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I need an engine expert

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Old 03-27-2004, 03:03 PM
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Superscott
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Default I need an engine expert

Ok I need some help from an expert. My wife has an Thunder quake that I bought her for christmas. It has a Torq .21 engine in it. Since I am a noob, when I started it for the first time like a dumb A&$ I did not do a radio check. I mean come on, RTR means I should just take it out of the box fuel, batt, GO! Well because I did not do the radio check the servo for the throttle was wide open when it started. If I did not grab the truck it would have gotten away. *** is this some kind of joke from the factory? Anyway I broke in the motor after the incedent, the way the manual said. So now the motor constantly overheats no matter how rich the motor is. I canot drive for more than 5min before the engine shuts down. I am running 10% fuel and a silver glow plug (hot like an O.S. #8 i think). I was wondering if I change the glow plug to a cooler one and got 20% nitro would this fix my problem?. I have e-mailed duratrax and they said that it may overheat because the piston and sleve is damaged. How can this make it overheat, wouldn't that make it lose compression and not cause overheating. Well does anyone think that changing nitro percentages, and a cooler glow plug fix this problem? I really don't want to shell out 50 dollars for a new piston and sleeve. My wife has had this truck for three months and not really gotten to play with it. BTW all this happens with the body off so its not airflow problems. Gets a nice smoke trail at full throttle! I don't know, I am about ready to scrape the TORQ and get a XTM 24.7 with a roto start because pullstart sux!!![>:]
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Old 03-27-2004, 03:09 PM
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bill61
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Default RE: I need an engine expert

I am not an engine expert, by I have a bit of experience. Yes the damaged piston sleeve could cause overheating because of the blow by. I don't think that the glow plug and fuel change would bring the temp down enough to run much longer than the 5 minutes you are getting now.
I think you should go for the engine upgrade, you will be much happier with it.
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Old 03-27-2004, 03:52 PM
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R/C Madman
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Default RE: I need an engine expert

That's a shame! The Torq .21 is a great starter engine that is easy to tune and has good power. I have 2 of them and have not had any problems with them. It must be the first bad start. I would get the XTM engine if you are going to spend your money. You will want more power in the end anyway.
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Old 03-27-2004, 04:02 PM
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Default RE: I need an engine expert

Unfortunitely, you may have damaged more than just the piston and sleeve (scratch), closely inspect the wristpin, conrod and/or crank.
I'd try upping the nitro content to 20 or 30% before rebuilding.
The higher nitro content has a cooling effect when run just a tad rich, perfect for extending bashing time. You'll need to reset the carb to factory (rich) settings and do another "break in" procedure, it may
prolong the need for a rebuild. A nitro engine will overheat and run like pooh once its exceeded its life, its possible you got all your wear at one time, a new engine REQUIRES proper break as to seat the piston to the sleeve, much like rings in a gas engine.

RTR means "ready to rebuild" for most manufacturers and to eliminate any surprises you should get familiar with your RC's inner workings before installing the batteries or fueling up.

Something you said doesn't make sence, with the radio/receiver on, the servo wouldn't go WOT, regardless of polarity (hooked up backwards) unless your applying brakes or throttle input, or you failed to set the end points (if applicable). Under normal conditions the servo goes to the neutral (middle) position when energized with the TX on. Even if the linkage needed to be tweeked, surely it wasn't to the point that the servo was neutral yet at WOT. It sounds as if you didn't have both the TX and RX on and/or didn't have the radio adjusted properly.
Come on, FESS UP!
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Old 03-27-2004, 04:41 PM
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Default RE: I need an engine expert

Well, i think your problem is already in your post. There are 2 things you are doing that are gonna cause any motor to run hot. One, you have a hot plug. Two, you are using 10% nitro. Bad combination. You say it overheats, but didnt mention temps. How hot is this engine getting? Is your cooling head dis-colored? Try a cold plug, and some 20% fuel. There are soo many things you can do to bring temps down. And soo many causes of overheating. How long was this truck WOT before you shut it down?

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Old 03-27-2004, 10:03 PM
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Default RE: I need an engine expert

Hey thanks for posting! I will try the fuel and glowplug change first. I don't know what happened with the radio but all I did was switch the reverse the servo on the tx, and it worked fine. The cooling head is still the same color as always. I checked with a temp gun and it was about 289 almost 300. It was hot enough to make the engine die. The truck stayed at WOT for like ten seconds and I shut it down as fast as I could. But I haven't taken the engine apart to inspect it, but I will do this if the engine still overheats with the fuel change.
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Old 03-28-2004, 06:20 PM
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Default RE: I need an engine expert

ten seconds is too long for an engine to be at WOT. but that engine isnt exactly a revver anyway. you might have stretched your rod and this would be causing high temps, from the now small head clearance.

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