jeffsend

My Feedback: (4)

Hello,
I have been out of the hobby for a very long time and decided to clean up an old plane and try to get it flying again. I had an Avistar with a Thunder Tiger Pro .46. I did not run it very many times before I lost interest after a malfunction(fuel tank split and leaked inside the plane). The last time I ran it,I put after run oil in it but then it set for a few years without use indoors. I opened it up recently and there appears to be rust looking at the back of the crankshaft through the backplate. It is gummy and i'm not sure if it's damaged or just needs cleaned. It will turn over,but feels gummy. I don't know much about these engines. My questions are......

Is it worth repairing,or would it be better for an inexperienced person to just buy a new one?

Is it easy to find parts for this engine?

If it's worth a try,what parts might likely need replacing if there's rust inside?

How can I keep the insides from rusting next time?

Thanks in advance for any help,
Jeff

proptop

My Feedback: (8)

I would flush it out well first...
Drop it in a coffee can (remove the backplate and glow plug ) and pour denatured alcohol over it until covered, and let it soak overnight...that will clean it out nicely...then you can tell if the bearings are rough.

The TT .46 is a great engine, and it's easy to replace bearings (if necessary )...and parts are readily available.

As far as "preventing" rust...the best steps are to run it dry after the last flight, while it's still warm, then add the after run oil (plenty of it ) and pull the plug out, then motor it over w/ the elec. starter (if ya got one )

bigedmustafa

My Feedback: (2)

I'd agree, clean it up and try running it before you start ordering parts. Surface oxidation on some engine parts may get cleaned away ten seconds after you fire up the engine for the first time.

If you need parts, you can get them from:

http://www.thundertiger4u.com

http://www.infinitehobbies.com

http://www.ehobbies.com

Any local hobby dealer with an Ace Hobby account can order them for you as well, so long as you provide them with the part numbers.

Good luck!

BankYank

My Feedback: (63)

IF you end up needing new bearing's and you don't want to do it and can't find anyone around you who knows how. You pay for part's and shipping and i'll do it for free. I can ship it back the next day after i get it.
Pat

jeffsend

My Feedback: (4)

Thanks for the suggestions and links. I will try cleaning it up and see what happens.

blw

My Feedback: (3)

Glow fuel works faster. The gumminess is probably normal. I had an engine do that to me after a year of sitting. I just cranked it up and it ran fine on the second tank. First tank was a little rough.

jeffsend

My Feedback: (4)

Got it cleaned up. Soaked it in denatured alcohol as suggested. It definately has rust in it. The bearings appear to be covered in rust as well as the back of the crankshaft and crankpin. I have not pulled the crankshaft or bearings out yet. I'm hoping I don't have to replace the crankshaft. I ordered some bearings and gaskets and oiled it and put it back together for now(while waiting on parts). Compression feels good and it turns over smooth.

Pat,thanks for the offer. I would like to try and fix it myself just for the experience. Found some photo illustrated tutorials online. They suggest heating the case in an oven to get the bearings out. I will probably try that method.

Sport_Pilot

You may be simply looking at oil stains. The mix of castor varnish and the red dye in many fuels will often be about the same color as rust. If you have somthing that is actually rusted it will usually be a brighter red than that stain. I would not take it apart unless the front bearing has too much radial play. The problem you had before was from congealed castor oil, so of course it would have some varnish left over after cleaning with fuel.

jeffsend

My Feedback: (4)

Ok, I may just try to run it then. I know it sure looks like rust and the denatured alcohol got it squeaky clean everywhere else. But I don't feel any roughness when turning the shaft so maybe it's ok.

DarZeelon

Jeff,


In addition to running the engine dry at the end of the flying day, the first thing is to use fuel that contains a good measure of castor oil.

Castor oil sticks to steel surfaces with great tenacity and if the engine is run dry at high throttle at the end of the day (to burn away all the methanol and nitro), no rust will form, even if you forget to use the ARO.

'A good measure' meaning at least 8% of the fuel must be castor oil (and no less that 18% total oil).

If the bearings prove to be rusty, [link=http://rc-bearings.com/]Paul of RC-Bearings[/link] can supply either normal steel bearings, or ceramics, for a very nice price (about $6-7 for a normal engine set). Don't bother going to outlets that sell them for more, or the OEM set.

jeffsend

My Feedback: (4)

Thanks for the tips. Wish I'd known about the cheaper bearings. I already ordered the OEM's for 14.95.
As for fuel,I was running Omega 10%. Their website says it has 17% oil in a 30/70 mix of castor/synthetic so it's probably a little below your suggested figures.
I have a question about these fuels.....I have 2 unopened gallons left and they have been sitting as long as all my other stuff did. The fuel in my pump jug is brownish so I figure it has gone bad,but the unopened jugs are still bright pink. Does that stuff have a good shelf life? I will probably try to run some once I get it all back together.

DarZeelon

Jeff,


As long as it is not a minute amount of castor oil, so no one will say that there isn't any, it will be helpful to prevent rust.

...It will also be more protective for the engine while it is running. Omega is 4.9% castor oil.



Fuel in a sealed metal container could be stored for very long periods. The translucent plastic jugs most fuels come in make it more susceptible to light and absorption of moisture from the air.

Try some of it. If the engine can run reliably on it, just use it.