Yes, I think a chrome or nickel bore will last longer if the plating doesn't peel. I don't know but several RCU members have complained here about plating peeling and I don't know if it's nickel or chrome.

Your point is well taken.

Regards,
Bill

Yes, I have broken a few. Mostly model engines. For some reason its easier to replace an automobile ring, though its easier if you do it often. But it made from grey iron I don't think even an experianced mechanic with a ring expander would be able to install rings.

The expanision rate is not that much differant, overstated IMO.

Note that the grey cast iron is heat treated, and note that they come out black. If you heat cast iron to a red color and slowly cool will cause the graphite flakes to form round carbon nodes, or nodular cast iron. The exterior color is black. From the wiki article.

[i]Malleable iron starts as a white iron casting, that is then heat treated at about 900 °C. Graphite separates out much more slowly in this case, so that surface tension has time to form it into spheroidal particles rather than flakes. Due to their lower aspect ratio, spheroids are relatively short and far from one another, and have a lower cross section vis-a-vis a propagating crack or phonon. They also have blunt boundaries, as opposed to flakes, which alleviates the stress concentration problems faced by grey cast iron. In general, the properties of malleable cast iron are more like mild steel. There is a limit to how large a part can be cast in malleable iron, since it is made from white cast iron.

A more recent development is nodular or ductile cast iron. Tiny amounts of magnesium or cerium added to these alloys slow down the growth of graphite precipitates by bonding to the edges of the graphite planes. Along with careful control of other elements and timing, this allows the carbon to separate as spheroidal particles as the material solidifies. The properties are similar to malleable iron but parts can be cast with larger sections.</i>

I suspect that the heat treat method described is not enough to make the iron fully malleable or nodular iron, but somewhere between. Still very hard but more flexible than plain grey iron. Poor heat treatment may also account the very soft and ductile rings some have experianced.

You must mean me. I never said they are not made of cast iron, just not plain ole grey cast iron. Other posts and my own research shows that most are made from grey cast iron, but most are also heat treated and this makes them more flexible. Plus we have found that there is a fine grain cast iron which is also more flexible than the usual grey iron used for foundry castings.

The Meehanite proprietary process brand of iron has this fine consistent grain

http://www.stlprecision.com/meehanite.html

http://www.meehanitemetal.com/

More than a-little interesting w8. And all I wanted to do was flip a prop for one flip starts.

Thank you,
Bill

I honestly don't know who made the reference but the good thing is it got me thinking. Check out w8ye's website refernces. Very interesting stuff.

Regards,
Bill

I may have already said this but a couple guys up town made their own rings and used old car engine cams for their materials.

They used the construction technique already described in one of the links up above.

Here are pictures of one of the guy's shop, engines, and guns

http://www.floridaame.org/GalleryPag...ich%20Shop.htm

http://www.daledetrich.com/index.htm

I'm confused. If you heat a metel and let it cool without any interference - annealing? When you heat it and plunge it into an oil bath like a Samuri sword is that heat treating/hardening. Would you anneal or harden a ring? Maybe anneal to remove cast iron's brittleness? Don't know. I know that Frank bowman heats his rings to 1,850 degrees F. What does he do after that?

Bill

Thank you.

Bill

Man, you can bet that when I tore down my new/used Enya .46-4C I was sweating but I had to check the ring land. I got it off and on OK. I guess I was nervous because I have broken a ring or two - on an out of production British motorcycle. It stinks when you have to wait two weeks for parts from England.

Bill

I'd love to watch their process. I love a show on the Discovery Channel called "How It's Made". for some reason I have always been interested in mass production.

Bill

Here are the pic of cam shaft from Peugeot 504 i send to Ron Chernich in November 2003 ( http://www.modelenginenews.org/ed.2003.11.html#tt2 )

The cast iron between the camlopes was easy to turn at lathe except the camlope was very hard and impossible to reverse back to unhardened cast iron.


RAMJET..
To be honest: Are you really afraid for the piston ring or ring gap will be wrong or too big while your engine worked very well with the original piston ring [sm=confused.gif][sm=confused.gif][sm=confused.gif][sm=confused.gif]
I found the thread is so long it is only talk about the tema was about "ring end gap" and there was mostly about piston ring mateiale that you may blends between model enginen and auto-/motorcycle engine.

I couldn't open the websites but I'll try again later. That beautiful little engine lloks like something out of a Jules Vern movie. I assume it runs. It must keep someone busy polishing all that brass - don't tell me it's gold plated.

Bill

I have seen all those engines run but I have not seen the guns fire.

He is often at the flying field

Wow, I wish I had your skill as a machineist, had your tools and knew how to use them.

The ring gap discussion started with my wondering what an acceptable or factory specification was for a ring end gap on an Enya .46-4C. I don't know how my Enya runs I bought it used and hasn't seen a drop of fuel yet. I did suspect that a .011" end gap was excessive since my Honda 500 single's end gap is .0118". I could care less if the piston ring is made of paper mache. I never brought that issue up. I have rebuilt many engines and always had a manufacturers specification for ring end gap. The is no such thing for my .46. Thanks to a fellow named Frank Bowman I now have a spec. that is credible and founded on fact and experience. I'm as happy as a pig in feces being armed with this information that even the manufacturer of my engine couldn't provide. When I work on engines I don't guess at tolerances and specifications. To quote Frank Bowmn "I don't get upset when someone wants to set their own (ring) gaps, I look at it as you want to get the most out of your engines." "All large gaps do is waste much needed power in small engines." The priciples of operation of an internal combustion engine are the same for a Cox .010 as they are for a 1710 c.i. Allison V-12 aircraft engine regardless of whether it's a two cycle or four cycle. Intake, combustion, power, exhaust. If ring end gap is of little importance then one might assume that a compression leak at the glow plug, cylinder head, intake valve, exhaust valve are also of little importance. Let's not get into intake manifold leaks or two cycle crankcase leaks.

"The apple doesn't fall far from the tree." I am my fathers son and upon his death he probably had forgotten more than I will ever know about internal combustion engines. Any job worth doing is worth doing right. Don't blame me, blame my father.

Sincerest regards,
Bill

I think you will find that your Enya will run fine as is.

It might be a little juicy though

Yes w8, it probably will. I have yet to run my .46 and I bought it used. It will have a Bowman ring in it when I do fire her up though. Heck, I paid $75.00 for the engine why not invest another $12.00 for a known good ring. I'm likely to come into a new/never run Enya 1.55 4C at the end of this month and I will not fire that with the stock ring. It will start life with a Bowman ring. I'll have to spend $325.00 for the 1.55 and to not spend another $12.00 for a ring that I can gap at .002" is, to me, silly. Just call me crazy.

Thanks w8,

Bill

That's why they call this a hobby

THANK YOU w8. Exactly. It's a hobby and I'm having a heck of a-lot of fun too. "A hobby pursued too vigorously becomes a profession." Enter Frank Bowman. He spends his day volunteering for his local church and making piston rings for next to nothing for addlepated buffoons like myself. By the way the range of Franks experience is interesting - racing go carts, drag bikes, hot rods, combat C/L, team race & power FF model engines, Chevy V-8s. He worked as a proto type machinist, heliarc welder for aluminum and magnesium. His dad hopped-up model speed engines, flew speed planes in the 40s and 50s, and broke several Western and National speed records. Interesting fellows.

Bill

My computer is fixed. Dale is a very interesting craftsman. Those firearms are wonderful. The little black powder rifle is a-lot like the full scale Kentucky long Rifle kit I'm building now. Cool stuff, thank you w8. I've seen some of the scale Offys and Ford flat heads that are being made out on the internet - at $5,000.00/copy. If I win the lottery I'll have a little Offy.

Bill

I was going to say why don't you drive down and see them but you live farther up than I was thinking.

Looks like there is a private airstrip close to your house. Its on the right just out Burtch rd and stretches back almost to State Rd. You might could fly RC there?

Yes, I think I see what you are looking at. Traveling West on Burtch Road on the right there is a strip-like swath cut through what looks like woods running from Southwest to the Northeast. Does that sound right? I don't know what it is as I'm a fairly recent transplant from upstate New York. I'll have to check it out. I had to download Google Earth to find it. Google Earth is nothing short of amazing by the way.

Thank you,

Bill

The Tee hanger is right behind the house on Burtch rd. and then there is a mowed path that leads back to the air strip