Thanks for taking the time to post this - it was very helpful!

I just did the repair and I think I can add a couple of things.

I purchased the whistle to locate Top Dead Center, but I found that the marks on the flywheel worked fine - the crank didn't want to move even with 100psi in a cylinder.

I found that when I pressed down on the spring retainer with the valve spring compressor it opened the valve and let all of the air out. Placing a piece of wood on top of the valve and giving it a quick rap with a hammer loosened the collet up enough the allow the retainer to move independently of the valve.

Make sure to inspect the cam, lobes and rockers for wear. Although my engine was not showing symptoms of any damage, I found that three of the cam lobes and their rockers were worn down. MB improved the cam and rockers in 1989 so it would seem that pre-'89 103 engines are most at risk.

Bob Kopicki

With the cylinder head removed what do I do different?
Thanks,
Cliff