BenzWorld Junior Member
Date registered: Jan 2009
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W126 Timing Chain
Hi folks, I am new to this site and it’s been a fantastic resource. I have a W126 380SE…love this car!. so decided to do a number of maintenance jobs starting with TIMINING CHAIN replacement. I performed the following steps;
1. Replaced all three chain rails, tensioner rail and tensioner
2. Rotated engine and everything aligned OK back to TDC
3. Connected new chain with old and preceded to feed the new chain.
4. During the process of disconnected old chain and to linkup the new chain things jumped a little so I then panicked.
5. BRAIN PHASE…In my stupidity I decided to rotate the left cam by three teeth to make the chain meet so I could connect it. Didn’t think to check alignment marks in relation to right cam…though everything apperaed OK
6. Started to rotate engine to see if all was OK and noticed that I couldn’t rotate any more.. and chain was very tight…PANIC
7. Backed of slightly (anticlockwise ….I know not a wise move but it was only a slight rotation)
8. Tried to then rotate clockwise again…STUPID I know…. I was thinking that the problem will go away!
9. Had a BREAK and time to think
10. Now that the chain was looser around Left cam sprocket, I disconnected the chain and rotated the cam back three teeth connected and everything aligned properly
All is well….I think!..My question to you guys is
1. Rotating the engine by hand when left cam is three teeth retarded (meaning that number 4 exhaust valves was hitting the piston) Has this caused damaged to this valve..I know it’s a merc and part are hard as nails but that crank has a fair amount of momentum even when rotating by hand. I was using my torque wrench to rotate the engine and noticed it did click at around 60Nm before I stopped
2. Secondly, rotating counterclockwise by say 10 degrees…can this cause any damage to anything ( I suspect bottom two rails ??)
Please someone put my mind at rest one way or the other