How to change model airplane engine bearings (part 1 of 2) 

How do you know when a baring is going bad? I have a OS 46AX and I can hear a metallic sound or mabye more like the engine is dry. What surprises me is that this engine has only a gallon of fuel and is 3 years old. I didnt use it for 2 years and it was always kept inside away from the elements.

chevy362000 , glow fuel is hygroscopic (it attracts water vapor from the air). The water gets into the bearings and results in rust. You can feel the roughness in the bearings when you turn the shaft. You can hear it too. Your bearings are probably rusting due storage. The single best way to to significantly reduce the effects I described is to use a light machine oil after you’ve flown for the day. First, drain the tank, then start the engine, allowing it to run all the fuel remaining in the fuel line and engine. Open the throttle and squirt a few drops of oil in the carburetor. Spin the engine with your starter for a couple of seconds then close the throttle. You’re done. NOTE - when sucking the oil into the engine, it MAY run for a few seconds even with the glow igniter disconnected. Be prepared. I’ve been using Marvel Mystery Oil in all my glow engines for years and rarely have any trouble. I ran my O.S. 46 for years before they finally gave up.

@@extra330sc I do appreciate your quick response. I am going to follow your advice. Marvel Mistery Oil I never heard I could use it for that too and I love how it smells. Thanks for all the info you have shared today. Alberto

chevy362000 , no problem. Glad to help. If you buy a pint of the oil that will last you for quite a long time. The tiny bottles the hobby outlets sell is fine but it’s overpriced. Check it out on Google or Amazon.

@@extra330sc One last question putting bearings aside. What are the signs of an engine going bad besides low compression? and what is your oldest engine still in service? Thank you in advance.

Julie Cheal You're welcome. You might find some of the stuff on my RCModelReviews channel to be useful as well.

xjet ..hi !! I have a biplane nitro engine but the engine stuck due to lack of use .. can you tell me what can I use to wash the parts ??? Gasoline or other liquid ?? Thanks!

Lisseth the best thing to use is rubbing alcohol or plane fuel will work. It is never a good idea to us gasoline.

28 year old Hirobo Shuttle? Shuttle's not THAT old..? wait I guess I AM... I would expect that, if or when you get it flying, that you put up the vid, and share. I would do it myself; except that I got so frustrated, and just sold the heli, and kept the tranny.

A few people have tried and they've usually gone back to steel bearings after a while. Ceramic bearings are a little more fragile (when subjected to shock loads) and really don't like any form of dirt (which is hard to avoid with an RC engine because they don't have air-filters). Far better to use a good quality steel bearing with phenolic cage and just change them when/if they wear or corrode.

The cylinder sleeve of most ringed engines has a chamfer at the bottom so that if you carefully lower the sleeve onto the piston (using lots of oil), that chamfer will automatically compress the ring as it goes into the bore. You just have to make sure that the ring-gap is lined up with the little peg in the ring-groove or it won't fit.

***** Thanks, works great on my Super Tigre 61's. Now you wouldn't have any idea where to purchase a piston and ring for a OS 1.08 since I broke the piston and ring not knowing how to re-insert.

Try putting your engine in your freezer. Wait until engine has completely frozen. An hour or two, or even overnight. Now keeping the engine as cold as possible, using a mini torch, heat only surrounding of the bearing. The idea of this is that freezing the engine makes every part contract. Then quickly applying heat to the surrounding are of the bearing. This will expand, what is holding the bearing in. Think;; maximum temp differential. The bearing might just DROP out, using this method. To thoroughly de-gum my engines, I heat a pot of antifreeze/radiator fluid over a stove top (low heat) and dip all the parts in. This is actually is a lot less caustic to the engine parts; and why wouldn't it be? Your car has it in, for years at a time, without having the radiator being eaten up, from inside out. If I feel that the new bearings are well made, and do not contain any machined shavings, I do nothing else prior to install. If I see shavings, I dip them as well and lube them afterwards. I don't know what has made your engine stop working, way back.. but if you can get your hands on a new sleeve, I would replace the old one. If you NEVER EVER want to replace the sleeve again, and want your engine to run with brand-new cond. of 99.99% of new compression/performance, you should preheat the engine head EVERYTIME prior to starting. This is a lots of work, and forces you to carry extra equipment, but when you realize that all ringless ABC engines start to loose compression(performance) IMMEDIATELY, if not preheated to prevent parts scraping pinch, during startup, you just may adopt this method. After several flights, your engine compression is similar to a 100,000 mile car engine. I use a mini torch or a heat gun on med high setting. I will be ordering a engine warmer to see if it gets hot enough to get the job done. www.hobbyking.com/hobbyking/store/__51642__TrackStar_12_volt_DC_Nitro_Engine_Heater.html?strSearch=engine%20heater

YEAHHH!!!! OBRIGADO AMIGO DEU CERTO TANK'S MAN... CONSEGUI RETIRAR OS ROLAMENTOS!

Vinicius Henrique Porto Silva Very Nice..

So long as you do not damage the bearings when removing them then you can re-use the bearings but since they are so cheap, it would still be a good idea to buy new ones.

yeap u right i should put the new ones!

a seks

The 40la is a pretty weak motor for a 40-size. Given that the minimum size for that plane is a 40 I'd try to find something a little more grunty. the 40la is also a very light motor -- just over half the weight of a normal 60-sized engine so you might also have a balance issue.

@@xjet Thanks for that as i,m new to this fun, that helps me a lot

If you have the head off the engine block already, rotate the crank and you should see that the piston should have pushed the sleeve out of the block at least a 1/3 of it's length. When your engine is assembled on a plane, just remove or turn out the glow plug, so that the air can escape. Then turn over the propeller and feel for the pinch. You should be able to feel a solid resistance of the pinch, for at least 1/6 of the rotation. If not, you are loosing compression big time.

Try boca bearings. You can search by engine for the correct set. They usually offer several options, go with stainless.

Are you having a stroke mate

Me too. Cannot get con rod off

I'm not a great fan of the SuperTigre engines. Look for a Thunder Tiger 46Pro, ASP46 or an OS55AX if you want a good reliable, powerful engine.

@@xjet thanks for that. I have been lookup engines, have you heard of saito FG 11 motors and i see the os motor is popular

Most small RC engines don't have rings... they often use an ABC setup (Aluminum piston running in a Brass liner that is Chrome plated). This produces less friction and significantly reduces the risk of seizure in the event of a hot-run.

@@xjet Do they just bleed chamber pressure to the crank case then, or is the clearance between the piston and sleeve so tight that its a non issue?

@@beachboardfan9544 The piston/bore seal is actually better than when using rings because there is no ring-gap to allow gas through.

How can thee be mistakes on something so simple as warming up components to remove them ? it would be more constructive if you to tell us what you are on about ??