Speedometer Conversion
Speedometer Conversion
07-26-2010, 05:06 PM
#1
Are the tailshafts swapable between the old auto and new manual trans or would some magnets and a magnetic pick up on the driveshaft work better?
1981 300SD 230k miles "Gently Modified" Daily Driver
1999 F-250 7.3L Power Stroke 150k miles "The Usual Mods" Tow Rig
1981 300SD 190k miles "Heavily Modified"
GONE
DrewGerhan
07-26-2010, 05:06 PM #1I just recently swapped a manual transmission into my 300SD and am putting the finishing touches on the swap. My question is, does anyone know of a way to adapt the stock electrical speedometer to the mechanical manual transmission?
Are the tailshafts swapable between the old auto and new manual trans or would some magnets and a magnetic pick up on the driveshaft work better?
1981 300SD 230k miles "Gently Modified" Daily Driver
1999 F-250 7.3L Power Stroke 150k miles "The Usual Mods" Tow Rig
1981 300SD 190k miles "Heavily Modified"
GONE
07-26-2010, 09:01 PM
#3
(07-26-2010, 07:59 PM)aaa I doubt the tailshafts are swappable. The stock electric setup appears to be picking up 4 pulses or whatever per rotation, from the appearance of the speedo "gear" inside.
You could probably just use a hall effect sensor and position it so the balancing weights or the flex disc bolts or some such thing actuate it. In any case, unless it has the same properties as the stock electronic speedo pickup, you will need some sort of circuitry to convert the signal...
GREASY_BEAST
07-26-2010, 09:01 PM #3(07-26-2010, 07:59 PM)aaa I doubt the tailshafts are swappable. The stock electric setup appears to be picking up 4 pulses or whatever per rotation, from the appearance of the speedo "gear" inside.
You could probably just use a hall effect sensor and position it so the balancing weights or the flex disc bolts or some such thing actuate it. In any case, unless it has the same properties as the stock electronic speedo pickup, you will need some sort of circuitry to convert the signal...
07-26-2010, 09:26 PM
#4
you need a special socket to get the nut off the yoke though, Snapon sells them, its a 30mm deep 12pt socket, might be able to procure it elsewhere tho.
if you were closer, I'd let you borrow mine.
This post was last modified: 07-26-2010, 09:28 PM by SurfRodder.
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
07-26-2010, 09:26 PM #4yes, you can swap the tailshafts... I pulled an auto out of a 300SD and swapped the tailshafts to make it work in my 300D...so you should be able to do the same/opposite.
you need a special socket to get the nut off the yoke though, Snapon sells them, its a 30mm deep 12pt socket, might be able to procure it elsewhere tho.
if you were closer, I'd let you borrow mine.
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
07-26-2010, 11:36 PM
#5
1987 300SDL 6spd manual om606.962 swap project
1985 300td euro 5spd wagon running
willbhere4u
07-26-2010, 11:36 PM #5can you really swap tail shafts from auto to manual? witch trans did you put in 4spd?
1987 300SDL 6spd manual om606.962 swap project
1985 300td euro 5spd wagon running
07-27-2010, 02:24 AM
#6
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
07-27-2010, 02:24 AM #6totally missed the manual part.... thought he was replacing an auto with the opposite one... I dont think it can be done either, but prove me wrong!
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
07-27-2010, 05:31 AM
#7
The world EPC probably has the part number and year range.
This post was last modified: 07-27-2010, 05:35 AM by ForcedInduction.
ForcedInduction
07-27-2010, 05:31 AM
#7
Find the tailhousing from a 280SE with a manual, they're out there. Probably makes a 5-speed 300D look common though.
The world EPC probably has the part number and year range.
07-27-2010, 06:58 AM
#8
(07-26-2010, 07:59 PM)aaa I doubt the tailshafts are swappable. The stock electric setup appears to be picking up 4 pulses or whatever per rotation, from the appearance of the speedo "gear" inside.
x2. Can you put the mechanical speedo in the 300SD? Might be easier to adapt a mechanical speedo out of a 300D if possible instead of trying to create and convert a signal to work with the SD stock speedo.
1974 240D 617 turbo swap, W201 5-speed, in the works project
1983 240D 616 stock, DD
1989 Chevy Astro, 617 turbo swap, T5 5-speed, 4.56 diff, work van
(07-26-2010, 07:59 PM)aaa I doubt the tailshafts are swappable. The stock electric setup appears to be picking up 4 pulses or whatever per rotation, from the appearance of the speedo "gear" inside.
x2. Can you put the mechanical speedo in the 300SD? Might be easier to adapt a mechanical speedo out of a 300D if possible instead of trying to create and convert a signal to work with the SD stock speedo.
1974 240D 617 turbo swap, W201 5-speed, in the works project
1983 240D 616 stock, DD
1989 Chevy Astro, 617 turbo swap, T5 5-speed, 4.56 diff, work van
07-27-2010, 09:34 AM
#9
(07-27-2010, 06:58 AM)dropnosky(07-26-2010, 07:59 PM)aaa I doubt the tailshafts are swappable. The stock electric setup appears to be picking up 4 pulses or whatever per rotation, from the appearance of the speedo "gear" inside.
x2. Can you put the mechanical speedo in the 300SD? Might be easier to adapt a mechanical speedo out of a 300D if possible instead of trying to create and convert a signal to work with the SD stock speedo.
I have a speedo from a W116, it's mechanical. I agree with Dropnosky, it may be easier to adapt a mechanical speedo with a cable than try to adapt a different tailshaft housing. Plus, with swapping to a mechanical speedo, you can change the ratio with an inline adapter for much cheaper.
82 300SD aka The Flyin Pumpkin (Gone): 7.5mm super M-pump, T3 60 trim turbo, Coldish air intake, A/W intercooler, propane injection, SW Boost and EGT gauges, Monark 265 nozzles, ported/polished cylinder head.
84 Euro 300D 4 sp: White with black trunk and hood. Blue cloth interior. Manual everything. 300DT front swaybar. C320 17" wheels. Now with the Flyin Pumpkins engine!
(07-27-2010, 06:58 AM)dropnosky(07-26-2010, 07:59 PM)aaa I doubt the tailshafts are swappable. The stock electric setup appears to be picking up 4 pulses or whatever per rotation, from the appearance of the speedo "gear" inside.
x2. Can you put the mechanical speedo in the 300SD? Might be easier to adapt a mechanical speedo out of a 300D if possible instead of trying to create and convert a signal to work with the SD stock speedo.
I have a speedo from a W116, it's mechanical. I agree with Dropnosky, it may be easier to adapt a mechanical speedo with a cable than try to adapt a different tailshaft housing. Plus, with swapping to a mechanical speedo, you can change the ratio with an inline adapter for much cheaper.
82 300SD aka The Flyin Pumpkin (Gone): 7.5mm super M-pump, T3 60 trim turbo, Coldish air intake, A/W intercooler, propane injection, SW Boost and EGT gauges, Monark 265 nozzles, ported/polished cylinder head.
84 Euro 300D 4 sp: White with black trunk and hood. Blue cloth interior. Manual everything. 300DT front swaybar. C320 17" wheels. Now with the Flyin Pumpkins engine!
07-27-2010, 09:57 AM
#10
I think this is the way to go for the w126.
.
Gota love Mercedes Diesels!
.
DeliveryValve
07-27-2010, 09:57 AM #10There is a guy in PeachParts who had stated his mechanic weld supposedly welded on some magnets to the driveshaft and used a modified pickup from the SD autotrans. He says it works beautifully. I've asked him for some pics in the past, but never got a response.
I think this is the way to go for the w126.
.
Gota love Mercedes Diesels!
.
07-27-2010, 11:49 AM
#11
I would not recommend doing it that way permanently!
I would think the magnets out of a couple sets of headphone would work! As I remember they are rare earth magnets???
This post was last modified: 07-27-2010, 11:50 AM by willbhere4u.
1987 300SDL 6spd manual om606.962 swap project
1985 300td euro 5spd wagon running
willbhere4u
07-27-2010, 11:49 AM #11I've seen magnets electrical taped on to a drive shaft for just this purpose
I would not recommend doing it that way permanently!
I would think the magnets out of a couple sets of headphone would work! As I remember they are rare earth magnets???
1987 300SDL 6spd manual om606.962 swap project
1985 300td euro 5spd wagon running
07-27-2010, 01:59 PM
#12
1981 300SD 230k miles "Gently Modified" Daily Driver
1999 F-250 7.3L Power Stroke 150k miles "The Usual Mods" Tow Rig
1981 300SD 190k miles "Heavily Modified"
GONE
DrewGerhan
07-27-2010, 01:59 PM #12I was planning on dealing with it either later today or tomorrow. I guess my plan will be to take apart the tailshaft on the auto first and see what the workings of the speed sensor are like and go from there.
1981 300SD 230k miles "Gently Modified" Daily Driver
1999 F-250 7.3L Power Stroke 150k miles "The Usual Mods" Tow Rig
1981 300SD 190k miles "Heavily Modified"
GONE
07-28-2010, 06:13 AM
#13
Quote:I guess my plan will be to take apart the tailshaft on the auto first and see what the workings of the speed sensor are like and go from there.
This is the difference for the auto, the tailhousings are interchangeable.
You could put the tone ring in place of the worm drive, cut and weld the cable portion out and weld a bung in place for the electric pickup.
ForcedInduction
07-28-2010, 06:13 AM
#13
The problem with adding magnets is that will significantly impact driveshaft balance and pick up road debris over time.
Quote:I guess my plan will be to take apart the tailshaft on the auto first and see what the workings of the speed sensor are like and go from there.
This is the difference for the auto, the tailhousings are interchangeable.
You could put the tone ring in place of the worm drive, cut and weld the cable portion out and weld a bung in place for the electric pickup.
07-29-2010, 11:40 PM
#14
1981 300SD 230k miles "Gently Modified" Daily Driver
1999 F-250 7.3L Power Stroke 150k miles "The Usual Mods" Tow Rig
1981 300SD 190k miles "Heavily Modified"
GONE
DrewGerhan
07-29-2010, 11:40 PM #14I assume the rotating pieces (from the first picture) are the same physical size and spline size?
1981 300SD 230k miles "Gently Modified" Daily Driver
1999 F-250 7.3L Power Stroke 150k miles "The Usual Mods" Tow Rig
1981 300SD 190k miles "Heavily Modified"
GONE
07-30-2010, 05:08 AM
#15
ForcedInduction
07-30-2010, 05:08 AM
#15
Yes. Its just the perspective of the picture that makes them look different.
07-30-2010, 08:32 PM
#16
1981 300SD 230k miles "Gently Modified" Daily Driver
1999 F-250 7.3L Power Stroke 150k miles "The Usual Mods" Tow Rig
1981 300SD 190k miles "Heavily Modified"
GONE
DrewGerhan
07-30-2010, 08:32 PM #16Got into both transmissions tonight. Nothing is similar between the two. My next plan is either to buy a gps and call it done or to get a speedo and cable that is from a 240 or 300D.
1981 300SD 230k miles "Gently Modified" Daily Driver
1999 F-250 7.3L Power Stroke 150k miles "The Usual Mods" Tow Rig
1981 300SD 190k miles "Heavily Modified"
GONE
07-30-2010, 11:54 PM
#17
1987 300SDL 6spd manual om606.962 swap project
1985 300td euro 5spd wagon running
willbhere4u
07-30-2010, 11:54 PM #17or w116
1987 300SDL 6spd manual om606.962 swap project
1985 300td euro 5spd wagon running
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