IMD BSA A10 piston kits (2) & cylinder sleeves (2)

[vemmi]

Hello

Need new sleeves due to one large mark on cylinder bore that cannot be compensated by reboring. Ordered IMD set but they did not send any instructions (I have asked instructions from IMD). So Meanwhile if anyone can assist proper heating of barrel and what is tolerance with sleeves? Do sleeves need to have same gap that is in the barrel marked red?

[Swarfcut]

  Fitting sleeves to cylinder barrels is not a backyard fix, this work is usually undertaken by specialist engine reconditioners and machine shops..at least in the UK.  These folks will be well acquainted with tolerances and procedures, and this is why instructions are sometimes absent. If you have the skill and facility, YouTube is a good source of how it's done but lower skirt is fragile, best to leave to the experts.

  Cut out (gap) in the barrel skirt is necessary on the A10 engine to clear the throw of the con rod. Smaller stroke A7 engine does not need this cut out.

 Swarfy.

[groily]

This is a job I have only done once in my life, when a friend turned up with the bits asking if I had a press and could help him out. Gulp.
(The only resleeved cylinders I have on one of my own machines I farmed out, for the reasons Swarfy gives, so I wasn't that keen to 'help' to be honest.)

The one in question was for a BSA M21, so a big 600cc single cylinder. He assured me that the dimensions of the liner he'd sourced were good and promised faithfully he wouldn't have a hissy fit if it all went wrong. He's a fitter and turner by trade, so he knew the risks. I didn't know what the inteference fit should have been, and doubt he did either.

I didn't know then and don't know now what the correct procedure is. With any luck IMD will tell you and you can share it.
But what we did was heat the cylinder to about 250-300°C and put the liner in the deep freeze for a couple of hours.
Then we moved the bits to the shed as fast as we could and pressed the liner in, having ensured the cylinder was squarely and centrally set, and using a 10mm-thick steel plate over a substantial mandrel my friend had made earlier to sit in/on the liner. Which seemed to us to be a 'must-have'.

My gnawing fear (rising panic more like!) was that we'd get stuck half way and be in very deep trouble, but in fact it went in smoothly to full depth/height.
I can't remember now if M21s need cut-outs for the connecting rod. If it did, we cut them after fitting.

It turned out OK and that engine is running well pulling a sidecar (so gets good and hot but has resisted falling to bits), but we shan't want to do another one in case that was just Beginner's Luck.   

[sean]

Been down this road with IMD they told me the machine shop will know the spec for  interference fit .
I believe it cost me $650 cdn to have the liners pressed in  and cylinders hone to size after.
The only thing I dont like with the IMD liners is there is no lip or top hat to lock them in place like some other liners have.
The machine shop that did mine wet blasted my barrels and when I picked them up he said they were ready to install took me a couple of hours to clean all the blast media out of the barrels it seem all they did was wash them in a varsol tank.

[RDfella]

I have fitted hundreds of dry liners (plus occasional wet ones) but mainly to med sized diesels. The majority of the dry ones had no lip and were approx .005" interference. Needed around 20 tons to press in, and then needed boring to size. The worry I have with engines like the A series, is how much does it weaken the flange / barrel join?

[chaterlea25]

Hi All,
If the liners were pressed in with a .003/.005in. press fit  i would bet the section below the base flange would fail disastrously 
The only time I had a Bsa single barrel lined that had the section below the cylinder base I had the shop make the bottom part a size for size push fit leaving the interference fit for the stronger part of the barrel

John

[Brian]

I have a pair of original Hepolite liners with their fitting instructions, the recommended interference is .001".

[sean]

I have a pair of original Hepolite liners with their fitting instructions, the recommended interference is .001".

                                                                                                                                                                                                                                                       

do the hepolite liners have a step in the top to hold  them secure ?

[Brian]

No, just plain sleeves.

[muskrat]

G'day Sean.
I've never seen liners with a spigot for our bikes. Recon they should have as my Cafe has sleeves and one has dropped a few though". It's on +80 so will need re-doing in the not too distance future. May have to make my own (with a spigot).
Cheers

[RDfella]

Chaterlea is right regarding liner protrusion at base.
When I built my latest vee twin (alloy barrels, cast liners) I opted for .005" interference (BTW, .005" is standard for the diesels I did). My vee liners are flanged, but it is important - especially in alloy barrels - to ensure maintenance of heat transfer. To reduce the risk Chaterlea raises, I tapered the OD of the liners down to zero interference, starting about 1/2" above the flange. Idea was to avoid the sudden pressure change at flange face likely to encourage liner failure.

[sean]

G'day Sean.
I've never seen liners with a spigot for our bikes. Recon they should have as my Cafe has sleeves and one has dropped a few though". It's on +80 so will need re-doing in the not too distance future. May have to make my own (with a spigot).
Cheers

I believe Seager Engineering in UK does them for Triumphs wish someone would make new thick flange barrels seems to be a big selection of replacement alloy barrels for Triumphs but none for BSA ....

[muskrat]

G'day Fellas.
Re alloy barrels. Remember JulianM and his build of a weapon chook chaser? He made alloy barrels.
https://www.a7a10.net/forum/index.php?topic=233.msg46673#msg46673  (reply #8) and Rookie posted a link to a mob that made them (reply#5).
Cheers