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  1. #1
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    Freaking HOT, HOT Motor (14.4 DeWalt)

    I have researched this a lot, but I'm finding conflicting info, both on this forum and others.

    First, stock gearing: It's 14/68, right? When researching that, I'm finding supposedly "stock" numbers all over the place. One guy even swore stock was 12/58. I don't think so!

    Next, I have found that, supposedly:
    Hot Motor, Cool ESC = Undergeared
    Cool Motor, Hot ESC = Overgeared
    Cool or warm Motor and ESC = They are happy!

    Finally, I found that the following should fix gearing problems:
    Undergeared = Add teeth to pinion or remove teeth from spur
    Overgeared = Remove teeth from pinion or add teeth to spur

    Are the above true, or have I misunderstood something?

    Based on a hot motor, my Summit is apparently undergeared.

    Last week, my Summit stripped the spur gear, so I decided that was a good time to disassemble, inspect and clean everything. I have so much to learn about this hobby, but I'm all in.

    When I took things apart, I found that the previous owner installed a 17T pinion, but left the Spur at 68T. Therefore, I left the pinion at 17T, but replaced the stripped spur with a new 65T to help with the undergeared condition. I used the "strip of paper" method of spacing the teeth when meshing the new gears. A quick throttle test felt and sounded great.

    I went out and ran hard for about 20 minutes. The truck was noticeably faster and could easily pull wheelies in high gear. It could not do that before. Unfortunately, the motor became too hot to touch! I had to yank my finger away after about a second. That totally surprised me since I thought my gearing change would make the motor run cooler.

    All I can think of is that I must have misinterpretted something. I'll buy some different spur and pinion combinations and do some experimenting. Until then, I'd love to get your feedback on what I might be doing wrong and how to correct it.

    FYI: I run Proline Trencher X tires and use dual 2S Lipos from SPC rated at 8200mAh and 50C.

    Thanks!

  2. #2
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    What motor u have? If it's the stock titan the previous owner probably had a Dewalt or something and probably tossed the stock titan back in to sell and did not put the stock pinion back in.. Easy fix got get a stock

    Sent from my SGH-I337M using Tapatalk

  3. #3
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    14 back in.. The stock size is in the manual you can dl of the traxxas site.

    Sent from my SGH-I337M using Tapatalk

  4. #4
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    Quote Originally Posted by Crock View Post
    What motor u have? If it's the stock titan the previous owner probably had a Dewalt or something and probably tossed the stock titan back in to sell and did not put the stock pinion back in.. Easy fix got get a stock.
    It's a DeWalt 14.4v

    Quote Originally Posted by Crock View Post
    14 back in. The stock size is in the manual you can dl of the Traxxas site.
    Yup, manual says 14/68. OK - I'll put in 14/68 and see what happens. It might take a couple of days, but I'll report back what happens. I think I'll also get an inexpensive temp gun so I can report actual temps.

  5. #5
    RC Turnbuckle Jr. jamann's Avatar
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    Well in all actuality,12/58 is stock gearing ratio wise,well pretty close.It does rotate the motor more to the centre and a bit lower.
    For crawling steeper stuff it helps a bit


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  6. #6
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    Quote Originally Posted by jamann View Post
    Well in all actuality,12/58 is stock gearing ratio wise,well pretty close.It does rotate the motor more to the centre and a bit lower. For crawling steeper stuff it helps a bit.
    Ahh, differing terms. I was thinking strictly in terms of teeth on Pinion/Spur, which I just found that the manual says is 14/68. Since I have two dedicated crawlers, I don't use the Summit for technical crawling. I want it to be a bit faster. But mostly I want it to run cool. I'll start with stock 14/68. If that does not bring motor temps down, I'll start messing with one gear at a time by a couple teeth at a time.

  7. #7
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    I'm not sure what gearing the Dewalt likes.. I actually missed that in the title. One of the Dewalt guys will chime in

    Sent from my SGH-I337M using Tapatalk

  8. #8
    Marshal ksb51rl's Avatar
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    Quote Originally Posted by MailManX View Post
    I have researched this a lot, but I'm finding conflicting info, both on this forum and others.

    First, stock gearing: It's 14/68, right? When researching that, I'm finding supposedly "stock" numbers all over the place. One guy even swore stock was 12/58. I don't think so!

    Next, I have found that, supposedly:
    Hot Motor, Cool ESC = Undergeared
    Cool Motor, Hot ESC = Overgeared
    Cool or warm Motor and ESC = They are happy!

    Finally, I found that the following should fix gearing problems:
    Undergeared = Add teeth to pinion or remove teeth from spur
    Overgeared = Remove teeth from pinion or add teeth to spur

    Are the above true, or have I misunderstood something?

    Based on a hot motor, my Summit is apparently undergeared.

    Last week, my Summit stripped the spur gear, so I decided that was a good time to disassemble, inspect and clean everything. I have so much to learn about this hobby, but I'm all in.

    When I took things apart, I found that the previous owner installed a 17T pinion, but left the Spur at 68T. Therefore, I left the pinion at 17T, but replaced the stripped spur with a new 65T to help with the undergeared condition. I used the "strip of paper" method of spacing the teeth when meshing the new gears. A quick throttle test felt and sounded great.

    I went out and ran hard for about 20 minutes. The truck was noticeably faster and could easily pull wheelies in high gear. It could not do that before. Unfortunately, the motor became too hot to touch! I had to yank my finger away after about a second. That totally surprised me since I thought my gearing change would make the motor run cooler.

    All I can think of is that I must have misinterpretted something. I'll buy some different spur and pinion combinations and do some experimenting. Until then, I'd love to get your feedback on what I might be doing wrong and how to correct it.

    FYI: I run Proline Trencher X tires and use dual 2S Lipos from SPC rated at 8200mAh and 50C.

    Thanks!
    Actually, 12/58 is about as close to 14/68 (stock) as you can get. Gearing is a ratio. There are usually one or two equivalents that fit in a vehicle.
    So far as temps are concerned, with a brushed motor, too much heat almost always is equivalent to too high gearing.
    Neither the Titan 775 nor the Dewalt 14.4 like to be overgeared. IMO the Titan works best at 13/68, or even 12/68 and the Dewalt is best used with gearing less than 17/68. Of course I am not interested at all in speed from my Summit, so that tends to influence my opinion in these matters.
    Alt-248 on the number pad =

  9. #9
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    Quote Originally Posted by ksb51rl View Post
    Actually, 12/58 is about as close to 14/68 (stock) as you can get. Gearing is a ratio. There are usually one or two equivalents that fit in a vehicle.

    So far as temps are concerned, with a brushed motor, too much heat almost always is equivalent to too high gearing.
    Neither the Titan 775 nor the Dewalt 14.4 like to be overgeared. IMO the Titan works best at 13/68, or even 12/68 and the Dewalt is best used with gearing less than 17/68. Of course I am not interested at all in speed from my Summit, so that tends to influence my opinion in these matters.
    Thanks! I had completely overlooked the possibility of more than one equivalent for a similar gear ratio. Doh! I'll pull out the offending 17/65 and use 14/68 as my baseline. I can go smaller on the pinion from there as needed.

  10. #10
    Marshal ksb51rl's Avatar
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    The Dewalt 396505-21SV should have no problem with 14/68 or 14/65 gearing.
    Alt-248 on the number pad =

  11. #11
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    DeWalts run particularly hot when compared to other similar motors (Titan). 17/68 is what I run w/o problems, but I seldomly use high gear. When too hot out I gear down to 14/68.
    My 2 cents.
    Working hard to appear reasonably sane.

  12. #12
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    Captain Switchblade - Thanks for the feedback. It's good to hear from other people with DeWalt experience. Do you ever use a temp reader on your motor, or do you use the touch method? I'm going to get a temp gun and get some actual readings. I hope that will help me make better adjustments. Since I have 17/65 gearing in now, I'll probably go all the way back to stock 14/68 and start from scratch.

  13. #13
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    Lost my Duratrax Flashpoint a few months ago so I went back to the finger method.
    Working hard to appear reasonably sane.

  14. #14
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    Quote Originally Posted by MailManX View Post
    Captain Switchblade - Thanks for the feedback. It's good to hear from other people with DeWalt experience. Do you ever use a temp reader on your motor, or do you use the touch method? I'm going to get a temp gun and get some actual readings. I hope that will help me make better adjustments. Since I have 17/65 gearing in now, I'll probably go all the way back to stock 14/68 and start from scratch.
    I have the Dewalt14.4, Spc 8200, Mudslingers tires and the stock spur gear. I have tried - 11t great crawling low top end, 12t pinion same as 11, 14t pinion great low end still slower than stock, 16t pinion great low end same speed as stock, 17t pinion great low end and little faster than stock, 19t pinion low end suffered faster than stock motor heating problems, 21t bad low end very fast and broke all kinds of stuff on the truck engine overheats. i use the 17t pinion and have had no overheating issues. I would agree with what you are going to do, put on the stock spur and try the 14t. i would suggest you buy some additional pinion gears and try those until you find your sweet spot.
    "Better Old and Devious than Young and Exuberant"

  15. #15
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    I like a good mix of bashing and crawling from my truck and actually prefer the stock motor to the dewalt as i find it has a wider rpm range and is a bit more versatile. But when i do run the dewalt i run at 14/65 or 15/68 and it keeps the temps in check. Also i found hard braking to heat the dewalt up at least as fast as hard accel.

  16. #16
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    Quote Originally Posted by Captain Switchblade View Post
    Lost my Duratrax Flashpoint a few months ago so I went back to the finger method.
    My finger is not calibrated and it still hurts from the last temp "measurement". I ran the truck for 20 minutes with stock 14/68 gearing and it burned my finger. I have ordered a Duratrax Flashpoint. It should arrive today. I was bummed that the stock gearing got the motor so hot. I'll have to start changing the pinion by one tooth at a time, then running hard and logging the actual temp. Hopefully I'll find the sweet spot before the DeWalt lets out the magic smoke and goes to motor heaven.
    A signature with less than 50 characters? Sheesh!

  17. #17
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    So my next question will be how new is the dewalt? Mine ran really hot for like 4-5 sets of packs before it really broke in and the temps started coming down i would really try to just half throttle cruz it around half throttlewith no hard braking for say three full sets of batts. I cooked the first one i had and just about gave up on the second but once i tried this my temps are just warm and im actually thinking of gearing up now from 15/65. Be patient and give it time to really work in and resist the urge to "rip on er" for at least 3 sets of packs before you make up your mind.

  18. #18
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    I have never owned another brushed motor that takes this long to break in

  19. #19
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    Quote Originally Posted by Reaxion911 View Post
    So my next question will be how new is the dewalt? Mine ran really hot for like 4-5 sets of packs before it really broke in and the temps started coming down i would really try to just half throttle cruz it around half throttlewith no hard braking for say three full sets of batts. I cooked the first one i had and just about gave up on the second but once i tried this my temps are just warm and im actually thinking of gearing up now from 15/65. Be patient and give it time to really work in and resist the urge to "rip on er" for at least 3 sets of packs before you make up your mind.
    I don't know how old the motor is. The truck was used when I bought it and had already been converted. I have run several packs through it, but only recently has it started getting so hot.

    Speaking of which, I got my Duratrax Flashpoint in the mail and used it yesterday. I put the stock 14/68 gears in, adjustever everything and verified the drivetrain was free-running, then went for a drive. I'm staying at a hotel this week (on travel for work), so I walked next door to an empty parking lot and ran it on some hard speed runs. To simulate a bit of bashing, I made sure to accelerate hard a few times and stop quickly a few times. I would run about 5 minutes at a time, then take a temp. I went through a full 7200mAh 2X2S batteryu set which lasted me about 45 minutes. Early in the run, the temp maxed out at 180-degrees, then it dropped a bit and leveled out at about 165-degrees and for the duration of the run. That's higher than I'd like, but at least it's not disasterously hot.

    On a side note, I noticed something different this time that I've not experienced before. I was getting major "hesitation" or "stuttering" on acceleration. It would spark more than usual and just be gutless as heck, then finally pick up speed and run fine at higher RPM's only to repeat the process if I slowed down too much. My 9-year old grandson was the last to drive it. He bashed it pretty hard on an extremly dusty BMX track. He had to end the bashing session early when it broke a right rear half shaft at the pin next to the differential. I think he got the motor really dirty and pretty stressed out. I bought him his own Stampede 4x4 so my truck won't suffer any more "child abuse".

    Back at the hotel, I pulled the motor and (for the first time) pulled the brushes. The motor was VERY dirty, but at least it did not smell burnt. The brushes were worn nicely, but were about half gone. I sanded them a little bit and grooved them a little bit in prep for a new break-in. Then re-installed them. I went to the computer and ordered another set of brushes. While at it, I ordered another new 14.4v motor as a backup. Until then, I'll run the old brushes.

    Since I did not have any motor cleaner at the hotel and did not feel like going out to by some, I hooked up the motor to a battery source and did a few controlled dips into a pitcher of clean water. The first 20-second dip made the water black, but I could hear the motor smooth out. I emptied that pitcher and did another 20-second dip in clean water. The motor smoothed out even more and the water only got slightly tainted. The third dip in clean water produced no residue.

    Since I did no have a compressed air source in the hotel, I ran the motor in the air for about a minute while shaking it a bit. That blew most of the water out of it. After that, I lubed the bearings and sprayed out the windings with a tad bit of WD-40. Then I ran it again for a few seconds to work the lube in. Man, that thing purrs now. I set it on end to dry for the night. I'll lube it again this evening before I use it again.

    After work today, I will take it back out for a run. I'll use the same stock gearing and see how the power and temps compare to yesterday. I'll report back on that this evening.
    A signature with less than 50 characters? Sheesh!

  20. #20
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    Cool ya it seems like these motors build heat really fast when the brushes arent making full contact. Oh and non chlorinated brake cleaner is the same as motor cleaner and is about $4. Tip o the day! Glad your getting somewhere on your issue. I say again i still really like stock 775 motors

  21. #21
    RC Turnbuckle Jr. JimmyNeutron's Avatar
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    What lube did you use?

    "Since I did no have a compressed air source in the hotel, I ran the motor in the air for about a minute while shaking it a bit. That blew most of the water out of it. After that, I lubed the bearings and sprayed out the windings with a tad bit of WD-40. Then I ran it again for a few seconds to work the lube in. Man, that thing purrs now. I set it on end to dry for the night. I'll lube it again this evening before I use it again."
    Whatever it is I just typed... could be wrong.

  22. #22
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    My Summit Cheat Sheet
    Model : 5607
    Front Differential Oil : 100K Diff Lube
    Rear Differential Oil : 100K Diff Lube
    Front Shock Oil : 30w
    Rear Shock Oil : 30w
    Stock Pinion : 14t
    Stock Spur : 68
    Transmission Gear Ratio (LOW) : 14.45
    Transmission Gear Ratio (HIGH) : 5.22
    Final Drive Ratio (LOW) : 70.19
    Final Drive Ratio (HIGH) : 25.35

  23. #23
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    Quote Originally Posted by Reaxion911 View Post
    Cool ya it seems like these motors build heat really fast when the brushes arent making full contact. Oh and non chlorinated brake cleaner is the same as motor cleaner and is about $4. Tip o the day! Glad your getting somewhere on your issue. I say again i still really like stock 775 motors
    Thanks for the tip on the cheaper motor cleaner!

    I’ve never experience the original Titan 775 since the Summit is my first RC truck and it came with the DeWalt already installed. I think I’ll buy a Titan for fun and compare the two. The Titan motors are so cheap compared to other RC stuff. I’ve already dropped thousands on this hobby in three months, so another few bucks is no big deal. I am actually stunned at how fast the money goes. I gotta start cutting back – I need to be able to retire someday.


    Quote Originally Posted by Jimmie Neutron View Post
    What lube did you use?
    I don't want it to attract any dirt, so I used Dupont Dry PTFE Lube. It goes on nice and light so it can soak in easily, but dries without a wet film. I haven't actually read about doing that on motor bearings, it was just something I wanted to try. If there's a better way, I'm open to it.
    A signature with less than 50 characters? Sheesh!

  24. #24
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    WOW! Since I am very new to RC trucks and this was the first time I've performed maintenance on a brushed motor, I had NO IDEA how much difference it could make. Cleaning the motor, re-seating the brushes, lubing the bearings and performing a new break-in process turned it into what feels like a new motor. No more stalling or hesitation, no more sparking, more torque, more top-end speed, and MUCH COOLER!!

    Yesterday, before maintenance, my motor temp maxed at about 180-degrees. Today, the max was 125-degrees, and that was only briefly under the hardest driving.

    I started the re-break-in process with the ESC set on the learning mode. I ran the truck in large figure 8's for about 15 minutes. I checked the temp each five minutes. It averaged 102-degrees during that time. Then I set the ESC to full power and ran more figure 8's for 15 minutes, checking temps each 5 minutes. It averaged 112-degrees during that time. Finally, I tried to get it hot. I did rabbit starts, wheelies, repeated hard breaking, crazy drifting on dirty asphalt and long speed runs. I did that until the LVC cut-in which was about another 15 minutes. As before, I checked temps each 5 minutes with a max temp during that time of just 125-degrees. No comparison to yesterday!

    So, for all my fellow newbies out there, don't skip the motor maintenance! If you've never done it before, watch a few videos, read a few posts, then just roll up your sleeves and do it. That's what I did. It was much easier than I anticipated and the outcome was SO worth it!!
    A signature with less than 50 characters? Sheesh!

  25. #25
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    Glad you got er figured out! I did some gearing changing and messing around yesterday too and found that 15/65 for the dewalt is perfect! I went up and down on gearing and what i found is that any higher and it gets a little bog and starts to heat up and any lower it just maxes out rpm with more power to spare. Here is a chart so you can see what ratio that is

  26. #26
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    That's a great chart! Thanks for sharing.
    A signature with less than 50 characters? Sheesh!

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