Who made these barrels?

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Doest pay to do it cheap .

If theyd tryed to do the best job available , cost no object .Then made it a bit less expensive , it might've worked . :p :lol:
Why , just Look at Rolls Royce . You cant beat Quality . Unless you Had a Bently . But that was before the war . :? :wink:
 
I think the problem was related to plasma type coatings working very well on very small diameter cylinders, but as the coating is very thin being far from ideal for use on things like m/c engine parts, with the main problem being rapid wear.

Nikasil type plating remains the favoured method of cylinder finishing for m/c use, with high levels of wear resistance, and is ideal for use on water cooled as well as air cooled cylinders.
 
Carbonfibre said:
I think the problem was related to plasma type coatings working very well on very small diameter cylinders, but as the coating is very thin being far from ideal for use on things like m/c engine parts, with the main problem being rapid wear.

Nikasil type plating remains the favoured method of cylinder finishing for m/c use, with high levels of wear resistance, and is ideal for use on water cooled as well as air cooled cylinders.
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Im sorry, of course you are correct, thermal sprayed cylinders are in fact not useful at all in motorbikes, cars or large diesel engines either for that matter. They are too thin (around 100 microns cf 0.002" typically used for platings) and wear far too fast
 
ludwig said:
Mercedes Benz nanoslide :
http://www.daimler.com/dccom/0-5-658451 ... 0-0-0.html

The days of cross hatch are numbered ..:

Who made these barrels?
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Sulzer Metco have got some pretty good coatings as well. The twin wire arc machines can give pretty good results even in my amateur hands, one nickel wire and a 90MXC hard coat wire give a surprisingly good cylinder surface as well
 
lcrken said:
rpatton said:
Is it true that Kenny Dreer had to delete the headsteady and replace it with the third iso because the alloy cylinders were distorting due to the loads on them from the HS? I've wondered about whether torque plates would be of any use for boring/honing Commando cylinders. I guy I knew told me no, but it would be a different story if they were alloy.
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I use torque plates for boring and honing 920 cylinders, both for iron cylinders sleeved to 920 and for alloy cylinders originally sleeved to 920. I found back in the late '70s that they were esssential for getting any kind of ring seal at the top of the stroke with stock iron cylinders sleeved out to 920.

Who made these barrels?


Ken
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I recently acquired a '75 850 Commando MKIII with an RGM 920 kit. It ran very poorly, has scoring in the cylinders and on the pistons. A lot of oil was getting into the combustion chamber. I noticed the cylinders were bored so much for the sleeve that it cut a into the oil passage a little bit, but the sleeve appeared to seal it up. It seems the sleeve was also not quite up to the level of the cylinder deck though, so oil may have been entering the combustion chamber through there. It seems this engine may have been a victim to the problems you are referring to about boring without torque plates. What exactly are the issues caused by that? I'm debating re-sleeving with a new kit from RGM which is available, but wonder if I would just be getting into trouble inserting new sleeves into these same cylinders. My other option of course would be to just rebuild it as an 850. I would love to hear your thoughts.

Best regards,

John Burke
 
John,

all the 920 conversions I've seen on the stock iron cylinders cut into the oil return hole, but it doesn't seem to cause a problem, at least not on the ones I've used.

The problem I encountered when first doing 920 conversions, using the normal boring and honing techniques, was that the engine seemed to run reasonably well, with lots of mid-range improvement, but no real increase in top end power. It also had significantly more blow-by and oil use. When I looked at the bores, I saw dark areas at the top of the bore at the locations of the counterbores for the socket headed through bolts. There is no suppport there for the sleeves, since you have to bore all the way into the counterbores to make room for the sleeve. It was very clear that the bore was distorting in those locations, and the ring was not sealing the top of the stroke. That's when I made the torque plates and started using them. That solved the problem. When I disassembled the engines built this way, the bore wear pattern was uniform, with no difference around the area of the counterbores, and the excessive blow-by problem disappeared. I've been sold on the torque plates for big bores ever since.

I haven't done a new 920 with iron cylinders for many years, but I've thought about doing one with a different technique. I've got some cast iron bar that I would use to turn plugs to fill the counterbore holes in the cylinders, with center holes to clear the 3/8" through bolts, but not the bolt heads. I could either bond them in with loctite, braze them in, or silver solder them. I'd then bore the cylinders and sleeve them, which would give solid suppport to the sleeves at the top end. I would use longer socket head through bolts, leaving the head of the bolt on top of the cylinder. I'd then drill holes in the head to clear the bolt heads, and make matching holes in the copper head gasket. I got the idea from Steve Maney, who has supplied his cylinders without the counterbores on request. That's the technique I'm using on the Maney 1007 engines I'm building, and I think it would also work well for the 920.

So many project ideas, so little time.

Ken
 
Forgot to mention the other issue you bring up. You said the tops of the liners were sunk below the deck surface a bit. That's definitely a no-no, and will lead to oil consumption and combustion leakage into the crankcase, both as a result of having a leak at the oil return hole. I've found that to be a fairly common failure in sleeved cylinders. I think it mostly comes from not keeping pressure on the sleeves until the cylinder has cooled to room temp. If you don't keep pressure on, as the cylinder cools it has a tendency to squeeze the liners up a bit. Then, when you face the deck surface smooth, the liners have room to drop back down after the engine is run a bit. When I fit new liners, I keep the cylinder in the press until it has cooled.

Going back to the question of the oil return hole being open to the liner, it is possible to get some migration of oil around the liner and out the front of the cylinders where the liners are exposed. My solution to that was to apply penetrating Loctite weld and pinhole sealer to the area at the front where the liners are exposed. An alternate solution would be to plug the oil return hole and run an external drain ilne from the intake side of the head to the timing side crankcase.

Ken
 
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