4 replies to this topic

[Brams96]

I am thinking of getting some +30 thou pistons and was wondering what peoples opinions of them are as they are not the standard +20, +40 or +60 overbores. Am I right in thinking that they give a 1303cc engine? What compression ratio would they be for a 1275GT block overbored +30 thou, would it give an 8.8:1?

Any opinions or comments would be greatly appreciated:-)

[Asphalt]

If you find a source for high compression +30 pistons and rings - let me know!

Increasing the bore does not neccesarily mean a reduction in compression.
It depends on the shape of the piston (dished, flat, deep dished etc.).

+.30 once was a common overbore size, nowadays it's only +.20, 40 & 60 left.
Don't know why...

Yes, thy give something about 1300cc, +/- 2-3 (that's why I'd love to have some )

[Brams96]

Minspares do these rings, HERE, but they are only 8.8:1 compression.

[Asphalt]

I read:

This item is no longer available. See below for any alternative items.

[Brams96]

Ooh yeah, I missed that bit. Not sure if I should get them now