Piston ring end gap

[1crosscut]

What should the end gap be on rings for an engine bored .040 over?

[SeaSlugs]

CHECKING COMPRESSION RING GAPS
RECOMMENDED
AUTOMOTIVE COMPRESSION
RING GAP CLEARANCES
Cylinder .............................Ring Gap
bore Diameter............... Ring Gap Tolerance
1.0000" to 2.3624".......... .006 to .014
2.3625" to 2.9524".......... .008 to .016
2.9525" to 3.5424".......... .010 to .020
3.5425" to 4.3299".......... .012 to .022
4.3300" to 5.1174".......... .014 to .026
5.1175" to 5.9049".......... .016 to .030
5.9050" to 6.8899".......... .020 to .035
6.8900" to 8.9999".......... .024 to .041

I got that off a different forum and they got it from hastings the piston ring manufactuers site. No idea if its relevant but a piston is a piston and ring a ring...i think

[BILL WILLIAMSON]

An OLD "rule of thumb" was .003" for each inch of bore.
I DON'T KNOW IF HIS IS ACCURATE OR NOT??????????? I would follow your ring makers' instructions!
Bill W.

[SeaSlugs]

Originally Posted by BILL WILLIAMSON

An OLD "rule of thumb" was .003" for each inch of bore.
I DON'T KNOW IF HIS IS ACCURATE OR NOT??????????? I would follow your ring makers' instructions!
Bill W.

well going by the chart I found that's not a bad rule of thumb, its pretty close to that.

[BILL WILLIAMSON]

Originally Posted by SeaSlugs

well going by the chart I found that's not a bad rule of thumb, its pretty close to that.

Some might think that LESS gap is BETTER, WRONG!!! If you ran OUT of clearance, just think about the ring WEAR & SCORING
As in MOST things, JUST USE COMMON SENSE!
Bill W.

[wrndln]

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Is the best way, maybe the only way, is to put the top 2 rings in the cylinder bore and use a feeler gauge to check the gap. I would think ring manufacturers would make the rings with the correct end gap right out of the box. I assume the oil rings don't need to be checked - right?
Rusty Nelson

[d.j. moordigian]

Originally Posted by SeaSlugs

CHECKING COMPRESSION RING GAPS
RECOMMENDED
AUTOMOTIVE COMPRESSION
RING GAP CLEARANCES
Cylinder .............................Ring Gap
bore Diameter............... Ring Gap Tolerance
1.0000" to 2.3624".......... .006 to .014
2.3625" to 2.9524".......... .008 to .016
2.9525" to 3.5424".......... .010 to .020
3.5425" to 4.3299".......... .012 to .022
4.3300" to 5.1174".......... .014 to .026
5.1175" to 5.9049".......... .016 to .030
5.9050" to 6.8899".......... .020 to .035
6.8900" to 8.9999".......... .024 to .041

I got that off a different forum and they got it from hastings the piston ring manufactuers site. No idea if its relevant but a piston is a piston and ring a ring...i think

Well ...close , but not true, it depends.

Originally Posted by BILL WILLIAMSON

An OLD "rule of thumb" was .003" for each inch of bore.
I DON'T KNOW IF HIS IS ACCURATE OR NOT??????????? I would follow your ring makers' instructions!
Bill W.

Good rule Bill..003"-.004"

Originally Posted by wrndln

Is the best way, maybe the only way, is to put the top 2 rings in the cylinder bore and use a feeler gauge to check the gap. I would think ring manufacturers would make the rings with the correct end gap right out of the box. I assume the oil rings don't need to be checked - right?
Rusty Nelson

I use a "squaring ring" that I've made for the common engines that I do. If it's an odd, not so popular one, I use a small square
to check it in the bores. I always check one piece oil rings and if 3 piece,
I check the rails. The piston material dictates the end gap,...cast and forged
run the same end gap,...Hyperutectic runs more end gap. The engine application, blown, fuel, NOS all change the end gap.

[BILL WILLIAMSON]

There you are, d.j, Dog here,
Thought you were sleepin' under the Roadster.
Dad still has that CREEPER for you, with 6 wheels & a tilt up pillow!
Buster T.

[1crosscut]

Thanks gentlemen.