Engine 302 rebuild Piston Ring gap

88foxy

New Member
Oct 6, 2020
4
0
1
29
St. Louis
Rebuilding the 302. First on my own build and ust got the block back from the shop. .020 over bore.

Got the cam and crank installed last night with new bearings. Went to move onto the pistons today. Assembly was balanced at the shop. Running stock crank, rods w/ ARP studs, Summit Racing SUM-17370FC-20 - Summit Racing® Coated Forged Pistons, Sealed Power E-251K20 - Sealed Power Performance Piston Rings.

Was checking ring gap today. Seems like it’s all over the place and this is what I got. (Double checked)

#1. Top - .021, Bottom - .018
#2 Top - .020, Bottom - .017
#3 Top - .020, Bottom - .017
#4 Top - .021, Bottom - .017
#5 Top - .023, Bottom - .019
#6 Top - .023, Bottom - .020
#7 Top - .023, Bottom - .018
#8 Top - .024, Bottom - .020

This is a street build. Plan on eventually running boost down the road as well. Rings did not come with a reference sheet. I’ve read .004 per 1” of bore is ideal. For boost, I’ve read .005-.0055 per “1 of bore. Also I’ve read the bottom ring should be .002-.004 bigger than top ring.

My question is, did I get a bad set of rings? Bad bore job? Should I file? Swap rings around into different cylinders? Buy a different set of rings and try again?

Just want to make sure I’m getting this correct and to have a healthy motor. Thanks in advance!
 
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