Ring and Piston Clearance

[cobra428]

Hi Guys,
Need a little help here. Coles plans calls for a 7/8 ID of the ring and a 7/8 OD of the piston groove. Well that will give me interference if I'm not dead on. The ID of the ring when placed in the cylinder is .912 the OD of my piston grove is .905. I have a tremendous amount of binding (bought new rings from Coles).

What should the clearace be between Piston Ring groove OD and Ring ID be? The original rings wore out prematurely, I think (I have .002 on the end play and .005 on the gap). :shrug:

Help
Tony

 

[Maryak]

Tony,

Attached is a Excel file based on Professor Chaddock, Tubal Cain and Paul Chernikeef which may help. It calculates the ring blank sizes for cold formed rings.

Hope it helps.

Best Regards
Bob

View attachment Pistoncalc.xls

 

[cobra428]

Bob,
Luv ya Mate
Tony