View Full Version : Sleeving 55 cylinders

01-02-2010, 02:37 PM
Hello-I have a set of 55 pan cylinders that need to be sleeved and 1 small fin replaced-can anybody recommend a good shop? thanks for any info, Jim.

T. Cotten
01-07-2010, 09:38 PM

The lack of responses is proportional to the desirability of a sleeved cylinder.

A more appropriate wording of your question would be: Given the pitfalls, what are the best techniques for saving a cylinder by sleeving?

Then, with some consideration, your local automotive machine shop can do the job to your specifications.

But you will still need: Good luck!


Chris Haynes
01-07-2010, 10:42 PM
Ya might ask the folks who make the sleeves. Their web site says they do installation.

01-08-2010, 07:37 PM
I think Bill's in Bloomsburg PA used to do them way back when.

01-08-2010, 09:41 PM
try www.truettandosborn.com

01-08-2010, 09:52 PM
I think Bill's in Bloomsburg PA used to do them way back when.

Bill still does sleeving. He is quite good at it.

01-11-2010, 10:15 AM
Thanks for all the info guys - this forum is a super big help to me!!! Jim.

Bill Pedalino
01-17-2010, 09:40 AM
I've sleeved a number of 74 and Sportster cylinders for customers over the years, maybe a dozen or so. I've never had a sleeved cylinder fail. Albeit, the last one I did was over 20 years ago when I still worked as a Harley mechanic for my livelyhood. But I still own and run one of my old sleeved Sportsters - and it's a 4-5/8" stroker.

One thing that we used to do is to apply brass to the lower spigot at the base of the sleeved cylinder before the sleeve is bored on the boring bar. If done properly, the brass is drawn between the lead-in taper on the sleeve and the bored cast Iron (L.A. sleeve used to have a taper) much like how solder is drawn into a plumber's joint.

Another thing is that we used only L.A. Sleeve products, as discussed above. If you bore the cylinder straight and true and use the correct press-fit clearances, and pre-heat the cylinder before and during the press, and you use green locktight, and yo braze the spigot you will PROBABLY be ok. But no guarrantees. I have a bunch of bad cylinders that I can't bring myselfe to throw out and I'll probably end up sleeving them at some point - and hope for the best!

Again, the guys who have written the above responses are not wrong and offer good advise, as I have seen sleeved cylinders fail as well. I've seen the sleeves slip and have also seen cylinders crack. So please be well-advised, these are my experiences only.

If the cylinder is really bad, you only have two choices - sleeve or trash. But if you decide to trash them, please let me know!!

T. Cotten
01-17-2010, 12:45 PM
I am certain that we will all agree,

A quality sleeve is critical,
And so is the skill of the machinist.

There are two (at least) inherent problems with sleeving.
The primary one is heat transfer.
The other is weird fastener distortion, which is easily remedied by fitting the piston while torqued to stress plates, just as one would for a large overbore.

To maximize heat transfer,
It does well to hone the casting bore to a microfinish when fitting for the sleeve. Tool marks cause insulating voids, as shown in the attachment of a burnt sleeve removed from a shoddily sleeved Chief cylinder.

The .0015" minimum press-fit on the sleeve is not to retain it, but to insure as much contact as possible.
A potting compound that conducts heat would be preferred, but please choose one that withstands a minimum of a constant 400F (~200C), and is actually intended to conduct heat.

It is usually preferred to find the largest piston available, as opposed to weakening the casting even further with a sleeve that would exceed that bore.
The decison rests upon careful measurements of the casting at its thinnest spots.

Blasting a hole to daylight (second attachment) can be tragic.


01-17-2010, 02:00 PM
Tom, I am to a point where I will probably need to do something with my 65 motor. I want to keep the original cylinders in order to take it to its former days of glory. Doesn't boring it out to the max make the cylinder extremely thin and create a greater risk of failure as opposed to re-sleeving if done by a competent machinist?

T. Cotten
01-17-2010, 03:07 PM
Boring to the max is still smaller than a sleeve.

The vast majority of thin-cylinder catastrophes and overheating legends are confused by either an extraneous problem like a vacuum leak sticking a piston, or the very relevant problem of distortion when metal gets thin.
H-D's long, long spigots into the cases are great! But they go wavy-gravy with fastener stress when thinned by overbores. They bend in and out, pinching the skirt, creating heat, and other distress. The use of stress plates while fitting for the pistons simulates the installed distortion, eliminating the problem dramatically.

A sleeve requires more of the matrix casting to be compromised than an enormous overbore. It takes a hole that might just reach daylight

Our first requirement for an educated assessment is to find a way to measure the casting thickness. I removed the top spring from a common caliper (attached) so that the thumbscrew could be reversed, thereby making it openable to clear the baseflange, as well as setting to a feel for the thinnest spot.
Re-closed, the gap can be measured with a feelergauges, or a dial caliper if that large.

The thinnest spots in the cylinder wall are in the milled cuttaways for
basenut clearance. I probe the radius of the cut to determine the minimal point, and set the caliper.So,..What happens if the 'window's of the basenut reliefs are too thin?
I have an oriental painhead cylinder gouged by a wristpin clip while otherwise running fine at .030" over. After disassembly I noted discoloration in an area about the size of a rice grain in the bore, directly above the basenut flange. I inspected it with my fingernail, and went right through to daylight!
The rings even came past this spot, but it never perforated in service, even though the wall was probably breathing in and out. It was less than .005" thick.
Core float had compromised the entire basenut relief to less than .050", with an area the size of a dime less than .010", yet even with the catastrophic wristpin failure, the Taiwanese cylinder never fragged.

I put machines into service with .070" remaining, without incident, and even though some were flatties, and they ran 'cool'.
This corresponds to the average OEM Pan cylinder at .100" oversize.
Yet it is smaller than a standard sleeve.

So we know an un-sleeved generic cylinder has incredible strength.
But I have witnessed (the hard way) a sleeved chubblehead cylinder separate and crush the rockerbox into the frame.
It had been cut to open up several windows, and was probably then torqued with a three-foot cheater no doubt.

My contention is that finesse-ing one last hurrah on the cylinder is more rewarding than dumping money into a sleeve job. But huge overbores cannot be performed at reasonable clearances without hone-fitting with a stress plate upon the base at least. A top plate preserves ring seal.
And please also consider in your decision that your cylinder bores need not match, when you assess their potential.

PS: Liberty no longer offers these services!!

01-17-2010, 04:24 PM
Damn, now that' an education. And BTW the carb you rebuilt runs perfectly. Got the motor assembled and ran on a bench...no leaks! Finally got it back in the frame.

01-17-2010, 05:07 PM
To add to what Tom said in regards to distortion at the cylinder base, the major cause of the distortion is the clearance cut for the cylinder fastener. I have corrected this on the milling machine and found the factory was very sloppy with machining at that area. Indicating from the cylinder gasket surface to zero and then checking the relief, it is common to find that the relief is rough and far out of parallel to the gasket surface. It is easy to imagine the distortion caused by the nut and lock washer making contact with only a third or less of the surface over a gasket.

T. Cotten
01-17-2010, 06:08 PM

I gotta get my rotary phase converter online, as my Bridgeport on a 110 buzzbox can't throw a tool like that.

The significance of the fastener stress is driven home by the early '80s triangular blanchards that the Factory found necessary for the already-overbored 80" Chubbleheads.

Just the technique of applying stress plates should distort the bore quite close to the same as when installed, even if the individual blanchard clearance deck isn't square..

There's always fastener stress, unless you re-design to through-bolts like evilevos.
Having square fastener decks would be ideal of course,,,
but the studs will be a skosh taller, huh.


Bill Pedalino
01-18-2010, 06:34 AM
Cotton's point about heat transfer is well made. We would bore the hole straight on a Van Norman boring bar at the slowest feed speed and then size the hole on our Sunnen hone using AN-300 stones.

We also used a 0.002" press fit. While a rule of thumb with steel is to press fit to about 0.001" tight per 1" of bore, cast iron is softer brittle. We used 0.0005" per inch of bore for cast Iron and pushed the press to 0.002" for cylinder sleeves, being that we heated the sleeves before and during the pressing operation (and prayed that we didn't hear a crack durinf the cool-down). This seemed to assure a tight fit, ample metal contact for heat transfer and it (apparently) was not too tight as to crack the cylinders.

Again I concur - luck was on our side!

01-19-2010, 01:07 AM
Thanks for all of the info guys-what would be the biggest bore I could go up to safely? I've been told 60 over?

Jerry Wieland
01-19-2010, 08:27 AM
A friend of mine run a pan head at .080 or .090 for years without a problem. .070 is absolutely no problem.


T. Cotten
01-19-2010, 08:35 AM
Thanks for all of the info guys-what would be the biggest bore I could go up to safely? I've been told 60 over?

As I posted already,
The individual casting must be measured to determine the remaining casting wall at the thinnest spot.

Some OEM 74" castings will take .100" overbore, and have a safe .070" remaining.
(Some oriental castings will hit daylight at .030" over!)
Great variation can occur beyond the original "core float", resulting from the additive errors of several bore jobs over the decades.

A skilled machinist can easily bias a boring bar away from the thinnest spot, hopefully back toward the true center.

And once again lest it be overlooked, the use of stress plates is manditory for excessive overbores. They should be applied for fitting any 74" cylinder at .060" or more over standard bore.
(And also applied to sleeved cylinders of any bore!)


01-27-2010, 02:43 PM
Thanks guys!

01-28-2010, 02:41 PM
Great thread guys, a real education, thanks.

01-28-2010, 10:22 PM
For what it is worth, Atlantic Machine in New Bedford Ma has the touch, and has even saved a few JD cylinders with sleeves.

03-05-2010, 02:00 PM
Is anyone out there experts on hard chrome as is used in the aircraft industry? For years the aircraft industry has used chrome to build cyls back to standard. The famous Pratt&Whitney 1340 & 985's cyls which havn't been produced since approx 1953 have been rechromed countless times as surplus NOS parts are long gone. The crop dusters have been running these engines for years. Chrome is used in many other aircraft cyls as well. That said most acft cyls that I am aware of were bored only once to .010 or .015 OS, so I do not know if cyls cam be built up .070 or more. A friend/owner of an aircraft shop that I sometimes worked at once in my off seasons asked a acft cyl chroming company if the would build up his jugs for his 50 pan. They were not interested, but this was about 30 years ago. Harder times have befallen the aircraft industry recently and maybe ther might possibly be a firm out there more willing to take on MC cylinders to help keep their doors open. I would think there could be quite a demand for this service, at least for a while. Maybe someone out there has some connections? Cam

George Greer
03-08-2010, 11:23 PM
Good info,

Does anybody know what would be the safest oversize for a set of KH cylinders going into a stroker rebuild?

I have measured the cylinders at almost .060"



T. Cotten
03-09-2010, 08:12 AM

No two cylinders have been bored, re-bored, and re-bored again and again to the same concentricity within the casting. Error is added every time a bar is centered into it.

It is far safer to actually measure the remaining wall, as I suggested previously, than to gamble on conjecture or anecdotes.