Piston Ring Question
Piston Ring Question
On the Kozo Heisler, he calls for graphited asbestos yarn for packing for use as a piston ring. Later projects call for graphited ceramic fiber yarn. These are both for 3/4" scale engines. My question is for a 1-1/2" scale engine, is this the recommended material? Also, if it is the best, where is a good source to obtain it?
- Benjamin Maggi
- Posts: 1409
- Joined: Wed Apr 25, 2007 10:38 pm
- Location: Albany, NY
Re: Piston Ring Question
I bought some from the local Ace Hardware store. It is use for packing plumbing fixtures.
See this link: https://www.acehardware.com/departments ... ng/4200366
Amazon probably has it too.
That being said, I cannot comment on whether it is the right choice for your project.
See this link: https://www.acehardware.com/departments ... ng/4200366
Amazon probably has it too.
That being said, I cannot comment on whether it is the right choice for your project.
"One cannot learn to swim without getting his feet wet." - Benjamin Maggi
- Building: 7.25" gauge "Sweet Pea" named "Catherine"
- Building: 7.25" gauge "Sweet Pea" named "Catherine"
-
- Posts: 151
- Joined: Sun Feb 08, 2009 4:27 pm
- Location: Surrey, UK
Re: Piston Ring Question
If the cylinders are cast iron then I would.go with proper piston rings.
Paul Edmonds,
Surrey, United Kingdom.
2.5" Scale D&RGW K36, 1/6" Scale Challenger 4-6-6-4 (nearly done!!)
Surrey, United Kingdom.
2.5" Scale D&RGW K36, 1/6" Scale Challenger 4-6-6-4 (nearly done!!)
Re: Piston Ring Question
For 1.5" scale your typically looking at a true piston rings of some sort. You don't mention material. My cylinders are cast iron. I have a 1.5" scale Kozo A3. I had originally bought some rings via a vendor on this site but I was without a lot of knowledge at that point and after I installed them I found that the piston damn near wouldn't move in the bore. Now I realize there is some wear that needs to take place but this was way beyond being able to actually physically push the piston through the bore so I ended up just making my own rings out of cast iron using the excellent instructions from David Moore. I was quite proud of the that fact that I completed them and they worked quite well, for about a year. I always felt like they were leaking. After one particular trip on a local track with some big grades I was sure it had something to do with the rings. The engine just couldn't get out of its own way, so on a tip from Don Yungling, I built new pistons and moved over to glass filled Teflon rings. That was an epiphany. After that, Ill never go back to true piston rings. There is no comparison. My engine became a completely new engine after that. $.02
Ken-
Ken-
- Dick_Morris
- Posts: 2846
- Joined: Sat Jan 04, 2003 2:09 pm
- Location: Anchorage, AK
Re: Piston Ring Question
Does that take a two piece piston?glass filled Teflon rings
- Bill Shields
- Posts: 10548
- Joined: Fri Dec 21, 2007 4:57 am
- Location: 39.367, -75.765
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Re: Piston Ring Question
I have successfully used graphite yarn.. would never use ceramic yarn as I feel it can be abrasive and damage the bote....ok maybe on a valve stem
I have used cast iron rings in 3/4, 1 and 1.5" engines for decades. I will let you know (or your grand kids) when any of them fail or leak.
Agreed that the PTFE will work well if on a brass cylinder..but in cast iron bore you cannot beat a properly designed and built cast iron ring.
I have used cast iron rings in 3/4, 1 and 1.5" engines for decades. I will let you know (or your grand kids) when any of them fail or leak.
Agreed that the PTFE will work well if on a brass cylinder..but in cast iron bore you cannot beat a properly designed and built cast iron ring.
Too many things going on to bother listing them.
Re: Piston Ring Question
I use cast iron rings from here OTTO GAS ENGINE WORKS 2167 Blue Ball Rd Elkton Maryland 21921-3330 http://www.ringspacers.com/rangcast.htm
Bill
Bill
Re: Piston Ring Question
I went with the graphite/teflon rings with an O-ring backer in built up pistons on my A3 in 1.5” scale. Ran well on air, no steam yet. I cant find the pic or info I had on them. I sourced them from McMaster/Car though.
Re: Piston Ring Question
It's just a single ring. Glass filed Teflon backed up with an o-ring. I use a modified cylinder head with a 1 degree angle cut in it to slip them into the bore.
Ken-
Ken-
Re: Piston Ring Question
In the Manual of Model Steam Locomotive Construction, Martin Evans briefly discussed the fit for iron piston rings and mentions using "one or more grooves" packed with graphite yarn. There are enough references to graphited yarns for it to be viable but I would say iron piston rings and polymer seals are the preferred methods.
You've seen my Dad's Pacific at Pepper's. He used overlapping iron rings for both the main piston and piston valves. The rings came from hydraulic cylinder rebuild kits. The cylinder bores are ductile iron and the valve chambers bronze. They have been in service since 1992.
You've seen my Dad's Pacific at Pepper's. He used overlapping iron rings for both the main piston and piston valves. The rings came from hydraulic cylinder rebuild kits. The cylinder bores are ductile iron and the valve chambers bronze. They have been in service since 1992.
Re: Piston Ring Question
Thanks for the replies. The bores are brass (or bronze) and the piston is stainless steel. (I took over the project from someone else who started it.) There are no ring grooves in the pistons as of yet. I will need to add them to fit whatever I use. So with this setup, would the recommendation be to use a PTFE O-ring with backup rings?
- Bill Shields
- Posts: 10548
- Joined: Fri Dec 21, 2007 4:57 am
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- Contact:
Re: Piston Ring Question
Cast iron rings would not be my first choice with brass or bronze cylinders but they will work well...is just a question of cylinder life @ high ring velocity.
If you have confidence in PTFE rings then go that direction. Nothing to lose
Question is.. why did the first set of rings fail?
If you have confidence in PTFE rings then go that direction. Nothing to lose
Question is.. why did the first set of rings fail?
Too many things going on to bother listing them.