McCoy 36 Super Stunt

Oldenginerod Mon Mar 27, 2017 6:15 am

Just managed to nab a McCoy 36 Super Stunt, 1955 apparently. Engine looks pretty good and fits seem really nice, with very good compression. For some reason someone seems to have removed the name "McCoy" from the bypass bulge. "36" is still there.

Engine is complete apart from maybe a venturi insert. The intake is quite large and searching for images shows they maybe have an insert. Any info or impressions would be appreciated. Clues on parts availability??

Marleysky Mon Mar 27, 2017 3:56 pm

Rod, I did not find any information jumping off the pages of the internet on McCoy 36. They are out there, but info seem to be scarce. Here's on for sale from 2006:

https://www.rcgroups.com/forums/showthread.php?898887-McCoy-36-Engine
And a thread from RCuniverse:
http://www.rcuniverse.com/forum/golden-age-vintage-antique-rc-196/248750-1957-mccoy-36-a.html
Here's a snippet from that thread:
According to Anderson's Blue Book, There were only .35's in 1957. Last .36 was the 56 Super Stunt, which is an all aluminum (no red) engine, ringed or lapped, with a tank (cast aluminum). I have owned and run MANY (have owned and run at least 40 McCoy redheads, rear intakes, superstunts, etc in the past years) and have sold quite a few. Good running engines, no matter what anyone tells you! The value of a good used SS .36 is about $45 US on ebay. NIB is usually double.

Andrew Coholic
ajcoholic

Oldenginerod Mon Mar 27, 2017 4:54 pm

Thanks Rene. The links were handy. It certainly appears to be the real deal, '55 SS model. Just can't figure out why someone would file the name off. It also seems pretty obvious that it needs the venturi insert. I'd be forever grateful if someone here has one and can measure up & sketch the insert so I can have one made.
Regardless of any negatives, it cost me $28 AUD ($22 USD) delivered. I'd call that a bargain if it turns out to be as good as I think it is.

Rod.

Kim Mon Mar 27, 2017 5:13 pm

Definitely a good score, and if I'm reading my Dannels book correctly, it was among the last true McCoys before Testors took them over in April of '56.

Probably a dumb question, but could a guy oil up the venturi, pour some kind of casting material in there to get the outside dimensions, and just drill out the intake 'till it seemed about right?

roddie Mon Mar 27, 2017 7:01 pm

Kim wrote:Definitely a good score, and if I'm reading my Dannels book correctly, it was among the last true McCoys before Testors took them over in April of '56.

Probably a dumb question, but could a guy oil up the venturi, pour some kind of casting material in there to get the outside dimensions, and just drill out the intake 'till it seemed about right?

It would seem that a venturi-insert (if desired/needed) wouldn't be a deal-breaker. 22 bucks for a vintage-engine with good compression.. someone will get a spec for you in good time, I'm sure.

Just for a comparison, my .35 (red-head/lightning bolt case) engine has a restrictor that measures .260" ID. The venturi-throat measures .335" above the restrictor.

As you can see by this photo.. there's nothing "precision" about the fit of mine. I purchased this engine as-is. The P.O. could have fashioned their own restrictor. I would think that that a sleeve would fit tighter.. but maybe it wasn't a precise-science back in the day.

Oldenginerod Mon Mar 27, 2017 8:45 pm

My housing looks to have an even taper top to bottom. I had thought about just jamming in some metal tubing the right size with a hole for the spray bar to locate it. The old Enya .09s just use a split tube in the same way from factory original. Shouldn't be hard to fashion something functionable, although it would be nice to have an original style.

Marleysky Mon Mar 27, 2017 9:12 pm

Oldenginerod wrote:My housing looks to have an even taper top to bottom. I had thought about just jamming in some metal tubing the right size with a hole for the spray bar to locate it. The old Enya .09s just use a split tube in the same way from factory original. Shouldn't be hard to fashion something functionable, although it would be nice to have an original style.

There you go, good old "Aussie Engineering" ! Keep a eye out for an orginal Venturi, but a short length of steel brake line, or aluminum tubing if larger OD is required ( check the a/c system of a junk car for pressure taps) and a wood handled scribe to wiggle the ID out to the flare required. Do you have the flaring tool for doing brake fittings? I'm sure there are lengthly math equations to determine the proper length and degree of flair to maximize air flow and pressure velocities for fuel mixing, but what the hey, that ring Roddie has looks like it would work too! These guys make aluminum and plastic venturis

http://www.rcparts.eu/images/detailed/2/r29204.jpg

...energize the new glow plug, add some fuel and have some flipin' fun!

roddie Mon Mar 27, 2017 10:09 pm

Oldenginerod wrote:My housing looks to have an even taper top to bottom. I had thought about just jamming in some metal tubing the right size with a hole for the spray bar to locate it. The old Enya .09s just use a split tube in the same way from factory original. Shouldn't be hard to fashion something functionable, although it would be nice to have an original style.

Rod, measure the ID of your venturi's throat at the spray-bar.. and check the OD sizes of AL tubing in your stock. You may be able to make a restrictor with what you have on hand. If you find a close-fit; measure the spray-bar's OD and drill a cross-hole for it. I doubt that the length of the tube matters too much. I would guess that between 7-8mm's would be long enough. It's only a restrictor.. and it will restrict. How much or how little depends on what you want from the engine.

rsv1cox Tue Mar 28, 2017 7:15 am

A couple of pictures of some of my McCoy's intakes Rod. Venturi inserts vary.

McCoy .19's

.35's

And later Testor's/McCoy Series 21. No doubt about the intake on these. One of my favorite engines that gave great service on my C/L N-28. Along with a vintage McCoy .29 with an overflowing venturi.

I have a scrubbed Enya .29. I don't understand your McCoy being scrubbed either, but perhaps the Japanese Enya is more understandable.

Forgetful John Wed Mar 29, 2017 6:54 pm

Have you tried to run it as it is?

Oldenginerod Wed Mar 29, 2017 7:54 pm

Forgetful John wrote:Have you tried to run it as it is?

No, but I plan to give it a shot. The engine is only destined for bench running & display, so performance isn't a priority, but I'd like it to look original.
I won't be able to fly with it because of noise levels (and I don't have a plane that big). I could strap a muffler on it but this engine has a huge amount of SPI so a muffler may completely kill its performance. This is the first engine of this type I've seen with SPI and it is huge, I'd say a good 1.5mm.

Oldenginerod Sun Feb 10, 2019 3:14 am

Just reviving an old thread of mine from a while back.
I haven't done anything with this engine, but we've had a few new members join in the past year or so and someone might have a suitable original type Venturi available. Yeah, I could make something up, but I'd prefer original.
Check your junk boxes guys (& gals).

Rod.

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