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Old 08-02-2018, 10:04 AM   #1
icdpride
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Default Proper ring gap

I am sure this is in a manual some where but I could not find it.

I am wondering what is the proper ring gap to set when replacing the piston rings on N/A pistons for a turbo application
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Old 08-02-2018, 10:24 AM   #2
freevolvos
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it will be greater the n.a. there's a formula for it,.008 times the bore size or something like that. are these new rings? or used?
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Old 08-02-2018, 10:34 AM   #3
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it will be greater the n.a. there's a formula for it,.008 times the bore size or something like that. are these new rings? or used?
They are new rings
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Old 08-02-2018, 12:28 PM   #4
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Ring gap should be .004 X bore diameter in inches, as a basic rule. Some hi/perf and turbo engines might require different gaps, check with the ring maker for their settings.
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Old 08-02-2018, 12:35 PM   #5
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What ^^^^ said. Gap size will depend on ring material, intended use, etc.

For example the CP rings on my build are .0045/inch for NA, .0065/inch for low boost street, .0075/inch for high boost/nos. Going on the looser end may result in a very minimal, if even noticeable oil use issue, going tight can lead to binding, scoring walls, snapping ring lands if they are tight enough to butt ends.
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Old 08-02-2018, 01:32 PM   #6
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Originally Posted by gsellstr View Post
What ^^^^ said. Gap size will depend on ring material, intended use, etc.

For example the CP rings on my build are .0045/inch for NA, .0065/inch for low boost street, .0075/inch for high boost/nos. Going on the looser end may result in a very minimal, if even noticeable oil use issue, going tight can lead to binding, scoring walls, snapping ring lands if they are tight enough to butt ends.
Those are either extremely tight, or you have an extra zero and they're extremely loose.
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Old 08-02-2018, 01:36 PM   #7
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Those are either extremely tight, or you have an extra zero and they're extremely loose.
That's what I thought as well. If I remember right, I think the Bentley manual says something between 0.020 and 0.022 in.
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Old 08-02-2018, 02:31 PM   #8
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You guys did catch the /inch bit right?

.0045" for each inch of bore...

In the 230 I'm running .028" top, .032" middle.
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Old 08-02-2018, 02:55 PM   #9
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call the ring manufacturer and see what they recommend, There are different gaps for n.a. nitrous-boost are usually the same but for sure get ahold of them. when rings but together bad things happen ring lands break, piston tops break off, bores get gouged, I'm surprised there isn't a paper with the rings with recommend gaps
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Old 08-02-2018, 03:06 PM   #10
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Normally there should be. First set of rings in my motor did NOT have that paper, plus the CP rep gave the wrong spec to the machine shop so the ends butted. Motor isn't quite what it was supposed to be since it had to get honed out to TRY and smooth some of the gouges.
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Old 08-02-2018, 03:16 PM   #11
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Originally Posted by gsellstr View Post
You guys did catch the /inch bit right?

.0045" for each inch of bore...

In the 230 I'm running .028" top, .032" middle.
Oh per inch, yeah .025-.030 sounds right.
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Old 08-02-2018, 03:33 PM   #12
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Quote:
Originally Posted by gsellstr View Post
You guys did catch the /inch bit right?

.0045" for each inch of bore...

In the 230 I'm running .028" top, .032" middle.
I missed it. Makes sense now.
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