ok here is the deal. I pulled the head off my friends motor to replace the gasket and the pistons were black as hell and even had ash on them. What to do about that. Is the motor even good?

 

Excess carbon = running rich

 

so what do I do. Can I just go in there and take rag to it and clean it up or is th motor still ok. I am thinking about buying it from him and then adding some boost. what is you guys opinion. thanks

 

you can clean the piston tops, but that still means the motor is running rich for some reason. is it a stock motor?

 

You could possibly correct the problem with a fuel pressure regulator, and FP gauge. But that still does not explain why it is running rich.

 

yea stock motor... I wil give it a try

 

u can leave the carbon build up which is comon for old motors and it will slightly up ur compression a lil bit nothin to worry about

 

motors not bad, if its running rich check the timing u might have to up it a couple of degrees.

 

This buildup on the pistons is normal after a good number of miles. Use some degreaser to clean it up and its fine.

 

put it back together and go to a dealership and buy some engine top cleaner... you put it in through a engine vac source and it will clean the **** out of it... but you DO need to clean it... carbon gets hot and creats hot spots that WILL cause detonation

 

JMO ZC + Boost = The build up is fairly common, just clean it off and slap it back together.

 

teh carbon also fills in gaps in the piston rings from old age and such which holds compression cleaning it with seafoam or whatever may cause a drop in compression

 

If I am going to boost it the n would I want lower compression or should I just leave the way it is. I also have fpr already ordered.

 

The rods in the ZC aren't capable of holding together much over 200 hp, and the rod bearings seem to go very easily on boosted motors. If you want to boost on a ZC and have it remain reliable, I would consider rebuilding the bottom end with stronger parts.