Irecently acquired a USED Hangar 9 Alpha Trainer for my son. It's about 8-9 years old. I'm told it was only flown1 or 2 times and Ibelieve that.The plane and radio are almost like new but the old fuel inside the engine hasvarnished up.I've removed the engine and opened it up todisassemble it for cleaning. But Ican't get the connecting rod out. It's almost like its crimped on or something.I've disassembled several other engines over the years and never ran into anything like this before so I'm just stuck. Any tips??

You may be better off filling the engine with glow fuel overnight. They're pretty good engines. Decent power, but not hot rods. Well balanced to run smoothly. They like 15% fuel. A hot plug like the OS A3 is a must. The OS 8 is too cold. You can upgrade the engine to a .46 NT with new parts.

There's junk in the bearings.  I can feel it "bumping" as it turns. So I really need to get this thing apart so I can clean the bearings, or perhaps replace them.  Just need to get the connecting rod off.  Perhaps at that time I may consider upgrading it to 46 if that truly is an option. 

I would try soaking the engine in kerosene for a few days take out the plug and remove backplate you may get lucky and not have to take it apart to replace the bearings that is of course if only if they are gummed up and not corroded martin

If it is congealed castor oil then place it in the oven at 225 degrees for about 15 minutes. It will liquify the crud and you can flush it out. It never pays to strip an engine needlessly. You will ruin the wear pattern and in general you are starting over ABC or otherwise. The engine is simple to dis assemble. Take the liner out and the piston will slip off the crank pin easily. Just make sure that you have the rod to the back of the piston when removing

The bearings may still be fine. See what a soaking and/or heat will do. I ran an older Evolution engine with the same things you mentioned and it was just gunk that I was feeling.

i NEVER take apart an old unused engine.  I have had old engines unused 20 years with congealed castor oil that have frozen the engine.  I simply pour fuel in a bowl and soak the engine in the fuel overnight.  They are free the next day.  May have some bump in the bearings, but after soaking, I turn the engine over a few times, take the backplate off and wash out the congealed bearing debris left in the crankcase.  When you take it apart you have to break it in again, especially with ringed engines.

Appreciate the tips on soaking and heat.  I've soaked it in wd40, then penetrating oil.  It loosened everything up but no luck getting the connecting rod released.  Last night I tried the heat trick and still no luck.  The bearings still bump and grind.  Either they're simply corroded or there's other grime in there that won't disolve away.    On other engines that I've disassembled the connecting rod simply lifts off the crank pin.  But on this engine the connecting rod simply won't lift off.  It's stuck tight like it's crimped on or something.  And on the bottom of the connecting rod there are 2 little dimples that look like it might have been crimped into a groove on the crank pin.  A friend suggested to try removing the cylinder sleeve first but I've no idea how to do that either.  

Dennis,  What the heck is a "Kiner"?  I've never heard that term before. 

Need a spell check. It is supposed to be liner, its corrected now. If you have the backplate and head off the engine and wish to remove the liner put a prop on the engine and place a popsickle stick inn the exhaust and take the prop up to compression slowly. It will put pressure on the top of the exhaust port and usually will lift the liner enough to give you some wiggle room to remove it. The stick is softer then the metal so it will not damage the liner. After it breaks loose you can use the end f the stick to push on the bottom of the liner to remove the liner. Gentle heating may be necessary to accomplish it but it really is not a difficult task.
Dennis

dennis

Ahhhh....  Thanks.  Youknow how to go about removing it?

ok. so something is weird here.  When I first read your last message all it said was the correction about the word liner.  After I responded now it comes up with more information.  So.. thank you.

Hi!
Been racing for 36 years and have never seen an engine with old castor congealed bearings clean itself with any liquid, be it aceton,methanol or heat.
The only certain solutiion when a bearings is old and worn and feels gritty is to replace it with a new bearing.
I have seen engines where the crankshaft spins freely and when the engine is taken apart the rear bearing is so rusty and full of orange congealed castor oil that the crank spinns on the inner bearin surface and the rest of the bearing is stuck.
Ofcourse the engine works...but how well? And for how long time?

If you are serious about your engines, take the engine apart and replace the rear bearing! It's so easy to do!

Thank you Jaka.  I agree.  I don't need convincing.  I've done this on several other engines over the years.  It (generally) is a very easy project.  I just need help with this specific evolution engine that is being difficult.

Sounds like a hot dip in antifreeze and a crock pot are needed. I do this when I change bearings. It also does a decent job cleaning and softening up gunk. In looking at the exploded diagram of a .40nx, the manual shows a cylinder liner. If it wont budge with the engine cold, you need to heat the engine and use some wood or plastic to pry it loose through the back plate opening. Prying from the top is risky. Dont use a screw driver unless its protected by something to keep from gouging the liner. With the liner out, you should have room to move the conrod off the crank pin. Depending on how the piston is made will determine if you can slide the conrod off the pin when in the liner.
Edwin

Jaka,

You should try soaking/cleaning like some of the members here have suggested. You may learn something new.

Those will not disolve nor mix with castor oil. Use glow fuel, or methanol.

This could ruin the connecting rod if the varnish has not been softened with fuel, methanol, or heat. Should not be necessary to remove the piston anyway, you only need to disolve the congeled oil from the bearings as it could cause the balls to slide in the race and ruin the bearing.

I can assure you that fuel will disolve the old congeaed oil. You might have to leave it longer than overnight in a few cases. It will not remove varnish, though it will soften the varnish.

If it works it works. How long? You will know when it quits. He is not racing and not as experianced as you. IMO he is best to leave it alone for now.

WD 40 will compound the problem. It is only a water dispersant. It will leave residues.

Gliderguy100- the 'dimples' that you are seeing are probably the lubrication holes drilled in the connecting rod ends for the bushings. There are no grooves on the crankpin. It is just a polished press fit piece. The connecting rods that I've seen have a chamfer.

Also, you mentioned interest in having a 46 sized engine. The upgrade on the Alpha is a 46 crankshaft, and a 46 piston/liner set. The cylinder head will still have the Alpha symbol, but that will be the only difference in the two engines. It would be worth doing if you ever had something eat up your piston and liner that caused you to buy parts. Evolution parts are cheap.

Very good information!!  Thank you guys!  I will start a "fuel soak" tonight and see what that does.

isnt the con rod a plain bushing bearing ? the cranshaft has 2 ball bearings .

Hate to say it but sometimes the piston pin can get so corroded to the connecting rod and it just wont come apart.

I had an OS 52 Surpass and a 70 Surpass that did that. I soaked each in a crock pot of antifreeze for a few days (now use ATF), soaked in acetone for weeks, 30 minute bake in a 300 degree toaster oven, even a small torch. NADA!

I finally cut the con rode with a dermal tool so I could get the engine apart. Once the piston was out I was still unable to press the pin out of the piston! In the end I damage the piston as well and needed to replace all three parts.

I think part of the issue is the fit between the piston and the liner doesn't really allow all that much liquid to get in to the pin to break up the crap that builds up, not to mention there isn't much room in there to begin with, and if the corrosion isn't able to be dissolved the parts will never come apart.

Right now I have a K&B 61 now that's in the same boat. Not even sure parts are available for it so its just sitting till I can come up with something new.

Bill S.

By now i would have just bought a new motor

Naaa, too easy to give up, besides parts were cheaper then a new engine as well.

Bill S.

Remember the orientation of the liner as it must go back in exactly as it came out of the cylinder.  Sometimes there is a notch and pin, others you have line up the exhaust port.  When the liner is out, it is also a good time to make sure the passages behind the liner are cleaned up too.  I have even heard of fellows polishing those paths but not sure it does much for such small engines.

I would use a heat gun on the bearings, that loosens and sometimes melts the old Castor.  Castor is a great protective material.  So once the coating is removed you may find a good bearing after all.  But changing the bearings is not a big deal.  Get a set from Paul (the bearing man), they are in expensive.