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  1. #1
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    Unhappy Traxxas 3.3 engine damaged by its own internal components help

    So yesterday i decided to run my tmaxx since the weather was cool, i tuned it and ran it for about 2 minutes on my street. It ran perfectly! So i got all my gear and i was headed to the park with my tmaxx. I started my new traxxas tmaxx engine and let it warm up. I gave it throttle and about 30 feet from it it turned off by itself. I walked to it trying to start it but the electric starter couldnt star the engine. The engine was really stuck. I even tried spinning the flywheel and it was stuck also. Really really stuck. I got home frustrated knowing that this trx 3.3 engine was new and most likely got damaged by an internal part. I opened it up and saw metal pieces on top of the brand new still gold plated piston. I removed the backplate and what i see is the starter shaft was cracked. I removed the piston and sleeve and piston was destroyed also. It is also damaged by the starter shaft. Now what do i do? I dont have alot of money since i bought this engine new for like $150. It was all good until that starter shaft broke. Sad and frustrated.

    Picture links
    https://i.imgsafe.org/6ae4ab0f9e.jpg

    https://i.imgsafe.org/6af26aebea.jpg

    https://i.imgsafe.org/6af2c82609.jpg

    https://i.imgsafe.org/6af40ea724.jpg


    https://i.imgsafe.org/6af4edff73.jpg

    https://i.imgsafe.org/6af5586c55.jpg

    https://i.imgsafe.org/6af5d54685.jpg

    Also the engine has only been ran with 1 gallon of traxxas nitro fuel.
    Last edited by Double G; 09-24-2016 at 01:55 PM. Reason: merge

  2. #2
    Marshal Double G's Avatar
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    That's a first, never heard of that happening. Since the pieces danced around in the engine the piston, sleeve, rod and probably bearings will need replacing. You could get a new engine from a chop shop for around $90 w/o the carb. Or you could contact Traxxas direct and see what they have to say.
    The Super Derecho

  3. #3
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    Man if only traxxas support was open saturdays. Im out of luck, i already spent my savings on a engine that failed already. Dissapointed

  4. #4
    RC Turnbuckle Jr. Nitronaught's Avatar
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    Quote Originally Posted by Eddie837 View Post
    Man if only traxxas support was open saturdays. Im out of luck, i already spent my savings on a engine that failed already. Dissapointed
    What were your operating temps?
    The coloration of the conrod and the darkish brown coloration are evidence of temps burning the oil and leaving carbon deposits, the blueish coloration on the conrod also is evidence of high temps. When the engine experiences high temps the internals can become brittle, specially at the piston skirt where there is not much material. The area of the thinnest material will fail in time if it has become brittle.

    Often, people who had temperature issues for a little to long then figure out their issue and get it performing well is when it fails, it was already weakened and now it it up to full performance when it fails leaving the operator scratching his head.

    When you have an internal failure like that, I'd replace the bearings, the piston, sleeve and conrod.

    When you do put in some nice ceramic bearings. A set of Avid Ceramics is about $30.00 for both bearings, piston sleeve AND conrod can be ebayed for $50.00-$60.00.... OR another Ebay pulled engine for $150.00...


    It does look like it had seen some temps over 300 F. from the colorations on what I can see on those pics though. Thing is most every person I know who first starts out with a nitro, their first engine never lasts as long as their second. It's the tuning learning curve that can get you.
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  5. #5
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    No i never got it over 250 degress to avoid buying another glow plug. This engine wasnt even ran hard. The piston is still golden and basically new but now ruined by a faulty piece traxxas probably did on purpose to get more cash.

  6. #6
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    Email Traxxas with the photos (I cannot see them since I'm at work) and explain what happened. A respectful and informative email to support usually results in favorable actions.

  7. #7
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    Called them and they want to replace it for $115. They tolled me they wanted to see the engine first before making any suggestions but i think they're not going to even bother looking at it and just say buy a new engine.

  8. #8
    RC Turnbuckle Jr. Nitronaught's Avatar
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    Quote Originally Posted by Eddie837 View Post
    Called them and they want to replace it for $115. They tolled me they wanted to see the engine first before making any suggestions but i think they're not going to even bother looking at it and just say buy a new engine.
    I see pitting on the top of the piston. then again the pics aren't the greatest. there should be no brownish coloring anywhere on the piston.

    The pics make it look like it got hotter than 250 at some point from what I see.

    But I will tell you this, if you send in the engine and if there is the slightest doubt I've seen them replace engines at just the cost of shipping in the old engine.

    I've 3 TRX 3.3's All modified by myself. I've used these engines ever since the 2.5 was out. I've rebuilt many.... Every single 1 went at least 4 gallons (that was my first nitro) others 6-8 gallons before noticeable performance issues.

    Traxxas purposely making a part to fail is pretty ludicrous.

    That skirt let go first, sending ,metal bits all through the internals, caused enough to jam the piston, breaking the starter plate, uet for a change I do not see a split conrod at the wrist pin which leads me to believe when things let go you were not pushing it yet ran until complete failure...

    Now your pics are dark, so my monitor may not be showing me the correct coloration and detail required to see.

    The only time I've seen this happen is from either high temps, or too low of temps which usually causes severe conrod damage (stretching and ovaling of wrist pin and acrankshaft bushings of the conrod).

    But if there is the slightest doubt, and it could have been a failure, often I've seen Traxxas replace the engine.

    I can assure you though the sheer amount of TRX 3.3 engines out there do not die in 1 gallon, 90% of the time I've seen it's been a bad tune or someone got dirt in their engine taking the glowplug off before cleaning, things like that.
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  9. #9
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    I had a conrod pin to break after about 8 gallons, trashing the piston and sleeve. I've always ran it rich just to prevent early failure. I didn't have any problem until switching to 33% TRX fuel. I've put 7 gallons of 20% through it with absolutely no problems. Switch to 33% and BAM (still running 200*-220* btw).
    The coloring looks fine to me on my screen...??? I've NEVER ran my 3.3 over 240* @ the most. But it still has dark burnt spots inside the engine. IDK? Time for a new one (I LOVE the 3.3 engine). I'd buy 10 if I could.

  10. #10
    RC Turnbuckle Jr. Nitronaught's Avatar
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    Quote Originally Posted by diRt_JATO View Post
    I had a conrod pin to break after about 8 gallons, trashing the piston and sleeve. I've always ran it rich just to prevent early failure. I didn't have any problem until switching to 33% TRX fuel. I've put 7 gallons of 20% through it with absolutely no problems. Switch to 33% and BAM (still running 200*-220* btw).
    The coloring looks fine to me on my screen...??? I've NEVER ran my 3.3 over 240* @ the most. But it still has dark burnt spots inside the engine. IDK? Time for a new one (I LOVE the 3.3 engine). I'd buy 10 if I could.
    Normal running temps should be between 220 and no more than 270, running it too rich will cause more fuel to be in the case than air, your conrod is swimming in it. Combine the extra fuel with the fact that below 220/210 the case will not be fully expanded, that means added stress on the internals....

    8 gallons is a pretty good run.... I have 3 TRX 3.3's 2 of them modded, 1 stock. non of them like to run at the same temps even when they were all stock. One of them liked 260, another liked it at 230, and I think the other one was around 220. Running 30% Odonnels Racing fuel...

    But, to add to this,,, I've ran my share of Traxxas fuels. While it is not my preference, it is a very good fuel and tons of people, including non-Traxxas engines use it....
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  11. #11
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    Looking at the carnage, I'd guess that the piece on the starter shaft is what went first. Which then took out the skirt and mangled the con-rod. I've never seen a starter shaft that damaged before. It's way harder than the aluminum that the piston/con-rod is made out of and under far less stress. If it was something that locked the piston, I'd see the con-rod splitting before the starter rod broke as there's nothing pushing the starter rod. It's just being drug along by the engines power.

    The browning looks fairly normal to me, with high oil content fuel. FYI, pistons start off silver and shiny, not gold/brown. The pitting on the piston face does look like it was detonating a bit on you, too hot of a plug/too high of nitro or being a bit lean can cause that. But you say 20% and not more than 250F... not sure where your taking the temp or if your gun is off, but I'd guess it got north of 250F a few times at least.

    Personally, I've never had great luck with traxxas engines. I've never had one grenade on me though. I've had a 2 2.5's (t-maxx, jato), 2 2.5R's (revo,jato) and 2 3.3's (revos). High RPM engines that just never put out much power, didn't idle well and ran best when ran between 250F and 270F. Fine in smaller rigs like the jato or rustler, but why they put them in MT's, I'll never know. Well, I say "not much power", but comparing the 2.5 to another .15 sized engine, it would hold it's own. I just don't think the MT's (revo/t-maxx) should have had anything less than a decent mid-block .21 in them to start with. I guess Associated and Tamiya both ran comparable trucks with 18's in them... so the 3.3 should be able to do ok, but neither of the ones I had in revos did well. I guess that's a whole other issue anyway.
    Expert rigging at it's best!

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