Sleeve questions

[55fairlane]

As a professional machinist I have never built a "model engine ", I have built several alcohol injection Hemis, but that's a different story....
So as I am (not so) patiently waiting for my new milling machine to arrive ( apparently $6k just adds your name to the list of people already waiting)
I cracked open a minty copy of "elmers engines" I have kept hidden from the "general population " here at the phunni pharm I call home..

I have settled on a scaling up (2x in size) Elmers Scotty, as I am redrawing the parts, and noting what parts must play nice with other parts,, I got yo the cylinder & piston & started to (over?) Think things.

Should I sleeve the cylinder with a 12L14 sleeve & aluminum piston?

If I sleeve this , how do I finish the sleeve? Bore brush/cylinder hone?

Do I need to "hone" the cylinder to a .001/.0015 under fit? Fitted to the cylinder bore or matched.

My plan is to bore the aluminum cylinder thru, to .877 , then using 648 Loc-tite, glue the sleeve/liner in place. You need approximately. 002 clearance for the Loc-tite (as per there engineering staff) the sleeve will .875 OD and a reamed .750 ID.

And if I get really bored I may take the parts to work and "static" balance the rotating parts

Thanks in advance

Aaron

 

[SmithDoor]

As a professional machinist I have never built a "model engine ", I have built several alcohol injection Hemis, but that's a different story....
So as I am (not so) patiently waiting for my new milling machine to arrive ( apparently $6k just adds your name to the list of people already waiting)
I cracked open a minty copy of "elmers engines" I have kept hidden from the "general population " here at the phunni pharm I call home..

I have settled on a scaling up (2x in size) Elmers Scotty, as I am redrawing the parts, and noting what parts must play nice with other parts,, I got yo the cylinder & piston & started to (over?) Think things.

Should I sleeve the cylinder with a 12L14 sleeve & aluminum piston?

If I sleeve this , how do I finish the sleeve? Bore brush/cylinder hone?

Do I need to "hone" the cylinder to a .001/.0015 under fit? Fitted to the cylinder bore or matched.

My plan is to bore the aluminum cylinder thru, to .877 , then using 648 Loc-tite, glue the sleeve/liner in place. You need approximately. 002 clearance for the Loc-tite (as per there engineering staff) the sleeve will .875 OD and a reamed .750 ID.

And if I get really bored I may take the parts to work and "static" balance the rotating parts

Thanks in advance

Aaron

12L14 is great for models or low run engines.
If I was rebuild a engine for long run then 4140 will last a longer time.

Dave

 

[timo_gross]

All this overthinking seems to boil down to question. Cat or horse?

Cat, only converts chemical energy into heat, makes some noise, moves sometimes a little, does not work. Most important it sleeps most of the day.
Horse, gets as less food as possible, has to get up early to work all day. It will only sleep at night.

My "cat" engines are constructed with a lot of "free-interpretation" of dimensions and material.
If you want the engine to "roll his sleeves up" you should give him some.

 

[mrehmus]

I"d not use 12L14 for the liner. Use a full-length hone to finish the liner bore. Trimble-style rings.

 

[Vietti]

Agree with Mike! Use cast iron for liner.

 

[SmithDoor]

I"d not use 12L14 for the liner. Use a full-length hone to finish the liner bore. Trimble-style rings.

I seen even water pipe used.
Hone tubing is a lot easier but costly. I can get that in 4140 and chrome plated.

Most model engines are never or very little used. So use what is easy and low cost.

I do agree if was rebuild a engine the hone tubing is great and I can charge for tube with profit too.

Dave

 

[55fairlane]

I"d not use 12L14 for the liner. Use a full-length hone to finish the liner bore. Trimble-style rings.

Ok cast iron it is, but please tell me why no leaded steal?

Trimble style rings....what are they? Where do I get them? How much piston to bore clearance? What size is the bore in relation to the ring size, i.e. .750 rings, .751 +/- .001 ??

Please enlighten me

 

[kuhncw]

Scotty is a small steam engine? If so, I'd think 12L14 would be ok for a liner.
What does Elmer's drawing specify for rings?

Do you plan to run on steam or on compressed air?

Chuck

 

[kf2qd]

Are you going to try and run it on steam, or air? if air, then just use aluminum and don't worry about sleeving it. It will work just fine with a sliding fit and an occasional drop of light oil. those engines can run without rings, or a light running fit with an o-ring. Nignition, low pressures, no heat.

 

[55fairlane]

Scotty is a small steam engine? If so, I'd think 12L14 would be ok for a liner.
What does Elmer's drawing specify for rings?

Do you plan to run on steam or on compressed air?

Chuck

Correct, steam engine. Elmer calls for a brass (ringless) piston in an unsleeved aluminum cylinder.

I will run it on compressed air

 

[55fairlane]

Are you going to try and run it on steam, or air? if air, then just use aluminum and don't worry about sleeving it. It will work just fine with a sliding fit and an occasional drop of light oil. those engines can run without rings, or a light running fit with an o-ring. Nignition, low pressures, no heat.

Will run it on air. As I said, am I over thinking this. I wanted to run a sleeve with an aluminum piston to help get some weight off the reciprocal assembly. Try and keep the rod /piston/yoke from hammering itself

 

[minh-thanh]

I seen even water pipe used.


Dave

Yes, I've used water pipes to make cylinders, flame eater, internal combustion, stirling and it's pretty good
Even with small stirring engine (power cylinder diameters are 6 and 8 mm) I used aluminum for the cylinders and pistons and they were good enough.

 

[timo_gross]

The bottle neck seemed to be the gland nut, steam chest covers and cylinder head. I had the impresson piston blow by was not the biggest issue. The smaller leackages everywhere else are adding up.

 

[Charles Lamont]

For running on air grey iron or mild steel would be fine. For steam I would prefer iron. If you are using an aluminium piston with an o-ring seal then the bore needs a suitably fine finish. Also avoid the ring crossing any sharp port edges. In this application it is common practice to use much less ring compression than the 'book' says.

 

[Johan Theo Maritz]

Here is my Scotty in Elmer's true size. I have a clip of it running but seems to be not of a format recognizable when trying to upload.
Mine has an aluminum piston running in stock standard brass without any rings, just oil grooves as per his drawing and a good sliding fit.

 

[SmithDoor]

If look at some manufacturer like B & S they use aluminum casting for there engines.
But later the rebuilds would sleeve with DOM 1020 steel liners.

Dave

 

[55fairlane]

Here is my Scotty in Elmer's true size. I have a clip of it running but seems to be not of a format recognizable when trying to upload.
Mine has an aluminum piston running in stock standard brass without any rings, just oil grooves as per his drawing and a good sliding fit.

Wow is that nice! I see we must at least think somewhat alike.....the longer bushing in the out board support....

 

[Charles Lamont]

Here is my Scotty in Elmer's true size.

I like the base. Is it Padauk?

 

[Johan Theo Maritz]

I'm not sure, we call it Red Ivory in South Africa. You also get Black Ivory wood, hard as steel and heavy, you can drill and tap threads in it.

 

[Richard Hed]

I'm not sure, we call it Red Ivory in South Africa. You also get Black Ivory wood, hard as steel and heavy, you can drill and tap threads in it.

In the Philippines all the woods, even the lightest of them, are very heavy compared to what I am used to in the USA. The Phil woods are very hard but also brittle comparatively. The Philippine mahogany is very hard and strong and heavy but very beautiful when polished. There is a wood that is black cored that is fabulously beautiful--ipil ipil.