450SL Timing Chain Inspection Click on the
pictures to get a larger view in a new browser window. Close that window to
return here.
I decided to replace the timing chain and guides on my Mercedes 450SL. There
are lots of warnings on the net that this should be done before the engine is
ruined.
First a picture before opening the hood.
Disconnecting the battery is a good idea since the
Alternator will be removed.
The hood is open and the job may begin.
The mechanic at work
The timing chain is secured to the sprocket with cable
ties preventing the chain from slipping and loosing it's timing. This
picture shows the camshaft sprocket already removed. In order to loosen
the chain, I opened the chain tensioner and removed the spring.
The chain and plastic guides must have been replaced
before I bought the car. There is no chain wear on the guide. So I
decided to proceed no further and put it all back together.
The next
day I took the car for a nice top-down drive BUT at engine idle speed
there was an awful knocking sound. I had visions of loose connecting rod
bearing and engine re-build.
I found the small spring and small metal button
(piston) on the driveway the next morning. This explained it all. The
hydraulic tensioner without this small piston was bouncing resulting in
the slapping chain hitting the engine casing.
I removed the tensioner
and inserted the missing parts. It was difficult to re-install the
tensioner because of the force of the spring.
The shiny nub is the tensioning rail that gets pushed
against the chain.
After re-assembly, the engine was as relatively
quiet as before. What a relief! Moral of the story: Don't take the
tensioner apart.