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  1. #1
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    Revo 3.3 budget brushless conversion, The Sequel

    This is a build thread inspired by reflexa's "Revo 2.5R budget brushless conversion" thread, as it uses the same electronics, but some different hardware, all of which anyone could buy or do.

    History:
    This is my buddy's truck that used to have a rotostart STS.28 (of which the entire BB conversion: motor, mount, clutch, pipe, etc. are for sale). There was nothing wrong with it other than the fact it was nitro and took a preparation to get going. He liked to just run it on a whim for a few minutes, but the effort (including post efforts) wasn't worth those whim moments, so it didn't get a lot of use. He saw my e-conversion (thread coming in a few weeks) and loved it but the cost was high. I told him I could do it a lot cheaper, so here we are.

    Here are the players:
    Integy motor mount, ********* SC120A ESC, ********* program card, HK S3674-2370 motor, FAN5010-3665 heat sink, Scorpion 300mm velcro straps, Losi SCTE battery tray, /xt60 connectors, TGY-1501MG servo (236 in-oz) servo, two 4s 20C 5000mah hardcase battery packs, 4mm bullet connectors, three M3x6 button head screws, three M3 hex nuts, 6" servo lead extension, Traxxas FOC, Traxxas p/n 5145 screw pins (not shown), three 6-32 X 1/2" screws, 18T Mod1 5mm pinion, foam strips (not shown). Not counting the shipping, this comes out to $280, for which about $45 was shipping.

    Ignore the Du-Bro parts

    Things to note:
    The Integy mount is only good for 36mm motors unless you do some mods to it. The SC120 "clearly" states that it is "intended for 4x4 short course or smaller." Reflexa burnt up his motor no long after installing it. I didn't believe and don't believe the torque specs of the servo purchased.

    1) All the nitro stuff was removed.
    2) Mechanical brakes were remove.
    3) The tranny was gutted of all reverse hardware.
    4) The 2nd gear lock was done.
    a) remove the grub screw, ball, and spring from the clutch. I then put the grub screw back.
    b) put the clutch back in the 2nd gear and extend the steel clutch tooth/shoe while installed
    c) take it out without letting the tooth move and add one drop of CA to hold it in place.
    d) put the clutch back in the gear (tooth against pin) and mark for the holes for the 3 screws
    e) use a Dremel tool to notch out 3 areas for the screws to pass the clutch and screw into the gear
    f) Cut the screws to .40 inches and install them.


    Robinson input gears shown were not put in this build.

    5) Use a 2.5mm drill bit to open the pin hole in the aluminum main shaft of the FOC.
    6) Use a 1/8" drill bit to open the to-be-threaded hole on the main shaft gear.
    7) Unless you have a lathe, place Traxxas 5145 pin in a corded drill [spins faster than cordless usually]
    8) Place the drill in a vice, turn it on full blast and use Dremel to cut the bottom 1.5 threads down to the diameter of the pin.




    9) Attach the gear to the aluminum main shaft with your modified pin.
    10) Rebuild the tranny, minus the large 1st gear.
    11) Shave some of the features off the bottom of the SCTE tray as shown below.
    12) Remove the passenger side servo.
    13) Flatten out the two tabs of the chassis next to the passenger side servo.
    14) Bend the long tab near the rear to be co-planer with the passenger side servo area.



    15) Drill where required and install the battery try with the M3x6 screws and M3 hex nuts.
    16) Install the single servo on the driver's side.



    17) Do ll necessary soldering and change of connectors.
    18) Install the motor mount, motor pinion, velcro straps, goo-down the ESC and add zip tie.
    19) I used the mounting tray that came with the ESC for the RX and put it on the front shock mount.
    20) Shave some of the heatsink fins to fit into the motor mount.
    21) Use the servo extension for the motor fan.
    22) I drilled out the fuel tank mount and made it into an antenna tube mount.



    Motor fan not shown because I crashed during a speed run and destroyed it. I'll have another tomorrow.

    23) charge battery
    24) Program ESC (autolipo, 3.2V cutoff, 0 drag brk, 100 brk, 0 punch, Prop Rev Lock out, 8% timing
    25) Hit 50mph

    Last edited by metoo2; 08-29-2012 at 01:13 AM.

  2. #2
    RC Racer
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    After 10 actual running minutes of playing around, setup, and a few speed runs, motor never passed 126F, ESC was 106F, and battery case was 100F. We'll see how things go with the owner.

  3. #3
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    wow...i want to do this sooooo bad...i want to buy just the chassis and moving all the parts on my e-revo to the revo chassis....debating between this and the kershaw body...soooo difficult...and ur not making it easier for me to decide by putting up these step by step instructions...

    keep up the good work...me se likey...

  4. #4
    RC Turnbuckle Jr. MITCH316's Avatar
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    Looking good mate...

    I would change my auto cut off to 3.4V, a lot of guys are at 3.4V
    Rock n Rolla !

  5. #5
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    Nicely done! I've come to believe the my motor may have just been defective :-/

  6. #6
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    That is awesome mee too nice work.I like the esc placement looks like it will be better protected compared to where i mounted mine.Brilliant!!!!

  7. #7
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    Or could it have been driving around relatively slowly that burnt it up?

  8. #8
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    Quote Originally Posted by metoo2 View Post
    Here are the players:
    Integy motor mount, ********* SC120A ESC, ********* program card, HK S3674-2370 motor, FAN5010-3665 heat sink, Scorpion 300mm velcro straps, Losi SCTE battery tray, /xt60 connectors, TGY-1501MG servo (236 in-oz) servo, two 4s 20C 5000mah hardcase battery packs, 4mm bullet connectors, three M3x6 button head screws, three M3 hex nuts, 6" servo lead extension, Traxxas FOC, Traxxas p/n 5145 screw pins (not shown), three 6-32 X 1/2" screws, 18T Mod1 5mm pinion, foam strips (not shown). Not counting the shipping, this comes out to $280, for which about $45 was shipping.
    Correction: $280 includes the $45 in shipping costs.


    Quote Originally Posted by craig.mitch316 View Post
    Looking good mate...
    I would change my auto cut off to 3.4V, a lot of guys are at 3.4V
    Will do, especially considering how cheap the batteries were.

    Quote Originally Posted by reflexsa View Post
    Or could it have been driving around relatively slowly that burnt it up?
    I doubt it. You had a fan on it. The fan is not all that strong, but probably adequate. Slow will heat the motor up if it's under load, like going uphill or thru chunky mud or high grass. Hard and frequent braking will do the same. I used Traxxas thermal compound under between the heatsink and motor. I'm not sure how much that is helping. Since the motor has only been used for a few minutes, it's too soon to talk about its longevity.
    Last edited by metoo2; 08-29-2012 at 08:26 AM.

  9. #9
    RC Turnbuckle Jr. humayrayakongkinaon's Avatar
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    cool, i found my twin, LOL.



    i've seen those lipos on ebay for $40 i'm tempted to buy one unless you have a link to where i can buy it cheaper? thanks.
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  10. #10
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    Quote Originally Posted by humayrayakongkinaon View Post
    cool, i found my twin, LOL.
    Well, not exactly, you have much pricer electronic (...not to mention faster and most likely better quality), lower center of gravity, and there was fabrication involved. Why did you chop-up the roll bar/handle? That receiver box looks tempting. The truck I posted is not mine, I just built it. I'll let my buddy know of this option.

    Quote Originally Posted by humayrayakongkinaon View Post
    i've seen those lipos on ebay for $40 i'm tempted to buy one unless you have a link to where i can buy it cheaper? thanks.
    If you get them from the source, you can get 2 of them for $58 including shipping. PM sent.

  11. #11
    RC Turnbuckle Jr. humayrayakongkinaon's Avatar
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    Quote Originally Posted by metoo2 View Post
    Why did you chop-up the roll bar/handle? That receiver box looks tempting. The truck I posted is not mine, I just built it. I'll let my buddy know of this option.
    i cut it cause its rubbing the motor mount, i put spacer on mine to get the motor mounted forward a bit and that i dont have to use long shank pinion. the reciever box does looks cool in there, its the one you find from stampede 4x4. thats cool your helping your buddy.
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  12. #12
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    Hows the motor running?

  13. #13
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    is that not a 1/10 scale motor how much did you pay for it

  14. #14
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    The $40 motor is running great. It's been run everyday over the last few days.

    However, there was a problem... DO NOT BUY THE ********* ESC!!!!!!!!
    There was fire just a couple minutes into the 2nd battery charge. Complete ESC melt down...literally. This also puffed the battery. Everything else was fine. I'm working with the warranty department now.

    Knowing that dealing with the warranty would not be a rapid process, I decided to buy the seemingly well loved (based on the several reviews) store brand 120A ESC, which was actually $10 cheaper than the *********, but it's physically huge. It barely fits in the space I had designated. That said, it's been working like a champ. The owner of the truck loves it.

  15. #15
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    Interesting, my ESC is still working pretty well considering it now has the 2200 motor on it.

  16. #16
    RC Turnbuckle Jr. humayrayakongkinaon's Avatar
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    good to hear from you again metoo2 and sorry to hear about your burnt up ESC. got any pic of the damage for us to see?

    me on the other hand, got me a RR steel tranny set. i'm feed up with strip gear.
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  17. #17
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    what esc are you using

  18. #18
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    Well I guess it's not really fair saying don't buy that ESC, as plenty of the Castle ones have also gone up in smoke.
    Perhaps it was just a faulty one from the start.

  19. #19
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    Quote Originally Posted by humayrayakongkinaon View Post
    good to hear from you again metoo2 and sorry to hear about your burnt up ESC. got any pic of the damage for us to see?

    me on the other hand, got me a RR steel tranny set. i'm feed up with strip gear.
    I can post them later. The warranty issue went quicker than expected and I got my money back in the form of store credit, which is fine since I order so much stuff from there.

    I only only have the one steel gear in my truck (not the truck shown in this thread). I just broke the pin that's held in by that silly C-clip.

    Quote Originally Posted by revoman78 View Post
    what esc are you using
    HK 120A in this build, but not in my personal truck.

    Quote Originally Posted by reflexsa View Post
    Well I guess it's not really fair saying don't buy that ESC, as plenty of the Castle ones have also gone up in smoke.
    Perhaps it was just a faulty one from the start.
    Yeah, it's fair to say. I was warned by several of the reviews for that ESC, but bought it anyway and paid the price. Everyone seems to love the cheaper HK 120A replacement that I put in.

    I've heard of several Castles going to poop, but I wouldn't shun them just yet. The Tekin RX8, I would definitely stay away from. I've known of way too many of those to bite the bullet, but its still popular.

  20. #20
    RC Turnbuckle Jr. MITCH316's Avatar
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    Nice....
    Rock n Rolla !

  21. #21
    RC Turnbuckle Jr.
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    Looks good! I will see how long I can keep mine stock!

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