smallrc

This is my original Cox Babe Bee engine. It was on a Cox Spitfire control-line model that I bought around 1968. The Spitfire flew very few flights before it was destroyed by a crash. In 1972, I built my first R/C plane, a Goldberg Jr. Falcon and used this engine with a Kavan tank extender added for longer flight times.

I am wanting to bring it back to running condition after being in storage for 30+ years, and would like input and advice. I don't want to try to "hop it up", just get it running reliably again. I plan to clean it thoroughly, reset the rod-piston ball joint and replace the fuel pickup tubing. What else would you suggest? New gaskets? Replace the reed valve?

Thanks for any suggestions.

Tom Nied

If you don't want to "hop it up", you'd do well to buy a new reed and glowhead and maybe the back gasket. Check Cox International. http://coxengines.ca/ They've got all you need and are great to work with. Props and parts, they got it all.

ffkiwi

Can i point out that that engine shown is NOT a standard Babe Bee-it has been fitted with one of the Kavan tank extensions to increase its fuel capacity-so depending on what you propose to do you might have some issues-these might include getting the right length screws if the originals are u/s or damaged-in which case you'll need a set of long tank screws (such as used on the Golden Bee, Black Widow or std Texaco reed valve engines. For an overhaul/refurb I would replace the reed valve and all the gaskets as a matter of course-you might or might not choose to replace the glowhead (though looking at your engine it appears to be a 'belt cylinder' one-which would put in around the mid 1970s for production.....in turn that means it might have the hemispherical 302-1 glowhead or the later (and still current) 325 glowhead....the latter being slightly higher compression than the earlier one-but not high compression like the 1702 TD head. You now have a choice of reeds-they are available in copper, stainless steel, mylar and teflon-all of which are claimed to be superior by various people! Likewise there are two types of reed retainer-the 'e' clip type and the 'top hat' version. All available from Cox Int'l...
The single component that causes more grief than anything is the very small black rubber gasket (like a tiny O-ring) that seals between the cast backplate and the central induction tube in the tank-if this is not seated, frayed, or damaged it will really spoil your day when it comes to getting consistent running. Definitely #1 for replacing in any overhaul. They come in the Babe Bee gasket/overhaul kits or you can buy them separately. The fuel line inside the tank has probably gone rock hard with time as well-as you suggest so replacement, along with the anti-kink spring is advisable (but of course might depend on the last fuel used-if castor based then definitely!.... Finally check the NV tip for either being bent or the very tip snapped off-which can also lead to inconsistent running.

You will also need to check the fit of the red Kavan tank extension fittings to ensure it seals OK-the plastic may have warped over the years....

ChrisM
'ffkiwi'

smallrc

Thanks for the suggestions - I'll add some parts to my Cox International wish-list!

Jennifer Curtis

The original had a brass or bronze
reed valve. If you are going to run
the engine replace it with the new
mylar one. Otherwise keep it. It
is a sure sign of a vintage engine.

The same goes for the spring inside
the fuel tube.

The prop screw is a 5-40. Don't try
to put the wrong screw in there. You
probably need to go to a machine shop
to get a 5-40 screw. It probably originally
had a stud and a cup shaped nut/spinner
mount and rubber spinner. Good luck
finding them.

If the shaft is froze, you might need to
drive it out. Put a screw in the front and
turn it all the way in. Leave some space.
between the screw head and the drive plate.
Remove the tank, cylinder and piston,
and rest the crankcase on a board.
Tap the screw head to drive the crank
out of the drive plate. Screw torque
will re-seat it later.

As I recall the babe bee didn't have
flats on the cylinder fins for the special
wrench. The wrench stuck across the
exhaust ports. It kind of worked ok,
but risked damaging the cylinder.
You might need to heat the crankcase
to remove the cylinder.

The brassy color on the tank back may
be plating. Using abrasive may remove
it. Look in the venturi hole from the
tank side (where the o-ring goes) to see
if it is aluminum under the brass.

The carb hole may have a screen over
it. It is probably quite delicate now. Be
gentle with it. I don't think it can be replaced.

Jenny

Andrew

Thumbs up on the venturi gasket.

If you want to use the Kavan Tank Extender, you'll need two venturi gaskets. The Extender came with a tube necessary to to extend the venturi tube from the existing tank to the backplate. Many of these extenders had a reputation for leaking and being difficult to get to seal well. Although you'll get a longer run time with the current tank, my inclination would be to remove the extender until you can get the engine up and running. Being plastic, it may well have age cracks and could even crumble while replacing parts.

EX Models here in the US will also have rebuild kits.

Tom Nied

If you can't find the exact gasket, don't rule out slicing some silicone tubing (I'm guessing 1/2 a type tubing) to make a new gasket. The old fashioned double edge razor blade slices silicone tubing with ease. A little experimentation and I'd bet you get the right fit.

combatpigg

My Feedback: (3)

I'd dunk the engine in a jar of Marvel Mystery Oil, or auto trans fluid and let it simmer in a hot car for a day or two. I believe Marvel Oil is a mixture of ATF and Oil of Wintergreen. I'd like to think that this stuff can rejuvenate old dried up rubber parts, but probably not unless you knew of just the right temperature / pressure to use. I have seen old military teletypes with all of their rubber / plastic parts restored to what almost looked brand new after being submerged in a hot bath of some magic potion.

Hoppes #9 Gun Solvent is a real good de-varnisher, especially when used with the plastic bristle bore brushes and cloth swabs.
Don't use steel wool on any internal surfaces and never stick a tool of any kind in the exhaust slits.

aspeed

My wife, and I used to work at Marsland Engineering and made teletypewriters there many moons ago. I am surprised they are needed now. That was a high tech industry then. Made IBM computer parts too. Water cooling for the huge computers of the time.