I'm hearing noises (sounds like tapping) from my engine. I'm wondering how loud anyones elses LS1 is. I heard that they are pretty loud sometimes depending on your engine. I know its not a exahust leak or anything. the car only has 20,000 miles and i only have put 1 bottle of nitrous through it. The noises sound like valves or piston noise. and it onts only loud when it under a load. Any thoughts? Should i be worried?

 

Knock under load is piston IMO. I have that and it's definately a piston. Replaced lifters and pushrods and it is still there. One cylinder looked as there is major piston slap going on ... I just hope there is enough room to hone most of the scores away from my 98 block, 31k miles...

 

Anyone else have an idea how i can tall? maybee a compresion test or something?