[Strick]

A buddy of mine is trying to diagnose a top end knock. It started after a high RPM freeway run. He 'says' he never spun past 5500, but he has no rev limiter and was shifting the car with a column shifter :noway:

The motor is a 350 - 488/510 lift cam, Edel RPM heads, roller rockers, and timing gears. He said after the valves were set again after the high RPM run it quieted it down at idle. He sent me a sound/video clip and at aroung 2500 rpm or so it has a knock (not a tick or clatter - a knock) and it is definitely on the top of the motor. I initially told him to check the push rods - glass roll them, and check the valve springs.

Is there anything else, other than a lifter (hydraulic) that any of you can think of?

Thanks in advance for any thoughts.

 

[BlackoutSteve]

If no pushrods are bent, then it's possible for a lobe to be going on the cam perhaps.
If so, wait for the knock to reappear after the adjustment.
Cut open the oil filter and look for clues.

 

[fatblock]

At 2500 rpm and a top end Knock..I would suspect a cracked piston skirt.Drive the car part throttle and lightly accelerate.The bad piston will rattle in its bore like a cold diesel engine.A stethoscope around the upper block may help isolate the noisy cylinder.