E: Engine Nip up Comet

[Tony Wilkinson]

I had GPM in my Egli when it was !000. There was an article by Neville Higgins in MPH many years ago explaining that they are good pistons but as Bill says they are round. You need to relieve the skirts at the four points close to the cylinder studs with a fine file and they will be fine. Mine did many thousand miles without a problem.
Cheers Bill

I have now done that, thanks Bill.

 

[vibrac]

Your piston is a GPM. SCRAP. GPM pistons are round. The fore/aft dimension should be at least 10 thou bigger the port/starboard dimension. GPM's are noted for seizures.
Robin.

Thats what Robert aluded to in post #30. GPM?(Good Piston Maker or Got Pis*d machining) Its new name to me