Sleeving of cylinder

Is it possible to sleeve a U 74" and bore it to +.040"? If so, what may be apropriate sleeve wall thickness?

Torstein

someone will jump in here and say it can't be done. I'm not sure why because sleeving of vintage engines to use non-standard pistons is common in the UK, but it seems to be looked on with disfavour in the US

On the contrary, sleeving of big twin cylinders is very common. Los Angeles sleeve company has sold sleeves for UL/ULH and VL as well as knuckle, pan, and 45 sleeves. I have done several in the past. Sleeve wall thickness is quite large so you can fit from Std to .070 OS with UL (3 5/16) pistons. If installed properly there are no issues. Robbie

well, that would be my experience also. However you don't have to look far on this forum to find the opposite view.

sleeving is common in UK, because a lot of the pistons used on various British marques were Hepolite, and so they have similar wrist-pin and deck height dimensions, just the bores and crown profiles vary. BSA made their own but tended to use various common dimensions over long periods of time, Triumph 71mm pistons can be made to fit all sorts of things, and so on

plus they are usually sleeved in the first place

The LASCO sleeve normally used is 3-9/16" OD, 3-7/16" ID and suitable only for VL and 120-37/371 (UH, ULH, any 13 fin) cylinders. Expect a crack right under the guide ledge if used on a 120-38/381 (11 fin) U, UL cylinder.
Many used UL cylinders have already been bore to ULH.
If you can find a sleeve that's only 3-1/2" OD it may work, but I'm not aware of any offered as a regular item.

OK! I found LA sleeve Company's home site. There online catalog states:

LA-35: OD 3.5" / 3/16" (0.1875") wall thickness
This gives wall thickness of 0.094" on std-bore and 0.074" on +.040" in 74"

LA-606: OD 3.487" / 3/16" (0.1875") wall thickness
This gives wall thickness of 0.087" on std-bore and 0.067" on +.040" in 74"

LA-701H (recomended in another tread and suggested by Panic) OD 3.562 / 1/16" (0.062") wall thickness
This gives wall thickness of 0.062" on std bore in 80"

For comparison:
The India-produced sleeve: OD 3.437" / 0.087" wall thickness
This gives wall thickness of 0.062" on std-bore and 0.042" on +.040"

So maybe LA-606 and +.040" is a healthy choice?

Torstein

Looks good, and LA-35 if it won't clean up at 3.487".

The question is whether any of these except 701 (or a custom sleeve) is long enough...?

I'm not sure where that suggestion appears, but 701 is the "generic' sleeve sold as "suitable for all flathead big twins", and I don't agree.

I have seen 74" Knuck cylinders that were sleeved by LA Sleeve crack completely around the middle and the top half slide up the sleeve. Fortunately the intake manifold developed a large air leak and the engine died before much damage was done.

Torstein -

Just out of curiousity. Are you immediately boring to 0.040" OS after the new sleeve is installed? Or, do you eventually want to reach that OS? I am confused as to your first question, as to why go to 0.040" OS after sleeving, if that is indeed what you are asking. It's also past my bedtime, and I may not be seeing the obvious.

Jack

are you boring 0.040" over on a new sleeve to use existing pistons? I've known people do that and wouldn't bother, I'd go new at the same time. Keep the o/s pistons for future use.

regarding the cracked cylinder issue I don't know about knuckleheads, but I DO know that it is important to choose a sleeve which is the correct OD for your casting, also that it is a shouldered sleeve so that the top end is positively located and it can't slip. That's a last resort but can save at least the main parts of your engine. Early Land Rover Freelanders are notorious for this, for example.

Sleeved cylinders are fine as long as you have the right parts and the workshop knows what they are doing, but that's a fair-size 'IF'

The case is this: Both cylinders have +020". It was bored in the late 1980's. The previous didn't have a good air filter, so it was some very light stripes. The front cylinder also had some light marks after lack of lubrication before I removed the baffle. But the honing marks still is wissible under where the rings have svept. Dispite of this the old engine goes without complaint and without oil consumpion.

Nevertheless I have ridden the bike for 12 years now. I have ridden it over 20000 miles, the last owner I don't know how much. The last thing to rebuild is the cylinders. So my plan was to bore both to +.040 sometime.

When I pulled the front cylinder because of a lifter base leak I noticed something strange. It was erosion in the cylinder, but only only where the piston pin have svept (both sides). Very light in most of the bore but deep on the top/right side. I do not have a good explaination for this. The only thing I have thought of is that some piece of metal has been trappet inside the piston pin (a tiny tiny corner of one of the piston pin clips is missing...) It's 7 years since I pulled the cylinders the last time.

So my new plan is to sleeve the front cylinder to match the rear on +.040".

The bike is stock exept for:
- non-CV Keihin from -85 XL
- modified intake manifold
- panhead cigar muffler
- Aluminum heads from FHP
- modified combustion chamber shape
- 6.8:1 compression ratio
- return oil filter, always on full syntetic oil

About cracking: there is always a possibility for cracking as long as I start the engine, even if I have no sleeves. It's a matter of taking the smalest possible risk I think.

Panic: my cylinders are right under 7.5" long. All of the LA-sleeves above are stated 8" or more. Can you explain where the cylinders usually cracks? (guide ledge, sorry I don't understand).

Torstein

I would say that if the bike has plenty of compression, starts well and doesn't smoke or use any significant amount of oil, bore it to 0.040" on the existing cylinders and put it back with new rings and pistons. I would never overbore, or do any operations like sleeving without a very good reason

From what you have stated about the present condition of each cylinder, I would take the approach that the old Harley shops used to do. Bore or hone, whichever takes the least amount of metal out to clean them up. And, size them independant of each other, reguardless of size outcome. The difference in weight of the two will not affect the balance of your engine at all. I have pulled many 45's appart that had mismatched pistons in them. I explain this to a customer, and give them the choice of matched, or just replace the offending piston. Most don't care. Once you put the heads back on, they all look the same. It was/is an accepted practice of economics, that I'm sure the 'Factory' taught it's dealers.

I'm also with 45Brit on the sleeving. I wouldn't install sleeves until the cylinders have reached their maximum safe overbore.

Jack

Most fragged cylinders over the ages could have been avoided if torqueplates had been applied for the final piston fit.

Rather than conjuring, why not measure the cylinder's remaining wall?
( I found .070" remaining on 13 fin'd cylinders bored to .070" over)
If you don't, sleeving risks cutting disastrous "windows" into the casting, as shown on a Chief the first attachment.

Another risk of sleeving is when common automachine shops cram in a sleeve without paying any attention to the finish of the casting bore. A rough toolmark allows for an insulating gap, leading to a very short life, as shown in the second attachment.

If and when there is no alternative to sleeving, then the casting should be honed to a microfinish before installation, and torqueplate(s) should still be used for a final fit: Sleeved cylinders distort even at stock bore.

....Cotten

If you are going to install new sleeves why not use STD. bore pistons? NOS STD. bore pistons show up at swap meets and eBay.

Here are a few,

http://cgi.ebay.com/ebaymotors/VL-UL-NEW-80-IN-SET-PISTONS-STANDARD_W0QQcmdZViewItemQQcategoryZ35558QQihZ020QQitemZ300186910609QQrdZ1QQsspagenameZWDVW

http://cgi.ebay.com/ebaymotors/UL-N-O-S-PISTON-SET-005-OVER-NEW-IN-BOX_W0QQcmdZViewItemQQcategoryZ35558QQihZ020QQitemZ300186787317QQrdZ1QQsspagenameZWDVW

http://cgi.ebay.com/ebaymotors/UL-N-O-S-PISTON-SLEEVE-KIT-ORIGINAL-HARLEY_W0QQcmdZViewItemQQcategoryZ35558QQihZ020QQitemZ300186346473QQrdZ1QQsspagenameZWDVW

This tread raises as much questions as those being answered. I was afraid that this was not an easy decition. I messured the front cylinder damage today. Its less than 3/16" in diameter and 0.028 at the deepest. It's on the right side (remembered wrong) 1.3" from top. Cylinder maybe clean up at +.080". Appart from this the cylinder will clean up at +.040". If this bike had not been such a baby for me, I would have bored to +.040 and se how long it would last.

The outside diameter og the cylinder is about 3.7" (casting number 120 38).

Chris: I'm not going to sleeve both cylinders. Piston availability is not a problem even in Norway.

Cotton: Are you certain that the marks on that sleeve isn't there because of uneven temperature in cylinder (hot on the right side causing distortion)?

45Brit: Yes I want to use new pistons.

Jack: I have also had engines with .020" mismatch in bore. I will have at least .040" without sleeving. Hm....

Thanks for the very good responce!!

Not only is the balance weight difference too small to be significant, but the difference in compression ratio and power between the 2 (if .040" diff) is less than accepted cylinder-to-cylinder variation for a new motor - about 2.4%. Don't worry about it.

Sidewinder asked:
>>Cotton: Are you certain that the marks on that sleeve isn't there because of uneven temperature in cylinder (hot on the right side causing distortion)?

Let us first assume that a sleeving job can be performed successfully, as they have for generations. But most of those generations had more experience than ours.

The photo shows the outside of a sleeve removed after service.
(Just the fact that it could be removed indicates a poor installation..)

Sorry to use a Chief sleeve for an example, (And I have since edited it to show it right-side-up),
But the carbon indicates a large gap between the sleeve and the casting, or it wouldn't have been able to get in there and cook.

In a solid casting cylinder, the major distortions in service are, as you mentioned, heat-related adjacent to the exhaust's heat-sink finnage, bordered against the cooling of the intake. The lop-sided aspect of flatties is a fact o' life (and frankly, dismisses the usefullness of a top torqueplate..)
A sleeved cylinder faces this as well, but also must contend with friction and hydraulic forces of the piston skirt against a spring-within-a-spring spigot at the bottom. A bottom torqueplate will allow the bore to be fitted while 'sprung' to the fastener's stress at least.

Chiefs do not even have an extended spigot, no more than the scallop at the bottom, yet the example in the photo shows the heat was contained half-way up the piston's travel. U's have very large spigots that pucker both inward and outward from the base nut's torque alone.

Whether the fuse is lit from the top by unusual combustion (advanced timing, vacuum leak, etc.), or at the bottom by a rubbing skirt, temperatures quickly rise to burn valves, stick pistons, warp heads, etc.
But with simple techniques, these problems can be minimized: Reduce the insulating gap between sleeve and casting by finish-honing,... and pre-distort the cylinder base with a torqueplate when finish-honed.

...Cotten

Here's something to ponder on. I brought this up a while back (maybe a few years, now) on this forum. My buddy Pat plates copper to the inside of the bored cylinder, in preparation for a sleeve. I believe he uses a 0.003" interferance fit, after plating. As metalurgy is one of his favorite subjects, I'll give him the benefit of the doubt as to the pros and cons of dissimilar metals and such. He chills his sleeves with CO2 and heats his cylinders in an oven. He says that he can push the sleeve through to better than 2/3's, rapping it as gently as he can with a heavy wooden mallet. Then, quickly to the hydraulic press where he says that it slips the rest of the way easily. He says the copper is soft enough to fill the microscopic voids and give complete heat transfer. Just thought I'd bring it up again.

Jack

I don't know about the copper plating, but the shop who have fitted my sleeves for many years ( most of my vintage racers have them ) always do the warm cylinder / chilled sleeve for fitting

the pic of the windowed casting is a good reminder. One thing I have found over the years with older Big Twins ( ohv and sv ) is that they are sometimes under-engineered, which is a curious thing to say about something that heavy, but nonetheless it is so. 45s are much better off that way, plus of course 45 riders can always buy new barrels from Kurt rather than take the risk. It was an important factor in my choice of a 45 for my new project. I could have got a U, but decided against it.

also, British practice is to stop boring at 0.040" and sleeve, or simply replace, the cylinder and they have plenty of meat for that range. Harleys, people go on boring to 0.070" and more. I wouldn't do that, personally.