Nose dive crash hurt engine???? - RCCanada - Canada Radio Controlled Hobby Forum
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Old 12-31-2007, 02:29 PM   #1
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Nose dive crash hurt engine????

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My OS61FX glow engine endured a nose dive crash, hard!!! I have not tried to start it since and now a few years later I would like to use it again. My concern is, is it possible that the shaft was pushed back into the motor sliding on the bearings or not? I have closely viewed it but can not see that it has moved. What prcautions can I take to ensure the motor will not be damaged by running it now. Thanks for any advice you can give me. Wayne C
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Old 12-31-2007, 03:33 PM   #2
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I would take at least the back plate off and see if it pushed the crank back to it. Most OS's have a clamp type keeper on them and not a key so it may very well have moved back a bit. You should be able to feel it also when you turn it over by hand(sometimes) but if it is rubbing there will be the tell tale mark on the rear plate. It would not hurt to remove the back plate and flush out the crud from sitting so long and you can check and lubricate the bearings before a start up.
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Old 12-31-2007, 03:52 PM   #3
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Nose dive OS


One thing you should REALLY check out is whether or not you have ANY dirt in the carb. If you do, you should probably take as much of the engine apart as is reasonable. Any little bit of foreign debris that may have been taken in through the carb will score you cylinder. Engines are really easy to go through but if you're not sure you want to tackle the job, I'm sure your club likely has a motorhead as a member and can walk you through or clean the engine for you.

The only other thing I would be concerned about is whether the crankshaft shifted or twisted/bent at time of impact but I think that's pretty rare.

In terms of the crank moving axially to the rear on impact, you'll likely cause more damage running a starter motor on an engine that 's difficult to start as the crank does get pushed back and ends up rubbing against the back plate. This leads to quite a good amount of fine particles floating around that would also end up scoring the cylinder. An engine with a properly set up carb should be able to ignite just by finger flicking as you may have seen other modelers in your club doing. I find that's the best way to start an engine provided you are careful.

Any of my engines that I even suspect of having had contact with dirt get a teardown for complete cleaning.

Best of luck,

Build your dreams
Crash your nightmares

Damian Polanic
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Old 01-01-2008, 10:06 AM   #4
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As stated, a teardown is the best thing.. Andrew Coholic did one in a FlyRC issue on a OS 46sf, so that would be helpful.. 2 strokes are an easy teardown/rebuild... My only concern is what Damian mentioned, that the crankshaft might have gotten bent... It's hard to tell in the engine (until you run it "then you'll know it's bent" vibration city )... No prop balancing is gona cure that .. The way I tell is put in in the lathe and put a dial on it, but not everyone has a lathe... you can try and straighten them but it's hard... If it is bent buy a new one (crank that is)... good luck
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Old 01-02-2008, 11:17 AM   #5
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Things I would check for (after a complete dissassembly)

- dirt (especially as stated in the carb)
- bearings (which can be damaged in a bad crash)
- any run out in the crank front end (bent)
- any damage to the backplate if the crank was hit hard enough to force it back

Unless you hit reallyhard on pavement, its pretty much impossible to hurt the cylinder or piston/rod. I have seen engines that have had the case cracked though and the head portion of the case bent back a degree or so. But thats a straight down crash on a hard surface.

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1/2A to giant scale, IMAC, SAM, R/C sport, turbine jets, Heli's...
if its got a wing or two and an engine - I like it!
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Old 01-02-2008, 05:20 PM   #6
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Motor maintenance thank you

I would like to thank all that give me their views and answers to my question on the motor crash. I now have the informations to carry on with this motor. Thanks again Wayne C.
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