Hello, i am building my new abf engine and i wonder if would worth skimming head for raising CR, if it would how much do you think will be ok? On my old engine i skimmed bottom engine 6 tenths (for having 1 mm of squish), but at the end i had problems with engine and knocking. BR.
Difficult to answer this....so many variables. With std cams there is no real benefit of raising cr (except from factory it might not be quite the cr quoted due to tolerances) and can indeed cause issues with knock etc The main benefit of a skim is a flat machined surface for the gasket to seal to. If you are going high lift cams then the cr and squish needs to be calculated correctly to work best for the cams and may involve a skim from the head and the block. Ideally you need to cc the combustion chambers and the top of pistons to get it right.
