I recently pulled the head off the right side of a 302 engine to replace broken rings on the 8th cylinder. Because of the loss of compression in the 8th cylinder, there is a lot of black buildup on the top of the piston (which, makes sense).

However, the other three cylinders have a fair amount of black buildup on them as well. What is this buildup, what causes it, and how can I clean it off?

Thanks,
Robert

 

Its normal carbon buildup. I don't recommend this but some people actually spray a little water down their intake to clean the piston tops but the engine must be running fairly high in the rpm just to be on the safe side and use very little water. If the heads are off then clean them with anything just be careful you may get gunk on the rings and cause more problem than you care to have. How does someone know the water works well if you have ever seen a piston that had heads cracked they are almost spottles from the coolant/water hitting them during combustion and the rest of the pistons will be dirty, so it will work, good luck

 

drive fast every now and then to blow the carbon loose

 

LOL

Nice!!