tribaltalon

my car has a knocking sound that occurs occasionally at idle. it doesnt do it constantly, just whenever it hits the right pattern in the cam lope, if that makes sense. the oil pressure gauge also fluctuates a bit during the noise, going down to around 20-25 then back up to 30-35. everybody says its piston slap, but it doesnt go away when hot. it always does it. also, i changed the oil recently and there was quite a bit of metal shavings on the drain plug. car does not smoke or run abnormal other then the knocking sound at idle.

CroonerSS

iTrader: (3)

Do you have a video clip? Sounds like what your describing is piston slap.

slt200mph

iTrader: (42)

Piston slap will only last for about a minute ... once the engine warms up a little it goes away.

tribaltalon

yeah this sound doesnt go away. but it only happens at a certain point in the cam lope pattern.. and it vibrates when its knocking, and the oil pressure drops a little.. then it goes back to loping. doesnt knock at all when i get on the throttle. i cant figure it out. everybody thats heard it has said its piston slap, but everything ive read has said slap goes away when it warms up, and this doesnt go away. from the back of the car it almost sounds like a popping sound coming out of the exhaust when it does the knocking.

2001ws6-500hp

spun bearing. does your motor have stock pistons? mine did the same thing, once the bearing spun it got enough play in it to hit the valve. but it would only do it at a certain rpm

tribaltalon

yeah motor is stock.. 81k miles. i sure hope its not a spun bearing, cant afford a rebuild for quite some time.

99RTA

iTrader: (-1)

When you changed the oil did it have a silvery look to it? When a bearing starts to fail it will color the oil making it look like it has silver in it.