Cylinder Sleeves

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TriangleTom
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Cylinder Sleeves

Post by TriangleTom » Fri Nov 15, 2019 2:09 am

I recently called a local foundry to inquire about having my cylinders cast, however I was surprised to learn that while they do work in steel, they won't pour cast iron. I've redesigned my engine to use aluminum cylinders and receivers, but I'm concerned that aluminum may be too soft and will be scratched by the piston rings.

Is this something worth worrying about, or am I crazy for thinking that sleeving the engine is necessary at all?
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Lopez Mike
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Re: Cylinder Sleeves

Post by Lopez Mike » Fri Nov 15, 2019 2:43 am

If you have the cylinders cast in aluminum then the thing to do would be to sleeve them with cast iron. Sleeves of almost any size are available from automotive sources. I've been shrinking them in for years.

This scheme has the added advantage of allowing you to do a very accurate job of locating the ports. In other words, pre-machine the ports before installing them. This isn't a bad practice with cast iron cylinder castings. It's possible to have very large ports in the sleeve by drilling and milling them such that there is no chance of rings catching on the port openings.

I have heard of bronze cylinders but have no experience of them.
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Re: Cylinder Sleeves

Post by TriangleTom » Fri Nov 15, 2019 2:51 am

Lopez Mike wrote:
Fri Nov 15, 2019 2:43 am
If you have the cylinders cast in aluminum then the thing to do would be to sleeve them with cast iron. Sleeves of almost any size are available from automotive sources. I've been shrinking them in for years.

This scheme has the added advantage of allowing you to do a very accurate job of locating the ports. In other words, pre-machine the ports before installing them. This isn't a bad practice with cast iron cylinder castings. It's possible to have very large ports in the sleeve by drilling and milling them such that there is no chance of rings catching on the port openings.

I have heard of bronze cylinders but have no experience of them.
That's a fantastic idea, thanks!

On the topic of bronze cylinders, I looked in to having them cast in C954 bronze, but it just didn't make sense given the greater expense and more difficult machining.
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Re: Cylinder Sleeves

Post by Mike Rometer » Fri Nov 15, 2019 9:11 am

Tom, check out this thread, about half way down page one. My block is cast iron but the principal is exactly the same. Note I didn't use auto sleeves due to cost and availability (over here).

viewtopic.php?f=8&t=1318

Edit : - My chunk of cast bar was only £10 (GBP).
Last edited by Mike Rometer on Fri Nov 15, 2019 3:06 pm, edited 1 time in total.
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Re: Cylinder Sleeves

Post by RGSP » Fri Nov 15, 2019 9:57 am

With aluminium it is SOMETIMES possible to convert its surface into a hard anodised layer, which is wear resistant and can be suitable as a cylinder surface, but not all grades of alloy will allow good strong anodising, and in any case finding someone to do it properly may be more difficult and expensive than buying a cast iron liner. Decorative grades of anodising will most likely not like hot steam, and the materials science behind it all is seriously complex, even though the basic principles are simple enough.

I'm surprised at anyone having difficulty getting appropriate liners in the UK: these people come to mind:
https://westwoodcylinderliners.co.uk/pr ... e-by-size/
I'm pretty sure there are a couple more comparable stockholders in the UK, and liners for chainsaws and other small engines are easy enough to find by size from other suppliers. I can't believe that there aren't similar stockists and suppliers in the U.S. The liners aren't cheap, but then making a decent steam engine isn't cheap at all, and liners won't hugely add to the total cost

With a good quality cast iron cylinder block, the material will certainly be fine as a cylinder wall, and while liners may be desirable for optimum port size and shape, they are an extra expense and complication, and many, many, thousands of steam engines have performed well without them. It is perhaps worth noting as an aside, that several recent new-build steam locomotive replicas in the UK have employed shrunk-in liners, which have permitted "piston ring friendly" multiple divided ports, and highly complex fabricated and welded cylinder blocks.
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Re: Cylinder Sleeves

Post by ccdewitt » Wed Dec 18, 2019 10:41 pm

A good source for many diameters of sleeve is: https://www.lasleeve.com/tech/all-purpose-sleeves.
I have purchased from them and found them to be as advertised.
Definitely put a sleeve in aluminum. It will save the heart ache.
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