OzVMX Forum
Clubroom => Tech Talk => Topic started by: topari on November 15, 2013, 11:09:00 am
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Has anyone tried to make piston rings ? Seems to me the hard part if finding suitable material and the heat treatment. The machining seems straight forward.
Opinions ?
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Erm with rings so cheap what's the point? Even if you could get the machining down pat there is the chrome facing you would have to consider, which would wipe out and cost advantage you got from machining your own rings. I don't think rings have heat treatment they are just cast iron with chrome face and plain iron if your still persisting with a hard chrome bore.
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I have made some out of cast iron for a model enthusiast many moons ago. To suit model steam engines and model two-stroke airplane engines.
We sourced the right grade of stock by acquiring an old gigantic piston ring from an engineer friend on a mega ton ocean going freighter.
I cut a piece of it, chucked it up in a center lathe, bored, produced a good surface finish on the OD and face of it.
The trick was parting it off at the exact thickness required and still maintaining an acceptable surface finish.
I ground down the thickness and set off an old hacksaw blade to cut them open with an end gap. The rings were of course produced oversize to provide an expanding sealing tension.
A jewelers vice was used to hold them whist finishing and setting end gap with a flat points file.
We ran the better faced surface finish toward the bottom/lower ring land surfaces.
Quite frankly they worked very well but modern Motorcycle rings are mostly laminated with a variety of plated finishes these days, so that would count my back yard facilities out of that step.
What I would be considering if you are really desperate Topari? is setting the piston up for readily available rings that are close and just simply trimming the piston ring groves to suit.
A hell of a lot quicker and easier.
And is a standard gig throughout the industry, all the way through to extreme performance builds.
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Me old Gran Pappy made rings back a couple a centuries ago, by getting the right bit of pipe (size and material ) obvious he didnt use lead pipe or copper ;D then bored it (lathe with boreing bar) turned down, parted it off and last cut the ring and gave it its end gap, might have been a bit of sharpening stone work for acuracy. :o
so would be interested to see how its really done ;) hey wernt they useing wooden pistons back then with tin plate nailed on top ;D ;)
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Erm with rings so cheap what's the point?
I am posting this in the context of vintage MX. Making rings could be useful in situations where they are no longer available.
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Get a set of rings from something else that needs minimal machineing ;) there is alot out there, or go to the chinese they will knockem up for ya for 2cents
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Erm with rings so cheap what's the point?
I am posting this in the context of vintage MX. Making rings could be useful in situations where they are no longer available.
Swap the piston and/or rod to something more readily available makes much more sense.
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Erm with rings so cheap what's the point?
I am posting this in the context of vintage MX. Making rings could be useful in situations where they are no longer available.
Swap the piston and/or rod to something more readily available makes much more sense.
that to as well ;) :)