I just replaced the timing chain on my 380sl, and the cam marks
aligned perfectly with the 0 mark on the vibration damper. However,
when I was rotating the chain manually to reinstall the rockers,
before installing a new tensioner, I noticed that the chain would
ocassionally jump on the passenger side, and now the cam marks and
vibration damper are off by app. 18 degrees, which I think correponds
to 1 tooth.
Can anyone tell me what's causing the new chain to jump like this, and
how to correct it?
Thanks a lot.
There was no tensioner installed to control the new chain's slack.
The right cam's lobes controlled the cam as the lobes sought to avoid
opening their respective valves. The lobes prevailed over the slack
chain and the chain jumped a tooth.
Additional thought, turn the engine to TDC or whatever mark you
previously used to check the cams' synchrosity with the crank. That's to
ensure the cam is restored to its correct position and not 36 degrees -
as would probably happen to me!
Thanks very, very much for the help, T.G.. After pulling the chain
back, the left cam marks are aligned, and the vibration damper is at
0, but the right cam mark is still about 1/4 - 1/2" past the cam tower
mark. However, I haven't installed the tensioner yet, and i'm assuming
that when I do, hopefully tomorrow, it will take up the slack, and
cause the right cam marks to also align. Am I correct about this, or
should the left marks also be aligned, even though the tensioner isn't
in there yet?
My sincere thanks again, T.G..
Good point - that the tensioner may bring the right cam to TDC.
It may be so, I don't know.
I read your first post as affirmatively stating that the cams were at
TDC but then the right cam had jumped, thus my suggestion to cheat the
cam back one tooth.
Install the tensioner and see how it looks, worst case the tensioner
must be removed and the cheat method employed.
Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here.
All logos and trade names are the property of their respective owners.