The engine has roughly 6000miles on it. I started it up the other day and let it warm. I let it idle its way out of the garage to where I parked it. After letting it run a few minutes, I reved it to 2000rpms to kick the idle down. It ran smooth for a few seconds and then it happened. I heard a quick knock, then another, and it slowly became a constant knock. The car also started to run alittle rougher. I still have close to 80psi of oil pressure. And with the valve covers off I am unable to see anything unusual. All the valves seem to be opening and closing. We think that the noise is coming from the valve train. Its a brand new crank and rods bearings, everything. There are new cam bearings in the engine but the cam was installed a few miles before the rebuild and the lifters from that cam were reinstalled as well. I am hoping it is not a rod bearing. The knock doesn't seem to be hollow enough to be a rod. Could it possibly be something with the cam? I think it could be as the car started to run differently when the knocking occoured. I am just looking for some opinions. Its a 1980 corvette 2bolt main block. All the specs are in my profile below this post. I would appreciate any ideas and opinions. I plan on giving the car a new cam,lifters, carb, and heads in the spring. I hope the bottom end is ok. I could understand if I was running the snot out of the car when this happened, but it seems strange it happened at idle. Thanks :confused:

 

Might want to drop the oil pan and start pulling rod and main caps, knocking noices are not good, I know from experience. :(

 

Before you pull anything apart, check the bolts on the torque convertor. When they are loose it will have a sound just like a rod knock.

 

:iagree: with Pete.

I had a broken or should I say cracked flex plate and I thought that the whole motor was coming apart. I actually was starting to pull the motor when i got underneath to unbolt the TQ converter when I saw the problem.

If you us a automotive stethascope you can pinpoint where it's from.

 

I would drop the oil pan for a look see. It's not that bad of a job, just un-bolt the idler arm from the frame to drop the steering linkage out of the way and it will clear everything. Running the engine can cause more damage, especially if a rod broke or let go. I hope everything works out for you, sometimes things just let go because of a little defect you just can't see.

 

Is it a knocking sound or closer to a ticking sound?

 

If it's adjustable lifters check all the rocker adjustments. I heard a big block that sounded EXACTLY like rod knock, but it was just a lifter out of adjustment.

Dep