sleeved cylinder vs. thin cylinders

[jorrow]

I'm in the process of building a 46 FL. I have a dilemma with cylinders. I have 2 sets of originals. One set will have to be taken to .70 over. Ive not run .70 over cylinders on a knucklehead before. The other cylinder set have been sleeved by an unknown source, to stock bore. Since I will never know who has done the sleeve work I am rather worried on being the test bike for these. Can anyone who has had more experience with this shed some advice? My third option is aftermarket. Im not looking to do cross country runs on this bike, but I do not want needless damage should the cylinders break. Thanks Jeff

[Rubone]

Jeff,
+070 is OK if bored correctly and used in a normal manner. And if the cylinders are indeed 74 type. A sleeved cylinder isn't too big an issue if done well, and if a sleeve shifts slightly it generally does not do the amount of damage an exploded one does. I've had the misfortune of looking down after the bang to see the base bolted to the cases, the top ring bolted to the head, and nothing in between. Keep the compression down...

[T. Cotten]

Jeff!

By experience, (I have seen them "separate", too,...)
I would avoid a sleeve until absolutely un-avoidable.
And even then, stress-plates for the final fit are highly desireable.

....Cotten

[jorrow]

Thanks guys, very good advice and much appreciated. Jeff

[exeric]

Tom, could you describe the components in your posted photo.

[T. Cotten]

Eric!

On the left is a fixture lagged to the tabletop to hold the bottom stress or 'torqueplate'; If the assembly is not held firmly, no torque reading would be accurate.
The cylinder has plates attached, and the torsion torquewrench with ninety-degree adapter should be self-explanatory.
(Clickers are for kids.)

The pitfalls of sleeving are many, but avoidable.
The remaining wall of the casting must be carefully measured and compared to the sleeve to avoid "windows" when bored for the sleeve.
Assuming the sleeve will fit, the casting should be bored undersize, and honed to as fine of a finish as possible for the desired interference fit.
A minimum of a thou and a half is not so necessary to hold the sleeve, as it is to insure full contact for heat transfer.

Attached is a Chief sleeve that had been installed by a common poke-and-hope auto shop. The toolmark in the casting insulated to where the bottom of the sleeve burned.
Even with a skilled installation, the cylinder should have at least a bottom stress or 'torque-plate' installed for the final hone-fit: An intact over-bored cylinder is springy, and a sleeved cylinder acts like a circular spring within a spring.

Assembly to the motor should use the same torque spec as it was honed, of course....

I would bet on a huge but a properly stressed-fit OHV cylinder before anything sleeved by an unknown source.

....Cotten

[Chris Haynes]

I have seen sleeved Knuckle cylinders separate. Panhead cylinders are stronger and sleeve well.

[T. Cotten]

I have seen sleeved Knuckle cylinders separate. Panhead cylinders are stronger and sleeve well.

Just for perspective, Chris,...

I have put .155"-over Knuck cylinders into service quite successfully without sleeving;
but I inspected a sleeved Shovel that shot its head into the gastank like a cannon, the first time it was fired.

....Cotten

[Chris Haynes]

Just for perspective, Chris,...

I have put .155"-over Knuck cylinders into service quite successfully without sleeving;
but I inspected a sleeved Shovel that shot its head into the gastank like a cannon, the first time it was fired.

....Cotten

.155 over? That I would have to see.

[T. Cotten]

Chris!

I found ~.070" wall left at the very thinnest spots on 61" cylinders after fitting cast 10:1 .030" OS 74" pistons, at a skosh over .002" clearance.

Ran like a scalded dog through two owners; Lost track of it in Chicago when I stopped taking in chassis.

Without stressing while fitting, it would be impossible.

....Cotten

[PRG]

Howdy Jorrow,

If you have cylinders needing .070 to clean up they are perfect candidates for a process that will yield a running surface superior to the original: hard chrome. As this requires a bit of material removal to achieve finished results anyway, essentially your current bores at, say, .050-.060 over will be taken back to stock with no significant additional material removed except to nominally straighten them up if off center. Though not cost justifiable to some on less valuable machines very worthwhile here from that standpoint as well as enabling the use of modern thin ring technology when selecting pistons.

http://www.usnicom.com/

[T. Cotten]

Anything to avoid this!

....Cotten
PS: Middle cylinder is an un-sleeved oriental Pan 'reproduction' at .O30" OS.
It apparently ran successfully, and only opened to 'daylight' after disassembly, when I put my fingernail through it.