Well, I believe I have found the cause of the noise. If not, the engine needs to be removed and serviced by a machine shop anyways.

Take a look at the following pictures of the camshaft bearings. #4 cam bearing seems to be the worst. Excessive wear is present to the top and bottom of the bearings. The bottom is worn worse then the top.

This is the second time this has occurred with this engine block. The first time I found it early on during a camshaft swap, no noise was present at that time. About 1000 miles on the engine at that time. Current mileage since camshaft swap about 4,000 miles.



Note: This engine was lined bored after installation of Pro-gram billet main caps. For three seasons after that no camshaft bearing wear like this was present. The engine was then disassembled to install different pistons for a different engine combo. At that time the machine shop replaced the camshaft beatings with Clevite 77 bearings AND installed a new Cloyes timing chain (which is still in the engine), the new Clevite 77 bearings wore excessively within 1,000 miles but no noise was present. Then the KING camshaft bearings were installed by another machine shop. The King bearings last 4,000 miles and are the bearings that are currently still in the engine.

Note: The camshaft currently in the engine was the one used for 3 seasons without any camshaft bearing failure. So the current camshaft was swapped back in after the first set of cam bearings failured with another camshaft.

Has anyone seen accelerated camshaft bearing wear like this before?

Could the timing chain be too tight? I would think that the #1 cam bearing would be worn worst and its not, its #4 again.

I would think if the line bore was an issue I would have seen it within the first 3 seasons.

Maybe time for engine block swap...


At one time this engine housed a few different solid roller camshafts. The bearings never wore like this but the COMP cams 829-16 lifters failed continuously and I swapped back to a Hydraulic flat tappet.