weird knock ??
10-27-2010, 09:25 AM
#1
weird knock ?? Car is a rebuilt stock 6.0L LQ4, LS6 cam, vic jr, turbo, ... guestimate 700ish whp.
When its cold it starts up and is smooth and quiet. I can go make a couple hard passes (25 degrees timing, E85, 15psi boost) The car runs AMAZING!
once it is warm it sound like a rod knocking. You have to give it a little gas to hear it, slowly give it gas and the knock comes on about 2000rpms. And I can make a 1/4 mile pass and it still is quiet untill ive driven it around and its got nice and warm.
It is not a rocker, I know the sound and the rpm that its traveling it is not valvetrain related... seems consistant w/ the crank, not 1/4 the speed like valvetrain.
Car can sit over night.... and is quiet again the next day.
I put some serious abuse to it and it doesnt get worse, and is always quiet when its cold.
I plan on pulling it all apart within the next couple weeks... and I dont currently drive it. Just curious if anyone has an opinion.... as it seems weird to me.
If it were a rod im sure it would have spilled its guts. And it wouldnt get quiet again. Pistons heat up and expand, so extensive piston slap would happen more when cold then hot... right?
I know its hard to diagnose a prob like this. Ive spun rod bearings, blown pistons, thrust bearings, trashed cams... this is just odd.
When its cold it starts up and is smooth and quiet. I can go make a couple hard passes (25 degrees timing, E85, 15psi boost) The car runs AMAZING!
once it is warm it sound like a rod knocking. You have to give it a little gas to hear it, slowly give it gas and the knock comes on about 2000rpms. And I can make a 1/4 mile pass and it still is quiet untill ive driven it around and its got nice and warm.
It is not a rocker, I know the sound and the rpm that its traveling it is not valvetrain related... seems consistant w/ the crank, not 1/4 the speed like valvetrain.
Car can sit over night.... and is quiet again the next day.
I put some serious abuse to it and it doesnt get worse, and is always quiet when its cold.
I plan on pulling it all apart within the next couple weeks... and I dont currently drive it. Just curious if anyone has an opinion.... as it seems weird to me.
If it were a rod im sure it would have spilled its guts. And it wouldnt get quiet again. Pistons heat up and expand, so extensive piston slap would happen more when cold then hot... right?
I know its hard to diagnose a prob like this. Ive spun rod bearings, blown pistons, thrust bearings, trashed cams... this is just odd.
