myfirstbenz

replacing the headgasket in my brothers m104 300ce and decided to go ahead and do some other maintenece things while we had the engine apart... put a new timing chain, guides and tensioner in... but the timing chain is really tight (as in no play what so ever) now, I have turned the engine over and there isn't any binding...

are the new timing chain tensioners adjustable... because the factory manual doesn't say anything about adjusting... just installing it

neanderthal

the engines use a ratcheting mechanism that is hydraulic to tension the chain. i dont recall the exact way to determine chain stretch, but i think you have to put #1 at TDC (on the crankshaft pulley,) then see if the timing mark on the camshaft is also at TDC or just off a little.

i could be wrong. its been many years since i was inside a benz engine. but i know that once the chain is getting noisy that it needs replacement.

Wolftin

I just replaced my headgasket too, what you have to do is to remove the timing chain tensioner completely then take it apart ( there is a large alan in the middle of the bolt) then push the plunger through so it comes out( push it in the direction that it pushes the chain) then put the body of the tensioner back on the engine then put the plunger back in the body of the tensioner.( you might need to give it tap to make it go through to the rail) once you see it is pushing the rail put the spring and the rest of the unit back together like it was before you took it apart. Because when you lossen the chain the tensioner comes out and it wont go back in that direction it has to go back from the back. I hope this helps.

myfirstbenz

I got everything in place just fine, it is just that it is tight! and I would hate to prematurely wear down any parts ... I know the head is tight too so that shouldn't be an issue...hmm, maybe it just needs to break-in.

myfirstbenz

Anyone?

Wolftin

http://www.continentalimports.com/ser_ic100345.html

myfirstbenz

well got the 300CE fired up a few days ago and it runs fine, however it does have a bit of a whrring sound coming from the front of the motor, not in the head. It isn't horrible but it is a sound that I have not heard in the motor before the timing chain and tensioner. THe car does however run with much more pep and power but does not idle as well with some light surging but no engine lights come on, so I think it might just be needing to run some more.

Thoughs?

Kestas

As wolftin suggested, the tensioner needs to be installed correctly after the timing chain is installed. This is covered in the link he provided. One poster mentioned after the fact that he didn't do this which resulted in overtension and the timing chain rails grenaded. I'm afraid this may happen to you.

Since you have the timing chain reassembled, you need to remove the tensioner assembly. Undo it using the big nut, which removes the tensioner assembly.... the little nut is for the plunger. The plunger inside the body ratchets in one direction only. It is overratcheted (overextended) when the timing chain is removed. You need to remove the plunger, install the body to the engine, then reinsert the plunger, spring, and nut back into the body.... Done!

The true tension comes from the oil pressure. The ratchet limits the movement backward so there is little slack in the mechanism during startup and shutdown.