Hot Rod Forum banner
1 - 5 of 5 Posts

·
Registered
Joined
·
4,265 Posts
Discussion Starter · #1 ·
I will spare you guys the book on the engine I have been off and on napkin figuring for years.
The below link shows a very rough basis for the engine if the cylinder was mounted vertical.



Here is the very short explanation that you need to know to help with my question.

I have a 3/8" shaft that is moving 2" vertically. That shaft is moving a piston within a cylinder. That piston has no rings or oil inside it because it can not. This means tolerances inside that cylinder are tight and I need that shaft to remain perfectly vertical.

I want to use a external "wet ring pack" above and below the cylinder to align the shaft. The lower ring pack will be bigger of course to counter the rotational forces of the rod turning the crank.

The rings will act act as bearings as well as seals. I want oil to be able to get in between the rings so there are no air gaps allowing metal on metal contact. The thought I am having now is to offset the ring openings. But the question is by how much and just how many rings to use to ensure I have alignment and sealing. I am flirting with making the rings out of a sacrificial material such as brass to be swapped out after so much use.

Side loading is my biggest concern right now which leads to what I thought was a simple question.

Are cylinder rings self aligning within a cylinder?
 

·
Registered
Joined
·
4,265 Posts
Discussion Starter · #3 ·
I was thinking step gaps for ease of construction.

But because of the gap does one side "push" more against the shaft/cylinder.

These rings will be stationary and the shaft will be moving vertically so if i was to go 180 with the gap between two rings that would counter any "pushing" or do the rings "squeeze" equally self aligning themselves?
 

·
More for Less Racer
Joined
·
20,943 Posts
Outward radial pressure is equal all around the ring, regardless of where the gap is...does that answer your question??.

if you think rings floating in a groove at the top and bottom of a piston are going to keep it from touching a cylinder wal, it is not. Oil film between piston and bore is the only thing that will hold the pistom off the cylinder's walls.

You may want to look into what an industrial ring company has available before you go to larger cost to re-invent the wheel making a ring that you could already just buy for a lot less cost.

I'm thinking maybe something like a large dialeter hook gap iron or aluminum ring, like what is used in automatic transmissions
 

·
Registered
Joined
·
4,265 Posts
Discussion Starter · #5 ·
Outward yes. I am assuming inward also then? I can not have any oil inside the working piston as the pressure is being produced by sco2 which will then need to be cooled then heated. Any oil at all is going to cause issues.

I could have smaller pistons below and above the working piston with rings on those moved by the same shaft the working piston is on . Then have those pistons submerged in oil.
 
1 - 5 of 5 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top