Piston Ring Material

[MichaelRParticipant @michaelr]

I make my own Piston Rings for my Hit and Miss IC engines, and have to use solid cast iron bar, of course most of the bar is bored out to swarf and bar is not cheap.

I have never come across cored cast iron in any advertisements in the modelling press, anybody know if cored cast iron is available in model engine sizes.

[MichaelRParticipant @michaelr]

[steamdaveParticipant @steamdave]

Perhaps someone like College Engineering Supplies would be able to give you a definitive answer.

Dave

The Emerald Isle

[David Bartle 1Participant @davidbartle1]

The only problem with cored cast iron that I could see is that the casting is harder on the surfaces. This means that the inner core surface would now also be hard. No reason a small foundry couldn’t cast cored bars though.

[John LadlowParticipant @johnladlow78959]

I agree with David Bartle that the cored stuff is harder on the surfaces. The stuff I had was also not such good quality as the solid bar which might be critical for piston rings.

I have not been able to find any for some time and have used the stocks I did have.

I now keep a large drill on the bench for removing the centre of the bar quickly before finishing off by boring.

As you say it is a bit wasteful.

John

[MichaelRParticipant @michaelr]

Thanks for the info, I hadn’t given any thought regarding hard spots in the cored bar, not a good thing with piston rings.

Like John I will get a large drill and continue to make swarf

 

[Jens Eirik Skogstad 1Participant @jenseirikskogstad1]

Posted by Stick on 26/06/2009 15:42:11:

…. and have to use solid cast iron bar, of course most of the bar is bored out to swarf and bar is not cheap.

 

 

 You can use cast iron from old cam shaft (not cam, impossible to working with tools) or brake disc from car as piston ring material.
 

I has used the material from cam shaft/brake disc with good results in my model engines.

 

[Ian S CParticipant @iansc]

Thanks Jens I’v been looking for material to make piston rings for an open crank motor that I’m building,you reminded me that I’v got some old brake discs and old automotive flywheels,I did want to make a cast iron piston as well,but I’v made it out of aluminium.IAN S C

[Jens Eirik Skogstad 1Participant @jenseirikskogstad1]

Posted by Stick on 27/06/2009 18:52:37:

… I hadn’t given any thought regarding hard spots in the cored bar, … 

 

To be honest i has never seen hard spots in cast iron in the used car parts such as in brake disc, cam shaft or flywheel, they are of good quality cast iron.

 

Do not unharden the hardened cam in camshaft!!! You will get hard spots in soft cast iron between cams after the camshaft has been redglowing.. It is impossible to unharden the cams, they will be still hard.

 

 

[MichaelRParticipant @michaelr]

Thanks Jens, I will be visiting my local car breaker, never gave a thought to the cast iron content of a scrapped car.

 

Stick.

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