400 build
Laughing Gas
Joined: Aug 2010
Posts: 896
Likes: 55
From: Bothell
The deck height of Tims pistons is listed to be 0 and he says they have a 13.3cc dish. Stock heads are about 76cc for the chambers...
Milling the head .005 nets a 1cc reduction in chamber volume... That said, it is suggested that for every .01 you take off the heads you should take .01 off the intake (intake to head surface) and .0143 off the intake end surfaces.
Tim's pistons give about a 9.4:1 ratio with stock heads
I'm going to throw out a max of .050 for decking the heads, some say the max is more and some say it is less.
.050 off the heads will give you 67cc chambers and that will give you 10.28:1
10.28:1 with these open chamber heads puts you well out of 92 octane.
With the cost of machining the intake and heads added to the cost to rebuild the heads I would think you would be better off buying some new heads with small quench chambers. It is possible to run 10:1 and more with aluminum quench chamber heads.
Milling the head .005 nets a 1cc reduction in chamber volume... That said, it is suggested that for every .01 you take off the heads you should take .01 off the intake (intake to head surface) and .0143 off the intake end surfaces.
Tim's pistons give about a 9.4:1 ratio with stock heads
I'm going to throw out a max of .050 for decking the heads, some say the max is more and some say it is less.
.050 off the heads will give you 67cc chambers and that will give you 10.28:1
10.28:1 with these open chamber heads puts you well out of 92 octane.
With the cost of machining the intake and heads added to the cost to rebuild the heads I would think you would be better off buying some new heads with small quench chambers. It is possible to run 10:1 and more with aluminum quench chamber heads.
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