[67 Nova Boy]

A reply from Hilborn specialist.. Andrew Star on just what info is posted.

Nice car, sucky issue.

My immediate observation was that the rockers weren't laying on the valves right, possibly the push rods are too long or the angle of the picture tells a different story. But that isn't his problem nor is it his cam bearings.

He didn't mention if he had a hydraulic or solid cam. Since the lobes aren't flat and if he has a hydraulic cam then it sounds like he has a suction side issue on the oil pump. Namely a cracked pick-up or loose/incorrectly installed pick-up. When the oil is hot the crack starts to suck air allowing the air to get into the hydraulic tappets causing the lifters to bleed down and become noisy. A simple test is to get a high quality oil pressure gauge, such as one from Snap-on, and watch the needle as you rev the engine. If it vibrates back and forth wildly then it's sucking air. I've fixed numerous noisy tappets by replacing the pick-up tube. I ALWAYS tig the pickup on after installing it with the correct tool. This ensures that it will never come out or leak. Cheap insurance for such a sweet build. This also explains why the lifter swap had no effect, which is typical first repair for this issue.

Dave
67 Nova Boy