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  1. #1
    RC Racer
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    Aug 2019
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    150

    Engine burning through glow plugs and other engine problems.

    Recently the trx 3.3 in my revo has started eating through glow plugs. It has been as bad as one plug per tank of fuel. What am I doing wrong? In the past I would typically go through about 1 plug per gallon, but I can't seem to get two tanks from one anymore.

    To make it worse I had gold/copper color metal flakes occasionally coming out the exhaust with some items as large as ~2/3mm long. I have taken apart the engine multiple times and can not find where they are coming from. I ended up putting rc helicopter fuel in the car(over 20% oil), putting the engine at full throttle and turning the high speed needle so rich that the engine was running just above an idle. During the process the engine was spraying a ton of fuel and oil out the back end and I was able to clean a ridiculous amount of the metal pieces out of the engine. Since then it has almost entirely stoped producing the metal shavings, but it still worries me.

    This is all driving me a bit crazy as the engine has no performance loss and is running as good as it ever has, but metal is coming from somewhere in the engine and a glow plugs last me 2 tanks if I am lucky.

  2. #2
    RC Racer
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    Mar 2020
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    NE Wisconsin
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    The metal flakes you are talking about are most likely causing the glow plug failures. Turn over the engine, flush it with WD-40, and get the metal flakes out of the engine. You're gonna loose compression if you keep running it with those flakes in there. I think you just need to keep cleaning.
    I'm not afraid of my fellow man.

  3. #3
    RC Turnbuckle Jr. Nitronaught's Avatar
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    Oct 2005
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    South Florida
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    Metal flakes out the exhaust and the glow plugs getting destroyed is usually a sign of internal parts failure.
    When running what was the temps?
    Did you see any fuel around the flywheel or at the base of the engine?
    How is the compression when you turn the flywheel in a counter clockwise direction when facing the flywheel?
    How many gallons of fuel have been through this engine?

    Flushing the engine may clean out the metal particles but it is not going to resolve the issue... Using a large amount of oil in the fuel may mask/hide the problem, it will not solve it though.
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  4. #4
    RC Racer
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    Aug 2019
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    I tend to run around 250 degrees, no fuel around the base of the engine, compression is excellent (holds for 30+ seconds at TDC), just over 2 gallons through the engine.

    Like I said before, I have had the engine apart a few times to try and find the source of the metal particles, but never have been able to. I have about a dozen other nitro engines, but I have never seen anything like this.

  5. #5
    RC Turnbuckle Jr. Nitronaught's Avatar
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    Quote Originally Posted by Bob2.0 View Post
    I tend to run around 250 degrees, no fuel around the base of the engine, compression is excellent (holds for 30+ seconds at TDC), just over 2 gallons through the engine.

    Like I said before, I have had the engine apart a few times to try and find the source of the metal particles, but never have been able to. I have about a dozen other nitro engines, but I have never seen anything like this.
    It can only be from either the bearings, the wrist pin, the conrod bushings,backplate bushing, the sleeve or the piston. Metal particles coming from ANY engine is not good.
    The fuel flows from the carb through the case then up the sleeve to the intake port. One thing you also need to be careful of is running overly rich. Too much fuel can cause resistance in the bottom end of the motor and can cause the conrod to stretch so be aware of that.....

    Those particles are coming from somewhere... Did you fully disassemble the engine or did you just open it up?

    Here's the worst case, engine failure. This is when you go to ebay and purchase a piston/sleeve & conrod combo for like $60.00, grab some Avid Ceramic bearings for $25.00 and you now have a brand new engine and the ceramic bearings really do make a difference. As one who raced I noticed improved lap times, more laps before having to refuel....

    Those particles are coming from somewhere and usually the damage is already done. Remember these things run up to 30,000 functional RPM's.... Not very forgiving when something is breaking apart and flying around the internals (metal particles). Good luck....
    Last edited by Nitronaught; 04-19-2021 at 12:20 PM.
    All Lives Matter
    United We Stand, Divided We Fall

  6. #6
    RC Racer
    Join Date
    Aug 2019
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    150
    I completely disassembled the engine except for removing and inspecting the bearings, so that could be the source.

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