i have had my nitro for about a month. It got hung up and before i could get to it she revved out to max rpm and then died. i let her cool off and tried to run her again and she ran real rough before the plug died. New plug installed and now she wont idle for more that 10-15 seconds. either way she revs up slightly and then dies. If i try to run her up she lasts less than 10 seconds. I took the head off and I have metal filings on the piston head. any suggestions?



edit** oh yeah, i have a Tower Nitro ST-15..............ease off me, its all I could afford.

Time for a new engine.These engines require a breakin period. You went past it. When running a new engine never run it at max . Go slow and break it in easy.It will last longer.

check the plug.The metal might be from the coil which is normally inside the plug.

Clean out the whole engine with the fuel you use. Take the whole thing apart. Check the sleeve and piston for damage(deep scratches), check that the front and rear bearing are clean of shrapnel and put your engine back together, seal it air tight so you dont get no air leaks or you'll ever heat it. When that's all done look in your manual to find the factory carb settings for you high speedand low speed needles so you no where you are, fire up the engine and keep it alive using the transmiter throttle. Dont give it to much gas(1/4-1/2 is plenty). Now set your idle screw so the engine keeps ticking over on it own. Let the engine warm up to running temp. Now tune the HIGH speed needle but watch the temperature and make sure there is ALWAYS an nice trail of smoke coming from your pipe. Hope this helps.

I FOLLOWED THE BREAK IN PROCEDURE LIKE I WAS SUPPOSED TO. THE GLOW PLUG WAS STILL INTACT, THE WIRE HAD NOT BLOWN APART IN THE CYLINDER HEAD. I CHECKED THE CYLINDER WALLS AND COULDNT SEE ANYTHING OUT OF THE ORDINARY. NO SCRATCHES, NO PITTING. THE TOP OF THE PISTON WAS GOOD AND DARK THOUGH. THE FILINGS WERE SMALL AND ALL OVER THE PISTON HEAD. IS THERE ANYTHING BETWEEN THE CARB AND THE PISTON HEAD THAT COULD SHRED LIKE THAT? THE TRUCK WAS POINTED STRAIGHT UP WHEN IT WAS HUNG UP AND STARTED TO REV UP. COULD THE FUEL/LUBRRICANT BEEN DENIED TO ANY PARTS THAT NEED IT? THIS IS MY FIRST NITRO AND BOY IS IT A LEARNING EXPERIENCE.

If there's no damage to be see after a carefull inspection put it all back together, make sure you do it properly, seal the back plate and seal the neck of the carb and fire her up again. Let the engine tick over for a while and listen if you hear any strange sounds that where not there before.
GOOD LUCK

So, I tore it down to an empty caseing. The piston rod was shredded. It looks like it got super hot, but I dont see any other signs of heat damage. The cylinder and Sleeve look good. No gouges or pitting. If these pictures will link up right you will see what it looks like. When I re-assemble the engine is there any timing or tuning that I have to worry about? Im sure there is, I just havent looked it up yet. I blew the casing out with compressed air, cleaned it all with alcohol, re-lubed the bearings, and have it all back together minus the piston/sleeve. Just waiting for the part now.................

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Yup...that would be the culprit right there.

If everything else looks good inside the engine, you should be good to go once you replace that part. While you're at it, replace the con-rod and the two locking springs (never re-use these)

I don't mean to sound like you don't know what you're doing, but I've made this simple mistake myself and destroyed a piston. Make sure you put the piston back in the right way round. You should see that one side of the lower piston edge has a curved 'cut out' section, this is to allow clearance between the piston and crank shaft at the bottom stroke.

I once re-assembled a costly OS without ensuring I did this correctly. Needless to say.....1 shattered piston with large bits-n-pieces flying around the inside of the case....[:@]

Good luck

Yep, that con rod looks definatly out of shape. Replace it but you'll probably need to replace the piston also(which comes with a new liner so do that aswell) it's abit like the domino effect. Are the bearings running nice and smooth???(Main bearing and front bearing)

All the bearings are smooth. THe front bearing is sealed so no metal got into it. the bearing inside next to the cam was exposed and right smack in the middle of the action but somehow no damage seems to have been done. Iguess the presure from the incoming fuel kept it going to the top of the cylinder and out the exhaust. Iblew it out and oiled it and blew it out again. I was able to get the air stream into it in a way tht the bearings were spinning inside the races like a buzz saw. They zoomed with no grinding or drag. Wtih it all back together it spins smoothly. No rough spots or hitches. Igotta go by and pick up an exhaust gasket, Ill prob see about getting the bearing anyway.The cylinder looks ok. There are some very minor scratches on them, but nothing deep. I could be wrong, But I think they are pretty well off. If Ipush the piston head in the sleeve Ican push it in to where it is flush with the top of the sleeve but it wont go any further. It slides in and out pretty smooth.........................take it easy gutter brains.....................so Im goint to try it for now.

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That speaks volumes about the poor quality of their motors. That con rod is beat all to hell just from some overreving.I've overreved many engines and never had that happen. Ibet the metal used to make that engine is very soft

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How do you keep your hands so clean while you work on the RC?

I'd change the connecting rod and reuse the rest of it for now. It'd be better to save the rest of the money for a nicer engine.

thats funny, when I get hit on most people complement my eyes.......................

lol

The photos tell me that the connecting rod bushing (where it mates with the crank shaft) failed, creating play between the crank shaft pin and the connecting rod. This play allowed the connecting rod to come into contact with the engine case causing the rest of the damage.

Over-revving did not cause the problem, a bad bushing did (no sign of stretching or hole elongation I could see in the photos). I would contact tower hobbies regarding a manufacturing defect that led to the engine failure (always being polite and provide the photos as evidence). Worst case, they do nothing. Best case is they provide you with an engine swap.

ok, tower says ship it back to them, they will look it over and decide what to do. I got the part in the mail and decided to just put it back together. Its all back in one piece with some new waterproofing on the servos and some new wire and fuel line management. I get the needles back to close to factory and start. no deal......unless the glow igniter stays plugged in. IF i leave it on, it runs. I take it off, it shuts down. they are brand new plugs. I took one from the package just to see if the other plug was a dud. same thing for both. Any suggestions?

I think over-reving could easily cause bearing failure, especially if the engine is already running lean.

If you have plenty of pinch yet when you turn the fly wheel by hand you might just have a tuning issue and the engine is to rich. I would put it up on a block and try to get the engine to heat up with the glow plug starter on the engine when it is running and tune it. What size is the engine and what temp is the glow plug. If it is a big block engine you can run a medium plug or if it is a .18 engine run a hot plug. I have seen a glow plug that was working when I put it on a glow starter but when I tried to run it on the engine it would just die when I took off the starter.

its a .15 size engine. Its a basic tower ABC model. I thought about the glow plug issue. I opened a new one (med heat..it ran before the motor issues with a med heat...) and it wouldnt run with that one either.