I took the head off the engine today to have some work done on it and also to figure out if the block had been bored before so I cleaned the carbon off one of the pistons to unearth the below... is this 60 thou over?? if so what does that make the capacity... 1330?

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Jenk.

yes

yes

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The bitterness of poor quality (or Crappy Workmanship) remains LONG AFTER the Sweet Taste of Low Price is forgotten.

The piston is a Hepolite Cooper S piston.

9.75:1 compression ratio on a standard bore.

2 compression rings and one oil ring.

A good quality UK made piston.

Hope this helps.

thanks but now I'm confused if its a standard bore why does it have +60 on it? so you're saying its 1275?

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Jenk.

All compression ratios are worked out on a standard bore.

1275 bore is 2.780".

Standard size 21253 pistons = 9.75:1

+060" = 1327cc.

With no head work,etc comp ratio wld be about 11:1 .

You would need see see what head volume you have (std is 21.4cc) plus deck height and bowl size.

Awesome thanks.

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Jenk.

I have the same pistons in my car and I have just cleaned up the head and cc'd it.
My head has only had a mild skim and the chambers measured around 20cc.
A 40 thou head gasket gave me 11.5 to 1 CR and with a 60 thou head gasket I got 11 to 1 CR.

I use this calculator
http://www.gtsparkplugs.com/CompRatioCalc.html

Thanks gtogreen.... that's a handy calculator.

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Jenk.