80 Valve Clatter

[EMS]

Pulling the cylinder head will only allow you to easily replace the small cam chain. And you wouldn't even have to pull the head for this. Whether it needs replacement can easily be determined by following the procedure for installation and proper alignment of gears and cams. If the two chain gears don't align properly, the chain needs replacement because it is stretched. If they do align, save yourself the money, especially because you will not be able to replace the long chain driving the exhaust cam.
I would definitely check the valve seats and at least relap the valves before reinstallation. A recut of the seats maybe necessary.

[twinegar]

OK, thanks.

[alimey4u2]

In the light of day I was wondering if the Oldham couplers would be an issue . Seems to be a load related problem however....

Any thoughts... ?

[EMS]

In the light of day I was wondering if the Oldham couplers would be an issue . ... ?

I was thinking of that too...

[twinegar]

The couplers would be bound tightly under a load but the couplers could be what makes noise at idle. I did a rebuild of the alternator assembly to eliminate the noise to no avail and it isn't valve shims so maybe the couplers?

[alimey4u2]

Oldhams couplers.... Load sensitive ?? Possible...Maybe at a resonant frequency that may comply with loading but then It's all subjective....

[EMS]

Due to the changing load the cam lobes put on the drive, the cam rotation is not steady. It fluctuates, even under load. In addition, the engine rotation receives three acceleration impulses per revolution which results in an "un-uniform" angle speed of the crank and thus the cam drive. I know it sounds all like "hair-brained" theory, but I went through this at work while trying to find failure reasons for engine driven components due to miniscule speed fluctuation.

[alimey4u2]

Makes perfect sense Mike...