All, sorry to abandon and resurrect a post, but over that winter, the noise went away for a while due to lower temps but it has come back. To catch everyone up, I have an annoying squeaking noise relative to RPM from the engine compartment after running for 10-15 minutes, caused by heat. From my last post, I did replace crank shaft thrust washers and got the crank end float in spec at around 0.006". The noise was still present. It's worth noting the distributor shaft play is in spec and the noise is not the tach cable.
With a stethoscope, I have finally isolated the noise to within the timing chain cover. Here are my thoughts on likely causes:
1. Since the noise is affected by forward drive train pressure (clutch or braking on a hill), I suspect the most likely is the cam shaft end float is out of spec and rubbing toward the front of the cover.
2. Possibly chain or tensioner are loose.
3. It could be crank shaft end float but it was previously in spec, but I'll check again.
I plan to remove front apron, fan, pulley, and timing cover. I'll be prepared to replace crank sprocket, cam shaft sprocket, uprated timing chain, tensioner, gasket, and oil seal. If cam shaft end float is out of spec, I'll be prepared to replace front cam shaft bearing.
Can the front bearing easily be replaced or do I need to remove camshaft (including lifters, distro shaft, fuel pump) and then press it in? While I'm in there, is there anything else I need to be prepared for?