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Granite Brushless Install

Discussion in 'Granite & Senton Mega 4x4' started by GuyFromCanada, Jul 6, 2018.

  1. GuyFromCanada

    GuyFromCanada Premium Member!
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    I have my first brushless install complete, here is a the final look
    2018_07_06 Brushless Install Complete.jpg

    The Mamba X is a little longer than the stock ESC, so it overhangs the edge of the receiver box. It seems to be mounted pretty securely. The lid is actually a little concave, so I used two layers of tape to ensure the entire bottom surface was taped where it could be.

    The servo feels quicker even on the 5.5V default BEC output. I have the Castle Creations Quick Connect wire in place so I can program things without having to leave the receiver box open...though the receiver box itself is quite packed and that might impact reception/range a little bit.

    A tip for soldering connectors on a battery: use a plastic spring loaded clamp on the exposed part of the wire you aren't working on. This will add some weight, and cover the terminal until you are ready to work on it and prevent short circuits.
     
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  2. Mentolio

    Mentolio Well-Known Member

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    Looking good! Which motor/what kv?
     
  3. GuyFromCanada

    GuyFromCanada Premium Member!
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    It is a Mamba X, with the 1410-3800kV both from Castle Creations.

    I think this combo on 2S is really nice. I'm using the stock 14T pinion. Good speeds, and motor temps seem to peak around 140F or 60C. ESC is around 40C I think. Since I have one I'll probably toss a fan on the motor just to minimize temps. I haven't played with Castle Link yet...
     
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  4. GuyFromCanada

    GuyFromCanada Premium Member!
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    My latest temps after some mixed bashing and speed runs are about 72 C at the motor which seems a bit toasty.

    I was reading in another thread something about the dangers of under gearing. Am I at risk for that with 14t?
     
  5. GuyFromCanada

    GuyFromCanada Premium Member!
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    Another pinion-spur death. This time it resulted from a root flip that caused it to tumble a little. It makes me wonder though, if perhaps the mesh is just slightly too loose or slightly too tight. The motor shaft wouldn't have much flex I would guess, and for the spur, I suppose that is limited by the slipper shaft and bearings.

    Anyone have any ideas to reduce this recurrence?
     
  6. Jerry-rigged

    Jerry-rigged Premium Member!
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    Throw up a pic of the spur. If you are worried the gear mesh is too loose, then oval one of the motor mount screw holes and set the mesh by hand. Note - this can be tougher than normal in this truck because while you are setting the mesh, the spur is only held in by one bearing, so it may move a bit.

    Or swap to 32p, and worry no more.
    See post #5 HERE.
     
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  7. GuyFromCanada

    GuyFromCanada Premium Member!
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    I'll get some pics tomorrow after I take it apart. I have two dead spurs/pinions that I can post. Is there a particular angle to capture? What I notice when it goes is that it starts to go slowly, then if I keep driving, it quickly deteriorates. I have an extra motor mount, so I could try the hole elongation to tighten things up a bit. Given that it seems to start in one area, and then spread to others it makes me thing the spur is wobbling a bit and the conditions in one area of the spur just happens to provide a starting point for grinding.

    It is definitely an annoyance the way the motor mount is done for pinion adjustment. Is this common in other RCs for it to be assembled this way?
     
  8. Mentolio

    Mentolio Well-Known Member

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    "It is definitely an annoyance the way the motor mount is done for pinion adjustment. Is this common in other RCs for it to be assembled this way?"

    In my experience: NO. All of my other RCs have one hole and one slot, allowing/forcing me to set my own pinion to spur gear mesh. As a rule, I set the mesh so that holding one gear still, I can rock the other gear just enough that it moves one half the width of the teeth. Works with all "pitches" of gear. Amen to the annoyance, I really dislike the inability to set gear mesh. As delivered, I find the gear mesh to be too tight.
     
  9. bicketybam

    bicketybam Well-Known Member

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    How much of the spur does your pinion cover? Didn't you say only like 60%?If so, that would definitely be a problem area.
     
  10. Jerry-rigged

    Jerry-rigged Premium Member!
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    On the pics, What I would be looking at is how much damage is done. Is the pinion centered? (as Bicktybam said) Are just the top of the teeth knocked off? (mesh too loose) Are the teeth ground down all the way to the root? (Mesh too tight).

    Also - is your pinion damaged? When the spur dies, sometimes the pinion will get damaged too.
    Yeah, the pinion blows out a few teeth, then grinds away the rest of the gear.

    Mostly I see this on entry level cars, but some mid level cars do this - like the Losi Baha Rey. The slotted motor mount is much more common.

    To me, half a tooth of gap would be too loose, but if it is working for you, then it is working.

    When I set the mesh by eye, I will try to point a tooth right into the root of the other gear, and still have a small gap - just enough to rock the spur a hair without moving the pinion. Bigger teeth need a bigger gap, but not half a tooth (IMHO)

    A lot of people use the paper trick, but I find it easy to both make it too tight and too loose with the paper. If you use the paper, then you need to eyeball the backlash after. And give the motor some gas and listen to the mesh.
     
    #10 Jerry-rigged, Jul 11, 2018 at 7:44 AM
    Last edited: Jul 11, 2018 at 7:52 AM
  11. bicketybam

    bicketybam Well-Known Member

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    How about driving habits? Is there any commonality to the events leading up to the spur/pinion failures (happened after jumps, hard launches, etc)? Back in the day when I got my first nitro, the very first mishap I had was a destroyed spur from landing a jump while on the throttle. Huge no no, but I didn't know. I did after that though. I don't jump my Granite much. I basically go off-roading with it in an area that I cleared on my property. It used to be woods. I removed a few trees, a ton of vegetation and dead leaves, and a bunch of rocks. Now it's more like an obstacle course. There are still things that will put the hurt on my Granite if I hit them (tree stumps and rocks, mostly). I blow through this area as fast as I can with a lot of power slides, donuts and quick changes of direction. My pinion/spur help up fine. But I only get a foot or two of air. If you are jumping, make sure you don't land under power or you will definitely rip teeth off the spur.

    I would also suggest setting your punch control.I put mine at 25% and I can't really tell performance wise. There are a ton of setting you can play with on the ESC (throttle curves,max throttle,throttle from stop, etc.). That might be a way to lessen the stress on your spur/pinion.
     
  12. GuyFromCanada

    GuyFromCanada Premium Member!
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    In general, in the worst spot, the teeth are ground down completely:
    2018_07_11 Most Recent Spur.jpg

    This is my last damaged 14T pinion vs a new 17T...both are Robinson Racing. If the pinion looks damaged like the picture, then I replace it...seems to be 1:1 though...spur and pinion die at the same time, though perhaps I could detect it early and save the pinion...
    2018_07_11 Pinion Teeth.jpg

    The usable pinion area where the teeth are "full size" only covers the spur about 60% or so. In addition to this, when this pinion is mounted on the motor shaft, the set screw sticks out enough that if I don't put the pinion off to one side, then the set screw interferes with the spur, and damages the spur immediately. I will add a picture when I do the next assembly showing this if it isn't clear. The stock Arrma pinion (which I don't have anymore) definitely had a wider usable area on the pinion which covered the spur 100%.

    No significant jumps, maybe half foot air? A lot of roots though, so that would interrupt the ground contact periodically which maybe puts more stress on the spur.

    I haven't explored the ESC yet...I ordered the B-Link interface and I found an iPhone 5S for $50 CDN. Once I have that, I'll try setting the punch control at 25-50% and see how that does.

    In my other thread, I'm also thinking about playing with the slipper a bit more and trying to loosen it up a bit.

    https://www.arrmaforum.com/threads/audible-snap.7293/
     
    #12 GuyFromCanada, Jul 11, 2018 at 10:52 AM
    Last edited: Jul 11, 2018 at 11:18 AM
  13. Jerry-rigged

    Jerry-rigged Premium Member!
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    Ah yes, the out of round molded spur gears. One side the mesh is too tight, the other side the mesh is too loose. Grr... I'd say do the 32p conversion and forget about this spur issue.
     
  14. GuyFromCanada

    GuyFromCanada Premium Member!
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    Would you suggest trying to loosen the mesh slightly? Or will that get me nowhere? I have another motor mount in case I really screw things up, so I'm not too worried about that part of things.

    What does the 32P conversion get me? It is a coarser, larger mesh I guess which would be overall more durable? For the conversion, I'll take a peak at the video today (I meant to last night) to see what I would be getting into. Do you have any updates to add to it, due to changes in your spiral spacer thing you tried and failed?
     
  15. Jerry-rigged

    Jerry-rigged Premium Member!
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    I don't think you will get any better mesh than you had. If you loosen it, the side with the tall teeth left will be WAY too loose, and strip quick. If you tighten it, the side shaved close will be binding.

    32p - bigger teeth, so tougher. Plus bigger teeth, so they can tolerate the run-out issue better than the smaller teeth in the 48p.

    When I switched to the big motor (BLX185, 4074 2000kv) I blew the stock spur on the first run of 3s. I switch to the 32p spur, and to 4s, and the spur has not given me any more issues. Also, I am running the plastic version of the Yeti spur, not the steel, and still, no issue.

    The downside - if you want to stay close to stock gearing, you need the 60t 32p spur - which I have only been able to find in steel. I have the 56t gear, and that is a pretty big jump in gearing. With your 1410 motor, you may be able to turn this gear safely, but you will need a small pinion, I am guessing. And you will need to slot the motor mount to make it work. Now running the steel gear is not really an 'issue', but the gear costs 3x the price,($20) and it will be louder. But bullet-proof, so winning, right?
     
  16. GuyFromCanada

    GuyFromCanada Premium Member!
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    Well, that's where I'm not sure, I screwed around with it a fair bit before I clued in that it was not recoverable. If I rolled the mesh so the "good" side made contact, it would turn the spur until the "bad" side made contact. By that, I feel like perhaps the mesh is tight all the way around. I have some more pinions on order, and need to find some more spurs just to get back in the game.

    That said, I'll start collecting a list of posts for the Yeti spur and see what I can come up with. I'm targeting a "stock" brushless experience with 2S...I just want a robust platform.

    Thanks for all the dialog, it's helping me work things out since I'm pretty much solo here :p
     
  17. Jerry-rigged

    Jerry-rigged Premium Member!
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    Stock experience, but with brushless? That is what I got from my 3000kv F540. A bit better grunt, similar top speed. If I was buying a new one, I would probably go for 3300kv-3500kv, gain a bit of top end, but not lose much low end grunt.

    I have log post about my F540 HERE, my Granite update is the last post in that thread.

    But seeing as you already have the Castle combo, I'd use that, and go with the 32p spur. The truck is fun stock, but is more fun with a bit more oomph.

    One more option - wait a month and see if the BLX 4s models drop. If they do, then you can use their M.8 spur in your granite.
     
  18. GuyFromCanada

    GuyFromCanada Premium Member!
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    I'll play around with the CC ESC to see what I can achieve to soften the start/stop. I was just thinking, and realized that there is one case that I didn't elaborate on that I think might be linked to my latest failure. When one side lifts of the ground, the diff allows much faster wheel speed for the wheel in the air. When that touches down again, that might be enough to stress the mesh.

    I'll post again when I start playing with the ESC settings.
     
  19. bicketybam

    bicketybam Well-Known Member

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    For what it's worth, this is whaty gear mesh looks like. Both pinion and spur are stock. The only difference is that the pinion gear is upside as opposed to when it had the brushed motor (the shaft was longer).
    20180711_134658.jpg 20180711_134717.jpg
     
  20. GuyFromCanada

    GuyFromCanada Premium Member!
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    That is the stock pinion? I order a few of those, they have more surface area to mesh with the spur. I couldn't get my old ones off the brushed motor.
     
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