380 Timing chain installation trouble.

[joesl]

Hi all, I bought an 1980 380 SL and found that the engine is badly in need of a new timing chain. Having quite a bit of mechanical experience, including rebuilding an 911SC engine, I read the Peach Tree technical article which seems straight forward and went ahead with the project. The engine was free turning and had good compression when I started. To turn the engine over easier, I took out the tensioner which in retrospect looks like it was a bad a idea. Now,
as I turn over the engine with a wrench, I am getting piston interference even though I put the tensioner back and all 3 timing marks line up. I haven't changed chains yet.
Any ideas?
Thanks, Joe.

[rowdie]

Must be something else. If both cams are on the mark and the balancer is on TDC this can not occur. 1980 model? Must not be a U.S. 380.

[RadioTek]

Just as a "d'oh" type question: Have you removed the spark plugs? You could be working against cylinder compression.


Barring something as simple as that, there have been reports that trying to roll in a new chain with the tensioner removed can leave enough slack in the chain to give a couple of problems. The chain can slip a cog on one of the gears, or the chain gets a 'kink' and binds up between parts down in the timing cover, especially if it was turned counterclockwise (opposite direction of normal rotation).

You might want to go over to the 107 forum on benzworld (dot) org (sometimes this site "eats" URL's to other sites), There have been a couple of guys that have had problems with timing chain replacement jobs there that could provide some help.

Just a couple of wild guesses from over the internet, take it for what that's worth.
Scott

[joesl]

I have the spark plugs out. I am getting a definite metal to metal feel when I wrench the pulley.
Like you say, I bet the chain got tangled or jammed. I'll give the other site a try.
Thanks, Joe.