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ReVtech 17.5 Motor help PLEASE!

ReVtech 17.5 Motor help PLEASE!

Old 05-27-2012, 05:43 PM
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Default ReVtech 17.5 Motor help PLEASE!

Hello,

Just bought a revtech 17.5 motor on here and finally had a chance to try it out. Im running it in my Sc10 with tekin rs pro in blinky mode. I started at 30/78 with 2 clicks over on the motor timing, and after 6-8 min the motor got to about 160 degrees. That wasn't right so I went down 2 teeth on the pinion and still the same result after letting the motor cool off completely.

What could be the problem with this premature heating? Anyone have any gearing suggestions? Am I over gearing? I used to run 28/78 on my D3 17.5 and it was fine with no problems. Is something wrong with the motor itself? Thanks
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Old 05-27-2012, 05:53 PM
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Originally Posted by NofriendsTaco
Hello,

Just bought a revtech 17.5 motor on here and finally had a chance to try it out. Im running it in my Sc10 with tekin rs pro in blinky mode. I started at 30/78 with 2 clicks over on the motor timing, and after 6-8 min the motor got to about 160 degrees. That wasn't right so I went down 2 teeth on the pinion and still the same result after letting the motor cool off completely.

What could be the problem with this premature heating? Anyone have any gearing suggestions? Am I over gearing? I used to run 28/78 on my D3 17.5 and it was fine with no problems. Is something wrong with the motor itself? Thanks
Based on what I have run my Revtech at, you're significantly under-geared. My motor does have the HT rotor, but I run a 72 spur with pinions in the 27-29 range. The HT rotor seems to be good for 2-3 more teeth on your pinion over the standard rotor, so if yours is standard adjust your gearing accordingly. I haven't found it to be worthwhile adding endbell timing at all in an SC10 with this motor- just builds heat IMO.
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Old 05-27-2012, 05:55 PM
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Originally Posted by Jonny5
Based on what I have run my Revtech at, you're significantly under-geared. My motor does have the HT rotor, but I run a 72 spur with pinions in the 27-29 range. The HT rotor seems to be good for 2-3 more teeth on your pinion over the standard rotor, so if yours is standard adjust your gearing accordingly. I haven't found it to be worthwhile adding endbell timing at all in an SC10 with this motor- just builds heat IMO.
Thanks... being under geared can cause heating issues too right? I think I heard that. I have a 75t spur. You think maybe 28 or 30t pinion and 75t spur would help? I put motor timing back to the middle line too.
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Old 05-27-2012, 06:01 PM
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I would put timing back to zero and start your gearing at 28/78. Then check the temps get the gearing right for your track before you add timing then add a little timing and keep checking temps. Also make sure bearings are good in motor and everythin is good with your tranny.
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Old 05-27-2012, 06:03 PM
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So i took my spur assembly apart and found that I was actually using a 75T, not a 78T. So I was in the same range as you. Is this a motor problem itself then?
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Old 05-27-2012, 06:27 PM
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What's your track surface? How much does your slipper slip? Is your driving style smooth or aggressive? In stock class these are all important factors. I gear my motors to run around 150 after a 6 min race- running 8 min can lead to excessive heat. There's also a big temp difference- 15-20 degrees - between driving smooth or aggressive. Drop down to 26/75 and do a timed run that is as long as you race for. (Even better if you can check every two mins) If still hot, go down a tooth. If not, go up a tooth and re-check. It's very important to establish a baseline gearing for your truck/track to work off of.
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Old 05-27-2012, 07:57 PM
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Originally Posted by Jonny5
What's your track surface? How much does your slipper slip? Is your driving style smooth or aggressive? In stock class these are all important factors. I gear my motors to run around 150 after a 6 min race- running 8 min can lead to excessive heat. There's also a big temp difference- 15-20 degrees - between driving smooth or aggressive. Drop down to 26/75 and do a timed run that is as long as you race for. (Even better if you can check every two mins) If still hot, go down a tooth. If not, go up a tooth and re-check. It's very important to establish a baseline gearing for your truck/track to work off of.
Thanks for the help Jonny. Im going to just return this motor to the seller cause i opened it up and found a bunch of burnt carpet fibers in the motor and it looks pretty bad in there. Dont want to deal with it. Thanks for the help. Im going to buy a brand new 17.5 Revtec w/ 12.5 HT rotor and start fresh. Thanks again for the help.
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Old 05-28-2012, 08:20 AM
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whats wrong with 160 after a 8 min run?
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Old 05-28-2012, 10:22 AM
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Are these motors prone to heating up that high that quick?
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Old 05-28-2012, 10:29 AM
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i run 3 notches from max' 78s/28p with a ht rotor. i also run same gearing without ht rotor and no heat issues. got 3rd at the jconcepts indoor nats with the ht rotor. about 145 degrees on a tight diff
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Old 05-28-2012, 01:29 PM
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I think you are over geared. I run the d3 17.5 in my Kyosho with a 78-24 pinion with no timing on can and almost nothing for boost. After a 10 minute main I'm at 116 in a 86 degree day. I don't even get to max it out down the straight at all so I may even take the little boost it has or gear down more.

What's esc do you have? My friend kept thermaling his in 5 minutes and his esc was not getting enough air flow and had drag brake, etc etc. don't forget to check you motor bearings often. Since my x-12 motor is open slotted they would get dirty raising the temps by almost 20 degrees
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Old 05-28-2012, 01:32 PM
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Originally Posted by NofriendsTaco
Are these motors prone to heating up that high that quick?
Mine d3 does not but then I bought it new. The used lrp motor I got from here used had really gritty bearings and my temps were higher than my liking. When buying used always tear it down and clean everything, better safe than sorry. After clean motor and beari gs my temps have dropped 10+- degrees
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