The car is an 89 420 sel with 195,000 - m116 4.2l v8 engine. I recently replaced the timing chain, rails (three on top), tensioner rail, chain, sprockets, tensioner and cam oiler tubes (the plastic pieces).The chain and such were all original (as far as any records I have state) and I changed everything after the dreaded chain slap started occurring. One of the guides was broken in several places and I can't believe that it didn't get caught in the chain and jump time...

My question is related to the timing. I put everything back together, crank at tdc and both cam marks aligned along with the rotor pointing towards #1. When I use the timing light, it shows that I am out at 20 (there is a pin in the balancer at this point). How can I correct this? The car started and ran a little rough initially but seemed to smooth itself out somewhat. The idle is quiet and the car does not shake. I did try moving the rotor but it didn't help.

In addition, I can still hear a knocking noise from the engine. Not as loud as the chain slap from before but similar. It doesn't sound like it's coming from a lifter as it appears to be based in the front of the engine - could I have a bad tensioner? Everything seemed tight when I put it back together and the engine cranked several times (by hand) without any problems.

In addition, I took it for a short drive and found smoke (oil smell) coming from the valve cover near the 4th cylinder. I didn't see any oil coming out of the cover and thought it might just be some excess oil on the exhaust but I am concerned that it might be something more serious.

Any thoughts would be appreciated. I have searched the forum for hours but haven't found what I thought could help. Thanks.

HI, Until someone with more experience replies, I'll chip in. I did my '86 420 about three years ago. Although mine was not noisy, it was worn to the limit and I replaced the tensioner with an OEM part: I got some opinions at the time that the OEM part was superior to the after market parts, etc. In any case, your chain should not be noisy once replaced, and you do not want a faulty tensioner allowing the chain to slap around.
To install the distributor, I barred the engine to TDC cylinder 1 (top of compression stroke) then installed dist. with rotor pointing to #1 plug terminal on cap. I understand the timing is controlled by ignition system from this point on. The indication you mention may be what's expected, I don't remember.Anyway my car has run great ever since, although I don't drive it much, but consider it in semi-retirement. My passenger-side cam cover has a small leak from under one of the bolt heads, just enough to get on the manifold and stink. I am thinking of removing it and applying a little silicone, to see if that stops it. The bolt heads have seal rings underneath; best I remember I replaced these, maybe not. Otherwise if the gasket surfaces are good the covers should not leak. Be sure the gasket is in place under the oil filler cap. Hope this helps some; Happy Motoring!

Thanks for the reply. I'll check on the oem tensioner - does anybody know who manufacturers it? Here is a link to the engine noise I posted on youtube. Can anyone confirm that they feel the chain is still slapping and that I should go ahead with the oem tensioner?

Thanks,

http://www.youtube.com/watch?v=etnYN7xs0l8

Sounded like a lifter to me; a slapping chain is not so even and rhythmic, I think. I heard one once in another car, it made an irregular crunching sound.

did you remove the cam sprockets? i bet you did.under the 22mm bolt head there is a washer that needs to be turned over and put back the other way when you retighten the cam bolt.if you take it off and look at it and the surface to which it fits you will see why.if they are not flipped when reinstalled you will get the sprockets rocking against the keyways while the engine is running and it sounds just like chain noise.

__________________
David S Poole
European Performance
Dallas, TX
4696880422

"Fortune favors the prepared mind"
1987 Mercedes Benz 420SEL
1988 Mercedes Benz 300TE (With new evaporator)
2000 Mercedes Benz C280
http://www.w108.org/gallery/albums/A...1159.thumb.jpg

Good call - I did loosen those bolts and did not flip the washers when I tightened them up again. I will pull the valve covers and check them over.

Now I am wondering about this for my car; I don't remember this. I did have to remove the driver's side cam sprocket to get the guide changed. Anyway, mine is not making any noise.