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Old 07-24-2010, 08:30 PM   #8
Farmallgray

Name: Farmallgray
Title: Diesel Enthusiast
Status: Not Here
Join Date: Nov 2009
Location: Spring Mills, Pa
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Posts: 110
Quote:
Originally Posted by paulb View Post
Bore is 4.02. Standard honing diameter is 4.0165 +- .0008. These specs are from the 05 Dodge FSM. Top ring end gap, .010 - .014, second ring .033 - .045.

For high performance applications these are considered to tight. .007 - .009 is more generally excepted, but with coated pistons (sides AND tops), I go with .005 - .006. The coated tops helps keep the piston expansion down, and the coated skirts help reduce scuffing.

I use .023 for the top ring end gap. The second I leave at the factory end gap. The cummins top rings out of the box seem to be around .012.

These are spec and values based on a 05 CR.

Hope this helps.
Paul
So these figures are what you use for a 4.02" bore, correct? So I should calculate a percentage of those for mine, right? My bore is right around 3" so if I multiply those figures by .75 then it should be eqivilant for my application.
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