I'm working on a 1984 380SL and have changed the timing chain and guides. Upon replacing the sprocket to the cam, I noticed that the TDC marks on the cam did not match the 0 TDC on the vibration damper. I had assumed that I had somehow let the chain slip on the cam, so I removed the rocker arms, reset the cams to TDC with the vibration damper and reinstalled the rocker arms. To my shock, I found that the TDC for the #1 and #6 were not at 0 TDC but at 270 degrees; 90 degrees off! I verified that #5 and #3 were at TDC at 0 TDC, so the million dollar question is how can the crank get 90 degrees off?

Please correct/educate me if I am missing something; but, why check it on #'s 5 and 3, are they the opposing cylinders? Shouldn't it be the crank at 0/TDC when #1 is on the compression stroke with the cams at their respective TDC marks?

Good luck!!!

__________________
"Rudeness is a weak man's imitation of strength" - Eric Hoffer

Perhaps these PDFs from the FSM will help

https://www.startekinfo.com/StarTek/outside/11883/PROGRAM/Engine/107/M116_38/05-215.pdf

https://www.startekinfo.com/StarTek/outside/11883/PROGRAM/Engine/107/M116_38/05-320.pdf

__________________
1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!

DH:

What procedure did you follow to replace the chain? You have used the singular in speaking of replacing the "sprocket to the cam"; did you remove only one sprocket from its cam? Which side?

If you had removed cam followers (rockers) on both sides as a first step, the cams can be turned freely when the chain is removed.
In such a case, timing can be restored by first setting the crank to #1 TDC by feeling for piston position thru the spark plug hole. Then, set the cams w/ sprockets in alignment with their respective timing marks. If the chain has been fed in, the sprockets can be slid off the cams, and the chain hooked over the sprockets, and the sprockets returned to the cams. With the chain on the sprockets, and the sprockets on the cams but not over the keys, check for alignment of the keyways to the keys. It may be necessary to re-index the sprockets in the chain to obtain simultaneous alignment of crank at TDC and the cams on their marks.
When all three marks are aligned, and the tensioner reinstalled, then reinstall the followers.

After making changes, be sure to slowly turn the engine by hand and stop if you feel resistance. Having the plugs out makes this easier.

^^^This!!!^^^

It is very easy to bend valves on these even cranking by hand. Good Luck!!!

__________________
"Rudeness is a weak man's imitation of strength" - Eric Hoffer