"Catherine", a USA "Sweet Pea" engine build

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JohnR
Posts: 59
Joined: Wed Feb 19, 2003 8:08 pm
Location: Northern Ohio USA

Re: "Catherine", a USA "Sweet Pea" engine build

Post by JohnR »

When you get it running come to Northern Ohio.
EMLS. We have 2 Sweet Williams running there. Currenltly
working on a third and fourth.
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Benjamin Maggi
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Joined: Wed Apr 25, 2007 10:38 pm
Location: Albany, NY

Re: "Catherine", a USA "Sweet Pea" engine build

Post by Benjamin Maggi »

It was during the timing of the chassis that a terrible truth hit me: we had not yet installed the cast iron piston rings (previously purchased from Allen Models). Honestly, I didn't know they were needed at this time and I naively assumed they were to be put on right before actually running it on steam. I thought that running the engine on air didn't require the rings. And while technically I think that is true, we decided it was better to put them in now (and sufficiently lube the cylinders to prevent their binding and/or rusting) rather than wait for the future. So, part of the valve gear on each side was removed, the piston assembly was extracted, and the rings were carefully slipped on.
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I had heard horror stories of how easy they were to break but I didn't have that problem. But, one of my piston slots was cut slightly narrow on part of the piston and I had to gently open it up with a file until the ring slid into the groove.

Putting the piston back into the cylinder without the rings binding was another matter. After trying random prodding/squeezing/poking methods my shop mentor hit upon the great idea of using a hose clamp. We slipped it over both rings, tightened it up, and gently slid the cylinder into the piston. The clamp was adjusted to only cover part of the ring, and we slid the exposed ring portion into the cylinder. The clamp was slid down further to only cover the other ring and the process was done again. In a couple of minutes it was done.
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I would LOVE to know how others do it though without a hose clamp!
Last edited by Benjamin Maggi on Sat Jun 03, 2023 4:56 am, edited 1 time in total.
"One cannot learn to swim without getting his feet wet." - Benjamin Maggi
- Building: 7.25" gauge "Sweet Pea" named "Catherine"
Mike Walsh
Posts: 955
Joined: Sun May 06, 2007 10:14 pm
Location: St. Louis, MO

Re: "Catherine", a USA "Sweet Pea" engine build

Post by Mike Walsh »

At the WF&P our cylinder pistons are ~3" diameter. AS such we use a standard piston ring compressor as you'd see in automotive shops.

I don't think I've come across one small enough for our valves, which are about the same size as 1.5" scale main piston rings...

I've had some ideas for something, but no time. I was thinking a simple tapered bore to compress it enough to press in. But that'd take some effort.

Mike
Odyknuck
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Joined: Mon Aug 08, 2022 4:21 pm
Location: Chardon, Ohio

Re: "Catherine", a USA "Sweet Pea" engine build

Post by Odyknuck »

My Logger loco project came with a ring compressor for the main pistons, and they are 2 1/4"
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PistonRingCompressor.jpg
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Bill Shields
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Re: "Catherine", a USA "Sweet Pea" engine build

Post by Bill Shields »

I have used the hose clamp trick for 40+ years

Did not ever think to look for another way.

Think Charlie Purinton described it to me way back when when I was building my first engine and like a bright bulb asked how....
Too many things going on to bother listing them.
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Benjamin Maggi
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Joined: Wed Apr 25, 2007 10:38 pm
Location: Albany, NY

Re: "Catherine", a USA "Sweet Pea" engine build

Post by Benjamin Maggi »

Thanks all. I guess we were lucky and stumbled onto it (and I hate to think of how we would have done it otherwise!) If it was mentioned in a Live Steam magazine article I don't recall seeing it.
"One cannot learn to swim without getting his feet wet." - Benjamin Maggi
- Building: 7.25" gauge "Sweet Pea" named "Catherine"
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Bill Shields
Posts: 10460
Joined: Fri Dec 21, 2007 4:57 am
Location: 39.367, -75.765
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Re: "Catherine", a USA "Sweet Pea" engine build

Post by Bill Shields »

I also seem to remember doing it on a motorcycle 50 years ago when we were too poor to have a ring compressor of the correct size.
Too many things going on to bother listing them.
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