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Old 01-24-2019, 07:20 PM   #1
goodcar
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Default Rebore vs Sleeves

Have a block that had .070 oversize pistons. Should I rebore to the next suitable size or sleeve to standard? Suggestions?? Thanks
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Old 01-24-2019, 08:52 PM   #2
Kurt in NJ
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Default Re: Rebore vs Sleeves

go with rebore till you can't get pistons, then sleeve
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Old 01-24-2019, 10:11 PM   #3
George Miller
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Default Re: Rebore vs Sleeves

I agree bore over size as long as you can. I only use a sleeve when you have to.
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Old 01-25-2019, 04:08 AM   #4
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Default Re: Rebore vs Sleeves

Your next oversized will be .080, measure carefully and see if it will clean up there.
You can have it honed being only .010 away.
Your next size is .125 it will have to be bored for that one.
I also agree sleeve only if you have to.
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Old 01-25-2019, 05:49 AM   #5
Bruce of MN
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Default Re: Rebore vs Sleeves

Brattons lists .100 pistons.
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Old 01-25-2019, 09:32 AM   #6
BRENT in 10-uh-C
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Default Re: Rebore vs Sleeves

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Have a block that had .070 oversize pistons. Should I rebore to the next suitable size or sleeve to standard? Suggestions?? Thanks

While the above comments are correct, the one comment that I will add is that sometimes the walls have been eroded away where it is not prudent to go 0.100" or 0.125" over because of wall thickness. I actually have a sonic tester that is much like an ultrasound for humans. Ask your engine rebuilder if he can check the wall thickness for you, and also get him to mic the bores to determine if it will indeed clean-up on 0.080.


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Old 01-25-2019, 02:49 PM   #7
Jim Brierley
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Default Re: Rebore vs Sleeves

Brent has a good point but I have never seen an A or B block that couldn't be bored to 4" (+.125") Racers used to bore them +.185".
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Old 01-26-2019, 08:23 AM   #8
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Default Re: Rebore vs Sleeves

I'm not sure how sleeves seal in the Model A block which wasn't designed for sleeves. My experience (one engine) is that coolant leaked around the sleeves into the combustion area.
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Old 01-26-2019, 09:42 AM   #9
BRENT in 10-uh-C
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Default Re: Rebore vs Sleeves

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I'm not sure how sleeves seal in the Model A block which wasn't designed for sleeves. My experience (one engine) is that coolant leaked around the sleeves into the combustion area.
In a nutshell, the cylinder is bored undersized (-typically .0025") of the cast iron sleeve that will be inserted into the bore. The sleeve is chilled with Nitrogen to shrink its diameter and the cylinder bore is heated to expand the diameter. The sleeve is inserted into the bore, and when the two metals equalize in temperatures, there is an interference fit. If there happens to be a pinhole into the cylinder wall, a correctly installed sleeve will dam the coolant. If incorrectly installed, it likely will wrap into the crankcase.
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