterproductive, is all I'm saying. If you go with the 2.46s and pull up to the same car with the same power with stock gears, the stock geared car will leave you behind, and both would be beaten by a car running the 3.46 set, all other things being equal, off the line. So it depends on what you want to spend your money on and what you're after, you seem to have thought this out more than I may have given you credit for. Let me know if you indeed see an appreciable mileage increase. I'm looking into this Toyota 5 speed thing to do at the same time as the 617a - no sense in reconfiguring it twice. Better shifting box than the MB and has a fifth gear for highway cruising, so you can keep your acceleration and have the reduced highway rpms. I could probably sell the 4 speed to a forum member and recoup the conversion cost.
One of the things people have to realize is that until the turbo system is upgraded this engine may have good low end torque, but it's still not a huge amount. It is relative to the size of the displacement, but the displacement is modest. If you're running a VGT then I could see, then, comparing to the V8 cars for ideas, as a VGT'd 617a puts out a comparable amount of power.
In the morning rush hour I rarely get out of 1st gear (also don't need any shorter gears there), but in the afternoon, its full bore everywhere I go, and this is not my 'dragster' so off the line im not too concerned about the pickup (hell, up until a few days ago, I had a funky throttle linkage that prevented the modest performance the car has now...almost feels like a gasser now that the linkage is fixed) IMO I would probably still think it was dragging ass even with a much shorter gear...
I highly doubt that I would see any mileage increase as my driving habits aren't exactly conducive to that... and from what I remember on mshop is that no one else saw an increase either.
2.47 is taller than I really wanna go as well, Im still holding out for a 2.65 which I think would be perfect for my taste, but if I get bored in the search, Ill try to a 2.47 for shits and grins.
I remember going to the pomona auto swap meet with my dad about 15 years ago and there was a '33 Caddy hotrod for sale with a 383 in it, a TH-400 and a Gear Vendors under/overdrive kit... they had dyno sheets indicating ~400HP & Lb/f and claimed it got 30+mpg... my dad is still kicking himself for not shelling out the 12K or so they were asking... one can accomplish amazing things if they build an engine with gobs of bottom end torque and gear it properly
I am really interested in a 5 speed swap as well... I'd like to get a one with an overdrive gear as well as a shorter 1st gear, that would go quite well with a 2.65. I really like the idea of swapping out to a manufacturer that has plenty of 4wd cars so there will be plenty of options for a 'granny gear' to help me out off the line...
anyway, if its mileage you're after, you need to be looking for a final top gear ratio of ~2.25-2.45, provided you make the torque necessary to support that for your particular application... I would venture that the the 'efficient' big block cars you wrote about are in that range in top gear...
W123 Mods: 4 speed ** manual climate control ** '85 Kalitucky intake ** manual windows & full tint ** Euro headlights retrofit w/bixenon projectors ** 4 brake light mod ** Vogtland 50mm drop front & Lesjofors S600 drop rear springs ** 16" rims ** late w126 brake spindles, rotors & calipers ** full suspension rehab ** Bilstein HDs ** AL129X alternator & 1/0 starter and charging cables ** 300GD clutch/flywheel ** AFCO 80103N radiator & Earl's 41610 oil cooler ** custom block-off plate, remote oil filter & t-stat ** MW IP w/ tomnik's 6.5mm 'Holly' elements **
S124 Mods: 400E Rear subframe ** SL600 Brakes ** Late 300E 210mm diff ** SLK230 6 speed ** 17" CLK rims ** Vented RF Fender ** Facelift Hood, Headlights, and Lower Cladding **
OBK# 62
SurfRodder
06-12-2009, 01:13 AM #23yeah, these cars are not exactly top end performers anyway, but the majority of my traveling is at 80+...
In the morning rush hour I rarely get out of 1st gear (also don't need any shorter gears there), but in the afternoon, its full bore everywhere I go, and this is not my 'dragster' so off the line im not too concerned about the pickup (hell, up until a few days ago, I had a funky throttle linkage that prevented the modest performance the car has now...almost feels like a gasser now that the linkage is fixed) IMO I would probably still think it was dragging ass even with a much shorter gear...
I highly doubt that I would see any mileage increase as my driving habits aren't exactly conducive to that... and from what I remember on mshop is that no one else saw an increase either.
2.47 is taller than I really wanna go as well, Im still holding out for a 2.65 which I think would be perfect for my taste, but if I get bored in the search, Ill try to a 2.47 for shits and grins.
I remember going to the pomona auto swap meet with my dad about 15 years ago and there was a '33 Caddy hotrod for sale with a 383 in it, a TH-400 and a Gear Vendors under/overdrive kit... they had dyno sheets indicating ~400HP & Lb/f and claimed it got 30+mpg... my dad is still kicking himself for not shelling out the 12K or so they were asking... one can accomplish amazing things if they build an engine with gobs of bottom end torque and gear it properly
I am really interested in a 5 speed swap as well... I'd like to get a one with an overdrive gear as well as a shorter 1st gear, that would go quite well with a 2.65. I really like the idea of swapping out to a manufacturer that has plenty of 4wd cars so there will be plenty of options for a 'granny gear' to help me out off the line...
anyway, if its mileage you're after, you need to be looking for a final top gear ratio of ~2.25-2.45, provided you make the torque necessary to support that for your particular application... I would venture that the the 'efficient' big block cars you wrote about are in that range in top gear...
W123 Mods: 4 speed ** manual climate control ** '85 Kalitucky intake ** manual windows & full tint ** Euro headlights retrofit w/bixenon projectors ** 4 brake light mod ** Vogtland 50mm drop front & Lesjofors S600 drop rear springs ** 16" rims ** late w126 brake spindles, rotors & calipers ** full suspension rehab ** Bilstein HDs ** AL129X alternator & 1/0 starter and charging cables ** 300GD clutch/flywheel ** AFCO 80103N radiator & Earl's 41610 oil cooler ** custom block-off plate, remote oil filter & t-stat ** MW IP w/ tomnik's 6.5mm 'Holly' elements **
S124 Mods: 400E Rear subframe ** SL600 Brakes ** Late 300E 210mm diff ** SLK230 6 speed ** 17" CLK rims ** Vented RF Fender ** Facelift Hood, Headlights, and Lower Cladding **
OBK# 62
I upgraded to 8x16 wheels with 225 tires, and I switched back to the 3.07 to try to mitigate the off-the-line performance decrease. However, the input shaft seal on the 3.07 is leaking (I didn't change it), and I like the quiet highway ride, so I'm probably going to put the 2.47 back in (new seals installed 3 years ago). The 300TD/617 will never be a rocket without an engine swap, so it might as well be comfortable. Highway mileage was also better by about 2mpg with the 2.47, no noticeable difference around town.
EDIT: Almost forgot, top speed with the 3.07 is somewhere around 110ish (limited by governor), with the 2.47 it absolutely would not go faster than 100 (limited by horsepower).
GREASY_BEAST
06-13-2009, 10:16 PM #24I ran a 2.47 rear for about 2 years, it was great! I had it in an 84 300TD with rack limiter delete, intercooler, and nothing else. Some tweaking of the transmission settings (mainly bowden cable, maybe the modulator as well) is necessary to get the shifting right. A "shift kit" (upgraded springs in the valve body) might also be desirable. The speedometer is exactly 10mph off, making estimation of your speed really easy, and no need to buy expensive conversion gears, etc. Driving around in "S" below 55mph is very similar to driving around in "D" with the stock rear.
I upgraded to 8x16 wheels with 225 tires, and I switched back to the 3.07 to try to mitigate the off-the-line performance decrease. However, the input shaft seal on the 3.07 is leaking (I didn't change it), and I like the quiet highway ride, so I'm probably going to put the 2.47 back in (new seals installed 3 years ago). The 300TD/617 will never be a rocket without an engine swap, so it might as well be comfortable. Highway mileage was also better by about 2mpg with the 2.47, no noticeable difference around town.
EDIT: Almost forgot, top speed with the 3.07 is somewhere around 110ish (limited by governor), with the 2.47 it absolutely would not go faster than 100 (limited by horsepower).
off the line, I LOVE it on the highway...
the swap is in this thread:
http://www.superturbodiesel.com/std/124-...t-325.html
cars
1991 W126 350SDL turbodiesel
1987 W124 E300D turbodiesel
1987 W126 300SDL turbodiesel
1984 W107 SL300D turbodiesel
1974 W115 /8 300D diesel
trucks
2001 Dodge RAM 3500 4x4 Cummins turbodiesel
boats
1974 Uniflite "Salty Dog" powered by
2x OM617.951 Mercedes Benz 5Cyl turbodiesels
oel_brenner
06-13-2009, 11:27 PM #25I am running effectively a 2.17 in my W124 and whil its a bit sluggish
off the line, I LOVE it on the highway...
the swap is in this thread:
http://www.superturbodiesel.com/std/124-...t-325.html
cars
1991 W126 350SDL turbodiesel
1987 W124 E300D turbodiesel
1987 W126 300SDL turbodiesel
1984 W107 SL300D turbodiesel
1974 W115 /8 300D diesel
trucks
2001 Dodge RAM 3500 4x4 Cummins turbodiesel
boats
1974 Uniflite "Salty Dog" powered by
2x OM617.951 Mercedes Benz 5Cyl turbodiesels
The 3.46 is a little too low for my 300, it tops out at 100mph too quickly. I may have to switch back to a 3.07 depending on how it does in the 1/4 mile with the power adders.
ForcedInduction
06-14-2009, 12:04 AM
#26
I like the 3.07 in my 240, but 4th can be luggy under 45mph. Highway RPM at 70mph is at 2800 instead of 3200.
The 3.46 is a little too low for my 300, it tops out at 100mph too quickly. I may have to switch back to a 3.07 depending on how it does in the 1/4 mile with the power adders.
Actually, I end up still getting a bit of the rage, because I'm sitting there going 'that truck has to have 200+ hp, how am I stuck behind you with 72?' It does make you drive more efficiently, looking far ahead and that kind of thing.
Having to navigate grades and such I'm grateful for the gears that are there. It's all about what you need. I rarely do over 80 except for fun in any car, but it can be ridiculous trying to navigate some stop and go traffic in the 240D. A 617a swap would make the car a relative rocket.
If you want the OD and a deep, deep first gear, get a W series 5spd out of a Toyota Truck. There's a link to a 4x4 forum in the 'Franken Five Speed' thread, the guy's running one in his 4Runner and that's the tranny you want. I've avoided them because for the gears I like first would be useless for anything except towing, but with 2.46 (or 2.17! Sweet Jeebus!) it would even things up. The guy got it to work with a simple 1/2" fabbed adapter plate and the right clutch components (Mercedes flywheel and pressure plate, Toyota disc). Might be the best of both worlds for you. It's how those 22Rs can move a Dolphin RV with a whole 100ish hp.
As for that 30mpg Caddy, it can be done, lots of people started building V8 cars for more than just in-town blasts (try a set of 4.11s with a three speed auto for 'highway comfort'!). I actually think a lot of the current mpg ratings are weak - you'd think they'd at least be up to 90s standards, but are actually worse (then again, a Civic Si weighs more now than a 69 SS350 Nova did). Weight might be the culprit (then again, so might be Exxon Mobil).
CID Vicious
06-14-2009, 12:49 AM #27If you think you're hating the 300D in terms of acceleration, try a 240D - even with a stick, you'll get passed by Miatas!
Actually, I end up still getting a bit of the rage, because I'm sitting there going 'that truck has to have 200+ hp, how am I stuck behind you with 72?' It does make you drive more efficiently, looking far ahead and that kind of thing.
Having to navigate grades and such I'm grateful for the gears that are there. It's all about what you need. I rarely do over 80 except for fun in any car, but it can be ridiculous trying to navigate some stop and go traffic in the 240D. A 617a swap would make the car a relative rocket.
If you want the OD and a deep, deep first gear, get a W series 5spd out of a Toyota Truck. There's a link to a 4x4 forum in the 'Franken Five Speed' thread, the guy's running one in his 4Runner and that's the tranny you want. I've avoided them because for the gears I like first would be useless for anything except towing, but with 2.46 (or 2.17! Sweet Jeebus!) it would even things up. The guy got it to work with a simple 1/2" fabbed adapter plate and the right clutch components (Mercedes flywheel and pressure plate, Toyota disc). Might be the best of both worlds for you. It's how those 22Rs can move a Dolphin RV with a whole 100ish hp.
As for that 30mpg Caddy, it can be done, lots of people started building V8 cars for more than just in-town blasts (try a set of 4.11s with a three speed auto for 'highway comfort'!). I actually think a lot of the current mpg ratings are weak - you'd think they'd at least be up to 90s standards, but are actually worse (then again, a Civic Si weighs more now than a 69 SS350 Nova did). Weight might be the culprit (then again, so might be Exxon Mobil).
(06-14-2009, 12:49 AM)CID Vicious If you want the OD and a deep, deep first gear, get a W series 5spd out of a Toyota Truck. There's a link to a 4x4 forum in the 'Franken Five Speed' thread, the guy's running one in his 4Runner and that's the tranny you want. I've avoided them because for the gears I like first would be useless for anything except towing, but with 2.46 (or 2.17! Sweet Jeebus!) it would even things up. The guy got it to work with a simple 1/2" fabbed adapter plate and the right clutch components (Mercedes flywheel and pressure plate, Toyota disc). Might be the best of both worlds for you. It's how those 22Rs can move a Dolphin RV with a whole 100ish hp.
Where's the shifter on one of those transmissions? Right out the top, or is it a linkage?
EDIT: Answered my own question and it's out the top, slung way out towards the back of the trans. Hope its in the right place!
GREASY_BEAST
06-16-2009, 11:12 PM #28(06-14-2009, 12:49 AM)CID Vicious If you want the OD and a deep, deep first gear, get a W series 5spd out of a Toyota Truck. There's a link to a 4x4 forum in the 'Franken Five Speed' thread, the guy's running one in his 4Runner and that's the tranny you want. I've avoided them because for the gears I like first would be useless for anything except towing, but with 2.46 (or 2.17! Sweet Jeebus!) it would even things up. The guy got it to work with a simple 1/2" fabbed adapter plate and the right clutch components (Mercedes flywheel and pressure plate, Toyota disc). Might be the best of both worlds for you. It's how those 22Rs can move a Dolphin RV with a whole 100ish hp.
Where's the shifter on one of those transmissions? Right out the top, or is it a linkage?
EDIT: Answered my own question and it's out the top, slung way out towards the back of the trans. Hope its in the right place!
If anything the shifter might be further back, which I'd welcome since I'm 6'2" tall and have to reach just a little for first and third. And the shift action is nice and light, the MB is 'interesting' in the way some setups on older cars are but for fast shifting the Toyota has it all over the MB.
CID Vicious
06-17-2009, 02:22 AM #29I've had those transmissions out of the car before, they're roughly equivalent to the length from the bell for the MB four speed. Since MB doesn't use a slip-joint yoke like a lot of companies, instead using the flex-disk, they don't have a 'tail cone', and for transmissions with them, it makes more sense to mount the shifter to the trans itself instead of utilizing linkages.
If anything the shifter might be further back, which I'd welcome since I'm 6'2" tall and have to reach just a little for first and third. And the shift action is nice and light, the MB is 'interesting' in the way some setups on older cars are but for fast shifting the Toyota has it all over the MB.
GREASY_BEAST
06-17-2009, 09:53 AM #30So assuming the shifter is in an acceptable spot, what about the driveshaft? Would it make most sense to modify the front section of the Mercedes shaft to accept the Toyota U-Joint, or???
In order to use a flex disc on the front you'll need the slip-yoke from the front of the Toyota drive shaft at the very least. Either way it takes a little surgery (as would a 4 speed MB swap).
Essentially it depends on what setup you want to be left with, because there's a couple of ways to mix and match the parts, and there are no 'bolt on' options (again, neither is there with a MB trans).. Personally unless you're thinking that NVH are going to be severely affected (which, come on, a diesel car designed in the early 70's, MB or not?) I'd say there are some definite benefits to eliminating three areas in the drive train with not essentially very cheap parts that can fail, especially after seeing a lot of use and all of a sudden dealing with more power than the engineers intended upon. You're going to have to have some sort of cutting, welding, and balancing done anyway, and personally I think that the flex discs work a lot better in automatic cars (which are far and away the majority of the MB cars sold) than in stick cars - driveline lash is not your friend when you're trying to shift fast.
I don't know how prone the discs and center bearing are to failure, but I don't like the idea of them lying in wait, so to speak, for my wallet. A U-Joint conversion makes sense as they're robust (as someone with fat rear tires and a big-block V8), simple (like 8 nuts to swap out) and cheap. One U-Joint is going to have far less driveline lash than two flex discs.
When I was working for the factory trained tech, we had an old German tech guy come by everyone once in awhile, and he was...opinionated! Cool, though. We were pulling the radiator out of a G Wagen and he was seeing the hard time we were having (the rad is bolted into the support by mounts that have a tendency to break when you remove them, removing the grill and skid plate were necessary, etc), and he succinctly said (and he's a MB fan!):
"Fucking over-engineered piece of shit - blow it up!"
CID Vicious
06-17-2009, 03:52 PM #31This is a matter of A) the engineering feasibility and B) personal taste, but if it were up to me, I'd have the rear of the 'yota drive shaft modded to accept a flex disc, and eliminate the front disc and center bearing, or eliminate both discs, adapting the pumpkin to accept a U-joint setup.
In order to use a flex disc on the front you'll need the slip-yoke from the front of the Toyota drive shaft at the very least. Either way it takes a little surgery (as would a 4 speed MB swap).
Essentially it depends on what setup you want to be left with, because there's a couple of ways to mix and match the parts, and there are no 'bolt on' options (again, neither is there with a MB trans).. Personally unless you're thinking that NVH are going to be severely affected (which, come on, a diesel car designed in the early 70's, MB or not?) I'd say there are some definite benefits to eliminating three areas in the drive train with not essentially very cheap parts that can fail, especially after seeing a lot of use and all of a sudden dealing with more power than the engineers intended upon. You're going to have to have some sort of cutting, welding, and balancing done anyway, and personally I think that the flex discs work a lot better in automatic cars (which are far and away the majority of the MB cars sold) than in stick cars - driveline lash is not your friend when you're trying to shift fast.
I don't know how prone the discs and center bearing are to failure, but I don't like the idea of them lying in wait, so to speak, for my wallet. A U-Joint conversion makes sense as they're robust (as someone with fat rear tires and a big-block V8), simple (like 8 nuts to swap out) and cheap. One U-Joint is going to have far less driveline lash than two flex discs.
When I was working for the factory trained tech, we had an old German tech guy come by everyone once in awhile, and he was...opinionated! Cool, though. We were pulling the radiator out of a G Wagen and he was seeing the hard time we were having (the rad is bolted into the support by mounts that have a tendency to break when you remove them, removing the grill and skid plate were necessary, etc), and he succinctly said (and he's a MB fan!):
"Fucking over-engineered piece of shit - blow it up!"
I attempted the swap from w123 to w126 2.88 differentials, and the axleshafts on the w126 are too long to fit the w123. This may be a "well duh" sort of question, but will the w126 axleshafts need to be switched for the w123. I now assume so, but would like to know if I'm correct before going further with my endeavor.
(06-20-2009, 03:17 PM)IsaacDW I attempted the swap from w123 to w126 2.88 differentials, and the axleshafts on the w126 are too long to fit the w123. This may be a "well duh" sort of question, but will the w126 axleshafts need to be switched for the w123. I now assume so, but would like to know if I'm correct before going further with my endeavor.
yeah, the 123 axles are what you need to make it work...
I think that the rear Lower control arm/trailing arm that the axle goes thru is also the same between these 2 chassis'
the main difference between the rear ends on these is the wider subframe and longer axles on the 126 to accommodate for the wider stance of the car... most of the other stuff just swaps over...I think on MShop a while back someone changed over their 123 rear trailing arms to the aluminum version for 126 for less weight and better corrosion resistance...
W123 Mods: 4 speed ** manual climate control ** '85 Kalitucky intake ** manual windows & full tint ** Euro headlights retrofit w/bixenon projectors ** 4 brake light mod ** Vogtland 50mm drop front & Lesjofors S600 drop rear springs ** 16" rims ** late w126 brake spindles, rotors & calipers ** full suspension rehab ** Bilstein HDs ** AL129X alternator & 1/0 starter and charging cables ** 300GD clutch/flywheel ** AFCO 80103N radiator & Earl's 41610 oil cooler ** custom block-off plate, remote oil filter & t-stat ** MW IP w/ tomnik's 6.5mm 'Holly' elements **
S124 Mods: 400E Rear subframe ** SL600 Brakes ** Late 300E 210mm diff ** SLK230 6 speed ** 17" CLK rims ** Vented RF Fender ** Facelift Hood, Headlights, and Lower Cladding **
OBK# 62
SurfRodder
06-20-2009, 10:41 PM #33(06-20-2009, 03:17 PM)IsaacDW I attempted the swap from w123 to w126 2.88 differentials, and the axleshafts on the w126 are too long to fit the w123. This may be a "well duh" sort of question, but will the w126 axleshafts need to be switched for the w123. I now assume so, but would like to know if I'm correct before going further with my endeavor.
yeah, the 123 axles are what you need to make it work...
I think that the rear Lower control arm/trailing arm that the axle goes thru is also the same between these 2 chassis'
the main difference between the rear ends on these is the wider subframe and longer axles on the 126 to accommodate for the wider stance of the car... most of the other stuff just swaps over...I think on MShop a while back someone changed over their 123 rear trailing arms to the aluminum version for 126 for less weight and better corrosion resistance...
W123 Mods: 4 speed ** manual climate control ** '85 Kalitucky intake ** manual windows & full tint ** Euro headlights retrofit w/bixenon projectors ** 4 brake light mod ** Vogtland 50mm drop front & Lesjofors S600 drop rear springs ** 16" rims ** late w126 brake spindles, rotors & calipers ** full suspension rehab ** Bilstein HDs ** AL129X alternator & 1/0 starter and charging cables ** 300GD clutch/flywheel ** AFCO 80103N radiator & Earl's 41610 oil cooler ** custom block-off plate, remote oil filter & t-stat ** MW IP w/ tomnik's 6.5mm 'Holly' elements **
S124 Mods: 400E Rear subframe ** SL600 Brakes ** Late 300E 210mm diff ** SLK230 6 speed ** 17" CLK rims ** Vented RF Fender ** Facelift Hood, Headlights, and Lower Cladding **
OBK# 62
(06-20-2009, 10:41 PM)SurfRodder yeah, the 123 axles are what you need to make it work...
I think that the rear Lower control arm/trailing arm that the axle goes thru is also the same between these 2 chassis'
the main difference between the rear ends on these is the wider subframe and longer axles on the 126 to accommodate for the wider stance of the car... most of the other stuff just swaps over...I think on MShop a while back someone changed over their 123 rear trailing arms to the aluminum version for 126 for less weight and better corrosion resistance...
That person reported back that the mounting position were different. I am still tempted to try. The second generation rear 126 diff will mount on a W123 with some metal work. They are offset of the std diff mount some 3-4".
1987 300D Sturmmachine
1991 300D Nearly Perfect
1985 300D Weekend/Camping/Dog car
1974 L508D Motoroam Monarch "NightMare"
OBK #42
(06-20-2009, 10:41 PM)SurfRodder yeah, the 123 axles are what you need to make it work...
I think that the rear Lower control arm/trailing arm that the axle goes thru is also the same between these 2 chassis'
the main difference between the rear ends on these is the wider subframe and longer axles on the 126 to accommodate for the wider stance of the car... most of the other stuff just swaps over...I think on MShop a while back someone changed over their 123 rear trailing arms to the aluminum version for 126 for less weight and better corrosion resistance...
That person reported back that the mounting position were different. I am still tempted to try. The second generation rear 126 diff will mount on a W123 with some metal work. They are offset of the std diff mount some 3-4".
1987 300D Sturmmachine
1991 300D Nearly Perfect
1985 300D Weekend/Camping/Dog car
1974 L508D Motoroam Monarch "NightMare"
OBK #42
(06-22-2009, 10:24 AM)winmutt I am still tempted to try.I might have to pull one from each car next time I hit up the yards and compare 'em, then we'll know for sure...
(06-22-2009, 10:24 AM)winmutt They are offset of the std diff mount some 3-4".
so how'd that work? Do you machine the 123 subframe to move the mounting hole fore or aft 3-4"?...or do you modify the newer style diff to mount up to the old subframe?
W123 Mods: 4 speed ** manual climate control ** '85 Kalitucky intake ** manual windows & full tint ** Euro headlights retrofit w/bixenon projectors ** 4 brake light mod ** Vogtland 50mm drop front & Lesjofors S600 drop rear springs ** 16" rims ** late w126 brake spindles, rotors & calipers ** full suspension rehab ** Bilstein HDs ** AL129X alternator & 1/0 starter and charging cables ** 300GD clutch/flywheel ** AFCO 80103N radiator & Earl's 41610 oil cooler ** custom block-off plate, remote oil filter & t-stat ** MW IP w/ tomnik's 6.5mm 'Holly' elements **
S124 Mods: 400E Rear subframe ** SL600 Brakes ** Late 300E 210mm diff ** SLK230 6 speed ** 17" CLK rims ** Vented RF Fender ** Facelift Hood, Headlights, and Lower Cladding **
OBK# 62
SurfRodder
06-22-2009, 01:05 PM #35(06-22-2009, 10:24 AM)winmutt I am still tempted to try.I might have to pull one from each car next time I hit up the yards and compare 'em, then we'll know for sure...
(06-22-2009, 10:24 AM)winmutt They are offset of the std diff mount some 3-4".
so how'd that work? Do you machine the 123 subframe to move the mounting hole fore or aft 3-4"?...or do you modify the newer style diff to mount up to the old subframe?
W123 Mods: 4 speed ** manual climate control ** '85 Kalitucky intake ** manual windows & full tint ** Euro headlights retrofit w/bixenon projectors ** 4 brake light mod ** Vogtland 50mm drop front & Lesjofors S600 drop rear springs ** 16" rims ** late w126 brake spindles, rotors & calipers ** full suspension rehab ** Bilstein HDs ** AL129X alternator & 1/0 starter and charging cables ** 300GD clutch/flywheel ** AFCO 80103N radiator & Earl's 41610 oil cooler ** custom block-off plate, remote oil filter & t-stat ** MW IP w/ tomnik's 6.5mm 'Holly' elements **
S124 Mods: 400E Rear subframe ** SL600 Brakes ** Late 300E 210mm diff ** SLK230 6 speed ** 17" CLK rims ** Vented RF Fender ** Facelift Hood, Headlights, and Lower Cladding **
OBK# 62
(06-22-2009, 01:05 PM)SurfRodder so how'd that work? Do you machine the 123 subframe to move the mounting hole fore or aft 3-4"?...or do you modify the newer style diff to mount up to the old subframe?By all means do try. I'd also like to find out if the subframe is diff size. might be a better solution.
This was the rear diff mount that is off set. The front is a whole nother bucket of bolts.
1987 300D Sturmmachine
1991 300D Nearly Perfect
1985 300D Weekend/Camping/Dog car
1974 L508D Motoroam Monarch "NightMare"
OBK #42
(06-22-2009, 01:05 PM)SurfRodder so how'd that work? Do you machine the 123 subframe to move the mounting hole fore or aft 3-4"?...or do you modify the newer style diff to mount up to the old subframe?By all means do try. I'd also like to find out if the subframe is diff size. might be a better solution.
This was the rear diff mount that is off set. The front is a whole nother bucket of bolts.
1987 300D Sturmmachine
1991 300D Nearly Perfect
1985 300D Weekend/Camping/Dog car
1974 L508D Motoroam Monarch "NightMare"
OBK #42
(06-22-2009, 01:05 PM)SurfRodder .....
so how'd that work? Do you machine the 123 subframe to move the mounting hole fore or aft 3-4"?...or do you modify the newer style diff to mount up to the old subframe?
Remember the rear mounst is bolted to the body's floor, more specifically the beam that runs across. So it should be a matter of drilling new holes for it. But it also bolts to the subframe, so to make it work, you would need to weld in donor piece from the 2nd gen subframe.
For the front two bolts, I think making a custom bolt in bracket with stock 2nd gen bushings which will mount in the stock w123 subframe front location would work.
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Gota love Mercedes Diesels!
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DeliveryValve
06-22-2009, 06:06 PM #37(06-22-2009, 01:05 PM)SurfRodder .....
so how'd that work? Do you machine the 123 subframe to move the mounting hole fore or aft 3-4"?...or do you modify the newer style diff to mount up to the old subframe?
Remember the rear mounst is bolted to the body's floor, more specifically the beam that runs across. So it should be a matter of drilling new holes for it. But it also bolts to the subframe, so to make it work, you would need to weld in donor piece from the 2nd gen subframe.
For the front two bolts, I think making a custom bolt in bracket with stock 2nd gen bushings which will mount in the stock w123 subframe front location would work.
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Gota love Mercedes Diesels!
.
(06-22-2009, 05:24 PM)winmutt I'd also like to find out if the subframe is diff size. might be a better solution.
well, considering that the 126 has~3" greater rear track width, I'd guess that you couldnt swap it into a 123... now an earlier 126 is probable and most likely has already been done...
it might be possible to modify it somehow to fit...
W123 Mods: 4 speed ** manual climate control ** '85 Kalitucky intake ** manual windows & full tint ** Euro headlights retrofit w/bixenon projectors ** 4 brake light mod ** Vogtland 50mm drop front & Lesjofors S600 drop rear springs ** 16" rims ** late w126 brake spindles, rotors & calipers ** full suspension rehab ** Bilstein HDs ** AL129X alternator & 1/0 starter and charging cables ** 300GD clutch/flywheel ** AFCO 80103N radiator & Earl's 41610 oil cooler ** custom block-off plate, remote oil filter & t-stat ** MW IP w/ tomnik's 6.5mm 'Holly' elements **
S124 Mods: 400E Rear subframe ** SL600 Brakes ** Late 300E 210mm diff ** SLK230 6 speed ** 17" CLK rims ** Vented RF Fender ** Facelift Hood, Headlights, and Lower Cladding **
OBK# 62
SurfRodder
06-23-2009, 12:39 AM #38(06-22-2009, 05:24 PM)winmutt I'd also like to find out if the subframe is diff size. might be a better solution.
well, considering that the 126 has~3" greater rear track width, I'd guess that you couldnt swap it into a 123... now an earlier 126 is probable and most likely has already been done...
it might be possible to modify it somehow to fit...
W123 Mods: 4 speed ** manual climate control ** '85 Kalitucky intake ** manual windows & full tint ** Euro headlights retrofit w/bixenon projectors ** 4 brake light mod ** Vogtland 50mm drop front & Lesjofors S600 drop rear springs ** 16" rims ** late w126 brake spindles, rotors & calipers ** full suspension rehab ** Bilstein HDs ** AL129X alternator & 1/0 starter and charging cables ** 300GD clutch/flywheel ** AFCO 80103N radiator & Earl's 41610 oil cooler ** custom block-off plate, remote oil filter & t-stat ** MW IP w/ tomnik's 6.5mm 'Holly' elements **
S124 Mods: 400E Rear subframe ** SL600 Brakes ** Late 300E 210mm diff ** SLK230 6 speed ** 17" CLK rims ** Vented RF Fender ** Facelift Hood, Headlights, and Lower Cladding **
OBK# 62
(06-23-2009, 12:39 AM)SurfRodder well, considering that the 126 has~3" greater rear track width
Better stability in the corners!
ForcedInduction
06-23-2009, 01:17 AM
#39
(06-23-2009, 12:39 AM)SurfRodder well, considering that the 126 has~3" greater rear track width
Better stability in the corners!
The swap is complete! The wagon lost a negligible amount of acceleration, but is fantastically quieter at interstate speeds. I just drove from Tennessee to Michigan, and it drove like a dream. I would highly recommend this swap to anyone that has the time, skill, and would like to have a comfortable cruiser. Thank you Superturbodiesel members for your insight!
(09-06-2009, 09:20 AM)dalek Dumb question: how much torque can those differentials take?
way more than these engines are likely to make... at 185mm, the stock w123 diff size is 7.28 inches, the 210mm diffs are 8.26 inches.. the smaller diff is pretty stout, but if the size concerns you, the larger ones are even beefier. What are you looking to turn it with?
W123 Mods: 4 speed ** manual climate control ** '85 Kalitucky intake ** manual windows & full tint ** Euro headlights retrofit w/bixenon projectors ** 4 brake light mod ** Vogtland 50mm drop front & Lesjofors S600 drop rear springs ** 16" rims ** late w126 brake spindles, rotors & calipers ** full suspension rehab ** Bilstein HDs ** AL129X alternator & 1/0 starter and charging cables ** 300GD clutch/flywheel ** AFCO 80103N radiator & Earl's 41610 oil cooler ** custom block-off plate, remote oil filter & t-stat ** MW IP w/ tomnik's 6.5mm 'Holly' elements **
S124 Mods: 400E Rear subframe ** SL600 Brakes ** Late 300E 210mm diff ** SLK230 6 speed ** 17" CLK rims ** Vented RF Fender ** Facelift Hood, Headlights, and Lower Cladding **
OBK# 62
SurfRodder
09-09-2009, 05:55 PM #42(09-06-2009, 09:20 AM)dalek Dumb question: how much torque can those differentials take?
way more than these engines are likely to make... at 185mm, the stock w123 diff size is 7.28 inches, the 210mm diffs are 8.26 inches.. the smaller diff is pretty stout, but if the size concerns you, the larger ones are even beefier. What are you looking to turn it with?
W123 Mods: 4 speed ** manual climate control ** '85 Kalitucky intake ** manual windows & full tint ** Euro headlights retrofit w/bixenon projectors ** 4 brake light mod ** Vogtland 50mm drop front & Lesjofors S600 drop rear springs ** 16" rims ** late w126 brake spindles, rotors & calipers ** full suspension rehab ** Bilstein HDs ** AL129X alternator & 1/0 starter and charging cables ** 300GD clutch/flywheel ** AFCO 80103N radiator & Earl's 41610 oil cooler ** custom block-off plate, remote oil filter & t-stat ** MW IP w/ tomnik's 6.5mm 'Holly' elements **
S124 Mods: 400E Rear subframe ** SL600 Brakes ** Late 300E 210mm diff ** SLK230 6 speed ** 17" CLK rims ** Vented RF Fender ** Facelift Hood, Headlights, and Lower Cladding **
OBK# 62
Just want to get something straight here... If I would want to swap out my stock diff from my 83 300D what ever it has in it now (under 5 layers of muck and road grim so I am not sure). What if any would you all recommend to bring down the highway rpms at 70 mph to a more resonable number like 2500, now I am at 3100 or higher.
So many threads so little time.....
Just want to get something straight here... If I would want to swap out my stock diff from my 83 300D what ever it has in it now (under 5 layers of muck and road grim so I am not sure). What if any would you all recommend to bring down the highway rpms at 70 mph to a more resonable number like 2500, now I am at 3100 or higher.
ForcedInduction
09-30-2009, 12:04 AM
#44
2.88 and 2.47 differentials are about the only bolt-in options other than a 5-speed manual. Acceleration would be very slow with the two diffs, the vehicles that use them have a low 1st gear to cope with it.
(09-30-2009, 12:04 AM)ForcedInduction ... Acceleration would be very slow with the two diffs, the vehicles that use them have a low 1st gear to cope with it.
And not to mention the '85 2.88 has a 2600 rpm stall speed torque converter to also deal with it.
I have a 2.88 installed in my car with a auto tranny. The acceleration is slower but not very slow. For reference, At 65 I am at 2650 rpms. At 70 mph, I am running 2900 rpms. At 90 mph I am at 3400 rpms.
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Gota love Mercedes Diesels!
.
DeliveryValve
09-30-2009, 12:43 AM #45(09-30-2009, 12:04 AM)ForcedInduction ... Acceleration would be very slow with the two diffs, the vehicles that use them have a low 1st gear to cope with it.
And not to mention the '85 2.88 has a 2600 rpm stall speed torque converter to also deal with it.
I have a 2.88 installed in my car with a auto tranny. The acceleration is slower but not very slow. For reference, At 65 I am at 2650 rpms. At 70 mph, I am running 2900 rpms. At 90 mph I am at 3400 rpms.
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Gota love Mercedes Diesels!
.
(09-30-2009, 12:43 AM)DeliveryValve(09-30-2009, 12:04 AM)ForcedInduction ... Acceleration would be very slow with the two diffs, the vehicles that use them have a low 1st gear to cope with it.
And not to mention the '85 2.88 has a 2600 rpm stall speed torque converter to also deal with it.
I have a 2.88 installed in my car with a auto tranny. The acceleration is slower but not very slow. For reference, At 65 I am at 2650 rpms. At 70 mph, I am running 2900 rpms. At 90 mph I am at 3400 rpms.
.
Thank you I think I will try to track down a whole trans and rear combo out of an 85 seems like benz reconfigured and changed the whole set up but kept the same power plant.
(09-30-2009, 12:43 AM)DeliveryValve(09-30-2009, 12:04 AM)ForcedInduction ... Acceleration would be very slow with the two diffs, the vehicles that use them have a low 1st gear to cope with it.
And not to mention the '85 2.88 has a 2600 rpm stall speed torque converter to also deal with it.
I have a 2.88 installed in my car with a auto tranny. The acceleration is slower but not very slow. For reference, At 65 I am at 2650 rpms. At 70 mph, I am running 2900 rpms. At 90 mph I am at 3400 rpms.
.
Thank you I think I will try to track down a whole trans and rear combo out of an 85 seems like benz reconfigured and changed the whole set up but kept the same power plant.
(09-30-2009, 07:46 PM)mrw5010 Thank you I think I will try to track down a whole trans and rear combo out of an 85 seems like benz reconfigured and changed the whole set up but kept the same power plant.
For clarification, I like to add that I have an '83 with the stock 1450 - 1650 rpm stall speed torque converter. Acceleration is a bit slower than with that 3.07, but not bad.
The Federal '85 transmissions are exactly the same as the previous years in 722.303 and 722.315 with the exception of the torque converter and vacuum setup/routing. Not certain that the "85 Fed does start off in 1st gear.
The California versions came with the 722.416. No parts interchange with the 722.3xx trans including the torque converter. This trans I know definitely starts off in 1st gear.
Gota love Mercedes Diesels!
.
DeliveryValve
09-30-2009, 08:59 PM #47(09-30-2009, 07:46 PM)mrw5010 Thank you I think I will try to track down a whole trans and rear combo out of an 85 seems like benz reconfigured and changed the whole set up but kept the same power plant.
For clarification, I like to add that I have an '83 with the stock 1450 - 1650 rpm stall speed torque converter. Acceleration is a bit slower than with that 3.07, but not bad.
The Federal '85 transmissions are exactly the same as the previous years in 722.303 and 722.315 with the exception of the torque converter and vacuum setup/routing. Not certain that the "85 Fed does start off in 1st gear.
The California versions came with the 722.416. No parts interchange with the 722.3xx trans including the torque converter. This trans I know definitely starts off in 1st gear.
Gota love Mercedes Diesels!
.
ForcedInduction
09-30-2009, 10:19 PM
#48
Both 85 Kali/Fed models were a 722.4. The .4 is much weaker than the .3 transmission.
(09-30-2009, 10:19 PM)ForcedInduction Both 85 Kali/Fed models were a 722.4. The .4 is much weaker than the .3 transmission.
Actually Lance, only the Cali version is 722.4. Federal's got the 722.3xx.
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Gota love Mercedes Diesels!
.
DeliveryValve
09-30-2009, 11:03 PM #49(09-30-2009, 10:19 PM)ForcedInduction Both 85 Kali/Fed models were a 722.4. The .4 is much weaker than the .3 transmission.
Actually Lance, only the Cali version is 722.4. Federal's got the 722.3xx.
.
Gota love Mercedes Diesels!
.
1) the gasser diff sourced still has the large round, six-bolt mounting adapter for the w126 axles and firstly i'm wondering whether the early w126 axles will fit into the rearend of my cd? i have read different things but have not been able to find a conclusive answer. if they do then i would source some nice w126 axles because a) i would not have to remove adapters and open up the diff box for re-assembly and b) i am guessing that the w126 axles are stronger than those on the cd.
2) will my existing 82cd driveshaft bolt right up to the w126 diff? i have read that, in some cases, the flange needs to be swapped and the installer has to be careful to 'make sure the preload on the pinion bearing is the same as it was on the original flange' (taken from a post on superturbodiesel.com).
3) if i do go with the w123 axles, will the spacers that are currently in there work with the new diff and is it just a direct swap?
looking forward to reducing my revs on the highway (currently 2500rpm at 55mph)
thanks for reading, newbie nick
nrwhite
10-01-2009, 09:55 AM #50i sourced a clean and 'tight' diff from an 84 w126 gasser this week. now i want to swap it into my 82 300cd and i have a couple of questions for you guys. the w126 diff has the same mounting points as the w123 but just looks like it's on steroids.
1) the gasser diff sourced still has the large round, six-bolt mounting adapter for the w126 axles and firstly i'm wondering whether the early w126 axles will fit into the rearend of my cd? i have read different things but have not been able to find a conclusive answer. if they do then i would source some nice w126 axles because a) i would not have to remove adapters and open up the diff box for re-assembly and b) i am guessing that the w126 axles are stronger than those on the cd.
2) will my existing 82cd driveshaft bolt right up to the w126 diff? i have read that, in some cases, the flange needs to be swapped and the installer has to be careful to 'make sure the preload on the pinion bearing is the same as it was on the original flange' (taken from a post on superturbodiesel.com).
3) if i do go with the w123 axles, will the spacers that are currently in there work with the new diff and is it just a direct swap?
looking forward to reducing my revs on the highway (currently 2500rpm at 55mph)
thanks for reading, newbie nick
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