hey whats up, if you have oil and coolant on or anywhere in you piston chamber you need a new head gasket. also check you intake manifold gasket to see if it is cracked. mine was and coolant leaked in through my valves and on to my piston heads. i work for the usaf and the only thing that touches my engine in or out of it is alittle something called aeroclean. if you use it on your pistons make sure you get all the aeroclean off before installing and ops checking it. it will take the sludge dirt grease or anything else you have on your engine completely off. with a simple rag or if you want to be really clean get space rags. there very very light and smooth rags that wont leave little imperfections on your cylinder wall that you cant see with you bare eye but your car can when you rev it up for a big drift or what have you. let me know if any of this helps