Ok everyone. What's your thoughts on the 2 ring vs 1 deal ? I'm only asking because I'm my stock pile of pistons i ran across a 1 ring two stroke piston and never seen that before so i looked into it a little. I personally have never seen a 1 ring piston but when i looked it up it was more common than i thought. Any opinions on it for a blaster or anything else? Better heat distribution, less drag, etc etc? any opinions on here?
2 rings vs 1
- Thread starter jus_me
- Start date
Some small bore pistons have no rings at all.
Some large bore pistons can have as many as 5 rings.
Why do some pistons have one ring whereas others have two
Especially on high end racing cylinders you’ll find pistons with only one piston ring. Let’s dig into the advantages of a single piston ring first:
A single piston ring allows for a higher RPM due to reduced friction
A single piston ring improves cooling due to lower friction
A single piston ring reduces the likeliness of piston ring issues
However, as always there are also disadvantages when using a single piston ring:
A single piston ring reduces the compression
A single piston ring makes the piston unstable
Two important assumptions can be made now when removing the second ring from a two ring piston:
1.The piston will last shorter and also stress the cylinder more due to its instability
2.The loss of compression needs to be equalized elsewhere
A single ring racing piston
The first assumption explains why we only find single piston ring pistons in aluminum cylinders. Aluminum cylinders have a Nikasil coated surface that makes them more resistant than cast iron cylinders allowing for a higher rpm and more unstable pistons.
The second assumption tells us that we need to take some material off of the cylinder head to achieve at least a similar compression as the engine with two piston rings. Racing cylinder manufacturers have of course taken this into account…
Some large bore pistons can have as many as 5 rings.
Why do some pistons have one ring whereas others have two
Especially on high end racing cylinders you’ll find pistons with only one piston ring. Let’s dig into the advantages of a single piston ring first:
A single piston ring allows for a higher RPM due to reduced friction
A single piston ring improves cooling due to lower friction
A single piston ring reduces the likeliness of piston ring issues
However, as always there are also disadvantages when using a single piston ring:
A single piston ring reduces the compression
A single piston ring makes the piston unstable
Two important assumptions can be made now when removing the second ring from a two ring piston:
1.The piston will last shorter and also stress the cylinder more due to its instability
2.The loss of compression needs to be equalized elsewhere
A single ring racing piston
The first assumption explains why we only find single piston ring pistons in aluminum cylinders. Aluminum cylinders have a Nikasil coated surface that makes them more resistant than cast iron cylinders allowing for a higher rpm and more unstable pistons.
The second assumption tells us that we need to take some material off of the cylinder head to achieve at least a similar compression as the engine with two piston rings. Racing cylinder manufacturers have of course taken this into account…
Great info from blaaster, and here's a link to another good source of info
Just One Ring on Two Ring Piston
Just One Ring on Two Ring Piston
