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  1. #1
    RC poster
    Join Date
    May 2007
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    3

    4-tec 3.3 not moving

    So I just bought a brand spankin new Nitro 4-TEC 3.3 and 1/2 way through my 2nd tank of break-in gas, the car stopped moving. The engine was still running, throttle worked, but the car wouldn't even squeak forward.

    Any ideas? Is this model junk or did I just get a lemon?



    Think I'll go charge my battery and run my RC10T while I cool off about blowing $400+ on something that sits there and looks pretty.

  2. #2
    RC Qualifier
    Join Date
    Feb 2007
    Location
    B-town, NC
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    331
    That happened to mine also. You need to check your gears you might have a little pebble caught up in your gears somewhere. Take a look at it and let me know if that's the problem. Like I said that happen to mine and that was my problem.......... it runs like a champ now all, but I need to replace my glow plug now.

  3. #3
    RC Competitor
    Join Date
    Apr 2007
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    56
    HI,

    If you didnt adjust the brakes out the box then they can jam on, its worth making sure the pads are not locked to the disc (normally clears by turning disc backwards a little) Either way the disc should not feel loose.

    I would be suprised if its a pebble because in my experience the engine is more than powerful enough just to crush them into the gears!

    Oh and if its new I would take out the screws in the ball joints on the front suspension and put some extra loctite on them, they seem to have a habit of working loose.

  4. #4
    RC poster
    Join Date
    May 2007
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    3
    Thanks for the responses. I checked for pebbles/rocks/debris - didn't find any. I took the gearing apart, grub screw looked fine, clutch looked ok.

    When I start the car up and gas it a little, the engine revs, but the gears attached to the clutch bell don't move. I didn't look to see if the flywheel(?) spinds or not (the plate the clutch shoes are attached to), I'll check that this afternoon.

    I'll check the screws in the ball joints and loctite them - thanks for the tip!

  5. #5
    RC Champion
    Join Date
    Jul 2002
    Location
    wichita, ks
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    1,622
    Quote Originally Posted by getndirty

    When I start the car up and gas it a little, the engine revs, but the gears attached to the clutch bell don't move. I didn't look to see if the flywheel(?) spinds or not (the plate the clutch shoes are attached to), I'll check that this afternoon.
    If the clutch bell doesn't move but the engine revs, then it has to be either the clutch being bound up (make sure the spring stretches ok and the shoes move in and out), The clutch shoes burned up for some reason and aren't engaging. Or as you said earlier, the crankshaft is just spinning inside the flywheel because the flywheel is not locked down tight enough. There is no point in going any further than the engine clutch. The rest of the drive line will not see any load until the clutch bell moves. These are easy things to fix, but should not have been that way from the factory. I would say that if you still can't fix it. Call Traxxas support and they will take care of it.
    -Terry
    "The best part of wakin' up....is Nitro" i

  6. #6
    RC poster
    Join Date
    May 2007
    Posts
    3
    Quote Originally Posted by terry
    ... the crankshaft is just spinning inside the flywheel because the flywheel is not locked down tight enough....
    That's the assumption I'm going to be working under when I take it back apart this evening - need to go get some snap-ring pliers - my whittled needle-nose pliers worked one time, but I don't want to repeat that fiasco again.

    I've seen the exploded parts view for the engine/clutch assembly, but I can't see anywhere in there where the flywheel affixes itself to the output of the engine - anyone got pictures or diagrams of what I should be looking for or will I know it when I see it?

    BTW - the clutch shoes looked fine (according to pics of the parts I saw on towerhobbies) and the spring put up some resistance when I moved the shoes apart with a small screwdriver (though I don't have a clue as to how to gauge this or describe it).

    Thanks for the replies everyone!

  7. #7
    RC Enthusiast
    Join Date
    Jan 2007
    Location
    Southeast Texas
    Posts
    47
    My 4-Tec Lost one of the two gears on the clutch bell... I found it in the parking lot. I used loctite when reinstalling it and it has been ok ever since. There should be a total of four gears sitting on the side of the car.. two on clutch bell and the two that mate with them. Look at the pictures on the Traxxas website and see if your gears look like that of the picture.

  8. #8
    RC Champion
    Join Date
    Jul 2002
    Location
    wichita, ks
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    1,622
    Quote Originally Posted by getndirty
    That's the assumption I'm going to be working under when I take it back apart this evening - need to go get some snap-ring pliers - my whittled needle-nose pliers worked one time, but I don't want to repeat that fiasco again.

    I've seen the exploded parts view for the engine/clutch assembly, but I can't see anywhere in there where the flywheel affixes itself to the output of the engine - anyone got pictures or diagrams of what I should be looking for or will I know it when I see it?

    BTW - the clutch shoes looked fine (according to pics of the parts I saw on towerhobbies) and the spring put up some resistance when I moved the shoes apart with a small screwdriver (though I don't have a clue as to how to gauge this or describe it).

    Thanks for the replies everyone!
    You shouldn't need to disassemble anything at the 2-speed clutch, so snap ring pliers aren't needed. After you remove the clutch bell and clutch shoe/spring assembly, there should be a nut on the crankshaft that presses against the front of the flywheel. This nut must be really tight as it pushes the flywheel onto a cone shaped bushing. The tighter the nut the more is compresses the bushing onto the flywheel and makes a tight fit between the crank and the flywheel. The bushing has a slot in it so that it can compress. There may be some shims behind the bushing to space it away from the main bearing. When you remove the nut, the flywheel should stay in place and if it is tight enough, you would require a mallet to knock it loose. To tighten the nut, you will have to lock the crank shaft. The easiest way to do this is to hydro lock the engine. Take out the glow plug, move the crank in the direction needed to tighten the nut until the piston reaches top dead center. Then back the crank up until the piston drops to the very top of the exhaust opening. Now fill the cylinder with after run oil or marvel mystery oil, or even fuel until it reaches the glow plug opening. Tightly reinstall the glow plug. Now when you turn the flywheel nut to tighten, the piston will hydro lock and the crank will not move allowing you to get the nut tight. When you are done, remove the glow plug, turn the engine upside down and drain the fluid from the cylinder. Crank the engine over a few times to distribute/expel the excess, and put the plug back in.
    -Terry
    "The best part of wakin' up....is Nitro" i

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