Steel cylinders and piston rings?

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philbert
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Steel cylinders and piston rings?

Post by philbert »

Assuming cast iron wasn't available, is it possible to make piston rings from steel, and use them in cylinders made of the same?

If so, how would the manufacturing process change from cast iron rings? If not, what other alternatives are there?
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Harold_V
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Re: Steel cylinders and piston rings?

Post by Harold_V »

I expect you'd get mixed results relying on steel. Because cast iron has free carbon (graphite), it has built in lubrication that prevents galling. That isn't true of steel.

Note that the oil rings in an auto engine are generally made of steel. However, they are very narrow, so there's very little of the ring in touch with the cylinder. Because their purpose is to wipe oil, they get adequate lubrication, plus the steel ring rides on cast iron, not steel. Gray iron is known to be a respectable bearing material.

All in all, I'd suggest to you that it's not a good idea. Steel rusts readily, unlike cast iron, which absorbs lubrication due to its porosity.

If you are truly challenged in using iron, you might consider using bronze for the cylinder, and O rings for the piston.

Those are my thoughts. Others may shed some light on alternate scenarios. For all I know, steel has been used successfully, but I have my doubts.

H
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philbert
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Re: Steel cylinders and piston rings?

Post by philbert »

Thanks for that. With the price of bronze I don't think it's an alternative to anything short of gold :lol:
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Dick_Morris
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Re: Steel cylinders and piston rings?

Post by Dick_Morris »

Check Amazon for cast bronze bushings (make sure the ones you find aren't sintered bronze, i.e., Oilite). I have some I bought for an engine three or four years ago and the price wasn't nearly as bad as I had expected it might be.
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Bill Shields
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Re: Steel cylinders and piston rings?

Post by Bill Shields »

There are several places where you can get cast iron rings for less than the $$ of the material to make them.

I think I paid about $4.00 each for 1.375 OD rings.

ringspacers.com is the place I use.
Too many things going on to bother listing them.
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Greg_Lewis
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Re: Steel cylinders and piston rings?

Post by Greg_Lewis »

Another option is to press in a cast iron cylinder liner. There are lots of sizes available and you can probably find one to meet your needs.
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SteveM
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Re: Steel cylinders and piston rings?

Post by SteveM »

Greg_Lewis wrote: Tue May 01, 2018 9:54 am Another option is to press in a cast iron cylinder liner. There are lots of sizes available and you can probably find one to meet your needs.
I had thought about building a stationary engine at some point, and building it around an existing cast-iron liner is an interesting idea.

Steve
rkcarguy
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Re: Steel cylinders and piston rings?

Post by rkcarguy »

There is a lot out there to choose from anymore. I was looking at some Viton? X-rings that were rated over 400*F from a hydraulics supplier, and then was thinking I'd run them on bronze pistons in a nicely finished stainless bore. This would be IF I venture into live steam.
There are lots of sleeves you can buy as well, existing stuff I'm sure if you look around in anything from small engine parts to industrial stuff.
pat1027
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Re: Steel cylinders and piston rings?

Post by pat1027 »

Grey iron rounds and heavy wall tubes are readily available. I have a Pacific that went on the road in 1992 with fabricated cylinders. The cylinders are made from a heavy wall grey iron round. The valve chambers have a bronze liner. Both the piston and valve spools are sealed with iron piston rings from hydraulic cylinder service kits. There is no leakage or wheezing after 25 years.
philbert
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Re: Steel cylinders and piston rings?

Post by philbert »

Thanks for all the info!
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ALCOSTEAM
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Re: Steel cylinders and piston rings?

Post by ALCOSTEAM »

rkcarguy wrote: Tue May 01, 2018 11:20 am There is a lot out there to choose from anymore. I was looking at some Viton? X-rings that were rated over 400*F from a hydraulics supplier, and then was thinking I'd run them on bronze pistons in a nicely finished stainless bore. This would be IF I venture into live steam.
There are lots of sleeves you can buy as well, existing stuff I'm sure if you look around in anything from small engine parts to industrial stuff.
Bronze does not make for good pistons, use cast iron. Bronze will need to have lots of clearance so as not to seize up when they got hot.
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Re: Steel cylinders and piston rings?

Post by rkcarguy »

My understanding after reviewing some other build threads, was that you do run the piston quite a bit undersize, and let the ring support it. After all, it doesn't have to support any side-to-side loads like a conventional engine. I've seen .006"-.010" recommended? My thought was the stainless and bronze are right next to each other and on the good end of the galvanic chart, and with a Viton seal would offer nowhere to corrode?
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