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Engine basics => Engine set up tips => Topic started by: frank mccune on April 18, 2022, 01:57:49 PM
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Hello:
Has anybody reduced the size of a cylinder by using this method? If so, how did you do it, what size collar did you use and how good was the final result?
Tia,
Frank
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Since I posted, I found that kwhat I was thinking about was a device named, a two piece shaft collar. These look like they would do the job!
Frank
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That is very very questionable butchering of high-precision parts. L
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Since I posted, I found that kwhat I was thinking about was a device named, a two piece shaft collar. These look like they would do the job!
Frank
What Lauri said. There is no way that you can reduce the diameter of a cylinder in this manor in any thing remotely resembling accuracy. It sounds like you want to reduce the diameter to a piston fits better? I believe there are methods to "shrink' cylinders by cycling them in heat and cold a very minute amount, but that is all I know about it. If you try what you describe you will just kink the cylinder, because two piece wheel collars aren't "round" like you think they are. If you managed to get any kind of reduction in the diameter by accident, you are going to have to have the machinery and expertise to make it round again and the correct diameter, hardly worth the effort. If the piston is an iron powder piston, I understand that they can be "grown" to make them fit a cylinder better but again, this takes proper technique and tools, then they need to be fitted to the cylinder again, and just not worth the effort, unless you have a pile of engines to to waste while you go through the learning curve. This is time better spent doing something more worthwhile.
Type at you later,
Dan McEntee
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The R/C car guys do this a fair bit, using sort of collets to reduce distortion
https://www.youtube.com/watch?v=rpcWs52J48g
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Rayaracing Ask for the medium pinch. I've used them several times with good results. Collar clamps are too crude. You will tighten the fit but, it won't have any compression because it won't be round.
Motorman 8)
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Since I posted, I found that kwhat I was thinking about was a device named, a two piece shaft collar. These look like they would do the job!
Frank
Not to pile on, but - no. The guys who do this for RC car engines use clamps that are exactly the right diameter, so when they squeeze it, it remains (mostly) round. Even then, it's an absolute last resort. Most of the engines you have that I know about have easily available factory spares, that is probably the way to go.
Outside the wildest coincidence, your split collars will be the wrong diameter, and crush the cylinder to a football shape. By wrong diameter, the tolerance is probably on the order of ten thousandths of an inch. Or, for the iron liners, crack them.
In any case, it seems inconceivable that you have worn out any engines, short of running debris through them, in which case the problem is not wear, but scoring. Even pretty modest and semi-disposable engines like the McCoy $10 jobs will last many hundreds of flights, a really good one, thousands (I know, I have done it). If the cylinder is scored, or otherwise damaged, squeezing will not fix it.
Brett
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Would chroming do what you want? ???
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Would chroming do what you want? ???
Who would do it?
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What they recon , somewhere , is the cylinder pressure / Temperature , (anneals ? ? ) EXPANDS the cylinder / sleeve .
So what theyre doing is RESIZING it BACK TO STOCK . Was in some high rpm ABC race set up .