Ring end gap
Supertech pistons, first overbore, 9.5:1, going to run ~15+ psi boost. Supertech says .021 top, .023 bottom compression rings. Do I run this, or run them closer? They are tight now, so I have lots of options. I will probably cross-post this on m.net if nothing shows up here.
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Originally Posted by webby459
(Post 515299)
Supertech pistons, first overbore, 9.5:1, going to run ~15+ psi boost. Supertech says .021 top, .023 bottom compression rings. Do I run this, or run them closer? They are tight now, so I have lots of options. I will probably cross-post this on m.net if nothing shows up here.
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What he said.
I bought a ring end filer for this. ~$60 shipped. |
Originally Posted by sn95
(Post 515305)
Do NOT run tight ring gaps on a forced induction or nitrous motor! The rings expand under load and can actually butt ends and cause ring/land failure. Rule of thumb on blown motors is .006" end gap per inch of bore diameter on the top ring and .005" on the second ring. This equates to .020 on the top and .017 on the second. If Supertech is suggesting .021 top and .023 bottom for your pistons in a turbo application, do not run any less end gap. Use a piston ring filing tool carefully, and check clearance by putting the ring in the bore and squaring it with the head of a piston. Each ring needs to be filed for a specific bore and kept organized so it gets installed in that bore. Use a small file to deburr the ends of the rings after you have them file fit to the proper clearances.
Originally Posted by JasonC SBB
(Post 515312)
What he said.
I bought a ring end filer for this. ~$60 shipped. |
Originally Posted by JasonC SBB
(Post 515312)
What he said.
I bought a ring end filer for this. ~$60 shipped. |
You should have gotten a sheet with your pistons that says what endgaps to run based on your intended use. If you don't have it, call Supertech and they'll email it to you. It's a multiplier based on street/roadcourse/drag/nitrous/etc use.
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Originally Posted by thymer
(Post 515315)
Do they take material off fairly quickly?
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I dislike the cheap ring filers. I use a diamond coated knife sharper. It is very quick and easy.
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Originally Posted by neogenesis2004
(Post 515320)
I dislike the cheap ring filers. I use a diamond coated knife sharper. It is very quick and easy.
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The filer I bought is the same one my machinist uses.
It removes material very quickly thus one has to be careful about removing too much. After using the filer, the edges have to be dressed with a very fine wet knife sharpening stone. |
This is why I use the diamond sharpener. Its hard enough to cut any metal quickly, but fine enough that I don't need to go behind it with anything. I just got the fine version from Lowes. I don't remember how makes it.
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Just follow the sizing chart they give you with the pistons. I did my wisecos at .017 for the top ring and .019 for the bottom ring. Oil rings didnt need any sizing. For example i did the .060 overbore on my 1.6, the bore size is 3.1299, follow the chart for the proper application (street moderate turbo/nitrous) .0055 x 3.1299 = .017ish(top ring) and .0060 x 3.1299 = .019ish(bottom ring). Just follow manufacturers specs, figure they've been making pistons for longer then ive been alive so they must know best. Be careful gapping too big as well, you'll have a smoke'mobile.
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Originally Posted by JasonC SBB
(Post 515367)
The filer I bought is the same one my machinist uses.
It removes material very quickly thus one has to be careful about removing too much. After using the filer, the edges have to be dressed with a very fine wet knife sharpening stone. Did you get the motorized ring filer or the hand crank ring filer?? |
Well this is serendipitous, I was just about to post the exact same thread.
I bought the NPR rings from eGay and found they had about a .012-.014" end gap which was slightly larger than the old rings I pulled from y8s old pistons. I was about to kick off at the seller. My engine is only NA but will still be making a bit more power than stock so is .012-.014" ok? My overhaul manual states between .006" and .009" as standard and a maximum (your engine is shot if you get to this point) of .036". |
60 bucks I'm guessing hand crank
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Originally Posted by sn95
(Post 515415)
Jason,
Did you get the motorized ring filer or the hand crank ring filer?? I once did it by hand as neo suggests, and it took FOREVER and I ended up FILING MY FINGERNAILS AND FINGERTIPS TOO. |
Originally Posted by JasonC SBB
(Post 515443)
Hand crank.
I once did it by hand as neo suggests, and it took FOREVER and I ended up FILING MY FINGERNAILS AND FINGERTIPS TOO. |
I believe I bought it from this store, and this is the brand I got.
I'll bolt it to my bench or squeeze it in my vise. Right hand to turn crank, left hand to hold ring and squeeze it against disk. No harder than holding a magazine with the left hand and jacking off with the right. |
classic, was just reading through this thread and that final post just made it lol
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Originally Posted by sn95
(Post 515305)
Do NOT run tight ring gaps on a forced induction or nitrous motor! The rings expand under load and can actually butt ends and cause ring/land failure. Rule of thumb on blown motors is .006" end gap per inch of bore diameter on the top ring and .005" on the second ring. This equates to .020 on the top and .017 on the second. If Supertech is suggesting .021 top and .023 bottom for your pistons in a turbo application, do not run any less end gap. Use a piston ring filing tool carefully, and check clearance by putting the ring in the bore and squaring it with the head of a piston. Each ring needs to be filed for a specific bore and kept organized so it gets installed in that bore. Use a small file to deburr the ends of the rings after you have them file fit to the proper clearances.
On stock pistons and and stock bottom block on a 1.6 I'm running 8-10 psi on a turbocharger what gap measurement should I have for top and bottom |
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