Timing Chain
Timing Chain
'84 300 SD w126 Race Car
'86 190E 2.3 w201 Daily Driver
'85 500 SEL w126 Scraped
'92 1.6 Geo Storm Totaled by a Uninsured Driver
serverman777
12-26-2011, 10:40 AM #1Yesterday I was doing 101 in a 55 and the thought came to me "Hey man, your timing chain may have over 400,000 miles on it". I really don't want it to break. I understand that om617's chains can last over 500,000 but do I really want to trust it? At at high RPM it might break sooner. Whats your ideas on this topic everybody?
'84 300 SD w126 Race Car
'86 190E 2.3 w201 Daily Driver
'85 500 SEL w126 Scraped
'92 1.6 Geo Storm Totaled by a Uninsured Driver
but for most normal driving i dont think its an issue. (imo)
1998 E300TD 7.5mm pump and hx35 to come!
00 Mustang gt drift car
iheartboost
12-26-2011, 01:22 PM #2idk. to much about em. but with almost 300k my timing chain has almost 0 stretch. so they are built pretty dam well. i mean if you sit at 6k all day then yea i would probably replace it lol.
but for most normal driving i dont think its an issue. (imo)
1998 E300TD 7.5mm pump and hx35 to come!
00 Mustang gt drift car
1998 E300TD 7.5mm pump and hx35 to come!
00 Mustang gt drift car
iheartboost
12-26-2011, 02:41 PM #4this is true. i have no records of the car. but from the rest of the condition i just assumed the previous owner dident do much in the way of maintenance
1998 E300TD 7.5mm pump and hx35 to come!
00 Mustang gt drift car
http://www.superturbodiesel.com/std/show...p?tid=3046
With that said, my opinion is generally 300K is a bit long on a chain regardless of stretch. On the other hand I would consider running it longer if the engine has been running synthetic motor oil since day 1 and had zero stretch.
.
Gota love Mercedes Diesels!
.
DeliveryValve
12-27-2011, 10:09 AM #5I got a few good unused chains.
http://www.superturbodiesel.com/std/show...p?tid=3046
With that said, my opinion is generally 300K is a bit long on a chain regardless of stretch. On the other hand I would consider running it longer if the engine has been running synthetic motor oil since day 1 and had zero stretch.
.
Gota love Mercedes Diesels!
.
http://www.superturbodiesel.com/std/show...4#pid30154
Scroll down from there
P.S. If there is no stretch, BALLS TO THE WALL!
1982 300D Turbo ... 3,6xxlbs, No fan, No AC, Hood Stack, No ALDA, No rear bumper and stuffed front, A/W Intercooled, Injectors by Greezer and HUGE Pre-Chambers with help from OM616 & Simpler=Better, Fuel Cranked up, 60 Trim Compressor wheel, EGT, EMP, Boost 50" Rigid Radius bar on roof Aux tank for a total of 48 Gal Of Diesel! Odyssey PC-1750 Battery in trunk, 27"x8.5"/R14 Maxxis BigHorn Mud Terrains, In June '14 issue of Off Road Mag
AX15 Jeep Trans swap in progress....
Captain America
12-28-2011, 05:12 AM #6Have you checked stretch? I did on the motor I recently got and its PERFECT!
http://www.superturbodiesel.com/std/show...4#pid30154
Scroll down from there
P.S. If there is no stretch, BALLS TO THE WALL!
1982 300D Turbo ... 3,6xxlbs, No fan, No AC, Hood Stack, No ALDA, No rear bumper and stuffed front, A/W Intercooled, Injectors by Greezer and HUGE Pre-Chambers with help from OM616 & Simpler=Better, Fuel Cranked up, 60 Trim Compressor wheel, EGT, EMP, Boost 50" Rigid Radius bar on roof Aux tank for a total of 48 Gal Of Diesel! Odyssey PC-1750 Battery in trunk, 27"x8.5"/R14 Maxxis BigHorn Mud Terrains, In June '14 issue of Off Road Mag
AX15 Jeep Trans swap in progress....
1998 E300TD 7.5mm pump and hx35 to come!
00 Mustang gt drift car
iheartboost
12-28-2011, 08:34 AM #7always the best advice captain! lol
1998 E300TD 7.5mm pump and hx35 to come!
00 Mustang gt drift car
1982 300D Turbo ... 3,6xxlbs, No fan, No AC, Hood Stack, No ALDA, No rear bumper and stuffed front, A/W Intercooled, Injectors by Greezer and HUGE Pre-Chambers with help from OM616 & Simpler=Better, Fuel Cranked up, 60 Trim Compressor wheel, EGT, EMP, Boost 50" Rigid Radius bar on roof Aux tank for a total of 48 Gal Of Diesel! Odyssey PC-1750 Battery in trunk, 27"x8.5"/R14 Maxxis BigHorn Mud Terrains, In June '14 issue of Off Road Mag
AX15 Jeep Trans swap in progress....
Captain America
12-28-2011, 01:14 PM #8Yeah buddy. I mean these things are (almost) bulletproof
1982 300D Turbo ... 3,6xxlbs, No fan, No AC, Hood Stack, No ALDA, No rear bumper and stuffed front, A/W Intercooled, Injectors by Greezer and HUGE Pre-Chambers with help from OM616 & Simpler=Better, Fuel Cranked up, 60 Trim Compressor wheel, EGT, EMP, Boost 50" Rigid Radius bar on roof Aux tank for a total of 48 Gal Of Diesel! Odyssey PC-1750 Battery in trunk, 27"x8.5"/R14 Maxxis BigHorn Mud Terrains, In June '14 issue of Off Road Mag
AX15 Jeep Trans swap in progress....
(12-28-2011, 01:14 PM)Captain America Yeah buddy. I mean these things are (almost) bulletproof
I've considered having an experiment to see if/what calibres/distances these cars are actually bulletproof, considering they are made out of some pretty stout steel
-1982 300D Turbo, 280k miles, ALDA apparently maxxed, fram 8038, 12 lbs boost, non-egr manifolds, W/M injection, 4 brake light mod, Gen II w126 front rotors/calipers, 4-speed swap
In the works: A/W IC, adjust pump, turbo rebuild (w/60 trim comp wheel)
-1980 300SD, 110k, project car. Goal is to get it lookin' like it did on the showroom floor (body and interior wise, not necessarily under the hood )
-1974 240D, FRESH PAINT!!!!!!
sassparilla_kid
12-30-2011, 01:30 AM #9(12-28-2011, 01:14 PM)Captain America Yeah buddy. I mean these things are (almost) bulletproof
I've considered having an experiment to see if/what calibres/distances these cars are actually bulletproof, considering they are made out of some pretty stout steel
-1982 300D Turbo, 280k miles, ALDA apparently maxxed, fram 8038, 12 lbs boost, non-egr manifolds, W/M injection, 4 brake light mod, Gen II w126 front rotors/calipers, 4-speed swap
In the works: A/W IC, adjust pump, turbo rebuild (w/60 trim comp wheel)
-1980 300SD, 110k, project car. Goal is to get it lookin' like it did on the showroom floor (body and interior wise, not necessarily under the hood )
-1974 240D, FRESH PAINT!!!!!!
What usually happens is that the spring loaded timing tensioner loses its ability to maintain sufficient tension due to fatigue of the aged and worn internal timing tensioner spring (decreased spring rate) + timing chain stretch which decreases and affects the tensioners tensioning range + Wear on the timing chain guide rail where the tensioner makes contact also decreases timing tension + the groove that the timing chain can wear into the chain guide must be compensated for as well + neglected maintenence just increases the wear of already worn and wearing components. ANY bit of wear on timing related components noted plus others that I probably did not mention add up because where the wear exists the tensioner must make up for it. We all know that when a spring is compressed to 50% of it's original size when new that it is " MUCH stiffer" than it would be if it were compressed to 60% of it's original size and aged 30 years with many heat cycles, cold, wear, decreasing oil pressure and constant movement/load. The tensioner spring always has load even when the engine is not running. It's slightly compressed holding the timing chain guide rail against the timing chain to keep it's tension. Load is slightly increased when engine is running/idle, activity is increased furthermore at normal driving conditions and load is significantly increased and certainly unstable when at full throttle. When the timing tensioner develops excessive play due to the above stated causes the chain itself can skip teeth on the cam/crank gear and slip, slip, catch, timings off, engine internals collide and SNAP!! Since the tensioner fail to maintain the chains tension the chain gets play and allows for it to come off track to cause the damage since they're related timing components and the timing is no longer maintained.
The timing chain tensioner spring is a wear item. From my parts supplier the timing chain tensioner spring is a $4.72 and is a GENUINE MERCEDES-BENZ item. The timing tensioner gasket which should be replaced at the same time to avoid an oil leak is only $0.91 and is also an OEM product.
TexasSuperDecel
01-01-2012, 03:13 AM #10Most commonly on vehicles it's the timing belt/chain tensioner that fails first causing a series of events which causes the timing belt/chain to fail as well. Inside the timing chain tensioner itself on our W126 diesel models is a spring (aided by oil pressure) which keeps tension by exerting a force to the timing chain guide rail against the timing chain reducing the "slack" keeping the chain tensioned.. (Example -The chain setup on a 10 speed bike)
What usually happens is that the spring loaded timing tensioner loses its ability to maintain sufficient tension due to fatigue of the aged and worn internal timing tensioner spring (decreased spring rate) + timing chain stretch which decreases and affects the tensioners tensioning range + Wear on the timing chain guide rail where the tensioner makes contact also decreases timing tension + the groove that the timing chain can wear into the chain guide must be compensated for as well + neglected maintenence just increases the wear of already worn and wearing components. ANY bit of wear on timing related components noted plus others that I probably did not mention add up because where the wear exists the tensioner must make up for it. We all know that when a spring is compressed to 50% of it's original size when new that it is " MUCH stiffer" than it would be if it were compressed to 60% of it's original size and aged 30 years with many heat cycles, cold, wear, decreasing oil pressure and constant movement/load. The tensioner spring always has load even when the engine is not running. It's slightly compressed holding the timing chain guide rail against the timing chain to keep it's tension. Load is slightly increased when engine is running/idle, activity is increased furthermore at normal driving conditions and load is significantly increased and certainly unstable when at full throttle. When the timing tensioner develops excessive play due to the above stated causes the chain itself can skip teeth on the cam/crank gear and slip, slip, catch, timings off, engine internals collide and SNAP!! Since the tensioner fail to maintain the chains tension the chain gets play and allows for it to come off track to cause the damage since they're related timing components and the timing is no longer maintained.
The timing chain tensioner spring is a wear item. From my parts supplier the timing chain tensioner spring is a $4.72 and is a GENUINE MERCEDES-BENZ item. The timing tensioner gasket which should be replaced at the same time to avoid an oil leak is only $0.91 and is also an OEM product.
Nice body, tons of ridiculous mechanical issues - 300d turbo 82' /motor 85'
That is some wicked valuable info. I have seen the spring but never knew it was a part that needed to be replaced as part of our preventative maintenance.
Nice body, tons of ridiculous mechanical issues - 300d turbo 82' /motor 85'
-1982 300SD, found out she has an '85 Engine, unknown mileage, redoing the top end and chain, head has been ported and polished, non EGR manifolds / non ARV turbo
-1982 300D, too many issues to list.
-Alt Fuel Buff
-Founder www.SWFLBenzCLub.com
SpecialDelivery
09-12-2012, 03:50 AM #13Anyone have any experience leaving an old tensioner and spring in when changing the chain? and what about the Febi vs OEM tensioners?
-1982 300SD, found out she has an '85 Engine, unknown mileage, redoing the top end and chain, head has been ported and polished, non EGR manifolds / non ARV turbo
-1982 300D, too many issues to list.
-Alt Fuel Buff
-Founder www.SWFLBenzCLub.com
MONSTER 300D
09-25-2012, 05:04 PM #14I know this is an old thread. And dont know if anyone reallly cares or not, but just a fyi thing you can purchase offset timing gear keyways to help with the chain stretch. there is a .7mm offset avalable somewhere. Scott got one for mine when he checked the backlash on my chain & installed it. I saw no preformace difference, but was good to know that everything was properly lined back up.
(09-25-2012, 05:04 PM)MONSTER 300D I know this is an old thread. And dont know if anyone reallly cares or not, but just a fyi thing you can purchase offset timing gear keyways to help with the chain stretch. there is a .7mm offset avalable somewhere. Scott got one for mine when he checked the backlash on my chain & installed it. I saw no preformace difference, but was good to know that everything was properly lined back up.
According to
http://biodiesel.infopop.cc/eve/forums/a...056362/p/3
Posted April 20, 2011 05:41 PM by Omar...
Mercedes Benz makes 4 woodruff keys for the correction of cam timing:
* Part # 621 991 04 67, Offset 0.7 mm, For correction of about 4 degrees.
* Part # 621 991 02 67, Offset 0.9 mm, For correction of about 6.5 degrees.
* Part # 621 991 01 67, Offset 1.1 mm, For correction of about 8 degrees.
* Part # 621 991 00 67, Offset 1.3 mm, For correction of about 10 degrees.
If memory serves, MB dealers sell these woodruff keys very inexpensively. I haven't done it yet on either of my 300D's, but did install a compensating woodruff key three times on the W123 230 gasser I owned 20 years ago in Germany (in ten years I put 300,000 kilometers on it, and changed the timing chain, tensioner, rail the second of those times, along with renewing the valve guides and replacing a burnt rearmost exhaust valve).
What I always did, was just buy a complete set --they were *very* inexpensive-- and, just in case someone has already installed one of these compensating keys, you need to also buy one of the zero-offset as-from-the-factory woodruff keys, so you can first install that to see how far your chain has stretched beyond what has already been compensated for by prior installation of such a key by a previous owner (or, you yourself, if forgetful).
Compensating for a stretched timing chain, raised top autobahn cruising speed of that car from 160 kph to 185. The difference between never-out-of-the-right-lane and occasionally-into-the-fast-lane. Still had to keep an eye on the rearview mirror for cars coming up behind at 220 or more. Especially when driving near Munich.
Gone but not forgotten: two W123 sedans and two W124 wagons.
W124 1987 300TD wagon, for sale, $1000 (some assembly required).
JustPassinThru
09-25-2012, 05:24 PM #15(09-25-2012, 05:04 PM)MONSTER 300D I know this is an old thread. And dont know if anyone reallly cares or not, but just a fyi thing you can purchase offset timing gear keyways to help with the chain stretch. there is a .7mm offset avalable somewhere. Scott got one for mine when he checked the backlash on my chain & installed it. I saw no preformace difference, but was good to know that everything was properly lined back up.
According to
http://biodiesel.infopop.cc/eve/forums/a...056362/p/3
Posted April 20, 2011 05:41 PM by Omar...
Mercedes Benz makes 4 woodruff keys for the correction of cam timing:
* Part # 621 991 04 67, Offset 0.7 mm, For correction of about 4 degrees.
* Part # 621 991 02 67, Offset 0.9 mm, For correction of about 6.5 degrees.
* Part # 621 991 01 67, Offset 1.1 mm, For correction of about 8 degrees.
* Part # 621 991 00 67, Offset 1.3 mm, For correction of about 10 degrees.
If memory serves, MB dealers sell these woodruff keys very inexpensively. I haven't done it yet on either of my 300D's, but did install a compensating woodruff key three times on the W123 230 gasser I owned 20 years ago in Germany (in ten years I put 300,000 kilometers on it, and changed the timing chain, tensioner, rail the second of those times, along with renewing the valve guides and replacing a burnt rearmost exhaust valve).
What I always did, was just buy a complete set --they were *very* inexpensive-- and, just in case someone has already installed one of these compensating keys, you need to also buy one of the zero-offset as-from-the-factory woodruff keys, so you can first install that to see how far your chain has stretched beyond what has already been compensated for by prior installation of such a key by a previous owner (or, you yourself, if forgetful).
Compensating for a stretched timing chain, raised top autobahn cruising speed of that car from 160 kph to 185. The difference between never-out-of-the-right-lane and occasionally-into-the-fast-lane. Still had to keep an eye on the rearview mirror for cars coming up behind at 220 or more. Especially when driving near Munich.
Gone but not forgotten: two W123 sedans and two W124 wagons.
W124 1987 300TD wagon, for sale, $1000 (some assembly required).
Austincarnut
09-30-2012, 09:18 PM #16The most common problem for the death of a 616/617 chain is the vacuum pump bearings falling in the chain drive. The newer style vacuum pumps have a cage around the bearings and can keep then out of the drive if/when they fail. It has been common place as I've worked on these engines to recommend and replace vacuum pumps in the usual maintenance intervals rather than a timing chain. I just recently purchased a victim 616 car that some hack just replaced the pump and left the damaged chain/gears. This led to the chain wearing out the idler and breaking the chain in several places. If you have access to the EPC you can read some on the super-cession #'s and calculate which pump was the problem one, I haven't yet figured which ones are good/bad, then again, I haven't looked very hard. I need to read through the old bulletin manual, because there have been numerous changes over the years to these engines and most are documented clearly in Yerman-English. These timing chains are tough as nails, I've had hell removing this old chain and not damaging the casting.
Matt.
'85 300SD Turbo
'92 Subaru SVX
'83 Pontiac Firebird S/E
'88 Pontiac Firebird
dieselsmoke300d
02-01-2015, 12:48 AM #17I'm glad I found this thread. All of the sudden my 300SD's chain decided to make a freaking racket as I was driving one day. Had the shop look at it and they confirmed it's chain slap. I'm planning on replacing it soon. Does anyone know how hard it is to replace the guide rails if required? Someone told me that it takes ripping the block apart.
Matt.
'85 300SD Turbo
'92 Subaru SVX
'83 Pontiac Firebird S/E
'88 Pontiac Firebird
(12-26-2011, 10:40 AM)serverman777 Yesterday I was doing 101 in a 55 and the thought came to me "Hey man, your timing chain may have over 400,000 miles on it". I really don't want it to break. I understand that om617's chains can last over 500,000 but do I really want to trust it? At at high RPM it might break sooner. Whats your ideas on this topic everybody?101 in a 55? Can't believe no one called you out on this and someone even encouraged you to go faster. Do we really need more safety videos in high school because one or two do stuff like this?
2005 CDI heavily modified 1984 300TD - Myna pump/TMIC/enlarged PC's/HX30Super/W126 II front brakes/Vogtland springs/EGT +Boost gauges/H4 Hella's
(12-26-2011, 10:40 AM)serverman777 Yesterday I was doing 101 in a 55 and the thought came to me "Hey man, your timing chain may have over 400,000 miles on it". I really don't want it to break. I understand that om617's chains can last over 500,000 but do I really want to trust it? At at high RPM it might break sooner. Whats your ideas on this topic everybody?101 in a 55? Can't believe no one called you out on this and someone even encouraged you to go faster. Do we really need more safety videos in high school because one or two do stuff like this?
2005 CDI heavily modified 1984 300TD - Myna pump/TMIC/enlarged PC's/HX30Super/W126 II front brakes/Vogtland springs/EGT +Boost gauges/H4 Hella's
fordheaded
02-02-2015, 05:24 PM #19Upper guide rails are easy, lower pins are behind crank pulley and balancer. Not to bad with the right tools.
(02-02-2015, 05:24 PM)fordheaded Upper guide rails are easy, lower pins are behind crank pulley and balancer. Not to bad with the right tools.
Good to know. Thanks.
I'm not sure if I need to mess with the rails yet. I'm pretty sure my tensioner spring broke and caused the whole Problem. Explains why the chain's messing up at only like 103k miles.
Matt.
'85 300SD Turbo
'92 Subaru SVX
'83 Pontiac Firebird S/E
'88 Pontiac Firebird
dieselsmoke300d
02-03-2015, 06:10 PM #20(02-02-2015, 05:24 PM)fordheaded Upper guide rails are easy, lower pins are behind crank pulley and balancer. Not to bad with the right tools.
Good to know. Thanks.
I'm not sure if I need to mess with the rails yet. I'm pretty sure my tensioner spring broke and caused the whole Problem. Explains why the chain's messing up at only like 103k miles.
Matt.
'85 300SD Turbo
'92 Subaru SVX
'83 Pontiac Firebird S/E
'88 Pontiac Firebird
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