not quite sure which forum this should be in, so i chose this one since it has the most posts (well, almost).

if i were to buy a b20 block with a cracked sleeve, and i wanted to bore it and resleeve it, how much could i open it up? i guess i'm sort of looking for a larger bore than 84.5mm, since i would be resleeving it. do you all think if the cracked sleeves were removed and replaced, i could go with like an 86 or even 87mm bore??? if not what is the biggest possible that would still be reliable. i def don't want trouble with weak walls when i do this.

also, if an 87mm bore was possible, where the hell would i get pistons that size? and what rods and rings would work with that? and how much would an 86 or 87mm set of forged pistons (say between 11-12:1 CR) cost? or whatabout a set of forged pistons with a CR of between 9 or 10:1 cost?

need some help. thanks.

 

85mm would be the biggest/safest route. you can "maybe" get away with 86mm bores but i dont know if there is enough space between the chambers on the head for a proper headgasket seal.

87mm would be for race only........im sure it has been done but it probably wont be very reliable.

either way you choose the pistons would have to be custom........

how about a set of custom 85.5mm pistons? hehehe.......contact JE or weisco for those.

good luck

 

thanks. an 85mm bore would be really cool.

anyone else have any opinions?