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Piston rings

General engine tech -- Drag Racing to Circle Track

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rocketracer380
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Piston rings

Post by rocketracer380 »

Is it possible to use 4.094 bore rings on a 4.087 bore with just a file fit
Nut124
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Re: Piston rings

Post by Nut124 »

rocketracer380 wrote: Wed Sep 16, 2020 10:28 am Is it possible to use 4.094 bore rings on a 4.087 bore with just a file fit
I would say yes. The difference in circumference is only about 20 thou. I did something similar in my recent build, had to file about 20 thou and have excellent cranking compression and no blow by.

The ring I used, from Total Seal, was for 3.330 bore. My bore measures 3.323.
piston guy
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Re: Piston rings

Post by piston guy »

.010 bigger than the bore "should" stay "light tight" in the smaller bore and be OK when file fit to match the bore.
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Re: Piston rings

Post by piston guy »

.010 bigger than the bore "should" stay "light tight" in the smaller bore and be OK when file fit to match the bore.
engineguyBill
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Re: Piston rings

Post by engineguyBill »

Net difference between your cylinder diameter and your ring set is .007" so you will be able to use these rings. Be sure to check gap and file fit as necessary. You will have slightly more radial tension with these rigs, but not enough to be concerned about.
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Mark O'Neal
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Re: Piston rings

Post by Mark O'Neal »

"Any increase in the diameter of the cylinder is being used in, over the designated size, results in an increase of approximately .003″ in ring gap for each .001″ increase in cylinder diameter"

The opposite is also true.

The "issue" isn't tension...and your tension in this instance will increase, not decrease. You're going to a smaller bore, not a larger one. If there is an issue it would be in triangulation, not pressure.
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