Has anyone replaced a Timing chain on 6 cylinder W108?

[MunichTaxi]

The shop manual says to first remove the timing chain tensioner, install timing chain and re-install tensioner.

Was wondering if the chain can be installed with the tensioner in place? Thanks in advance.

[joshhol]

Everything I've seen requires removing the tensioner. Is it really that difficult to remove on that engine?

[MunichTaxi]

Drain 1/2 the coolant, remove the thermostat housing, remove tensioner.

But the manual say in bold letters "Replace O-ring for tensioner"

I haven't foud that O-ring listed in Fastlane or elsewhere.

[joshhol]

Hmm, just thinking that you have a carb'd engine so your not worried about injector pump timing. So, if you loose the chain timing, you just line up the cam tower and balancer and everything will be fine.

So, if doing it with the tensioner in place proves troublesome, it wont be that big of a deal. I don't know though, I usually defer to the manual.

[nachi11744]

Hello,
The tensioner has to be removed. There were some with the o-ring seal, some with flat gasket seal. Look at the unit on your car's engine carefully, with a magnifying glass if need be, if it needs o-ring, there will be a groove. Sometimes previous uninformed repairers leave out the o-ring because it was not supplied in the gasket sets
Have a good week

[MunichTaxi]

I will indeed look closely for O-ring (or gasket). Sounds like something that coube easilt over-looked.

[ctaylor738]

Best to get the o-ring from a dealer. It can deteriorate over time and become a MAJOR oil leak. Many front crank seals have been replaced mistakenly because of this leak.

[nachi11744]

Best to get the o-ring from a dealer. It can deteriorate over time and become a MAJOR oil leak. Many front crank seals have been replaced mistakenly because of this leak.

Hello,
FYI, chain tensioner oil leak is one of the ALL time favorites on the *old* design engines, I mean the postwar to about 1985 fours and sixes, the later M102,103,104 and all V-8s are relatively *modern* designs for MB and have their own peculiarities and of course, leaks
Have a good weekend

[Aaron]

Part number for the tensioner o-ring is 002-997-36-45

[MunichTaxi]

Myself and others here appreciate that information.

[MunichTaxi]

The timing tensioner had seperated at the locking circlip. I managed to re-assemble the tensioner and install. So far the chain stays tight. I think the previous chain had lengthened so much, it caused this problem. The new chain seems almost too tight, but it seemthat the way it's supposed to be.

I copied this from a previous post in Archives, so don't be alarmed when the marks don't line up.

Factory instructions to check valve timing.
1. "Turn engine in direction of normal rotation until #1 cylinder intake valve is in the same postions as used to check valve clearance." (lobe of cam exactly opposite where the rocker arm will touch the cam when it rotates round.)

2. "Insert feeler guage (at arrow) of sufficient thickness to remove all clearance." Arrow points to top of valve, between valve are rocker arm). I assume this means a slight drag, maybe a bit more, just like checking clearance, no more.

3. "Install dial indicator to read the travel of #1 cylinder intake valve. Set scale to "0"." (You will need to "preload" indicator about half and inch so that it reads as the valve moves away from the indicator. Dial indicator must, of course, be exactly parallel to valve travel direction! Tip can sit on edge of valve cap or on feeler gauge if stiff enough).

4. "Turn engine direction of rotation until dial indicator reads 0.016" (0.04mm). The vibration damper should be a correct degrees.

Valve timing is 11 degrees before top dead center (almost one crank rotation).