Rather than hijack this thread completely "Need Automotive Grade Prozac = timing chain" I will start another.

Engine is a 603.970setting in a '91 350SDL. 283,000 on a broken odometer so who knows what it really has. Pervious owner had some head work done on it. I was told it picked up a gasket leak and was repaired.

Cruising at 60 mph it picked up an engine tick or knock. Coming from the top end. What I have done so far is flush the injectors, no joy. Broke each fuel line loose, no joy. Pulled the injectors and had them pop-off tested. Some joy, they are good. However, not the problem.

Valve cover is off. Engine is very clean inside. Turning the engine with the starter and the injectors out I do not get any ticks. When I bring each cam lobe up to the root diameter I can not push any down using finger pressure. Each one turns freely in the boring and all come up to the same height.

Oil and filter has been changed and a quart of Lucas oil stabilizer added.

I checked for timing chain stretch. With the engine at TDC the cam alignment marks are dead on. The tensioner, which I suspected, pumped up and there is no preciveable slack.

I really hate to pull the cam to test the lifters. Anyone have any other ideas?

Thanks