40/41 blocks sleeved

[3W Hank]

The blocks at Mercury 40 and 41 has both the std bore at 3.1875", and as I read some had sleeve from factory.
What wall thickness on the ( thin sleeve ) I don't know but wall was maybe 0.04" thick from factory is my guess, or ?
But I seen a std 40 block and it was sleeved from factory but it look way thicker wall on sleeve than ex 0.04".
But question is, why would this block design 'dance' ?
Ok, the factory was thin wall my guess and less bore, but if try go bigger bore say 3.375" or even 3.7/16" is there when the 'dance' issue comes in ?

If 1 sleeve in a block, what is the wall thickness do one like to see ?

When I bought the 41 Merc block I has 1 sleeve included to a bore the block at 3.500", so at a cylinderbore at 3.3125" the wall would be 0.0937".

If one use 8 sleeves like that ( bore 3.500" ) and go 3.7/16" or 3.4375" the wall would be only 0.0312".
-Maybe a block can't handle that.

[Kube]

Factory sleeves were typically .0415" thick.
In the "old days" a guy could simply pull the sleeves, hone the block and install .083" pistons.
I don't believe that size piston has been available for decades.
Once you remove the sleeves, you'll need to carefully check the diameter of the cylinder bores. That will determine the correct sleeve size.
These sleeves were designed for a standard bore engine.
I have rebuilt numerous '39 - '40 blocks that had been factory sleeved. Even a few that were sleeved later in life.
The factory sleeved blocks had "HS" stamped on the flat plane of the block adjacent the valve cover on the right side - front.

Boring out as far as you are contemplating may or may not cause issues. If you go through the bore "wall" yes, you can sleeve. However, you will most likely develop a hot spot in that area.
I have pulled the sleeves out of two blocks in the distant past and then went to bore the bare block to accept standard 3 3/16" pistons. Each time was nerve racking as I was fearful of an area(s) that were too thin.
In retrospect, I was lucky. Your results may differ.

[Kurt in NJ]

There were 2 different thin sleeve thicknesses for the 3-3/16 bore 99A block, .040 thick and .060 thick
The bore size for the sleeves —040 got bore of 3.2684- 3.2687
The bore size for the .060 ones 3.3084-3.3087
I have a set or 2 of the .060 ones

[3W Hank]

When you say 39-40 blocks I guess you mean the Ford, not Mercury.
Ford was that era 3.06” and the small bore. I talk about the Merc 40-41 the 3.18” bore std.
I guess the block I showed had a repair sleeve.
So maybe some 40-41 had the ( thin 0.04” ) sleeve.
As my block is bigger bore than std plus 0.08” it might was a sleeve block std.
But those block did they also dance ?
-Maybe just when go at 3.500” and then sleeved x8, the dance start.

[rotorwrench]

Tin can sleeves were a short lived manufacturing process. I think that they were aimed at some way to make future service easier but there was no follow up due to the short few years that this process was used. I don't install a lot of sleeves but I am familiar with problems that folks have had when replacing sleeves in the Ford tractor engines. They are kind of thin so a person has to take a lot of care to install new ones. Ford made tools to drive the old ones out but the old sleeves tend to buckle during the process so they either have to be hit with a welder on the walls to shrink them or they have to be bored thin so they can be flaked out. These are on the 172 OHV engine in the 800 series of tractors that I'm most familiar with.

[Als48]

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Yes, I sleeved my NAA Ford tractor (134 CI) engine a couple of years ago. I had trouble with one sleeve during replacement when I tapped it into place, using a wooden board. The ribbed shoulder broke off the upper lip when I got a little too aggressive, thinking it was a tighter fit than it actually was.(Murphy's Law in action again) I was able to get another single, sleeve from the vendor, which went in successfully. It was a big bore (thinner) sleeve.

Al Hook