110" Ring End Gaps...
#21
03-11-2023 | 11:08 PM
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From: poway
BTW the new ring end gap upper limit for a CB750 sohc is 0.0067" per inch diameter. Worn out is about 0.012 per inch diameter.
#27
03-12-2023 | 04:25 AM
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From: Honah Lee
A 3-4 will work or a 4-5. As long as your careful, they will read accurately .025 over or under. Just don't try to sale that to a Nuclear or shop inspector.
Where are you measuring the piston at for clearance?
Surprised I didn't get shot for my post above on what does what when it warms up.
Is there anyone here who agrees a cylinder bore gets larger when warm?
Not sure if technology for auto parts store rings has progressed but back years ago when I was taking mechanic classes, it was a lot easier and faster (cheaper) to make rings with .030 gap than .020.
However, for someone who is concerned about (or over) .0045 and .006, this is where you need to get rings .
Where are you measuring the piston at for clearance?
Surprised I didn't get shot for my post above on what does what when it warms up.
Is there anyone here who agrees a cylinder bore gets larger when warm?
Not sure if technology for auto parts store rings has progressed but back years ago when I was taking mechanic classes, it was a lot easier and faster (cheaper) to make rings with .030 gap than .020.
However, for someone who is concerned about (or over) .0045 and .006, this is where you need to get rings .
Last edited by Jackie Paper; 03-12-2023 at 05:55 AM.
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#28
03-12-2023 | 11:35 AM
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Joined: Dec 2005
Posts: 17,466
Likes: 6,195
From: poway
A 3-4 will work or a 4-5. As long as your careful, they will read accurately .025 over or under. Just don't try to sale that to a Nuclear or shop inspector.
Where are you measuring the piston at for clearance?
Surprised I didn't get shot for my post above on what does what when it warms up.
Is there anyone here who agrees a cylinder bore gets larger when warm?
Not sure if technology for auto parts store rings has progressed but back years ago when I was taking mechanic classes, it was a lot easier and faster (cheaper) to make rings with .030 gap than .020.
However, for someone who is concerned about (or over) .0045 and .006, this is where you need to get rings .
Where are you measuring the piston at for clearance?
Surprised I didn't get shot for my post above on what does what when it warms up.
Is there anyone here who agrees a cylinder bore gets larger when warm?
Not sure if technology for auto parts store rings has progressed but back years ago when I was taking mechanic classes, it was a lot easier and faster (cheaper) to make rings with .030 gap than .020.
However, for someone who is concerned about (or over) .0045 and .006, this is where you need to get rings .
The only thing, I'd be worried about is that if the ends were ground / filed, any burrs have been cleaned off with a fine diamond hone/file.
#29
03-12-2023 | 01:44 PM
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From: Honah Lee
So, why all this .0045 or .006 per inch of piston size? If you know your bore is straight and round from boring and just enough honeing to get a crosshatch. And you know your rings are are are finished so they are round at 4.000 by the manufacturer and you run them in a cylinder that's 3.999, why would it matter if your gap is .004 or .020?
Not talking about a little blow by. I'm sure as you start going way over .020 to say .040, you will obviously get more blow-by.
#30
03-12-2023 | 01:59 PM
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Joined: Dec 2005
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From: poway
Well it looks like an expert agrees on what I had read years ago and even Googled on heat and expansion.
So, why all this .0045 or .006 per inch of piston size? If you know your bore is straight and round from boring and just enough honeing to get a crosshatch. And you know your rings are are are finished so they are round at 4.000 by the manufacturer and you run them in a cylinder that's 3.999, why would it matter if your gap is .004 or .020?
Not talking about a little blow by. I'm sure as you start going way over .020 to say .040, you will obviously get more blow-by.
So, why all this .0045 or .006 per inch of piston size? If you know your bore is straight and round from boring and just enough honeing to get a crosshatch. And you know your rings are are are finished so they are round at 4.000 by the manufacturer and you run them in a cylinder that's 3.999, why would it matter if your gap is .004 or .020?
Not talking about a little blow by. I'm sure as you start going way over .020 to say .040, you will obviously get more blow-by.
Not sure what you are say but statically, if you have rings set for a 4 inch more at say 0.020" and you fit the ring into a 3.999 bore the gap will decrease a little more than 0.003". Simple geometry..