F7R Piston tech data

[dunlop]

I'm after ideally a drawing of a f7r piston, showing crown height in relation to the gudgeon pin.

[MAXIBOY]

i could measure one..there 5mm higher than an F7R item iirc

[dunlop]

I've heard on the grape vine that if i get f7r pistons and have the edge of the crown machined it's able to be fitted into a f4r and gives raised compression around 12:1

[MAXIBOY]

not sure on this mate..will pm stan and ask him though..

he will either know or have bits about to compare...

[stan]

There is 0.5mm difference in compression height with the wossner forged psitons, so i'd confidently say it will be the same with OE ones.

[dunlop]

f7r items ok to run at a 7500rpm limit?

[number1]

I thought the F4r items could be used in an f7r to gain compression and not the other way around?

[dunlop]

as posted above the pin height on a 7r piston is 0.5mm higher than a 4r item, so this means that if you machine the outer of the crown down it'll have a raised centre meaning higher comp ratio. or lower if you fit 4r in a 7r block.