Rebore to accept sleeve for .125 piston

M

mOSkit

Junior Member
Hi Guys

I`m trying to save a block and not pay to sleeve the entire block.
I have one rotted cylinder that was already sleeved before and considering the wear and all the bores being bored to .083 i`m considering to bore 7 cylinders to accept .125 pistons and fit one sleeve.
The question is, how much can i go on the wall to fit the sleeve and still have some meat left on the wall to support the .125 piston.

thanks
Kris
 
I would defer to others, but I would think it would also depend on what type of sleeve you plan to use.

There are thin walled (steel) and thicker cast iron sleeves. Each takes a different bore to install.

How bad is the bore you are trying to save?
 
I'v raced several of these blocks bored to 3 7/16. However, check with Egge ans see if they have a .100 over pistons. If the sleeve in question is a 3/32 wall standard, it might clean up. I don't like wet sleeves, but with today's technologies there might be a better way???
 
You may want to sonic test the other seven cylinders first, to make sure they not rusted on the inside also ........Mark
 
mOSkit said:
Hi Guys

I`m trying to save a block and not pay to sleeve the entire block.
I have one rotted cylinder that was already sleeved before and considering the wear and all the bores being bored to .083 i`m considering to bore 7 cylinders to accept .125 pistons and fit one sleeve.
The question is, how much can i go on the wall to fit the sleeve and still have some meat left on the wall to support the .125 piston.

thanks
Kris
Click to expand...




Kris i have had great success adding sleeves to save Flathead blocks with the final bore for 3-5/16 pistons. The brand I always use are from LA sleeve look them up on line you will find two versions of sleeves which will work perfectly. I prefer using sleeves with a flange this adds more work to the job. I prefer the flange type due to my experience finding the typical straight sleeve will move inward towards the bore at the top along the valve ledge area of the block when the cylinder has seen high heat. When this happens the top of the sleeve will now become a smaller diameter by approximately .0015 to .0025 small enough to tighten against the piston adding addition drag.
Ronnieroadster
 
Last edited:
I’ve seen .083 pistons in some of these old flatheads but they were all the 81A 3 1/16” bore blocks that were factory sleeved. It’s always been my understanding that the .083 oversize came from removing the sleeves . If this block is the 81A I don’t think it’s gonna take a 3 5/16” bore without hitting water.
 
A 221 block might be a problem. The old tin can sleeves were .040 thick so when they were worn out folks removed the worn sleeves & bought the .083" pistons and honed the bare walls to fit. Now that it needs a bore job, a person has to be careful how far you can go on the 221 blocks. 3 & 3/16" is about as far as you would want to go and as was already mentioned, the cylinder walls should be ultrasonic tested for thickness.

If it's a 239 block then disregard. For one cylinder, the new sleeve can be bored if it's a thick wall sleeve or punch it on out to get a good sleeve in it. As long as the cylinder has at least close to 1/8" thickness then it will work. If they get too thin, they tend to run warmer than normal.
 
mOSkit said:
Hi Guys

I`m trying to save a block and not pay to sleeve the entire block.
I have one rotted cylinder that was already sleeved before and considering the wear and all the bores being bored to .083 i`m considering to bore 7 cylinders to accept .125 pistons and fit one sleeve.
The question is, how much can i go on the wall to fit the sleeve and still have some meat left on the wall to support the .125 piston.

thanks
Kris
Click to expand...

It kind of sounds like this was a 221 engine that had the tin-can sleeves in it and that somebody knocked them out for the .083 overbore (starting from 3.0625). If so, I'm not sure you can bore this block to 3 5/16 - 3.3125 - typically that is NOT an option in blocks that started out with a 3 1/16 bore. The only way to know is to ensure that first the water jackets are clean and de-rusted and then sonic test the block. What is the current bore - 3.1455 or 3.2705???

You may be better off keeping the overbore to a minimum - and replacing the one sleeve. You can always bore the one bad cylinder first and see what it will clean up at? Maybe it will clean up at .100 and maybe the other cylinders will have enough wall thickness to go to .100.

Always check piston and ring availability before you bore ANYTHING!
 
Most of us old guys have mad a few mistakes and that's why we're so smart now. Using a flanged sleeve is a good idea, but i've never used one. However, it must take a special tool. Not sure how I;d do it with ny Van Norman 944. Might take alittle practice.
 
Ol' Ron said:
Most of us old guys have mad a few mistakes and that's why we're so smart now. Using a flanged sleeve is a good idea, but i've never used one. However, it must take a special tool. Not sure how I;d do it with ny Van Norman 944. Might take alittle practice.
Click to expand...




Ron I do it using the 944 i made a cutter for the job and I also add a stop to the bar so it cuts to the needed depth. Its a very slow process but works extremely well. Heck I also made a tool so i can "O" ring the decks for ARDUN heads.

Ronnieroadster
 
mOSkit said:
Hi Guys

I`m trying to save a block and not pay to sleeve the entire block.
I have one rotted cylinder that was already sleeved before and considering the wear and all the bores being bored to .083 i`m considering to bore 7 cylinders to accept .125 pistons and fit one sleeve.
The question is, how much can i go on the wall to fit the sleeve and still have some meat left on the wall to support the .125 piston.

thanks
Kris
Click to expand...

Hi Kris, with some accurate measurements you may be able to pull it off with a
3.456" OD sleeve, bore/hone to 3.312" and end up with about .072" of the sleeve wall intact??

Bunch of "ifs" but it should "fly"!

We would tackle this on our Hass (CNC) after a number of sonic tests! Would not feel at all comfortable using ANY deck-mounted boring bars for this type procedure, specifically the Van-Norman 944-"Perfect-O"??

Always leave a small "step" at the bottom of the bore for the sleeve to "rest" on, and use Loctite sleeve-sealer!

I may have the sleeve on the shelf, not sure at the moment!!

Thanks, Gary in N.Y.


P.S. Am going to try to keep my posts a bit short, still in the middle of some major health issues, half-way out of the woods so far!
 
Ronnieroadster said:
Kris i have had great success adding sleeves to save Flathead blocks with the final bore for 3-5/16 pistons. The brand I always use are from LA sleeve look them up on line you will find two versions of sleeves which will work perfectly. I prefer using sleeves with a flange this adds more work to the job. I prefer the flange type due to my experience finding the typical straight sleeve will move inward towards the bore at the top along the valve ledge area of the block when the cylinder has seen high heat. When this happens the top of the sleeve will now become a smaller diameter by approximately .0015 to .0025 small enough to tighten against the piston adding addition drag.
Ronnieroadster
Click to expand...

I've used a step at the bottom of the sleeve.
That is done by not boring all the way to the bottom of the cylinder, leaving about .125 or so, drive the sleeve in until it's stopped by this.

Just re-read this- you're talking about the top of the sleeve shrinking... OOPS'
Karl
 
Sorry all. This particular block is EAB 239. Only one cylinder was sleeved before, and this sleeve had water again. I have measured the other bores and they are very ok. I have emailed egge to see if they can supply .100 pistons. If so, the same type of new sleeve will work without an issue
 
If the current sleeve is leaking, you may have unseen problems like WAY too much original wall gone to hold a sleeve.
I would bore the original sleeve out by offsetting the bar and BARELY boring through one side, THEN inspect to see what condition the original metal is.
In any case you are going to have to take a skin cut in the hole for the new and maybe special sleeve.
It might be an easy fix or it could be a real can of worms.

RON: Your problem can be alleviated by taper honing the hole before you put the sleeve in.
Leave the top 2 inches .001 smaller. Usually not necessary on anything except blown or fuel racing engines.
 
Pete said:
If the current sleeve is leaking, you may have unseen problems like WAY too much original wall gone to hold a sleeve.
I would bore the original sleeve out by offsetting the bar and BARELY boring through one side, THEN inspect to see what condition the original metal is.
In any case you are going to have to take a skin cut in the hole for the new and maybe special sleeve.
It might be an easy fix or it could be a real can of worms.

RON: Your problem can be alleviated by taper honing the hole before you put the sleeve in.
Leave the top 2 inches .001 smaller. Usually not necessary on anything except blown or fuel racing engines.
Click to expand...



Great information Pete Im banging my forehead at the moment why I did not think of that. Still learning after all these years and i still do Go Fast with these old flathead Ford blocks. No Toyota, Honda or agent orange spoken here or worked on! :D
Ronnieroadster
 
You must log in or register to reply here.
Back
Top