So here it is, I have been asked to post a vid of the noise. It's not really a vid, as it was made in my garage at night, but you can hear the audio, which is the just of the discussion anyhow.


http://www.youtube.com/watch?v=3wQosz_05PA

Your opinions please.

I have been told these engines have a history of having piston slap. These are my details.

Noise is worse when cold, on cold start you can clearly hear the noise as you drive for about 30 secs or so, it speeds up with the RPM and is very audiable.

Noise gets less as the engine heats. finally settles to the level heard in the video. It's a little louder in the vid than in person, but not much. You can clearly hear it when beside cars in traffic with the radio and such turned off. Beside a building, ect.

Noise lessens/goes away when I unplug #1 injector. no other injector seems to have an effect.

Probing around the engine with a listening device you can hear the noise on both exhaust manifolds, EGR valve and is most noticeable on the oil pan directly behind and below the balancer on the front of the engine. It is very clear in that area.

Oil pressure is rock steady @ 70-80 PSI hot at 3k RPM. about 40 PSI hot idle.

My thoughts. I say rod bearing. but the louder when cold doesn't make sense then. I have tried thickening up the oil with some Lucas to dull the noise and attempt to pinpoint it, but it didn't make a difference.

The car has been raced full bore about 30 or so times with this noise, hasn't got better or worse. I just bought the car and noticed the noise after i fixed the exhaust and an engine vacuum leak.

any ideas? I don't want to get into a teardown, but it's looking more and more so.

 

video didn't work for me...

 

DoH! try it now.

 

please repost with this out of your garage i am sure you hear it fine but it is hard to distinguish. i think i hear a ping that starts and stops at times but i dont know

 

i mean the noise is not the clearest and is loud with all the noise reflecting off your garage inside.

 

will do, i'll get a new vid up tomorrow, it is kinda hard to distinguish but once you pick up on it it's there.

 

My ls1 makes the same noise just like yours its more noticable at start up and alot less when warmed up. Ive heard its common with these cars.

 

my initial thought was rod knock, and unplugging the injector would eliminate the combustion process from that cylinder, removing the load on the that rod/piston/bearing. So it sort of make sense, minus the oil pressure.

Pull a valve cover and run your finger through the oil, see if any powder/metallic stuff comes up on your finger.


Could be piston slap but it seems pretty excessive.

 

allright, here's the new vid.

http://www.youtube.com/watch?v=KNF_QRQ12Ck

 

i'm gonna be honest man my car has done that since i bought it and it has not gotten any worse in over 2 years. i know it sounds like **** but that's just what these engines do in stock form. my friends grandma has an 02 vette and it makes the same noise, just not quite so pronounced. this is a grandma driven vette that gets dealership service regularly, and has low miles.

fwiw, i have heard of cars under warranty go in for this noise, get new internals, and the noise only gets slightly better, so consider that before you go tearing it down.

 

Phew! thanks for the support. I'm new to the LS1 world, just got this one, owned a Mustang prior. Guess i'll go ahead and race her Friday! Gutted the cats and ordered the HP Tuner Suite, going for mid to low 13's.