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Old 01-09-2008, 04:44 PM   #1
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Default New Motor Toasted! Help! Pics inside...

Hey guys.

About 2 weeks ago my XXX-NT RTR II arrived at my door. The first night i took it out, using the out of the box settings, and put about 5 tank through it. I followed proper break in procedure, as it seemed to be rich enough based off the smoke and i didnt give it full throttle till the last tanks, and only 1-2 seconds at a time then.

A couple days later i took it to the park and put about 1/3rd of a tank through it with the body off, it was a little harder to start than before, but figured it was because it was getting richer as it broke it. I then flipped it and the throttle linkage went out of adjustment. Took it home (no tools with me) and fixed it. Later that night i took it out and was having problems keeping it running. After a few tries of starting it then it dieing, i couldn't get it to start at all. I figured it was a combination of how cold it was and it getting even richer yet.

This all happened maybe a week ago. It sit, in my living room, which stays at a constant ~70 degrees with very low humidity (very dry apartment, actually purchased a humidifier for the bedroom because how dry it is in here). It sat with the 2/3 of a tank of gas it had it in when i quit messing with it last week.

After some very appreciated info i got on the rookie forum on here, i decided to give it a try again tonight. I put the spin-start on it and it wouldn't turn over. Figured fuel had maybe hydro locked it so i loosed the glow plug and tried cranking... still was locked up tight I took the glow plug all the way out and noticed that there was some "crap" down in the motor that looked like dirt maybe? Decided to take the head off to satisfy my curiosity. Upon taking the head off i discovered this... a greasy looking piston with some traces of a brown slimy lookin stuff on there. The dome on the head had a lot of it on there too.

First pic is a picture of the head dome once i took it off the head (kinda blurry... hard to get a good picture)



After seeing this i decided to crank the motor over and it pushed the sleeve out... pic



The third picture is a pic with the sleeve removed, just to show the top of the piston better



What doesn't make sence... is that the first time i drove this truck for the initial, was in a parking lot and it had rained earlier that day so there was no dust in the air.

The second time was in a grassy yard at the park, and that was only for a couple min.

This truck has never been ran without both the filter and out foam cover that goes over it. The filter seems to have the filter oil on it like it should.

Im at a loss... this thing has been only ran once really and this happens.

I tried to put the sleeve back in, but it locks up once it gets about halfway up through the crank rotation.

I know a RTR motor isn't a high end motor by any means, but i expected it to last more than one run!

I would really appreciate any help, im baffled...
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Old 01-09-2008, 04:52 PM   #2
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Check to make sure there is no dirt in the fuel tank, lines or fuel bottle. Also how Thick Was the Grass. Was the truck struggling to go? you may have over heated the thing.
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Old 01-09-2008, 04:58 PM   #3
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I m not new to this at all but when u got the motor was their oil in it i have had the same motor same thing happen to it and it is from having lots of oil from the company in it or from after run oil or just the wrong oil they should of gave u a warrenty on it but if u have any more qustions ill give u my phone number i build alot of motors for people in alabama and i have seen that alot with these motors.and i dont care what people say about breaking in these motors i breack them in how i drive them and my motor s last along time its the same way with my dirt bikes and snowmobles.. every motor is the same except a four stroke
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Old 01-09-2008, 05:43 PM   #4
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Check to make sure there is no dirt in the fuel tank, lines or fuel bottle. Also how Thick Was the Grass. Was the truck struggling to go? you may have over heated the thing.
There was no dirt in the fuel tank. I took it right out of the box, put gas in it, didn't touch a thing, and took it to a parking lot to break it in.

The second time (when i ran it in the grass) it was not thick grass (2 inches high maybe)


When i broke this thing in i was very easy on it, between every tank i could grab the head on the motor and not get burned.

I just dont understand this. I just got off the phone with a friend and was basically told that these motors are known for this and that they are junk

I just got done totally taking the motor apart. When i turned it upside down a lot of black liquid came out, i just assume it was from the aluminum rubbing off and mixing with the fuel. The rod had a thick black residue (like grease type thick) on it.

The whole top of the piston, once wiped off, looked very "blotchy". If it were a full size car, i would best describe it as how a piston looks after it has experienced detonation.

Once everything was apart, i tried sliding the piston up into the sleeve from the bottom. It gets pretty tight and finally locks up with its about 3/16-1/4 of an inch from the top of the sleeve.

Whatever the reason, it looks like this motor is smoked, so i guess i should start shopping for a new one.

A buddy told me to look at Fantom engines, i gues they have a .15 thats pretty powerfull and pretty cheap too... less than $150.

Well here i was getting pissed at all my IB4200's messing up so i decided to tinker with my gas truck, only for this to happen
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Old 01-09-2008, 06:05 PM   #5
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OK, what fuel did you use? Hopefully you ran RTR or basher type with good oil content. Also, see if the marks on the piston and head are just marks that can be cleaned or polished off. If there are small pits in the head and piston, thats most likely detonation or something was in the engine. If the piston still builds compression after it closes the port opening and get stuck in the sleeve before it reached TDC, then it should still be OK to run. That would mean you still have good pinch. Also look for any scratches down the piston that go completely down the skirt. This will kill the compression eventually as it gets worn in, but like I said, if you can clean it off or polish out the marks, then you can at least still run the engine.
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Old 01-09-2008, 06:12 PM   #6
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OK, what fuel did you use? Hopefully you ran RTR or basher type with good oil content. Also, see if the marks on the piston and head are just marks that can be cleaned or polished off. If there are small pits in the head and piston, thats most likely detonation or something was in the engine. If the piston still builds compression after it closes the port opening and get stuck in the sleeve before it reached TDC, then it should still be OK to run. That would mean you still have good pinch. Also look for any scratches down the piston that go completely down the skirt. This will kill the compression eventually as it gets worn in, but like I said, if you can clean it off or polish out the marks, then you can at least still run the engine.
I ran 20% that i picked up at the track.

There are not small pits in the piston, but its not a uniform even color, its very blotchy.

I cleaned everything and it still wont get any closer than about 3/16 away from TDC. I would have to sand this thing down a little to get it to go to TDC.

It sucks that it happened this soon, but a better engine was in the plans anyway, so i dont mind buying one. Im just trying to see if it was an error on my part, or if this engine is simply hit or miss from the factory and i got a bad one.
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Old 01-09-2008, 06:12 PM   #7
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Look like your engine got bad detonation.
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Old 01-09-2008, 06:12 PM   #8
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Have you checked the sleeve to see if there is any damage other than having a black residue on it. What fuel were you using. I would check to see if their is any damage to the engine and if not then clean it by soaking it in a crockpot of antifreeze for a couple of hours. Make sure to remove the carb and any non metal parts when doing this. Reassemble the engine using afterrun oil and finsh breaking it in. If you were not heating up the head of the motor on breaking that might cause the black residue you see due to having alot of friction between the piston and the sleeve. If the motor is hanging up mid way though the stroke it just might be the pinch causing it which is a good thing and means the motor has not been worn out yet.
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Old 01-09-2008, 06:20 PM   #9
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Don't sand anything. Its supposed to be tight and lock up close to TDC when new. I only polish the top of the piston to clean up any bleamishes and the head button combustion chamber, but no sanding off anything! Clean it up, check the crank and bearings, apply afterrun oil, reassemble it, heat the engine with a heatgun or blowdrier to about 170F to 200F. Start it and finsih off the break-in. Use a basher or RT fuel with 15% or more oil. Race fuel will wear the P/S set out faster.
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Old 01-09-2008, 06:20 PM   #10
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Have you checked the sleeve to see if there is any damage other than having a black residue on it. What fuel were you using. I would check to see if their is any damage to the engine and if not then clean it by soaking it in a crockpot of antifreeze for a couple of hours. Make sure to remove the carb and any non metal parts when doing this. Reassemble the engine using afterrun oil and finsh breaking it in. If you were not heating up the head of the motor on breaking that might cause the black residue you see due to having alot of friction between the piston and the sleeve. If the motor is hanging up mid way though the stroke it just might be the pinch causing it which is a good thing and means the motor has not been worn out yet.

The sleeve looks really good, it skuffed towards the top where the pistons gets tight, but you cant feel it with your finger, its only a little more shiny.

I understand that its good for things to go together a little tight, but there is NO way that pistons is making it to top dead center...

Is there a spec for the diameter of the piston? Im gona bring home some calipers from work tomorrow and measure it, would be nice to have the spec of what it should be from the factory so i know if its expanded or not.
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Old 01-09-2008, 06:24 PM   #11
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Your description sounds like your motor still has good pinch. I would check out the carb and make sure you don't have a crap in it. What was your initail temp? What fuel were you using? Hopefully it didn't go bad. Looks like your motor got in the 300-400 degree temp with the burn marks and the looks on the button. You were very lean. Stay out of the grass until you get a proper break in. Remember to keep checking temps especially on a new plant.
My diagnosis: Get a dremal with a brass brush attachment and clean that button and head. Take the motor apart and check the bearing on the con rod. Clean those needles on the carb and rebuild. Clean and relube everything. A new motor will not go to the top of a sleeve. Drop in a hot plug and dump in some new 20%. Keep your temps around 200 degrees.
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Old 01-09-2008, 06:26 PM   #12
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Don't sand anything. Its supposed to be tight and lock up close to TDC when new. I only polish the top of the piston to clean up any bleamishes and the head button combustion chamber, but no sanding off anything! Clean it up, check the crank and bearings, apply afterrun oil, reassemble it, heat the engine with a heatgun or blowdrier to about 170F to 200F. Start it and finsih off the break-in. Use a basher or RT fuel with 15% or more oil. Race fuel will wear the P/S set out faster.
I dont have any after-run oil. Is there an equivilent to it? For example in a full size engine they say if you dont have assembly lube to use 30wt oil?

The rod has very little play on the wrist pin, and the crank doesn't appear to be messed up (although i dont know what the signs would be unless its would be visually obvious). The brass (or whatever) bushing on the crank end of the rod looks very good, and the journal on the crank itself doesn't appear to be skuffed or anything.
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Old 01-09-2008, 06:31 PM   #13
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Your description sounds like your motor still has good pinch. I would check out the carb and make sure you don't have a crap in it. What was your initail temp? What fuel were you using? Hopefully it didn't go bad. Looks like your motor got in the 300-400 degree temp with the burn marks and the looks on the button. You were very lean. Stay out of the grass until you get a proper break in. Remember to keep checking temps especially on a new plant.
My diagnosis: Get a dremal with a brass brush attachment and clean that button and head. Take the motor apart and check the bearing on the con rod. Clean those needles on the carb and rebuild. Clean and relube everything. A new motor will not go to the top of a sleeve. Drop in a hot plug and dump in some new 20%. Keep your temps around 200 degrees.
The motor never got hot even where it was uncomfortable to touch. Was using "Byron Originals" brand 20% nitro with 12% lubrication it says.

The black that you see in the picture isn't burn, it just dark fluid, im assuming its where the piston wore a bit and mixed in with fuel.

I also wanted to add... that upon taking the pipe off the motor, its has the same brown residue all over the inside of it. It looks like it has the consistency of wet clay/mud.

I assumed i wasn't lean because it had a good amount of smoke coming out of it.

The grass was a day or two after the 5 tanks in the parking lot, i guess thats still too soon?

Thanks for all the info guys, i really appreciate all the advise. The ways its sounding the motor may be ok, it just "locked up" because i neglected to put after-run oil in it and left fuel in it?
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Old 01-09-2008, 06:38 PM   #14
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Not sure what really happened, but if you can or want to, add some castor oil to the fuel. You can get some from the LHS in the airplane fuel section. Or, you can run the Omega 10 or 15% nitro fuel. I've used it to break in engines and it works fine. It has about 17-18% oil, so it will be greasy, but is very good on new engines for break-in. Also, if the glow plug looks funny, chuck it and get a new one. The last thing you need is the wire breaking and dropping into the engine. It can scrape the piston and leave marks. Make sure you keep it rich enough that it can't get full speed, till you get some more tanks through the engine. If you lean it too much to get fast top speed, it will take out the engine eventually.
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Old 01-09-2008, 06:41 PM   #15
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There is nothing wrong with your engine. This is an ABC engine. It has a TAPERED Sleeve and an ringless piston. When new it is very common not to be able to turn the motor over by hand. This is why you use a heat gun to heat the cylinder head up. This eases the pinch at the top of the sleeve and makes it easier to start and makes it easier on the motor too. As the motor breaks in (the piston laps itself into the sleeve while running ) the pinch will start to go away and the motor will also start to run cooler and make more power. This usually takes about a 1/2 to a full gallon of fuel.
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