Noticed in the mornings or anytime she has been sitting for a bit and I go to drive there is a fast paced knocking type sound that seems to come from the right side of the engine bay. At idle and revving I don't hear anything and it seems to pretty much go away after driving a while. I am not sure if it is the engine or possibly something rattling? I couldn't hear anything when I popped the hood and stuck my ear in the bay @ idle. Just an odd bumping/knocking sound that picks up decibels with the amount of gas I give it.. (could be coincidence?). Any ideas before I take it to the shop?

 

If it does it when its cold, it sounds like piston slap. As your car gets up to temp, the pistons expand and that could be why you don't hear it after the car is warm.

My only concern is that I don't think the LT1 is known for piston slap. Now the LS1 is another story.

Unfortunately could be a rod knock as well. Just a few things to think about.

Dan

 

Is this a stock car? Sometimes in the case of worn out motor mounts, you can develop some clearance issues where things start to contact each other. Hopefully that is the case and not something internal such as a bad bearing.

 

piston slap is fairly common on LT1's also. mine does it when its below 40 degrees

 

Yeah the car is stock other than a couple bolt-ons. This morning it was fairly chili outside and was audible. However on my lunch break it was nice and hot out.. Didn't hear it for more than 30 seconds. Once I got to the exit of my office driveway it was gone. Car runs good and strong. So is there much I can do about piston slap? It had a recent rebuilt with new crank and all.

 

piston slap or a lifter is bleading down when it sits for awhile and pumps up when ran

 

Either one am I looking at any serious issues? Just keep an eye/ear on it?

 

If it goes away after about 5min of driving, its most likely piston slap. Many, many engines have piston slap (even brand new ones, especially in the cold). As said above, the piston with expand as it warms up and the "knocking" will disipear. Just got easy on it till it warms up a bit.

 

could even be something as simple as an exhaust leak - metal expands as car warms up, and seals the gasket. cools down and contracts, and voila, the exhaust leak is back.

 

I would get that checked out fast. I had the exact same thing on my camaro and a day later just driving it through town it got worst and then the rod broek by the timei got it back to my house...

 

I think I will put her in the air and check for exhaust leaks in the morning on saturday. For piston slap I was actually told the same thing by a guy I met at a gas station today Ironically. Either way she drives great. as for Caves60 sorry to hear that.