Timing chain R&R
 

I'm planning to R&R my timing chain, tensioner and all guides, strictly PM (174k, with no service recs). Can anyone give me an idea what I need to teardown to get to the chain cover? Any pitfalls to watch out for? Special tools, etc.?

Thanks in advance for the shared wisdom,

This is going to sound bad but....... pay someone to do this. It's not a hard job but, you've got to cut the old chain, roll in the new one (tensioner out), recheck base cam timing, drop the cam gears, pull the accesorys off and pull the pins for the guides, then put the entire thing back together and recheck base cam timing. You miss or make a mistake in this process you lunch the top end.




Joe

If you still feel comfortable doing this yourself you might opt to only do the upper guides. At the relatively low mileage of 175K, the lower guides should still have a good 150-200K left in them. The upper guides are a piece of cake to do, once all the accessories are removed (Power stereing pump and backing plate, cruise actuator, alternator and bracket [plus I removed the distributor to access one pump backing plate bolt], as well as the fan and shroud).

Rolling in anew chain can be a bit dicey if you don't have the proper chain guide, but it can be done. Be sure to install a new tensioner when doing this job.

I recently did guides, chain and tensioner on the 560, took my time and had it done in a weekend.

If the car has a dual OHC, rather than the singles on a 560, I would definitely say "farm it out". DOHC are much more difficult and less forgiving.

Thanks for the replies
 

Mike, reading back over your experiences is what gave me the inspiration to tackle this in the first place. Great job resurecting the 560SEL!
I already have the parts, including the lower rails.
What is the downside to doing the whole job, rather than just
the top?
Would rolling in the new chain still be my best choice if I pull the timing chain cover?

Thanks again,

You can grind off any old link with a Dremel tool or similar, which will allow you to connect the new chain. Make sure no debris falls into the engine. A helper to help guide the new chain in is useful - no mechanical skill needed. You want to focus your attention on not skipping a tooth as you rotate the crank with a 27mm socket. Recheck timing once installed by checking the zero position on the crank with the alignment mark on the cam.

I would also recommend renting the chain crimper (Performance Products has it - maybe your local MB show will be nice enough to loan one to you) which will do a perfect job of crimping the connecting link. Worked like a dream when I did the chain on my 300SD at 100k (now at 200k). Some advocate peening the rollers on the connecting link with a hammer (!) but why take the risk(s)? BTW, OEM chains are made by IWIS - orange box as I recall.