Hi,
helping a friend to get some advise here as he is having noise on cylinder 1 (seems like piston slab) but when the engine fully warmed up, the noise goes away.

Secondly, whenever he revs his ride pass 6,500rpm he will get some black tiny oily dots around his rear bumper.

Is it time for a rebuilt?

No sign of any white smoke.

Thanks

 

Yeah sounds like piston slap. And depending on who tuned the car that black **** is just the car running rich. Its carbon deposites. Does the car throw black smoke at high rpms? Its not something I would worry about thats pretty normal.

 

oil on bumper is a bad sign. sounds like you have a bad cylinder. do a compression check yet?

 

+1 on a compression test. Run one cold and compare cylinders. Then run one hot and compare cylinders.

 

Thank you Guys for the advise and will do a leak down test asap...