How to resurrect an old McCoy 35

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How to resurrect an old McCoy 35

Postby pdb » Tue Nov 24, 2009 3:54 pm

Hi:

I have an old McCoy 35 on a Combat Cat which I hung up in 1969. It has been in dry storage since then but has had nothing done to it since. The prop still turns freely but who knows what the insides look like.

I would love to start it but don't want to ruin the engine. Should I disassemble the engine to remove varnish and rust, if any. My initial inclination was to flush it with penetrating oil, lube it with glow fuel, and try to start it.

Is there a better procedure?


Thanks

Pete Brown
Anchorage


Going home after a long day
http://farm2.static.flickr.com/1415/132 ... 8754_b.jpg

The fleet at Summit. Mt. McKinley is about 45nm away at 20,320 msl.
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The 170B at Bold near Eklutna Glacier
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Postby raglafart » Tue Nov 24, 2009 4:25 pm

Flood the engine with WD 40 or similar and gently turn over a few times with the plug out. Put a little oil in the engine and turn over again a few times. Put the plug back, fuel it up and fire it up.
Lovely pics, you live in an uncomplicated place with stunning views, engines are simple things, enjoy!
Cheers JG
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Postby dedaddy007 » Tue Nov 24, 2009 6:16 pm

If you take it apart you risk the following:

You may destroy the gaskets. They get stuck and brittle with age and tear easily. Some McCoys had metal head gaskets and are ok. You can easily make new backplate gaskets. I would not remove the cylinder from the block.

You can easily mess up the phillips head screws. Only use a screw driver that fits right. Use a dental pick or similar to make sure all dirt is out of the socket in the screw before you attempt to remove it. I don't know how many buggered up screws heads I have had to mill out of old engines.

If you don't want to take the engine apart, fill a can with enough automatic transmission fluid to cover the engine. Remove the glow plug and needle valve. Fill the cylinder and crankcase with ATF and immerse in the can. Let it sit for a week. This softens the gaskets, varnish and lubs the screws. Remove from the ATF. GENTLY turn the engine over and push out the ATF. Flush with some fuel or alcohol. Lub with anything but WD40. In my experience it makes steel parts rust because it concentrates moisture. I use ATF or 3-in-1 oil. Marvel Mystery Oil is good too.

Run a pipe cleaner through the spray bar. Old fuel can clog it up.

When you have all oil out of the engine that you can shake out. Install a prop and flip it several times to make sure there is no hydrolic lock in the crankcase. Install the glow plug and needle valve. Now it should be fairly "poppy".

Run a tank of fuel through it rich to clear out everything. Then go fly it!

I restore old engines as a hobby and sell them on eBay. I have all kinds of methods for different situations but the above is for an engine that does not need "restoration".

PM me if you have any questions.
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Thanks

Postby pdb » Tue Nov 24, 2009 6:29 pm

Gentlemen:

Thanks for the reply. I really appreciate the advice and will start the process this evening.

The only issue now is do I even dare try flying the the Combat Cat. It will be tough to resist the urge if the McCoy relights and its only been +40 years since I have flown any control line stuff. The cat was a bit twichy on launch and it usually took me a lap or two to get it stabilized.


Pete
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Postby Jim Thomerson » Wed Nov 25, 2009 7:16 am

Put a heavy hub on the McCoy and move the CG forward. That should help. Also, don't fill the tank full.
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Postby pdb » Wed Nov 25, 2009 1:04 pm

Jim:

I should have thought of that as well. A few years ago, a friend and I took delivery of a self launching sailplane from Russia. It's a great plane but its light, empty weight about 400 lbs so the pilot is a significant percentage of the gross weight.

The aircraft is pitch sensitive to begin with so for the test flights, we loaded it so that it was at the forward CG limit. We did this expressely to increase its pitch stablity.

Image

Later, when we wanted to extract maximum glide, we moved the cg to the rear of the envelope, accepting a higher degree of pitch sensitivity for better glide. Maybe we actually learned something of value building planes when we were young.
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Postby chiefss » Wed Nov 25, 2009 1:13 pm

Fly it. I flew a Voodoo that I built in 1964 a while back. It has a Johnson Sport Special on it. Since neither engine has ball bearings and since they were run on castor fuel, all you need to do is lube them. As stated, if you take it apart, you will destroy the fibre gaskets. I have some of the McCoy gaskets but am reluctant to sell them. I also have Perfect Products gasket material that I will sell.
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One more question....

Postby pdb » Sun Nov 29, 2009 8:57 pm

Guys:

I let the McCoy sit in a warm crock pot in ATF for two days and when I removed it, it was clean and nice. While I was removing the cylinder head, the cylinder slipped off. The piston seemed fine except for a bit of mild scoring which probably resulted from flying abuse years ago. It doesn't look bad at all so I am simply going to relube and reassemble.

I was surprised that only 3 of the six cylinder head screws hold the cylinder and head assembly to the case. When I screw the head back on, should I use any loctite or lubricant on those screws or just put them back in clean and dry?

When I took them off after two days in the pot, I was surprised at how readily they came out.

I have a two bladed 10/3 prop. Is that Ok to use?

I have a Sterling U/C P-51 kit that I might just pull out of storage of I can get this thing to fire up.

Thanks again.
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Postby dedaddy007 » Sun Nov 29, 2009 9:23 pm

Well done! Just wipe off any excess ATF and put it back together. Don't try to get the screws too tight. 4-40 screws only take about 5 in-lb of torque to seat them. Use a star pattern to tighten the head screws. Put it all together and go fly.
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Postby dedaddy007 » Sun Nov 29, 2009 9:25 pm

Use a 10x6 or 10x5 prop.
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Postby pdb » Mon Nov 30, 2009 1:08 am

Lee:

Thanks for the help. Its now all clean, oiled, and reassembled and resting comfortably in a sealed glass jar, free from dirt or moisture. The Combat Cat is only a couple of hours away from flying status but I might throw together the Mustang first. It will be a bit easier to fly, the rust, such as it was, is off the engine but not me, yet anyway.

I am about to leave on a business strip but when I get back, the first order is to mount it on a board and fire it up.

Pete
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Postby Phillip Hawkins » Mon Nov 30, 2009 8:58 pm

[quote="pdb"]Lee:

Thanks for the help. Its now all clean, oiled, and reassembled and resting comfortably in a sealed glass jar, free from dirt or moisture. The Combat Cat is only a couple of hours away from flying status but I might throw together the Mustang first. It will be a bit easier to fly, the rust, such as it was, is off the engine but not me, yet anyway.

I am about to leave on a business strip but when I get back, the first order is to mount it on a board and fire it up.

Pete[/quote]

Way to go Pete!
I am a big fan of McCoy Red Heads and have refurbished several.
First congratulations that you did NOT use WD 40! In the future you can use afterrun oil, Marvel Mystery or airtool oil. The Airtool oil works very well as it is designed to resist moisture.

One of the key elements to a fine running McCoy is the little "button" that is stuck in the hole that runs through the rod pin on the crankshaft. If this is missing you will never hold a needle setting if it will run at all.

The cylinder to case and, if it has a non metalic head gasket, the Perfect brand gasket material is the best thing (it is 1/64" thick) for the backplate gasket you can use a manilla or brown kraft envelope. cut around the round part of the backplate, punch through the screw holes, install on engine, then trim the excess around the case/plate with very sharp exacto or straight razor blade.

It sounds like you have this one pretty well ready to go, but if you want to take it to the next level of reconditioning use Plasticote Ford Red engine paint for the head. 4-40 x 1" & 4-40 x 1/4" cap screws for the phillips head replacements. If you want more info you can send me a PM from this forum and also join the fun at www.clstunt.com/htdocs/dc/dcboard.php
If that Sterling P-51 is mint in box it may be worth more as a collectable... But it sure would be a nice fit for the McCoy! build light!

keep us posted!
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Phillip

Postby pdb » Mon Nov 30, 2009 11:47 pm

I am motivated to build the Sterling Mustang and hang the McCoy on it. I think I have three kits and I only need one so I am going to fly it. Spring is a long way off so time is no problem.

I will let folks know when I get the McCoy running.
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Postby chiefss » Tue Dec 01, 2009 1:07 am

Are you guys talking about that old $5.95 Testors McCoy? I built that P-51 back in the early 60's. It had a K&B 35 on it. Pretty much just a Ringmaster with a different shaped fuselage. Flew like one.
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Postby walt » Tue Dec 01, 2009 8:47 am

(One of the key elements to a fine running McCoy is the little "button" that is stuck in the hole that runs through the rod pin on the crankshaft. If this is missing you will never hold a needle setting if it will run at all.)

This is very interesting information as I've always heard that it was only important if you were going to use an electric starter. Never heard that it affected running at all. Very interesting.

I have made replacements for these buttons from 1/8 inch dia. nylon screws from the hardware store. Cut the screw to the proper length and then grind/file the screw head down very thin so it doesn't interfere with the backplate when installed. I've always felt that these buttons were possibly necessary to keep the rod from backing up too far while running, and maybe damaging the engine.
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McCOY

Postby JOHN G » Tue Dec 01, 2009 9:46 am

Walt

If the engine is running I think the crank is pulled fwd

I think your first thought is right using a electric srarter pushes the

crank to the back causing the pin without the insert to damage the

backplate Just my thought

JOHN G
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Postby chiefss » Tue Dec 01, 2009 12:16 pm

They will run just fine without that little plastic gizmo on the crankpin.
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McCOY

Postby JOHN G » Tue Dec 01, 2009 4:56 pm

In my reply to Walt I never said you needed it for running but when
you use a starter you push the crank back into the back plate
the insert protects it
I do not want to start anything here but sometimes age seems to fog
our thinking
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Postby raglafart » Tue Dec 01, 2009 5:47 pm

The plastic gizmo is also to stop the rod walking off the back of the shaft and seizing the engine. Ask me how I know!!!!!!!!
I've rebuilt a few McCoy's, 29's 35's and 40's
The 40 I did for a friend would run for a few seconds then slow and stop, it felt stiff at all points, a very odd feel.
Took the back plate off and it was obvious what had happened. The engine didn't have the small plastic insert to begin with and I thought it would be okay, not so.
I took the one out of my 35 and that was an end to the problem.
By the way it was being hand started in a test stand, no influence from an electric finger!
Well worth making sure any McCoy has got the little dodad in place, rods always want to walk of the back of the crankpin, if left with too much clearance to the back plate it's a sure way of wearing out the big in the rod and putting a taper on the crank pin.
With the soft sintered piston, (the worst design part of the McCoy Red heads) you'll also wear out the little end, not in the rod but in the piston. Another quick way to lose all the horsepower! Seen a lot of oval piston wrist pin holes from these engines :cry: Still they were built to a price with quality a distant second :roll:
Cheers JG
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Postby chiefss » Tue Dec 01, 2009 5:52 pm

Who uses an electric starter?? Actually you will have more problems with the drive washer galling against the crankcase using an electric starter.
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McCOY

Postby JOHN G » Tue Dec 01, 2009 6:12 pm

Whoa goat
I am out of here
JOHN G thanks guy
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Postby pdb » Tue Dec 01, 2009 8:59 pm

Phillip:

I did not bother to take the back case off because the engine looked so nice inside and I wasn't sure if I would screw up the gaskets.... I am "If it broke..." sort of guy. However, I did not see any red pin. Would that have been visible looking down into the case when the piston was out or would I had to remove the back of the case? It was working well in 1968 when I put it away so if it was there then, it must still be there.

What do you think?

PS: I am looking at a Dec 1965 Engine Review article in MAN by Peter Chinn on a McCoy 19 with a photo of the engine in pieces and can't see it in that photo. Exactly where should I be looking?

Chiefss:

That same article has an AHC ad selling McCoy 35s for $7.95 and Ringmasters for $3.95. In those days, I could buy a gallon of gas for $.25, therefore a McCoy cost about 32 gallons of gas. At today's prices (~$2.35/gal), my McCoy would cost about $75.00. and a Ringmaster $37.00.

At least in prices relative to gasoline, things haven't changed that much.

Pete
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Postby chiefss » Wed Dec 02, 2009 11:15 am

All that is true but compare the selling price of a McCoy 35 to those of a Super Tigre G21 or a Johnson 36BB and you can see the difference. A Johnson Combat special was $17.95 and a Johnson 36BB was $24.95, a Super Tigre G-21 was $17.95 and even a Fox 36X was $14.95. Compare that to a McCoy at $5.95 and you see what kind of engine it was. Those were 1963 prices. I used all of them and still have most of them. If you want to use gas prices as a comparison the the JBB would cost $285 in todays' dollars.

Standard joke of the day was, if you ever got a McCoy started, you just wore it out. In the 62 Nationals, The Johnson engines (JCS and JBB) took all three places in junior, senior and open AMA combat. No one used a McCoy 35 in any event where they placed. Ed Southwick was the only major flyer that pushed McCoy and he was a shill for Testors.

The McCoy engine to use in those days was the 60 and it cost $40.00. Now that was an engine. C/L speed guys used them. Using gas prices it would cost $450 today. Where do you get gas for $2.35? We're paying $2.85 in Washington.

I have several Testor McCoys in my collection. I never used these ones but have them as an example of the cheap engines of the day.
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Postby loucrane » Wed Dec 02, 2009 1:10 pm

Chief,

The steel fin McCoys were inexpensive - you got what you paid for - but they did run fairly well, on Fox Superfuel or K&B100. I never did like Testors 39... and it seemed back then that most engines agreed with me on that.

Starting McCoys was not a problem in the days of open exhausts. A shlug of fuel into the stack worked, almost inavriably.

Early wear may have been a combination of several factors:

Most of us going with the $6 engines didn't know much better than to wind 'em up as loud and fast as possible on the cheapest fuel we could find. Not good for just about any engine. Break-in? What's that?

With a little kindness and care, and a lucky buy, the minimal QC that goes into a $6 engine allowed some quite decent service...

I kinda feel hurt at seeing Ed Southwick called a shill for Testors. He was such a fine, sweet and friendly guy that we all treasured him, even moreso over his last 16 or 17 years. He returned to CLPA Competition after the first Vintage Stunt Championships at Whittier Narrows in 1989. He and Dick McCoy were well acquainted. Dick McC prepped some engines for Ed. If Testors/McCoy used Ed's successes in their advertising, well, why not?

It's not as if he were hired to go out and use their engines so as to create advertising copy.

Bill Netzeband helped develop the Series 21 "Body by Fisher" Dykes ringed later McCoys. Their functional layout was very similar to the steel fin McCoy 29s and 35s: port timing, shaft dimensions, etc. ... The biggest problem I recall wiith them was with the "new" concept of that Dykes ring.

One frying run and it turned into a Pringles chip. ...Or otherwise lost compression seal for hand propping. Electric starters would have handled that, but it just wasn't done in sport CL back then.

The 21s were pretty decent, given that you kept the ring wholesome. They were heavier than the earlier close fitted casting engines, but that DID add some stiffness that allowed the engine to do reasonably well.

I've heard that they were even used in CL Racing "sport-type" events - and restarted well, providing the pit man had a cup of ice water to slam at the upper end before he refilled the tank... never saw that, but have heard from several...

My first "big" engine was McCoy Sportsman 36. Made lots of noise. Hauled a few models around well enough... There seems to be a first-love mystique about the older 'sport' (read: cheap) McCoy engines, doesn't there.

Like nostalgia, things aren't as good as they used to be... but, then, they never were...
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Postby chiefss » Wed Dec 02, 2009 1:48 pm

Yeah, shill was probably not the best term to use for Ed Southwick. He was a good guy. My first "big engine" was a McCoy 35. It took me about 10 runs to realize it wasn't the engine I wanted. That's when I went to Johnsons. For my money, the best engines you could buy for C/L in those days. Still very good engines. I have several and am actually using a JBB on a Demon, a CS on a Voodoo and a JBB on a Quickie Rat. Old High school buddy comes up a couple of times a year and we fly all the stuff we flew in High School.

I used K&B 100 or 500 in my youth along with some of Fox' hot fuels (Blast comes to mind). They always ran well in my engines and never had problems with wear. The McCoys always wore out quickly. Soft pistons in a soft cylinder. The crankcases never seemed to wear. When the compression got bad they were a bitch to start especially when it got cold. A shot of ether for prime helped. Also a shot a 3 in 1 oil got the compression up enough to start them. That was unacceptable in contest situations.

McCoys were OK for beginners and guys that just liked to fly on weekends in school yards. I flew Combat and Rat Race and they just couldn't hack it. Belonged to WAM and flew in California.vLike the old saying goes, you got what you paid for.

The type 21's ?? Junk. Even George Aldrich called them modern slag engines. They were McCoy's swan song.
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Postby Phillip Hawkins » Thu Dec 03, 2009 12:34 am

My own experience with the rodpin button was on a 19 redhead. It was a bear to start (hand flipping) and then ran erratic. After much foolin' I finally removed the engine, discovered it was missing the button. I replaced it and the engine runs great to this day. the only logical explaination I have is the button was/is an integral component. However... It did/does not make sense to me because I can not figure out how it could create a vaccuum leak. It is quite possible the problem was the rod dancing on the journal... hmmm.

As far as running goes, I run my McCoy's just about like a Fox 35. 29% castor, no more than 10% nitro, rich 2 cycle needle setting. the problem with these (as mentioned) was spotty QC but mainly the fuel and needle settings. lean runs, not enough castor, too low pitch prop (too much RPM) and that was all she wrote...one lean run and that purty redhead turned a nasty black and lost compression. I also agree that a bigger problem I have found with ebay McCoy's is the wristpin hole in the piston being out of round... again too much RPM?

I never owned a Johnson, but the Torpedo/Stallion vs Fox vs McCoy I always liked the McCoy for no other reason than the sound! A properly run-in Fox on the above mentioned fuel is just about fool proof for me though.
I like the idea of taking a nylon screw and making a replacement button. there is a guy on the Stuka Stunt forum (Scott Reise) who at one time had them milled out of delrin and I had bought 10 or so and have used them with no problems. he may still have these and other parts for McCoy.
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Postby Phillip Hawkins » Thu Dec 03, 2009 12:44 am

Hey Pete, just curious... What version do you have?

Glow plug location?
Lightning Bolt case?
Restrictor inside the venturi?
Looking inside the exhaust, are there four little square "windows" or one open slot in the cylinder port?
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Postby pdb » Thu Dec 03, 2009 1:05 am

Phillip:

Glow plug: Offset slightly to right side of cylinder head
Lightning bolt case: I don't know... there is no emblem on the case
Restricter in venturi: Not that I can see
Looking into the exhaust, there is only one window

I bought this in around 1965 and I am certain it was from the most recent production.

Does this make sense?
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Postby pdb » Thu Dec 03, 2009 5:48 pm

I got two high res images of a McCoy 35 engine instruction and engine outline dimension sheet. The red button described by Phillip is clearly shown on the diagram and is called a Crank Throw Spacer. Its function is obvious when viewed on the diagram and I would not have been able to see it since I never took the back plate off.

If anyone would like a copy, let me know and I will email them. They aren't totally complete but they are very useful and interesting to McCoy fans(?).
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Postby Phillip Hawkins » Thu Dec 03, 2009 10:55 pm

yeah Pete I'm in!

please send it to: philhawkins62 (at) earthlink (dot) net

My understanding is that Mr. McCoy did alot of field testing and the version with the offset plug ran the best. You would know if it was a Lightning Bolt, it clearly has two lightning bolts on each side of the displacement marker. The LB engines had the "window" cylinder, that was another improvement made along the way. Also I have not yet seen an R/C version that does not have the "window" cylinder. So if you ever encounter an R/C (blue head) and are looking for parts, that is the one to scavenge.

My McCoy inventory: all Red Heads

19
35 shinny case, offset plug, no venturi insert.
35 shinny case, offset plug, venturi insert
35 Lightning Bolt
40 Shinny case, that someone bead blasted making it dull. (eBay find)
40 Tom Lay modified, dykes ring, hardned piston
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