This might draw a lot of different suggestions, however here it goes.
What would a recommended piston ring end gap be for a circle track 358 cu. in. engine on racing gasoline and on asphalt.
The engine is a full roller set up with brodix flowed aluminum heads, 13.5:1 Diamond pistons and a 4.060 bore.
Top ring - ?
Second ring - ?
Thanks for your time, it is greatly appreciated.
Piston Ring End Gap
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Re: Piston Ring End Gap
site:speedtalk.com piston ring end gap
cut and paste that into google and if you have any further questions, follow up here.
this topic has been beat to death already, and your ring manufacturer has some good suggestions listed on the piece of paper that came with the ring pack.
cut and paste that into google and if you have any further questions, follow up here.
this topic has been beat to death already, and your ring manufacturer has some good suggestions listed on the piece of paper that came with the ring pack.
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Re: Piston Ring End Gap
Quick and easy answer:
Top ring .0045" per inch of bore diameter .0045" X 4.060" bore = .018" gap
2nd ring .0055" per inch of bore diameter .0055" x 4.060" bore = .022" gap
Top ring .0045" per inch of bore diameter .0045" X 4.060" bore = .018" gap
2nd ring .0055" per inch of bore diameter .0055" x 4.060" bore = .022" gap
Bill
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Re: Piston Ring End Gap
I'd run .020 top & .023 second.
It'll hook well on that surface & non alcohol fuel runs hotter, a little extra is safe, won't cost any measurable power or extra blowby, may save a motor if something is not quite right & cyl temps get a bit warmer than anticipated.
It'll hook well on that surface & non alcohol fuel runs hotter, a little extra is safe, won't cost any measurable power or extra blowby, may save a motor if something is not quite right & cyl temps get a bit warmer than anticipated.
Re: Piston Ring End Gap
I agree with this, a little safety margin. There just isn't anything to be gained and a lot to lose by being too tight.KnightEngines wrote: ↑Mon Feb 18, 2019 7:32 am I'd run .020 top & .023 second.
It'll hook well on that surface & non alcohol fuel runs hotter, a little extra is safe, won't cost any measurable power or extra blowby, may save a motor if something is not quite right & cyl temps get a bit warmer than anticipated.
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Re: Piston Ring End Gap
These dimensions are assuming that you will be using good quality piston rings, Steel or Ductile Iron top ring and Grey Iron second rings. There are steel second rings available but they are not necessary due to the fact that the second ring does not directly operate in combustion heat nor direct compression pressure. The second ring's primary function is oil control.engineguyBill wrote: ↑Sun Feb 17, 2019 10:36 pm Quick and easy answer:
Top ring .0045" per inch of bore diameter .0045" X 4.060" bore = .018" gap
2nd ring .0055" per inch of bore diameter .0055" x 4.060" bore = .022" gap
Bill
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Re: Piston Ring End Gap
evening fellas.
when talking about 2 cycle engines, where there are only 2 rings fitted to the piston of which both are identical...
does the second ring still like to see a little extra gap than the top ring?
when talking about 2 cycle engines, where there are only 2 rings fitted to the piston of which both are identical...
does the second ring still like to see a little extra gap than the top ring?
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Re: Piston Ring End Gap
yes to my own question - WISECO/PDFs/Manuals/RingEndGap.pdf
Applications -
Top Ring
Bore x
2nd Ring
Bore x
Dirt / ATV / Snow / PWC
.0040”
.0050”
High-Performance Street / Strip
.0045”
.0055”
Street-Moderate Turbo / Nitrous
.0050”
.0055”
Late Model Stock
.0050”
.0055”
Circle Track/Drag Race
.0055”
.0060”
Blown Race Only
.0065”
.0070”
Nitrous Race Only
.0070”
.007
Applications -
Top Ring
Bore x
2nd Ring
Bore x
Dirt / ATV / Snow / PWC
.0040”
.0050”
High-Performance Street / Strip
.0045”
.0055”
Street-Moderate Turbo / Nitrous
.0050”
.0055”
Late Model Stock
.0050”
.0055”
Circle Track/Drag Race
.0055”
.0060”
Blown Race Only
.0065”
.0070”
Nitrous Race Only
.0070”
.007