My old RG400 pistons in my TS100 used to come out looking like that after 2 meetings. It never broke but only because I replaced them regularly, every 2 meetings. I used to prep them by radiusing the edge of the bottom of the piston and polishing it as well. didn't seem to help but made me feel better.
Is your experiment with Roland Holzner-Modena that conclusive ? I know we are speaking on an abstract level since the actual race rules exclude alle 2 stroke development, but if it were permited, would you choose a 24/7 over a rear rotary valve like on the RSA if you were asked by a constructor to make them a winning 125cc mono at world championship level ?
Cutting grooves across a squish band just seems wrong to me. Wouldn't that undermine the reason and benefits behind the squish band and just promote chronic hot spots? Or am I missing something here?
If cutting grooves in the squish helped,why didnt the TopGun tuners use it?I'm sure Mr. Jan Thiel tried it or disqualified it do to 2T physics..
Here is a solution to that problem.https://s3.amazonaws.com/WEBPOSTS/KI...ston+trial.pdf
Don't need to worry about cross heads and linear piston movement.
Just make your own Ringless, Chrome plated, Steel pistons. Keep the revs over 5000.
Cheers, Daryl.
"First they tell you you're wrong, and they can prove it.
Then they tell you you're right, but it's not important.
Then they tell you it is important, but they knew it all along."
Charles Kettering.
This is from the patent shown earlier:
From 6000 up, with a 0.001" gap, the ringless engine BHP exceeds the ringed one. Fig4 (apparently)
Independent dyno testing for verification is required.
Cheers, Daryl.
"First they tell you you're wrong, and they can prove it.
Then they tell you you're right, but it's not important.
Then they tell you it is important, but they knew it all along."
Charles Kettering.
Last edited by Pursang; 19th November 2016 at 19:18. Reason: changed 5K to 6K
Cant see it in the picture but the exhaust fan has been put inside a piece of air duct that used to go around a pot belly stove chimney. The fan itself is a 200mm 400V 3 phase unit a friend rescued from the skip for me so I don't really know where you could buy one. Behind Cully is another 200mm fan that draws fresh air from outside and blows it over the dyno operators.
For an exhaust extractor fan, the gutted propane heater looks a very good idea.
An academic paper researching 'knock sensor' applications to small 2T mills ( Husqvarna chainsaw) - if of interest.
http://liu.diva-portal.org/smash/get...FULLTEXT01.pdf
My engine idles at 3,500 rpm and makes power from 7,500 up and max's out at 12,500.
Thanks Daryl. it's very interesting, I see the experiment was done by the USAAC ... US Aviation Army Command using a water cooled Suzuki RM250 engine, so done by a reputable institution on a practical real world engine.
Now to read it all carefully to see how it went and what gems there are if any.
www.google.ca/patents/US8127544
HCCI opposed piston..
Those 'Singh grooves' seem a tad basic..
Now if some talented machinist was game to try cutting a Fibonacci...
...or Schauberger, dynamic flow pattern..
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Ok, I read the whole thing. They had more seizures than I could live with. It was mostly about comparing the performance of a alloy and a steel ringless piston and neither made more or anywhere near as much power as the RM's conventional ringed alloy piston.
The possibilities of getting extra power buy using a ringless piston.
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True, but it worked and their process was Very Very Basic.
The alloy piston was a standard one without the rings fitted;
The steel one was a sheet metal, fabricated flat top;
They didn't get results for the ringless engine over 6000 rpm.
Changes to mixtures & jetting were random, if done at all.
Tuning to maintain a constant exhaust gas temp might have created a datum.
Seizures of the chrome steel piston produced no damage to piston or bore and were sanded/polished out.
(Except when the soldered support fell out)
More work was needed to establish gudgeon axis clearance and internal support & thermal control.
Using different materials for piston & liner with greater expansion of liner (Ti & Steel or Steel & Al) could limit seizure with increased temps. Lots to explore here.
Importantly the Patent was registered by the same bloke who did that testing.
Perhaps he saw more in it than the test results that were presented to the army.
Cheers, Daryl.
"First they tell you you're wrong, and they can prove it.
Then they tell you you're right, but it's not important.
Then they tell you it is important, but they knew it all along."
Charles Kettering.
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