Mysterious Knock...help Diagnose!
 

Okay, I got the 331 up and running and it was quiet for a minute or two, then all of the sudden there was a loud knocking that was rather fast pased. I shut the engine down, let it sit for a minute and then fired it up again. When I did, it knocked as soon as it fired up, then it stoped. WTF! Anyways, I have no clue what this is. I have 185 AFR heads with Trick Flow 1.7 roller rockers and the stock valve covers, but I had already cut out the oil baffle b/c I ran stock valve covers with my old Crane 1.7 roller rockers and they cleared fine. Anyways, I then took my valve covers off to run the engine without them to see if they were knocking. They knocked for a second again as soon as the engine fired, then it was quiet again. The knocking comes and goes. There is play in all of the roller rockers when the valvesprings are not compressed. Should there be this play? I can wiggle them back and forth. They are stud mount roller rockers. I hope someone can help me diagnose this. Josh

How's your oil pressure?

My oil pressure is about 50 or 55lbs of pressure. It's fine. josh

You mentioned that it was "fast-paced". Keep in mind that the crank spins twice as fast as the cam, so if it seemed faster than a normal valvetrain noise, it may be in the bottom end. Try pulling the dipstick out, and see if it has any marks on it. Other than that, you need to isolate where the noise is coming from, or at least top end versus bottom end.

Take care,
-Chris