Cylinder Sleeve Design

[Fidlstyks]

The head holding the sleeve in would be the best. Nothing would be more secure than a small ridge at the top to keep in place.
The head would not let it go up and the ridge prevent it from spitting out.

The relief prevents or insures there would be no crush effect.

Relief as a groove in a steel sleeve would be fine.
As Jason pointed out, the entire cylinder made of steel is a good idea.
Pinning a 2 cycle sleeve would be important.
One must consider materials when fitting parts with different expansion rates too.

 

[Kosiba]

Pins are also used on a ported liner to stop it rotating, if it did then the ports could become blocked or at least reduced in area . It also saves people putting the liner back in the wrong way round!

Steel is quite common for the liner or even the complete cylinder on model aero engines, you can turn it thin and it will be less prone to damage than a cast iron one where a thin fin could easily be broken. It also means you don't have similar metals runing against each other. As the engines get bigger you may find cast iron liners are more common as they can be cast hollow so less waste and quicker to machine.

To some extent materials will also depend on what the intended use of the engine is going to be. If it will just get the occasional run for display with no load then you may design differently to an out and out competition engine where speed and power are your main targets and you don't mind replacing liners and piston safter one or two runs which could see them worn enough to mak eth eengine loose performance.

I am familiar with the pin to stop the liner from rotating, and have seen it on nearly all my nitro engines! And now making the sleeve out of steel makes a lot of sense.

 

[Kosiba]

The head holding the sleeve in would be the best. Nothing would be more secure than a small ridge at the top to keep in place.
The head would not let it go up and the ridge prevent it from spitting out.

The relief prevents or insures there would be no crush effect.

Relief as a groove in a steel sleeve would be fine.
As Jason pointed out, the entire cylinder made of steel is a good idea.
Pinning a 2 cycle sleeve would be important.
One must consider materials when fitting parts with different expansion rates too.

Now that relief makes a lot more sense, and I do agree that pinning a 2 stroke sleeve would make the most sense, and I also agree that using the head on a 2 stroke engine would be the simplest way of holding the sleeve in the block, but for a 4 stroke I think just having a tight enough fit would also work, but you would have to be more careful with the material composition of both the sleeve and block.

 

[SmithDoor]

I Just started watching this youtube series of a guy making a motorcycle engine from castings, and when he started machining the cylinder sleeves he had cut a small relief into the sleeve, and then I went to look on one of my 2 stroke nitro sleeves and saw that there was one there too, and now I'm left wondering what they're for and how would you go about actually designing different cylinder sleeves? Like how could/should you position the holes on a 2 stroke sleeve, or what does that relief actually do?

View attachment 165318
The relief would be right below the lip at the top, this one doesn't have it

View attachment 165319
And this on does have it


All help understanding this would be greatly appreciated!

I may what to look at some big Caro ships using 2 cycle instead of steam and saves on fuel.

FYI This was a big surprised for me. I alway was thinking 2 cycles on small engines. Now on the biggest engines too.

Dave

 

[Bentwings]

So you are interested in building a model size, high performance, glow ignition two stroke? That's what that article is the history of. Friction outweighs nearly everything else as engines get smaller. A very long time ago I had a conversation with Glen Dye who said the most important factor in a racing engine was the piston to sleeve fit. The other articles in the series explain the procedures needed to build these very high performance engines and some modern examples.

Lohring Miller

Interesting. Man, many years ago when I was apprenticing tool making in the big machine shop. We got a full house Sunnen home machine. Piles of different hone stones. The cones doing a lot of carbide can industry tooling these carbide pieces required super finishes. Carbide turns almost black when ultra finished for draw dies. We had one of the first 1000 grit ID grinder wheels . These did not require dressing. Only precise indicating in to 0001” run out. They ran about 20 grand rpm on old rebuilt Brown and Sharp id grinders. The spindle bearings were sir supported. I YHINK the machines were old WW2 that was rebuilt to new standards . The gaging was air tool special
Made plug gage you used after initial diameter was reached the machine basically whistled as it ran. Feed dials were really big each line being 1 tenth of .0001”. Temperature controlled and measured. I also used the standard Sunnen hone machines . There was a contingent of model plane speed racers that worked there too. I often honed cyl liners and external honed pistons forvthe ngno guys. Some cyl had stick fit at The top. These were calculated to open up as they ran so sleeves were tapered in effect. 2 stroke nitro engines . Many used single blade props I didn’t go to their events as I was into full sized top fuel drag racing honing and fitting was much looser . Anyway I’m well familiar with tight honing