I have the JDM 4AGE 16V in my AE86. If you take the oil cap off and look in you will see nothing but black shit every where. The spark plugs seem to foul really quick and the exhuast blows black shit out (see photo below) I don't know how many km's the engine has done. If i rebuilt the top (valve's, cams etc.) would it run better or am I better off changing the pistons aswell? Any ideas?
