Fox .40 BB engine
 

My grampa used to fly planes and he gave me his old trainer. We figured out it would need minor repairs. We took the engine(fox .40 bb) apart and the bearings on the shaft that comes off the crank are gummed up and it won't rotate. How do i take it apart to clean it or replace the bearings?I am completely new to this. Thanks!

RE: Fox .40 BB engine
 

The good news is that replacing the bearing will be neither difficult nor expensive. My best advice is to have you check out the Glow Engines forum here at RCU:

http://www.rcuniverse.com/forum/forumid_114/tt.htm

Many of the regular posters are long time RC pilots with an amazing amount of knowledge concerning glow engines.

RE: Fox .40 BB engine
 

First a bit of model fuel in the carb will loosen up the carb and the bearings. The varnish that is built up is softer than the steel bearings so it won't hurt to turn it over to get the new fuel to disolve the varnish. One you get it started the heat will finish removing the sludge.

You could use gasoline but it's more dangerous to do so and you have to be very careful.

The .40BB was a great motor in the mid 1970 when it came out. A real power house motor that is pretty comprable with todays .40s.

Also Fox has a very resonable repair program. They only charge for parts for their repairs. Or at least they did the last time I checked, a couple years ago.

RE: Fox .40 BB engine
 

That motor is a keeper! Fox is still in business and parts should be no problem. The gum is dried and hardened castor oil and has likely preserved the engine. I 'll bet a cold can of Coke that your grandpa did that intentionally. :)

RE: Fox .40 BB engine
 

first off, you must losen up those crank brgs. or the balls won't roll just slide in their races. very bad news!!!! what i have done in the past is partly disassemble eng. remove carb, muffler, and back plate (probly will need new gasket or make 1 yourself, easy to do) with eng. in oven heat to about 225-250 degrees for about 20-30 mins. this will soften castol gum and varnish. let eng cool a LITTLE so you won't burn yourself and soak eng in some fresh glow fuel and start to spin eng to get sludge etc to be broken lose. you mite have to go thru procidure a couple of times to commpletely clean eng. CAUTION, CAUTION!!!!!!! do not put glow soaked eng back in the oven with fuel in it, it will catch on fire and so will your oven on fire!!!! [:o] flush with rubbing alcolal and dry with hair dryer or monokote heat gun, then do the oven thing as needed. just always dry eng out of that fuel/and or rub alohal. try it works for me.

RE: Fox .40 BB engine
 

As mentioned, just put some fuel in it and prop it over by hand and it will loosen up just fine. Once you have it all loosened up, put some 3in1 oil in it and put it away until you are ready to use it again. Good Luck, Dave

RE: Fox .40 BB engine
 

To take the engine apart will likely do more harm than good

RE: Fox .40 BB engine
 

carb, glow plug, back plate, no harm, no problem. mite only need a couple of gaskets, order from fox or just make yourself, very easy to do.