560SEC Timing chain and valve stem seals

The Timing chain replacement is almost finished on the 560SEC.   The new chain is installed, guides fitted and valve stem seals replaced.    I stopped by the workshop to pick something up that I had left in the car and I was able to see it almost done.

560SEC Timing Chain

The photo shows the new chain in place with all new guides.   They are a much better colour than the old ones!   My timing for this repair was good as one of the existing guides was broken.   This car is now my third 560SEC, and the third one where I have sent it in to have the chain done.   In all three cases, one of the guides was broken.    This makes the engine a ticking time bomb as if the guide gets caught up in the chain on startup, it can jump a tooth and valves/pistons collide.


At the same time the valve stem seals were replaced.   The old seals were really hard and i’m feeling confident that I will no longer get the puff of smoke on takeoff.  For both of these repairs the parts are not the major cost of the job.  I had supplied the parts as I wanted to use genuine or OEM parts where possible.   I have heard the genuine guides and valve stem seals are much better than the aftermarket options and will last a lot longer.   Unfortunately the genuine tensioner is really expensive so I went with a Febi unit in this case.

As the timing chain stretches, it affects the timing of the engine.  The combination of chain stretch and wear in the upper and lower sprockets.  As the upper sprockets need to be removed, it makes sense to replace them.   The lower sprocket would only be replaced when the engine is torn down.   I was pleased to see that the engine lines up perfectly, making me think that the lower sprocket is not worn.   The three photos below show the timing marks on the two camshafts and the crankshaft.

Timing marks

Timing Marks

timing marks


I pick up the car early next week.   The timing chain will give me a lot more peace of mind driving the car.    I will also be able to drive the car without giving the driver behind me a foul smelling surprise.    I’m looking forward to driving the car again.

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