ring end gap

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flatheadmatt
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ring end gap

#1

Post by flatheadmatt » Mon Mar 11, 2019 5:34 pm

I have a fresh bore of 3.436 for my U. The ring end gap (new rings and pistons as well) is as follows on both cylinders. top ring=.022, 2nd ring .017. I noticed the top ring is at the max of spec. I am debating getting a new top ring as I don't want to lose compression right off the bat with too big of a ring gap on my top set. Will .022 really be that noticeable with loss of power/compression? I know opinions will vary, but wanted to see what the board thinks. I appreciate the help, this is my first time doing this on my own. :D
Last edited by flatheadmatt on Mon Mar 11, 2019 6:06 pm, edited 1 time in total.



PanPal
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Re: ring end gap

#2

Post by PanPal » Mon Mar 11, 2019 5:45 pm

It seems the gaps are always at the top end of the tolerance. I always buy cast iron rings for the next size up and file fit the gaps. Example: if I have .040 over pistons I would buy .050 Hastings cast iron rings and fit them.

Blind Melon
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Re: ring end gap

#3

Post by Blind Melon » Mon Mar 11, 2019 7:56 pm

Better too big than too tight... any loss of compression past the top ring gap is so minute you could NEVER tell.
On a big twin flathead keep the tolerences (sp) on the loose side and it will last longer and run cooler.. If you
saw how bad the cylinder walls warp when slightly overheated you'd be amazed..

Andygears
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Re: ring end gap

#4

Post by Andygears » Mon Mar 11, 2019 9:54 pm

Blind Melon wrote:
Mon Mar 11, 2019 7:56 pm
Better too big than too tight... any loss of compression past the top ring gap is so minute you could NEVER tell.
On a big twin flathead keep the tolerences (sp) on the loose side and it will last longer and run cooler.. If you
saw how bad the cylinder walls warp when slightly overheated you'd be amazed..
Agreed, better loose/wider gap than tight, the ring needs room to expand when hot, not much room on top, bottom or OD so expand laterally and close the gap to running clearance. When gapping in cyl. I always avoid the low spot of the cylinder for the top ring, thinking that raw gas in there would run thru the gap and......

My two cents
Andygears

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