Help, hot motor Torment 4wd / HPI 15t Firebolt
06-23-2015, 06:05 AM
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Help, hot motor Torment 4wd / HPI 15t Firebolt
I got tired of reading dozens of help pages from 2011 so I'm asking again something probably already answered elsewhere that I can't seem to find. I had to replace the stock motor for my torment. I read decent reviews about the HPI 15t, which would replace the stock dynamite 15 T. I have also read the two motors are practically identical except for the stickers on them so it should have been an easy swap. Problem is after breaking in the HPI my first run the motor started smoking and I could not get it to cool down with lipo or Nimh installed., I did check to make sure a piece of paper would fit between the motor gear and the gear box gear. (newbie still learning terms/parts).
The HPI motor was a water break in and I used mystery oil for airguns on the outside of the 2 bearings. I know I should buy brushless so don't even suggest it I'm not at that point yet. I just want to fix this direct problem please. Help and thanks!
The HPI motor was a water break in and I used mystery oil for airguns on the outside of the 2 bearings. I know I should buy brushless so don't even suggest it I'm not at that point yet. I just want to fix this direct problem please. Help and thanks!
06-24-2015, 11:28 AM
#4
Are you the original owner? How many runs, or how long, did the original motor last before you had to replace it? Did you do a water break-in on the new motor?
With the old motor, were the ESC and motor temps OK? What is your maintenance schedule like?
You might've gotten some oil into the motor, that might explain the smoking, but it shouldn't be getting that hot. Have you checked all your bearings and rest of the drivetrain for any friction or binding?
With the old motor, were the ESC and motor temps OK? What is your maintenance schedule like?
You might've gotten some oil into the motor, that might explain the smoking, but it shouldn't be getting that hot. Have you checked all your bearings and rest of the drivetrain for any friction or binding?
06-24-2015, 08:07 PM
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Are you the original owner? How many runs, or how long, did the original motor last before you had to replace it? Did you do a water break-in on the new motor?
With the old motor, were the ESC and motor temps OK? What is your maintenance schedule like?
You might've gotten some oil into the motor, that might explain the smoking, but it shouldn't be getting that hot. Have you checked all your bearings and rest of the drivetrain for any friction or binding?
With the old motor, were the ESC and motor temps OK? What is your maintenance schedule like?
You might've gotten some oil into the motor, that might explain the smoking, but it shouldn't be getting that hot. Have you checked all your bearings and rest of the drivetrain for any friction or binding?
Old brushed motor had the fan go 'crooked' in the drum. didn't know about cleaning then so I assume a rock got in there and destroyed it. I bash hard on a dirt bike 'course' behind my house.
new HPI 15t was water break in, flushed water with electeronic cleaner, then oiled both bearings with mystery oil for air tools.
did not change a thing except the motor and both ESC and motor were 1 sec touch for heat at longest. HOT
Beginning to wonder if the pinion and spur might have been too far apart, if that causes that... I did the paper thing but not like the video I just watched. Definitely it was not mashed together anyhow, paper did go through the gears.
due to lack of interest until you, i just bought brushless setup in spite of my budget to get past this and have some fun, but i might have the same problems if i am doing something wrong. still DOA until new stuff arrives
06-25-2015, 07:44 AM
#6
Yeah, sorry about the late reply. I don't really know HPI stuff, so I was sort of over-looking it, waiting for an HPI guy to come along. But I noticed you hadn't had any replies yet, so I peeked, and found you had a fairly generic RC question, so I thought I'd chime in. 
You're probably right about a rock getting in the motor can. You just got unlucky. Bummer. A 1sec touch test is hot. You must have some binding somewhere. (I do strongly recommend you buy an IR temp gun. Duratrax sells one for $24)
Having the pinion/spur mesh too loose will not cause overheating. It will accelerate the spur wearing out (if you have a delrin spur, not metal). But your comment indicates that you probably should re-set it.
Back to your heat problem: 4wd trucks have A LOT of bearings. Two for each diff, three including the input hub, and two on each wheel, that's 8 bearings right there, 16 altogether. One bearing getting a little gritty probably wouldn't raise the temps that much, but if that one bearing had completely locked up? (Not an uncommon thing) It could raise your temps. And if you have more than one go bad? Definitely. It can be hard to tell sometimes where your drag is coming from, even if you disengage the pinion/spur mesh and roll the car by hand trying to feel where the drag is. You HAVE to take it apart and check every bearing. You said it's new, but you've been running it for a few weeks. It's due for some maintenance.
If you find some suspect bearings, you can usually revive them. Using a hobby knife, carefully pry out the bearing seals (I am assuming rubber-sealed bearings. Metal shielded is a little more involved) Using motor spray or WD-40, clean out the bearing. If you're using WD-40 it should start feeling a lot smoother. Make sure you get out all the grit, then put one seal back in, put some oil or light grease in the bearing and put the other seal back on. Test the bearing in your fingers. It should feel butter-smooth. If it still feels gritty, replace it.
Now, after you've gone thru the car and made sure all the bearings are clean and smooth, check the front CV axles for any binding. Use Odonnel's or TrakPower Dry Wax Lube for lubing exposed parts like CVDs and hinge pins. It's a liquid carrier for a wax lubricant that dries and doesn't attract dirt. Never use plain ol' 3-in-1 oil.
If you run the truck now, and the motor is still getting too hot, you may need to gear down a little by replacing the pinion with one that has one or two fewer teeth. The stock gearing should be fine, but if you're weather has gotten hot (it is summer!) ambient temperatures also affect the car. You could be fine in December, but need to gear down come June. Not too common, but it happens.
Hope that helps. Come on back with any more questions.
You're probably right about a rock getting in the motor can. You just got unlucky. Bummer. A 1sec touch test is hot. You must have some binding somewhere. (I do strongly recommend you buy an IR temp gun. Duratrax sells one for $24)
Having the pinion/spur mesh too loose will not cause overheating. It will accelerate the spur wearing out (if you have a delrin spur, not metal). But your comment indicates that you probably should re-set it.
Back to your heat problem: 4wd trucks have A LOT of bearings. Two for each diff, three including the input hub, and two on each wheel, that's 8 bearings right there, 16 altogether. One bearing getting a little gritty probably wouldn't raise the temps that much, but if that one bearing had completely locked up? (Not an uncommon thing) It could raise your temps. And if you have more than one go bad? Definitely. It can be hard to tell sometimes where your drag is coming from, even if you disengage the pinion/spur mesh and roll the car by hand trying to feel where the drag is. You HAVE to take it apart and check every bearing. You said it's new, but you've been running it for a few weeks. It's due for some maintenance.
If you find some suspect bearings, you can usually revive them. Using a hobby knife, carefully pry out the bearing seals (I am assuming rubber-sealed bearings. Metal shielded is a little more involved) Using motor spray or WD-40, clean out the bearing. If you're using WD-40 it should start feeling a lot smoother. Make sure you get out all the grit, then put one seal back in, put some oil or light grease in the bearing and put the other seal back on. Test the bearing in your fingers. It should feel butter-smooth. If it still feels gritty, replace it.
Now, after you've gone thru the car and made sure all the bearings are clean and smooth, check the front CV axles for any binding. Use Odonnel's or TrakPower Dry Wax Lube for lubing exposed parts like CVDs and hinge pins. It's a liquid carrier for a wax lubricant that dries and doesn't attract dirt. Never use plain ol' 3-in-1 oil.
If you run the truck now, and the motor is still getting too hot, you may need to gear down a little by replacing the pinion with one that has one or two fewer teeth. The stock gearing should be fine, but if you're weather has gotten hot (it is summer!) ambient temperatures also affect the car. You could be fine in December, but need to gear down come June. Not too common, but it happens.
Hope that helps. Come on back with any more questions.
