srx barrel rebore minimum / recommended clearance

[Steve Lake]

all was going well, took barrel + 50thou oversize piston to the engineers last week.

they rang me up today and asked for the factory recommended clearances.

being a race prep works (mainly 1275 S BMC A series engines & BMW JCW cooper S's) they are understandably a bit fussy about these things.

and i haven't a clue, my workshop manual doesn't help much so i'm reaching out to the club experts.....

[iansoady]

It's tricky as it depends on piston material, lubrication, block / liner material, air / water cooled etc. Can you contact the piston manufacturer? For my old clunkers, I generally use much bigger clearances than you would, eg .005" for a 79mm piston. I'd expect there to be quite a difference between A series and BMW mini engines.

My philosophy is always to err on the generous side as I'd rather put up with a bit of piston slap and oil consumption rather than risk seizure and spend hundreds of miles running in.

[Steve Lake]

pretty much my feelings Ian ....

but this afternoon whilst rummaging through copious SRX literature that i've amassed over the years i found this....

so have forwarded it to the engineer.

[iansoady]

Hard to read upside down but those are much tighter than I would use. It is a modern engine however.....