Hi guys, I just learnt after pulling my motor down that ring gap is Top .020 2nd .030.
from everything I read this sound to big for bore size of 4.280.
Is this correct? To big?
Motor is all standard approximately 380hp
Buy new set and start again?
Cheers

If you bought a standard set if rings that's where they usually end up. Especially if it was just honed and being put back together. To get tighter end gaps you'll need to buy "file fit" rings and size each one to the bore with a ring filer. I highly recommend Total Seal gapless top ring sets. They really do increase HP.

If my information is correct the Mercruiser spec is .010-.030 on both top and second. Personally if it has been running good that way and does not have blowby I would leave it alone. I would rather have it slightly on the loose side than take a chance on rings butting. Why did you pull it apart ?

Hi BillK
Thanks for the feedback...
Wanna change cam, have done all cam and mains, big end bearings etc... Also re-doing my EFI with after market Holley EFI.

Thanks Smitty, i did file em, approx 4 years ago. But i had info for .020 and .030 and since then i have read alot of other settings.
Last i read was .004 top / .005 2nd per inch of bore and im 4.280
So i figured .017 top and .021 2nd was where i should be... Im at .020 top and .030 2nd!!!!!
Cheers

Don't fix what's not broken...

Probably not really worth tearing down for that minor difference. Especially if you hang it out on the top end for extended periods.