Timing Chains Don't Last Forever - PeachParts Mercedes-Benz Forum

whunter · #1 09-04-2006, 06:54 PM

Timing Chains Don't Last Forever
by Rich Cregar

Edit: Removed bad link, will replace asap.

whunter · #2 01-12-2011, 12:32 PM

Roller chain
Roller chain - Wikipedia, the free encyclopedia

Roller Chain Wear Life
Diamond Chain | Roller Chain Wear Life

DESIGN FORMULAS FOR ASA ROLLER CHAIN SPROCKETS
OmniGear & Machine Corp.

Mechanical Design Handbook: Standard roller chain drive design

The Complete Guide to Chain
The Complete Guide to Chain

whunter · #3 01-12-2011, 01:23 PM

This was written in response to the owner of a 300SD, but is generic to all roller chains.

Timing chain stretch does not exist = it is wear on the pins and bushings = Wear Elongation Measurement.

Chain elongation/wear is not corrected by an offset Woodruff key..

I have stopped checking timing chain elongation/wear on any engine over 250,000 miles, the labor/time is identical to replace the chain.
The cost of a chain is cheap insurance, and generally improves performance.

My rule of thumb is 200-250K miles I replace the timing chain = don't waste money/time checking it..

If the timing has not been changed since new = replacing the timing chain will bring the timing back where it belongs.

IMO: If the chain has measurable elongation/wear = Replace it regardless of mileage!!!

A worn chain is damaging the sprockets.

What is running a damaged/worn out timing chain going to cost ?

At least (by the labor time guide) 4.7 hrs labor + all of these parts....

Crankshaft gear
MB# 617 052 00 03
http://www.pelicanparts.com/cgi-bin/ksearch/pel_search.cgi?SUPERCAT_FLAG=Y&make=MBZ&please_wait=N&forumid=&threadid=&command=DWsearch&descriptio n=617+052+00+03&x=12&y=11

Camshaft gear
MB# 121 052 03 01
http://www.pelicanparts.com/cgi-bin/ksearch/pel_search.cgi?SUPERCAT_FLAG=Y&make=MBZ&please_wait=N&forumid=&threadid=&command=DWsearch&descriptio n=121+052+03+01&I1.x=4&I1.y=6

sprocket gear
MB# 621 050 04 09
http://www.pelicanparts.com/cgi-bin/ksearch/pel_search.cgi?SUPERCAT_FLAG=Y&make=MBZ&please_wait=N&forumid=&threadid=&command=DWsearch&descriptio n=621+050+04+09&I1.x=15&I1.y=6

Timing device
MB# 617 070 05 45
http://www.pelicanparts.com/cgi-bin/ksearch/pel_search.cgi?SUPERCAT_FLAG=Y&make=MBZ&please_wait=N&forumid=&threadid=&command=DWsearch&descriptio n=617+070+05+45&I1.x=7&I1.y=4

Damage cost TOTAL $1,222.00
+ Labor

The minimum cost of parts for a DIY rebuild is roughly $1550 - $2000 USD.
OM617.952 Rebuild parts list
OM617.952 Rebuild parts list
***************************************************

There is only one brand of timing chain to use.
Warning, Danger: Please read this thread FIRST...
Need Automotive Grade Prozac
Need Automotive Grade Prozac = timing chain

OEM: brand IWIS
Timing Chain, With Master Link Double Row - 136 Links
MB# 003 997 62 94
http://www.pelicanparts.com/cgi-bin/ksearch/pel_search.cgi?SUPERCAT_FLAG=Y&make=MBZ&please_wait=N&forumid=&threadid=&command=DWsearch&descriptio n=003+997+62+94&I1.x=10&I1.y=3&FILTER_997M=ON

The best guide rail is SWAG
MB# 6150500916[
http://www.pelicanparts.com/cgi-bin/ksearch/pel_search.cgi?SUPERCAT_FLAG=Y&make=MBZ&please_wait=N&forumid=&threadid=&command=DWsearch&descriptio n=6150500916&I1.x=15&I1.y=9

upper guide rail
MB# 6150501416
http://www.pelicanparts.com/cgi-bin/ksearch/pel_search.cgi?SUPERCAT_FLAG=Y&make=MBZ&please_wait=N&forumid=&threadid=&command=DWsearch&descriptio n=6150501416&I1.x=10&I1.y=10

lower outer guide rail
MB# 6150521016
http://www.pelicanparts.com/cgi-bin/ksearch/pel_search.cgi?SUPERCAT_FLAG=Y&make=MBZ&please_wait=N&forumid=&threadid=&command=DWsearch&descriptio n=6150521016&I1.x=14&I1.y=5

lower inner guide rail
MB# 6150521116
http://www.pelicanparts.com/cgi-bin/ksearch/pel_search.cgi?SUPERCAT_FLAG=Y&make=MBZ&please_wait=N&forumid=&threadid=&command=DWsearch&descriptio n=6150521116&I1.x=14&I1.y=8

FYI: Links you may need:

PeachParts Mercedes ShopForum > Do It Yourself Links & Resources > DIY Links by Parts Category
Fast navigation Do It Yourself Links
Fast navigation Do It Yourself Links

Valve adjustment OM615, 616, 617 FYI.
Valve adjustment OM615, 616, 617 FYI.

Need Definitive OM617 Compression Test Procedure
Need Definitive OM617 Compression Test Procedure

Engine blow-by test, Blow a bag of blow-by
http://www.peachparts.com/shopforum/diesel-discussion/193602-engine-blow-test-blow-bag-blow.html#post1558819

Diesel Timing Chain Links Thread
http://www.peachparts.com/shopforum/diesel-discussion/162071-diesel-timing-chain-thread.html#post1251434

Timing Chains Don't Last Forever
Timing Chains Don't Last Forever

Diesel Injection:
Diesel Injection:

Crazy_Nate · #4 01-12-2011, 09:14 PM

So, what's the labor run (hours?) for a timing chain replacement. I was thinking about having my stretch checked when I have new injectors put in, however...if it costs the same, it's a no-brainer. Same advice apply for the OM603 as the OM617 above?

I'm at a little over 240k with no known replacement.

whunter · #5 01-13-2011, 04:09 AM

Quote:

Originally Posted by Crazy_Nate

So, what's the labor run (hours?) for a timing chain replacement. I was thinking about having my stretch checked when I have new injectors put in, however...if it costs the same, it's a no-brainer. Same advice apply for the OM603 as the OM617 above?

I'm at a little over 240k with no known replacement.

1.5 - 2.5 hours is average for checking.

engatwork · #6 05-08-2011, 08:29 AM

what?

We are at around 280k miles on the '95 E300 with the original chain. Once the shop gets up (within a couple weeks

) I am going to put the car in there and probably roll in a new chain along with rebuilding the front suspension. I have replaced all the guides on the timing chain and the oil pump chain on the car.

JB3 · #7 05-08-2011, 01:34 PM

Quote:

Originally Posted by whunter

The cost of a chain is cheap insurance, and generally improves performance.

If the timing has not been changed since new = replacing the timing chain will bring the timing back where it belongs.

100% true. Replaced the timing chain on my 83 300D at 335,000 miles on the original chain. Made this repair right before 10,000 mile plus road trip. Cheap insurance, 900 bucks spent with cost of new chain included, done by trusted shop down the street.

Performance of the car changed dramatically, as whunter said, timing had not been adjusted for 300,000 miles, and slop in the chain was directly affecting performance. Felt like another 15 to 20 hp added.

compu_85 · #8 05-08-2011, 05:03 PM

But I thought all chain drives were infallible and ran forever with no PM!

-J

whunter · #9 09-30-2012, 02:41 PM

Many examples of what a bad chain can do to any sprocket, from bicycles to stationary equipment or mega machines.
worn out chain sprocket - Google Search

.

unkl300d · #10 11-19-2016, 08:26 PM

[QUOTE=whunter;2634368]This was written in response to the owner of a 300SD, but is generic to all roller chains.

Timing chain stretch does not exist = it is wear on the pins and bushings = Wear Elongation Measurement.

Chain elongation/wear is not corrected by an offset Woodruff key..

I have stopped checking timing chain elongation/wear on any engine over 250,000 miles, the labor/time is identical to replace the chain.
The cost of a chain is cheap insurance, and generally improves performance.

My rule of thumb is 200-250K miles I replace the timing chain = don't waste money/time checking it..

If the timing has not been changed since new = replacing the timing chain will bring the timing back where it belongs.

IMO: If the chain has measurable elongation/wear = Replace it regardless of mileage!!!

A worn chain is damaging the sprockets.

What is running a damaged/worn out timing chain going to cost ?

At least (by the labor time guide) 4.7 hrs labor + all of these parts....

[sic] end quote.

///////////////////////////////////////////////////////

Thanks Whunter, I had my timing chain done on my 1979 300D @197,700 miles last week with your recommendation in mind.

Cheap insurance.

I could have waited another year or more but I needed the valves adjusted and I was available and mentally primed for this service.

Now my car runs noticeably better. Sure the valve adjustment helps but its a bit more than that.

For San Francisco bay Area folks, David Pham is a great mechanic . He is conscientious and has a holistic approach to your car. i.e. he goes the 9 yards on particular services but does not nickel and dime ya..
1.510.813.2456 Oakland CA. (has strong accent)

He also replaced my shut down valve that had begun to show oil seepage.

whunter · #11 11-19-2016, 09:30 PM

You are welcome.
.