Piston Rings

[Charles Lamont]

A clamping jig is required to hold the stack of 3---4 rings tight. Heat to cherry red and hold for min. of 5 mins and quench in water. View Paul's thread.

Paul Swifty, Please audit.

And, as I understand it, cherry red is far too hot.

 

[Swifty]

Charles, Malcolm Stride advocates holding the rings at red heat for 10 minutes, I must admit that I got tired of waiting after 5 minutes and left it to cool down after that. Of course, we are only taking the stress out of the rings, and perhaps some leeway could be taken with the amount of heat applied. My rings certainly stayed sprung open as required.

Paul.

 

[Cogsy]

The procedure I have used several times is the Upshur method and advocates dull red for 60 seconds then a slow cool. Mine too have always retained their sprung gap and sealed well.

I personally think that although there are many methods and undoubtedly a best practice, in reality cast iron rings at the size we use, and for the use we demand out of them, are not overly critical in their manufacture and heat treating procedures.

 

[Charles Lamont]

Charles, Malcolm Stride advocates holding the rings at red heat for 10 minutes

I know he does, but others disagree, with reasons:

http://www.jerry-howell.com/PistonRings.html

 

[dsage]

I've always tried to make them by the Trimble method but I leave out the final skim of 1 thou off the diameter. I found more eccentricity in the mandrel and the clamping than 1 thou so it was futile to try. My engines have never smoked even on first pull. The link to Jerry Howells site mentioned earlier http://www.jerry-howell.com/PistonRings.html is about the best summarization of the many documents written on the subject that I've found. And I've tried to collect all of the originals.
You can't go wrong if you read, understand and follow the instructions presented there.

Sage

http://davesage.ca

 

[mu38&Bg#]

Every time I read about making rings, the author mentions "heat treat". Heat treat describes any heat processing, but many associate it with quenching to harden steel. In ring making you are trying to stress relieve the rings to take the new open shape so as to provide pressure on the cylinder wall. Why is the term stress relieving rarely used?

Annealing of gray irons requires heating to 1290°-1400°F, 700°-760°C (cherry red) with slow cooling. Stress relieving needs only 1020°-1200°F, 550°-650°C (blood red -dark cherry). You stress the ring by stretching it open and when those stresses are relieved the ring retains that shape. The temperature difference is small. Above annealing temperatures, other things begin to happen changing the properties. Oil quenching does surface harden grey iron, but on a thin section such as rings you might expect other issues.

This is of value if you want to learn more. www.dtic.mil/cgi-bin/GetTRDoc?AD=AD0620556

Greg

 

[Swifty]

I know he does, but others disagree, with reasons:

http://www.jerry-howell.com/PistonRings.html

Next time I have to make some rings, I will certainly try using a lower temperature. The avoidance of scale is important.

Paul.

 

[gus]

Next time I have to make some rings, I will certainly try using a lower temperature. The avoidance of scale is important.

Paul.

Hi Paul,

Good idea. Keep Gus posted. Had a great day with the Outerheads. Was productive but a wee bitty hot and humid.Makes me tired.

 

[Philipintexas]

I guess ignorance is bliss, I've never done anything to rings in the way of heating/stress relief and they have worked just fine. Sometimes the KISS method works.

 

[stevehuckss396]

I guess ignorance is bliss, I've never done anything to rings in the way of heating/stress relief and they have worked just fine. Sometimes the KISS method works.

Not surprised! Bob Shutt has been running his Peewee V4 for about 5 years now without rings. I suspect they are not as important as we think they are at this scale.