Building Motor some questions....

[George Roffe]

Jon Pennington wrote:

>I don't think this will work.  Seems to me that the combustion chamber
>shape is too different between VG and SR heads.

The shape is not the issue.  Valve timing/lift/overlap is.

>No, you'll need the 11:1 program with *flat-topped* VG30DE pistons; the
>11:1 program was written expressly for the VG pistons.  You'll be much
>closer to 12:1 if you had domes on the pistons.  You *may* get away with a
>10:1 program with the VG pistons, but I wouldn't suggest it.

The pistons with the domes removed will yield 10:1 CR without
welding/reshaping the combustion chamber.  With the domes intact, the CR is
11:1.

If the combustion chamber is welded up and reshaped and cc'd to the correct
size (don't remember off the top of my head - 43cc comes to mind) then add
1 point to the CR in all cases.

George Roffe
Houston, TX  USA
http://www.nissport.com