The Ford Barn

Fourdy · 11-08-2017, 11:46 PM

I have an 8ba block that has two sleeves and appears to have been bored .030 over with very little wear. The closest I can get with all those teeny tiny numbers is 3.2180 (+/-) 1” below the top and 3.216 (+/—) 1” from the bottom. The sleeve wall thickness is .100 at the top and .080 strong at the bottom. Is there enough wall left to go to .060 over? If I am anywhere close to understanding all this, I would have a sleeve wall of .065+ at the bottom and more at the top.

I don’t want to pay for shake/bake etc. if I can’t use the block.

Thanks so much in advance

Fourdy

rotorwrench · 11-09-2017, 11:24 AM

There may be a step at the bottom of the cylinders with the sleeves. It sounds like the bores are still very near 3 7/32". A person would have to mike some new .030" pistons to see how close it is. I don't see any reason it couldn't go out to 3 1/4" if you want to. I wouldn't do anything without talking to your planed machinist unless you have your own boring bar.

flatjack9 · 11-09-2017, 01:35 PM

I also would check with the machinist. Would think you could go to .040 with just a hone job.

supereal · 11-09-2017, 01:50 PM

When we get an engine with one or two sleeves, we assume they were installed to repair a damaged block. The only way to see why is to pull the sleeves before you overbore. A sand hole or a cylinder scored by a loose wrist pin, or freeze damage would be possible.

Ol' Ron · 11-09-2017, 05:41 PM

Yes, .040 should do the trick.

Fourdy · 11-10-2017, 12:20 AM

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Okay - The thinking is that the machinist should be able to hone (not bore) the cylinders to fit a .040 piston?

To do:
1. confab with machinist
2. find .040 pistons for him to fit.

Supereal - I think you are suggesting not to pull the sleeves due to not know what I would discover?

Thanks to all.

Fourdy

Bored&Stroked · 11-10-2017, 08:36 AM

I would have the block magnafluxed and pressure tested first - just to make sure there are not any other issues to deal with. If it passes that, then you should be good as far as going to the next oversize on the pistons. Who knows, you may even find that the bores are good enough for a hone and a new set of rings (if you have good .030 pistons).

Your machine shop may not want to hone a cylinder to size (especially on a used engine). Your machine shop will probably want to bore to the next available size - after they mic the engine and check with piston suppliers. Once they know what they can do, then you can make a determination as to the best path.

Me - I'd go for the least possible overbore from where you are at . . . it you can go to .040, that would be great.

There are many piston manufacturers for these engines - so I'm sure you'll be able to find the exact piston size you'll need.

Best of luck,
B&S

11-08-2017, 11:46 PM	#1
Fourdy Senior Member Join Date: May 2010 Location: Port Townsend, WA Posts: 601	Your learned advice needed I have an 8ba block that has two sleeves and appears to have been bored .030 over with very little wear. The closest I can get with all those teeny tiny numbers is 3.2180 (+/-) 1” below the top and 3.216 (+/—) 1” from the bottom. The sleeve wall thickness is .100 at the top and .080 strong at the bottom. Is there enough wall left to go to .060 over? If I am anywhere close to understanding all this, I would have a sleeve wall of .065+ at the bottom and more at the top. I don’t want to pay for shake/bake etc. if I can’t use the block. Thanks so much in advance Fourdy __________________ My 24 T http://fordbarn.com/forum/showthread...ghlight=fourdy

11-09-2017, 11:24 AM	#2
rotorwrench Senior Member Join Date: Jun 2010 Location: San Antonio, Texas Posts: 16,440	Re: Your learned advice needed There may be a step at the bottom of the cylinders with the sleeves. It sounds like the bores are still very near 3 7/32". A person would have to mike some new .030" pistons to see how close it is. I don't see any reason it couldn't go out to 3 1/4" if you want to. I wouldn't do anything without talking to your planed machinist unless you have your own boring bar.

11-09-2017, 01:35 PM	#3
flatjack9 Senior Member Join Date: May 2010 Location: Oshkosh, Wi Posts: 4,527	Re: Your learned advice needed I also would check with the machinist. Would think you could go to .040 with just a hone job.

11-09-2017, 01:50 PM	#4
supereal Senior Member Join Date: Jul 2014 Location: Iowa Posts: 1,634	Re: Your learned advice needed When we get an engine with one or two sleeves, we assume they were installed to repair a damaged block. The only way to see why is to pull the sleeves before you overbore. A sand hole or a cylinder scored by a loose wrist pin, or freeze damage would be possible.

11-09-2017, 05:41 PM	#5
Ol' Ron Senior Member Join Date: May 2010 Location: Chester Vt Posts: 8,861	Re: Your learned advice needed Yes, .040 should do the trick.

11-10-2017, 12:20 AM	#6
Fourdy Senior Member Join Date: May 2010 Location: Port Townsend, WA Posts: 601	Re: Your learned advice needed Sponsored Links (Register now to hide all advertisements) Okay - The thinking is that the machinist should be able to hone (not bore) the cylinders to fit a .040 piston? To do: 1. confab with machinist 2. find .040 pistons for him to fit. Supereal - I think you are suggesting not to pull the sleeves due to not know what I would discover? Thanks to all. Fourdy __________________ My 24 T http://fordbarn.com/forum/showthread...ghlight=fourdy

11-10-2017, 08:36 AM	#7
Bored&Stroked Senior Member Join Date: Jan 2011 Location: Central Ohio Posts: 5,073	Re: Your learned advice needed I would have the block magnafluxed and pressure tested first - just to make sure there are not any other issues to deal with. If it passes that, then you should be good as far as going to the next oversize on the pistons. Who knows, you may even find that the bores are good enough for a hone and a new set of rings (if you have good .030 pistons). Your machine shop may not want to hone a cylinder to size (especially on a used engine). Your machine shop will probably want to bore to the next available size - after they mic the engine and check with piston suppliers. Once they know what they can do, then you can make a determination as to the best path. Me - I'd go for the least possible overbore from where you are at . . . it you can go to .040, that would be great. There are many piston manufacturers for these engines - so I'm sure you'll be able to find the exact piston size you'll need. Best of luck, B&S