Gapping Piston rings

[Minicooper1964]

Hi can anyone tell me what the piston ring and oil ring gaps gap should be for a 1275 cc plus 0.030 " Cooper S . - Just want to make sure I have the correct gap

[Exminiman]

just what I am doing at the moment as well - I understood, as a rule of thumb, minimum of 3 thou per inch of bore.

So A series is apx 3 inch bore so 9 thou minimum - to be safe,especially for road engine use 4 thou, so 12 thou.

Sure there are some more experienced opinions on this as well, hopefully they will chime in...

[Minicooper1964]

Thanks for the info . I need to get a replacement oil ring ( damaged in assy ) and I guess I will have to buy a set so who is the best supplier these days f

[Exminiman]

Maybe some one will have a spare one on here ?
What rings are they ?
Dont forget you can use a bigger one and file it down....

[Spider]

I agree here with Exminiman's advice for street use in regards to the gaps, however, if it's more, up to even as much as 0.020" I wouldn't fret as leakage here is way less than what one would think. I've seen results from back to back tests where they found negligible difference from recommended gaps to as much as 2.5 times that.

Better too much than not enough.

If no one here can help out with the Oil Ring, Thorntons sell loose rings.