jojo003

Dear experts,
I'm a complete newbie to RC, but for a little science project we have obtained a McCoy 0.049 diesel model airplane engine. After buying the engine on ebay, i'm a bit worried that something is missing. Shouldn't there be a piston under the red anodized top of the engine?
Thanks for the help in advance.
Best,
Joris

coriolan

If your engine looks like that it will have a contra piston to adjust the compression (in the McCoy .049, it had an O-ring which might need replacement). It was a nice engine in its time but depending what you intend to do with it a modern engine would probably have been easier to deal with. Why do you need a diesel engine specificaly?

spaceworm

I have had a McCoy .099 Diesel since 1953 if anyone is interested. I have never run it, although it is not new.

Sincerely, Richard

w8ye

My Feedback: (16)

I had a McCoy .09 diesel in the late 50's. I liked it very well. I flew it on the RC planes of the time period.

jojo003

Hi,
This is how this little engine looks like. To me it looks like the piston is missing, right?!
We wanted a small diesel because we wanted to use it for a high-school project to show that we could replace parts of the diesel-fuel with biodiesel made from algae. Of course we first mixed ether/kerosene/castor oil.
Thanks & Best,
Joris

coriolan

Joris
Seems to be many parts missing beside the piston (first picture) of course a model diesel engine will never work on bio fuel. They are more like compression ignition, kerozen is the main part of the fuel and the ether is just to lower the ignition pressure required (lower flash point). The conrod is probably broken or missing and the piston, contra-piston still stuck in the sleeve (which screw into the red anodized cover). Would be hard to find parts for it and you should tell your teacher to do some research before giving you impossible tasks!

gcb

Joris,

First step is that you should contact the seller and explain that the engine was not in runable condition and ask to return it.

Next step is to not get an extinct engine to do your testing. Even in new condition, the McCoy is not strong enough to accomplish your task.

Try a modern engine you can get parts for, like a PAW.

Bio fuel has been used in model engines but it usually requires a start and warm up with conventional fuel (ether, kerosene, castor oil, etc.), then switching to the bio fuel.

If you do a search on running model engines with bio fuel you should find written information and videos.

George

Recycled Flyer

Hmm, there seems to be the con rod, liner, piston, wrist pin and contra piston missing from that engine and that was most likely sold as a complete set when the engine was current.

Scouring Fleabay may bring some joy in finding that 'set' but I wouldn't hold my breath!

Oh, and di ethyl ether also does the job of combining the kerosene with the castor as without it the two are not miscable.
When mixing fuel dissolve the castor with ether firstly then add the kero as its most important to get the oil to combine.

Good luck.

P.S. If the liner really is missing, what is holding the cooling fins in place in your photos?
And you could try this forum for any further questions -
http://www.modelengine.org/forum/vie...f1547732a3b965

A review can be found here -
http://modelenginenews.org/ad/ok_diesel.html

SGC

Looking at your first photo , it looks like the crankpin is brocken off the crankshaft!!

dieselbloke

The crank sure is busted!

. This model McCoy was prone to crankshaft breakages. You can still get parts for 'em (including cranks) off a bloke called Chuck Bartunek at :

[email protected]

This will only fix the engine and perhaps make it runable. It's not a very good choice for your purpose, it fact one whould have to question the likelyhood of success of the whole project.

The kerocene in diesel fuel can be replaced by a whole lot of solvents and other hydro carbon based chemicals and this probably includes home-made biofuel. It's just that they run best with good quality kerocene.

Your project is probably based on a misconception about model diesel engines, perhaps you should talk to your teacher about it?

Bill Adair

My Feedback: (1)

Joris,

Just for your info, because I pretty much agree with most of what was said here.

The picture you submitted appears to be the later model McCoy engine, and that model did not have the crank shaft problem. It was also more powerful than the original, but it does appear to have an after market needle valve installed.

The later model can be identified by the beam mounts, an attached tank, and a venturi insert that retains a spring loaded disk. The disk acts like a one way valve, and only opens when fuel/air is drawn via the crank port opening. I think this was added to prevent over priming via the venturi, as hydraulic lock from too much fuel in the case can cause rod/piston failures.

I have examples of both models, and have run the early models extensively, with no crank failures! The key is knowing how to start and run model diesel engines, and being careful to prevent over compression. Over compression was probably the real cause of crank failures, but using improper fuel can also cause problems. The McCoy is a plain bearing engine, and was designed to run on mild diesel fuel, i.e. fuel with equal parts of Castor, Kerosene, and Ether plus a couple percent of ignition improver.

Diesel fuel with a higher percentage of Kerosene generates more power, and is usually used in more robust engines with ball bearing crank shaft support.

Best of luck getting your money refunded.

Bill

jojo003

Hi, thanks a lot for all the replies. For the record, i am the teacher.
And of course we realized that a model airplane engine is not the best mimic of a real diesel engine, but it is for sure the smallest, 'cheapest' and most fun one to show in a classroom, right?! And...there are a few examples on the web of people showing these little engines running on vegetable oil based biodiesel, or at least parts thereof.
In any case, thanks for the help. We will look into a more modern rc diesel engine.
Best wishes,
Joris

lildiesel

I'd suggest you spring for a larger engine that is listed on the DDD site. It might cost about the same as anew crank, rod, piston, and contapiston fort that wew beastly. Try an OS.10 or the large Fox .15 ball bearing. Both of those will stand up to some abuse with an electric starter. There are a couple of good threads about fuel mixes, make your own biodiesel from scratch, ignition improvers, and stuff like that. They are in the "Everything Diesel" forum.Joris,

The early OK glow engine had square cut cranks under the venturi and they tended to break with very little help. Apparently the square cut takes too much metal off the crankshaft and really weakened. Later glows had oval cut holes under the venturi and that solved the problem. My OK diesel has an oval cut hole too.

gcb

lildiesel,

Were you actually referring to the McCoys? I remember they had the same problem you describe.

George

earlwb

Well, it is probably a too late. But someone used what looks like a 25 or 40 size Norvel engine converted to diesel to run on biodiesel based fuel. I assume they used ether, bio-diesel, and castor oil for the fuel and maybe something extra as a small amount of additive.

http://www.youtube.com/watch?v=3g0ri...67F49DEB431B93

gcb

The engine was actually a NORVEL .15. I don't remember if it was a Big Mig or AME, but I THINK it was an AME (the BB one). I think they only used biofuel and lube, no ether. There was a LOOOOOOOONG thread on the subject. I stopped reading it after page 11, but I think it ended up 25 or 30 pages.

The results were that you could run on it but it had to be pre heated due to the amount of compression needed to start from cold. Generally, folks would start it on model diesel fuel and switch to biofuel after it was at running temp. Perhaps they later improved on that.

If you are going to experiment with biodiesel, make sure you have a modern engine that you can get parts for.

George

william hanshaw

I have a very old - but complete - McCoy .049 diesel that I flew C/L and single-channel r/c when I was 15, and I'm now 73! Anyway, I 'm cleaning upthe little jewel, and noted the contrapiston assembly is frozen in place within the cylinder. I need to know if it is to be removed out the top of the cylinder by punching it out from its bottom edge within the cylinder, or to punch it down from the top edge of the cylinder,,,,or whether it matters which direction to remove it.I can't tell by looking, which parts of the contrapistion are integral with the cylinder. From the bottom, it appears that there is a domed upper end with a pin in its center, the pin isabout flush with the adjacent domed surface. From the top of the cylinder, there is a flanged cylinder down about 1/16" from the top lip, with a disc about 1/32" further down. I don't knowto use a brass punch from the inside of the cylider coming up, or to punch the contrapistion down from the top of the cylinder.

Can you please give me some direction on this? I don't think the engine will run without being able to unfreezethe contrapiston to be adjusted up or down to alter the compression.

Thanks,

William Hanshaw, AMA 31631.

Bill Adair

My Feedback: (1)

Hi Bill,

I would not attempt to punch the contra piston out!

No doubt it is only stuck with dried Castor oil, which may loosen up by warming the cylinder head with a hair dryer. Use a strap wrench, or hold the warm head with a shop towel while you try to unscrew it from the cylinder.

The contra piston is actually in the top of the cylinder liner, so it's probably the head you can't unscrew. The contra piston used a rubber O-ring to seal, and I've replaced all mine with Bunna-N rings from the plumbing section at ACE Hardware. Viton rings are even better I'm told, but mine last long enough for my brief running.

I have three of these engines, and they are great runners, but very delicate.

Give me a call, or send me your phone number via private message, and I can try to talk you through the process. My phone number should be in my forum profile, but email me first with the name that appears in your caller ID, because we screen all of our calls.

Bill

SGC

William,
The McCoy 049 diesels have a contrapiston that uses an O'ring to seal it, it also has a flange at the top to prevent it being screwed down to far and contacting the piston. So it must only be removed out the top!

Recycled Flyer

Does this pic help?