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Author Topic:   H345NCP ring gap
Dirt Full Roller

Total posts: 69
posted April 11, 2005 06:59 PM  
H345NCP .040
Sealed Power E-251K 40

Advertisements say standard ring gaps for these pistons.

Does this sound like enough gap>
1st 4.04 X .0045 = .018
2nd 4.04 X .0055 = .022

Stock 350 on Gas, 76cc heads, small cam, clay oval
I'm leaning towards more, but undecided as to how much.


Dirt Forum Champ
Total posts: 635
posted April 11, 2005 08:25 PM  
That should be fine. With those pistons and heads, you won't be over 9:1... maybe 9.5 if you deck the block and heads a bunch.... so it's not that big a deal.

Dirt Full Roller

Total posts: 69
posted April 13, 2005 09:16 PM  
With the way things have gone so far, I went .020/.024 just in case and then proceeded to install them on the wrong bank of pistons. Swapped rings back to the correct hole and busted one of them. Parts shed search produced a used ring. Installed pistons and couldn't turn the crank. Mic'ed what I thought was a 20/20 crank. My handy dandy harbor freight digital caliper reads 2.425 and 2.087. Not being a machinist my guess is thats .020 mains & .010 rods? I'll pick up some 010 rod bearings and see if I can hammer out a long block before this weekend.

Thanks for the feedback.

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