A couple of quick questions.
Turbo Mini Forums

I know there are many many topics on compression ratios, and i have searched them honestly.

looking through them i have managed to work out what i believe my CR will be but i would just like someone to double check it for me pleaseeeeeee

right:

Bore - 72.2mm (1330? 1275 + 0.060)

stroke - 81.33mm

Gasket bore - 72.2mm (now i wasnt sure with this so i just done it the same as the cylinder bore)

Compressed gasket - 1.03 (got from another post i think using the BK450 gasket)

Chambers - 30cc

Piston Dish - 7cc

deck Height - 1mm

That gave me, using an online calculator, 8.35:1 Sound right?

i have missed the rign land volume because i have not got a clue what that is on my pistons.

secondly, when you lot get your cranks balanced do you get it done just the crank or do you get them to add the flywheel etc to get the whole assembly balanced?

Cheers, James.

Edited by James_H on 18th Jun, 2008.

I used this: http://www.csgnetwork.com/compcalc.html

but i think the gasket bore is about 74 mm normally?

Anyway i got 8.311 with your measurements but using a 74 mm gasket bore

Edited by miniboo on 18th Jun, 2008.

thats the calculator i used so im on some sort of correct track at the moment.

Deck height of 1mm sounds a lot?

with standard pistons in at TDC i seemed to have a rediculous deck height, an easy 4-5mm??? EDIT: What a freakin div! i have been looking at the combustion marks on the bores and going from that, not taking into account the ringlands!!!! TIT!!!!!

its a 95 cooper spi....but i wouldnt have thought it would be any different to normal. does this sound like alot to you? its the first mini engine ive stripped down.

Cheers, James.

Edited by James_H on 19th Jun, 2008.