Brushless Associated Monster GT
 

Has anyone seen/heard about someone converting an MGT to brushless?
I picked one up a couple weeks ago from a friend and am quickly re-confirming my dislike for nitro. I had it tuned just great and ran 3 tanks through it one night...the next time I tried to start it, it wouldn't start without adjusting everything again. :C:
Darn nitro...not to mention, I suck at keeping them going :)

From what I've read there are only 3 weak points to the MGT from stock:
1 - Engine needs to be upgraded; the stock engine is good and reliable, but not fast enough to be competitive. This one's irrelevant if I go electric, plus the guy I bought it from had already put a .26 in it, upgrading from the stock .21.
2 - Lower arms can break easily. This seems to be from the first factory run, which is where mine came from. Replacement arms are as cheap as any other truck, so that's not a problem at this point.
3 - Center CVDs wear relatively quickly. This is the only one I have any real concern with. Although I doubt they fail quick enough to bankrupt me, I'll still take a look to see if there's anything I can do to help keep them in good shape longer.

Has anyone heard anything else regarding faults with the MGT?

If nothing else, it will be an easy experiment in stock form since the gearing is already mod1. I figure I'll un-bolt the engine, exhaust, and fuel tank then see what room I have for batteries, and strap in a motor, ESC and battery packs. I'm sure I'll have to do some work with the tranny, but I'll see what it's like in stock form first. It'll also be a benefit to get the forward-only conversion kit as well, I'm sure.

Thoughts?

sounds like it would be pretty easy. the mgt has a ton of room on the chassis. you also may need a 1 speed for the tranny, and a FOC.

The MGT is a nice, stable, durable truck that is easy to drive and handles well. If i was converting it to electric, I would find a way to put the g-maxx single speed converted e-maxx tranny in it with a steel idler gear (I should have hardened steel idlers soon). Then, You could put a set of dogbones in the center (I can get custom made titanium dogbones made) and move on to the suspension arms. Here, you could go RPM or an aluminum upgraded arm set,

Mike,
Using an MGM 12012 with 3s lipo, which motor do you think I'd do best with in this conversion? 9L? 10L? I already have the 8L, but I'm figuring the MGT will be a heavier truck than the 1/8th buggy I have the 8L in.
Yes, I'd like to go Feigao with the motor clamp (price-concious).

I agree with Mike. E-tranny (possibly G-Maxx convert.) plus custom Ti Bones work flawless in my Revo. I got the very bones Mike is speaking of, btw. Nice pieces of workmanship.

The E-tranny solves your motorplate question, too. A nice by-effect;)

Do we know that the MGT tranny isn't worth using? I understand the g-maxx tranny is built for this type of thing, but I'd like to make sure what I have isn't worthwhile before I look at investing in something to replace it.
What is the pricing like on the g-maxx tranny?

The 8L or 9L would probably be the choice for 3s Lipo. The MGT tranny will hold up for a little while with 11.1 volts, but if you go to a 12 cell/4s Lipo system in the future, my money says it will fail.

Update
 

My father's day present to myself was to pull the nitro engine out of the MGT and start testing the waters for brushless in it.
:)

http://www.rc-monster.com/coppermine...s.php?album=38

There's a few pics to let you see what I've done so far.

Mike - I'm now set up to run either 3s lipo or 4s lipo, in addition to 8 or 12 nimh cells. I assume the 3s lipo and 8-cell nimh would both be okay with the 8L. Should I get the 9L or 10L for the 4s lipo and 12-cell nimh? Second, which should I put in which vehicle (MGT and OFNA MBX)? I'm guessing the 3s/8-cell would be better in the lighter of the two, yes? It'll be the MGM 12012 on both, as you know.
Once I get them both configured, I'll weigh them and see where they stand.

Thoughts/comments?

The 8L can handle 4s Lipo, 12 cells or more even, but not with 1/8 buggy gearing(too tall). The 8L in the 1/8 buggy should work quite well on a 3s Lipo. For the MGT, I would probably go with a 9L and 4s Lipo.
It looks like you jumped right in on the MGT! It is a nice, big truck that should be pretty easy to convert. Just take it easy on the tranny!

I'll probably be putting in the order for the 9L tomorrow during the day. Watch for an email on that, too.

I'll be putting an update on my 1/8th buggy thread, too.

I'm thinking about keeping the manual brakes on the MGT, so I have a question in regarding if I have the setup right in my head.
I assume I'll just program the MGM for forward-only operation and keep the throttle/brake servo plugged in with the ESC in a y-adapter. This way the motor will respond to the acceleration and not the brake, while the servo will move for both, but only be applicable for braking.
Is this right, or is there another "right" way to do it?

That is right, but I am not sure if the MGM can be set for forward only operation. I have to dig up the instructions, I guess.

I looked at the manual and it doesn't look like there is an option for forward-only.
Maybe I'll get another 9918/9920 from you ;)

I'll see how it works out with the MGM first.

Mike - I found the manual for the 12016 Expert on MGM's website and, although it doesn't specifically say it's for cars, it does have all of the settings one could ask for. It's even computer programmable. The manual says it's good for 7-24 cells nimh or 3s-8s lipo.
Are these available, or is MGM making a car/boat controller for 16 (or more) cells that's computer programmable?

The expert controllers sound good on paper, but they are not ideal in cars (they accidentally sent these to me at first and I sent them back after testing them and realizing that they were not set up for car/boat operation). The good news is that MGM should have a 16 cell 120 amp controller (not yet computer programmable) available any time, and I plan to get a few with the current order. I am not sure if these are programmable via computer, but they will have the "freewheel" option and should be ideal for "big" cars.

Keep me in mind when those arrive, please :)

I'll hold off on buying another controller for now.

Very nice Batfish, actually looks rather similar to the T-Maxx. Except is it belt?

Keep it up. :D

It's shaft-driven.
I'll snap a picture or two of the underside, and even put it next to my E-Maxx for comparison. I'll add those pictures to the gallery later tonight.

I've put a few pictures up in the gallery tonight:
http://www.rc-monster.com/coppermine...s.php?album=38

Mike - the gallery is limited to 1MB for pictures? It wouldn't let me upload any more.

I actually got the brushless MGT running tonight :)
I first ran it on six GP3300 (the pack you see in the pics) to make sure I had everything set up right, then switched to one 8-cell IB3600 pack. With 6 cells it moved at about 10-15 MPH, I'd say. with the 8-cell pack, I'm sure it was over 20, but not by much. At the end of the 8-cell 3600 pack (10 minutes or so) the MGM 12012 was 115F and the Feigao 8L was 120F.
The truck didn't get enough RPM on the ground to auto-shift into second gear, but it would do it while I had it in the air. I've got to get into the tranny and adjust when it shifts, or see about getting it stuck into second.
As far as my braking concern, it turns out that the MGM uses the double-pump brake method, which means it won't go into reverse until you let the throttle back into neutral and push reverse again. So, as long as I go right from forward to brake, the motor just stops and the brake servo does it's job. If I'm coasting in neutral, the motor will spin in reverse when I push on the controller. I'm sure this isn't good for the motor since there's no real load with the tranny just spinning freely, so I'll just have to be conscious of that while I'm running.
I was using my 15 tooth pinion, so I'm thinking of going with the 16 next since the temps were so stable. I don't recall what the stock spur is on the MGT, but I know there are delrin replacements from 47 to 52, that I've seen.

Now I just have to come up with a permanent motor mount and a good system for mounting the batteries. It looks like velcro around the rock guards will work great, at least for now.

Add some more cells and get the party started(although you should mount the motor with something besides zip-ties first!). Have to thought about trying an emaxx tranny in there? Perhaps a single speed would work quite well and allow you to drop the brake servo (although mechanical brakes make the controller/motor life easier). With the mechanical brakes, a forward only controller would be the way to go. I am looking forward to seeing this project through completion. The MGT is a nice, stable and easy to drive monster truck that should perform excellent with a nice brushless setup. Perhaps I can see it in person some day (you aren't terribly far from me, after all).

Small amount of progress tonight.

I got into the tranny and adjusted the two-speed shift. It now shifts at about 1/4 throttle and was easily as fast as my stock E-Maxx on 12 cells. This was with the 8-cell IB3600 pack.
Just for kicks, I finally plugged in one of my Kokam 3s 3200 packs...wow... I only ran it for about one solid minute since I didn't re-program the MGM for the 3s lipos, but it was a WOW difference. The peak voltage on the 8-cell is only about 1 volt less than the 3s, but I got my first glimpse of the way lipos don't drop voltage under load. If I didn't already say it; Wow! :)
Time to get a secure battery mounting system so I can put those packs to good use!
If I had to guess the difference, I'd have to say that the 3s lipo was about a 30% faster "feel". If I was running high 20s with the 8-cell, I'd easily say mid-30s with the 3s lipo. I really gotta get a GPS.

Also, the temps after 6 solid minutes of about 3/4 throttle on the 8-cell pack were: ESC - 125F, motor - 135F. The 8-cell pack started dumping right around 6 minutes of relatively hard running. Also, just about all my home testing is done in my back yard in the grass. At the track, I expect that it would have barely made a 5-minute race with hard driving. I think I have to cycle my packs a couple times since they haven't gotten much use over the past couple weeks.

A good 3s Lipo "feels" as punchy as 12 nimh cells, but the top speed isn't quite as fast. The MGT is a nice candidate for Lipo too, since the batteries will be up out of harms way. Sounds like you are having some fun with this, Joe!

We discussed the E-Maxx tranny earlier in this thread. I'm torn about using my existing stuff cause I have been wanting to sell the E-maxx as an RTR, but I've always got the option of stealing from it if I don't sell it.
I imagine it would run me well over $100 to get another E-Maxx tranny and do the right modifications to it, plus whatever it would take to mount it in the MGT. As it is now, I'm just puttering along with what I've already got and finding ways to make it work. I really don't want to spend too much money on it at this point. Of course, once the MGT tranny dies, that'll be another story ;)
I already have the Associated battery cups and am thinking about doing a stacked config with the lipos like I saw by Promod in another thread. 3s2p 6400 mAh should do me just fine at the track, but I'm sure it won't win any speed competitions.
Right now the brake servo is working out good. The one thing I may buy is the FOC kit for the MGT tranny since I've seen it on ebay for about $11. Is that something you can get, Mike?

I can get that pretty easily actually. I will pick one up for you the next time I am at my distributors. 3s2p should be pretty quick with the right gearing.

We should try to get together sometime. Google maps says our cities are 3.5 hours apart...that's not prohibitive.

Do you race at all(at a track)? I go to RC-Madness every year for the car action monster madness race. Enfield is just below Springfield I believe. I also get upstate sometime to visit my family. I used to work in Lee, Mass(western Mass) many years ago and i grew up in upstate NY on the Mass border (jiminy Peak/Brodie Mountain if you ski). I would love to hook up one day!

I was born and spent the first 24 years of my life in the Springfield area.
Madness may be a good place to meet up, since I might actually be able to make it there this year :)
Let's keep in touch on this via email as it gets closer.

Will do. I hope to meet you there!

After removing the carry handle I can easily fit the Associated battery cups. Here's a quick view of how it may look.
I have to decide if I'm going to remove all the stuff from the front of the chassis (receiver pack box, receiver box, forward/reverse servo). The two boxes are molded together, from what I can tell. I may cut the receiver pack box out and slide the batteries forward.
With the tranny, motor, and steering servo set to one side, two 3s lipo packs may be just the right thing to offset that weight. Decisions, decisions....

1 3s pack will probably offset the weight.

I'll be running 2 in parallel, so I'm hoping that the 2 doesn't put too much weight on that side. I think my only other option in order to put a pack on the opposite side (with the stock tranny) is to try and re-locate the steering servo so I can move the pack forward. I'm pretty sure that's beyond my current skill and equipment, at least if it's to be done with any accuracy or reliability.
I've seen a couple ebay buy it nows (the folks that part out new vehicles) that have the stock chassis and rock guards for about $15, and I'm seriously considering getting one so I can hack up what I have and still have something to fall back on.
My buddy at the track/shop is really looking forward to seeing it in action this Saturday because he's been wanting an electric MT, but doesn't want to spend the money to make an E-Maxx brushless-worthy.
All things considered, if I can take a used MGT and have such a relatively drop-in brushless solution (and if the stock hardware holds up for a while) this could be a great brushless MT platform.

I've regularly wondered when Traxxas will come out with a brushless electric truck, but now that I see how relatively easy things fit on the MGT, why not Associated as the first ones on the brushless MT front?

the reason they havent already is probly because it would cost ALOT of money to do it and that would drive the prices of the trucks up alot thus not much sales.

I've considered this as well, but I think most people don't take into account what it already costs for today's electric MT.
Take the E-Maxx, for instance.
The normal RTR E-Maxx sells retail for $315.
Let's make some assumptions on cost for a brushless E-Maxx, based on retail cost of parts and other considerations. I'll get pricing from Tower, since they are the standard for competitive prices.
First, let's take off the parts we don't need/can't use with a brushless Maxx. I'll base this on putting in the Novak HV.
Remove:
Sliders, front and rear - $15
EVX Speed Control - retail $107
Titan 550 motors (2) - $40
Plastic idler gear - $3
So that's $315 minus $165 = $150

Now to add the parts to make it brushless:
CVDs, front and rear - $62 (we can be pretty sure that Traxxas will not put MIP or another high-priced CVD on the RTR, so I picked the lowest priced CVD set for the Maxx on Tower)
Novak HV - $275
Steel idler - $5 (this is based on the retail for the T-Maxx steel idle gear/parts...if Traxxas sells the steel idler for the T at $5, it's sure to cost them the same to make a steel idler for the E)
So now we have a brushless RTR E-Maxx for $150 plus $342 = $492.
$492 minus $315 = $177.
Now consider how many people have done these upgrades and purchased the Novak HV - don't you think many of them would have bought the brushless RTR for only $177 more than the cost of the normal RTR? Heck, I know *I* would have :)
To build it yourself would cost well over $600 and you'd have no chance of selling the brushed electronics for the same price Tower gets. I know that one prohibitive factor is spending almost $500 all-at-once compared to about $300, then upgrading when you can afford it, and that's the reason for my next point.

All this in mind, I personally think that the best first option for a Traxxas brushless truck would be for Novak and Traxxas to team up again. Traxxas should offer the E-Maxx in kit form for $200, a "brushless upgrade pack" with the needed CVDs and gears for $75, and include a rebate form for $50 off the Novak HV in the E-Maxx kit. This would still cost more than the RTR, but it would allow both companies to sell only the parts that people need and sell them in "package" form.

Anyways, I've hijacked my own thread :W:

New question
 

I finally got my lipo pack back from FMA and got to working on the MGT again in anticipation of getting it running.
I put the forwars-only conversion in and have now come to a new question. I've looked around and can't find an answer on this one so I figured I'd ask here first.

Does anyone know how to turn a one-way bearing into a no-way bearing?

If I can find a way to freeze the one-way in the tranny, I can get rid of the manual brakes and keep using the same transmission. One idea so far is to see if I can fill in the bearing area with solder, but I'm thinking that may not hold. The next idea involves (probably) a drill press. If I could get a hole drilled right through the tranny shaft and slot the one-way I could use a pin to hold the gear from spinning. If it didn't cost about $40 to replace the parts if I screw it up, I'd probably try it anyway.

Any other ideas? here's a pic of the one-way, if it helps anyone.

<img src="http://i20.photobucket.com/albums/b239/1joeyoung/Brushless%20MGT/MGT_tranny_1way.jpg" alt="Image hosted by Photobucket.com">

I don't think the solder is going to work. Unless you solder the bearing on to the shaft. I not sure if the solder will hold. I would jb weld it before that. Not sure though if you may need to take the bearing off for something. If not can you weld it some how.

Since The one-way bearing is required for 2-speed functionality, the only way this will work is if you are converting your tranny to a single speed. How big is the gear you are working with? You can most likely get a large pinion gear from Mike, or Stock Drive Products with a hub and set screw that would facilitate this. You would need to grind some material off the shaft for the set screw to hold properly. Or, if you're feeling really ambitious, you could bore all the way through the hub and shaft to allow a pin for support on both sides of the gear/hub.

Personally, I would stick with the 2-speed and move to a smaller brake servo.

If your serious you can try mixxing up some jb weld. Then force it into all the open spaces in the bearing. I'v heard some of the crawler guys do this to there clod axels to lock the diffs. It's suppose to work very well.

I say leave it alone, Joe. Stick with what you have, or put in an e-maxx tranny.

Mike - where's the adventure in that? :)
After getting inside the tranny and seeing how beefy the mod1 pinion/spurs are for the two-speed, and the steel drive gears, I'm pretty sure this one will hold up forever. Now I'm just considering dropping the manual brake.
Since I installed the FOC it's so much lighter that I'm very pleased with it.

Starscream - drilling through the shaft and using a pin was one of the ideas in my post. It's probably what I'll end up trying first. The one-way functionality isn't really required for the two-speed to work, only it's physical presence since the second gear spur bearing fits over top of the one-way.

If that fails, I can just jb weld everything together :)

After reading a few other threads here and brainstorming some more I've come up with an idea that may work without physically modifying anything (thus not breaking anything :) ).

The second speed gear has one of those centrifugal force hub thingies to engage it. The hub is held onto the drive shaft via a set screw on a flat spot. The shift point is adjusted by a set/grub screw that you adjust by sliding a hex drive into a slot on the second speed gear to the set screw to loosen or tighten. If you can picture all that, you can picture my idea.
I removed the shift-adjust screw and took a normal screw with the same thread pattern, put that screw through the slot on the second speed gear and screw it in until the screw is even with the height of the teeth on the gear. This pretty much permanently engages second gear, which is stuck to the shaft via the flat spot and set screw.
This should eliminate the one-way and lock the tranny into second gear, effectively making it a single-speed transmission.

If it doesn't work out, I remove the screw and re-add the original set/grub screw and put everything back together.

I'll be trying this out later today (I hope) and will post my success/failures :)

Will it work in reverse is my only concern. It should work other than that. Let us know.