Cooper S 1275 engine

[rolesyboy]

Anybody know what cc a plus 30 piston will give? I reckon 1303cc but have never come across a plus 30 piston until today and thought they all went in increments of 20 thou till you hit the 73.5mm.

[Frogeye61]

They used to come .010, .020, .030, .040, then someone thought of doing .060, then they decided the odd numbers weren't selling so much so they discontinued them.
I believe it should be around 1301cc

[rolesyboy]

Brill, I feel relieved. The engine was built in the very early 1970's and hasnt turned since so that would explain matters. Cheers.

[Simon776]

+30 was a pretty common size.

[66S]

.030" pistons are still available, I fitted a set in my S. I can't remember the make but they were English and fresh. I could find out of someone really wanted to know.

Al

[rolesyboy]

Yes please. Not for me but a friend has also just found he has a plus 30 block and a set of shagged pistons. Cheers. Mark

[Frogeye61]

.030" pistons are still available, I fitted a set in my S. I can't remember the make but they were English and fresh. I could find out of someone really wanted to know.

Al

What was the dish on those?, If you can remember

[66S]

My supplier tells me he is pretty sure they came from Minispares but he is not sure of the bowl size. He says Omego also make .030" pistons too.

Hope that helps.

Al

[rolesyboy]

Thanks Al