8BA sleeve wall thickness

[Steve in Denver]

Anyone have any original 8BA cylinder sleeves that they could mic? How thick are original sleeves and how thin can they be safely machined? There must be a book on them somewhere that has these details or someone who really knows.

[KiWinUS]

I were unaware 8BA ever had sleeves originally. I would suspect has been bored and sleeved since leaving factory.

[Bored&Stroked]

I agree with KiwinUS (Tony) - I've never seen a factory sleeved 8BA (though with that said, no doubt at someplace/sometime, Ford did it!).

Any competent machine shop should be able to mic the sleeve thickness and determine the best course of action. For a performance engine, I don't like to have a fully sleeved block - just too many ways to have issues and too much invested in porting, etc.. For a street engine, if the work was done properly, there should be no issues.

Question: Were ALL 8 cylinders sleeved? If so, this may have been done by a rebuilder who wanted to re-use STD pistons and rings.

[Steve in Denver]

Guess I found some of my own answer. Mac's does show cylinder sleeves as 1/8 wall thickness. As 1/8 is .125 and my machinist has already bored it out .125 over, that would mean that there is only 1/16 inch wall thickness left. After my too long spark plugs causing some wall damage, he said it cleaned up at .130, really getting thin. Hope he is right.

[KiWinUS]

Steve. There are many manufacturers of sleeves in different sizes. Don’t count on your sleeves being like macs. Sounds way too thin to me.

[38 coupe]

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I have helped sleeve five cylinders in four 8BA blocks (+0.060 final bore in all cases ironically). We used Mellings sleeves in all four motors. We ordered two thick walled sleeves after I bored .001 too far on the first hole (learning experience). We ended up using the second thick walled sleeve on the last engine that had one cylinder where a wrist pin keeper failed and the wrist pin gouged the wall badly. All sleeves were precision as advertised by Mellings. I measured the supplied sleeves in 12 places and averaged the measurements to ensure final bore was as needed for the sleeve. Both thick wall sleeves bored into the water jacket in a small spot. No issues have been experienced in any of the motors.

Mellings sleeve catalog: https://www.melling.com/wp-content/u...ve-Catalog.pdf

[rotorwrench]

If a person has a block will little or no pitting in the water jackets and no core shift then it can be bored quite a ways. Now days a person has to sonic test the cylinder walls to find what can't be measured by conventional means. This will tell the machinist how far he can safely bore without sleeves. Cubic inch displacement can only be increased by boring and stroking if a person want a more potentially powerful combination.

[Mart]

I've used the .125 Mellings sleeves in the two desperately damaged 59A motors I repaired. I got mine from Rockauto. They also list a Mellings 7/32 sleeve. Rockauto is user friendly for overseas buyers. (Me.) I did touch through to the water jacket on a couple of bores.
I also went 25 thou over on one bore when boring for a sleeve and rescued the job with a bigger sleeve from a local supplier.

[Bored&Stroked]

One thing to note on sonic testing. It is not a guarantee that the block can be bored a certain amount and that there will be no issues - but it gives you a going in position.

The reason is that you can have a small casting flaw or rust pocket that you find on the overbore - which then requires a sleeve to be done. Most of us sonic test a cylinder in about 12 spots --> all four sides and top-to-bottom at three depths. This gives us a pretty good idea as to the general cylinder wall thickness (and the overbore we want to go too) - what it doesn't do is find a rust pocket or other casting issue.

If your desire is to bore a block a fairly heavy amount --> say to 3 5/16, it is always best to bore the block FIRST, pressure test it - and then order your pistons. You never know what you'll find when you start boring a 75+ year old block.

B&S