Hi,
ok so baisicaly if I skim a head for the first time how much will it effect my cr?i am after roughly 8.5:1 or 9:1 cr and was thinking of running accrilites but if I fit a metal head gasket and have the head skimmed (wich needs doing any way) would I still get roughly the 9:1 iam after using wossners as the gasket and head skimming will probably add to the cr, my fear is that if I fit accrilites have my head skimmed and fit a metalhead gasket and the cr will be alot higher than I wanted,or is a metal head gasket not important?
Thanks again Antony
All depends on how much the head needs skimming but obviously there is a limit to this. My set up was giving me a total clearance volume is of 39.9cc to give a CR of 9.4:1. That was with a metal head gasket, accralites and a BVH that had been skimmed at least once how ever im not sure exatly how much was removed! From what i have heard the standard HG will put up with alot however the metal one will be stronger!
What sorta boost do you run on that and do you have any det problems as I want to run around 20psi.I suppose what would be best for me is either just use a standard head gasket or to try and find some forged psitons wich are give me a cr of 8.5:1 I heard you can get je ones is this correct?I want to ensure I don't have a det prone engine but I also want more off boost reliability. Thanks for your reply though at least I got a rough guestimate of what the cr will be!
I'm running accrilite pistons, BVH and metal headgasket with 19psi and my head has been skimmed at least once probably twice and I have no problems with det
I'm currently running 0.0psi of boost and its been that way for a long time :D I'm still building the damn thing (over 2 years now) - only ever intended to swap the engine, brakes and suspension over ::)
Considering the chamber is in the pistons not the head on G40's you'll only really get any increase in compression if you skim it down enough to make the valves protrude from the head, which isn't the best idea.