DT-02 overheating problem

[alvinlwh 5895]

So I had already melted an old motor on this chassis. At that time, I was thinking it could be due to old age or just that it was really tired. 

Swapped in a 380ST with 10T (only option) in and last run, it was still burning hot. Today, it started smoking too after about 15 minutes. 

Now I know that the DT is not great for cooling but a 380 is not as tight a fit in there as a 540.

Everything turns as it should, nothing seem to be binding. The only thing is I have putty in the diff and I was running on a football field. Is this the problem or something else? 

[Pylon80 2631]

You probably considered this already but are you geared too long but any chance?

[alvinlwh 5895]

44 minutes ago, Pylon80 said:

You probably considered this already but are you geared too long but any chance?

There is only one gearing when a 380 is used. 

4 hours ago, alvinlwh said:

Swapped in a 380ST with 10T (only option)

 

[El Gecko 1344]

Some thoughts about things to check:

- are the tires glued on the wheels? Could be slipping and letting the motor spin too much.
- how long is the grass on the field? Could simply be too long for the car. Even short grass puts up a lot more friction to an RC than smoother surfaces.
- is the suspension set high enough? If not, maybe jack it up to maximum so the underside doesn't rub as much?
- what kind of battery are you using? My DT02 gets really hot with only a 6-cell NiMH.
- you mentioned in the other thread that there's no binding in the drivetrain, but did you check at all angles of suspension travel? I've had cars with tight spots in the driveshafts that I only discovered when the suspension was compressed. (usually it's at full droop sitting on the stand with the wheels in the air)

[alvinlwh 5895]

7 hours ago, El Gecko said:

Some thoughts about things to check:

- are the tires glued on the wheels? Could be slipping and letting the motor spin too much.
- how long is the grass on the field? Could simply be too long for the car. Even short grass puts up a lot more friction to an RC than smoother surfaces.
- is the suspension set high enough? If not, maybe jack it up to maximum so the underside doesn't rub as much?
- what kind of battery are you using? My DT02 gets really hot with only a 6-cell NiMH.
- you mentioned in the other thread that there's no binding in the drivetrain, but did you check at all angles of suspension travel? I've had cars with tight spots in the driveshafts that I only discovered when the suspension was compressed. (usually it's at full droop sitting on the stand with the wheels in the air)

OK, I will try to answer one by one.

- tyres are pre-glued set. After checking, they are firm. 

- this, I suspect it to be most likely. It was freshly cut yesterday, to football field standard if it makes any sense. But the grass is really "dense"? 

- I believe so. I had jacked it up, all the way up. 

- 2S lipo. Perhaps I should go back to NiMHs? 

- no, don't think so, as above full droop is in fact my resting position. I set it for max ground clearance, but will check again. 

I am wondering though, as I said in my first post, I have diff putty in the diff. Could that be a possible cause?

I had seen posts of DT-02s (and 3s) overhearing and owners chopping off parts of the gearbox for cooling. Although they are all 540s, I was using a 380, which has plenty of room around it. Gearing shouldn't be a problem as 10T is the pinion that will fit with the 380.

Somewhat off topic, I took a badly geared (4.83) TT-01 (R) out on the same field today, with a 18T motor on NiMHs, it heated up within 5 minutes and I had to use DR to limit the power to 25%. This though is a completely inappropriate setup for off roading. 

[Willy iine 18806]

One idea could be to run your SuperStock motor, but set end point lower so that the motor does not rev all the way.  This will help your overheating and max speed issues. 

I use to do this on my brushless setup when driving in small space (to limit speed).  Worked quite well for me.   Anyway hope you find a solution.  

[alvinlwh 5895]

3 hours ago, Willy iine said:

One idea could be to run your SuperStock motor, but set end point lower so that the motor does not rev all the way.

I am actually thinking of getting a 550 motor. More torque, less RPM. With the end bell sticking out, it may cool better? Got to do some measurements to see if a 550 will fit or does some DT-02/3 owners know? 

[ad456 331]

@alvinlwh I’ve got a spare 550 somewhere I think, won’t be in the best condition as it was the survivor from a pair in my basher clod but should work. I’ll have a look tomorrow and drop it past when I take the kid to his grandfolks.

You can take the sleeve off a 550 and get a few extra rpm too!
 

edit: were you at the KGS fields? That’ll be pretty rough on a 380 with lipo I’d have thought….

Edited July 16, 2022 by ad456

[alvinlwh 5895]

16 minutes ago, ad456 said:

@alvinlwh I’ve got a spare 550 somewhere I think, won’t be in the best condition as it was the survivor from a pair in my basher clod but should work. I’ll have a look tomorrow and drop it past when I take the kid to his grandfolks.

You can take the sleeve off a 550 and get a few extra rpm too!
 

edit: were you at the KGS fields? That’ll be pretty rough on a 380 with lipo I’d have thought….

Oh great thanks! You got to show me what you mean by taking the sleeve off. 

Yes, the KGS football field, in front of the entrance not the rugby field beside the road. I kind of knew it will be rough having melted a 540, I just thought that with a 10T pinion (vs 19T), the gearing will be low enough. 

[ad456 331]

Yeah, that’ll probably be too much for the little motor. My 550 is a bit tatty but it’ll turn for a pack I’d imagine. I’ll text ya tomorrow when I’m over the road and drop it off. 

[SlideWRX 785]

The grass is definitely a big contributor.  I can run my dt-02 fine on gravel/tarmac, but the grass really gets it hot.  In your situation I think with the lipo, it could pull more amps than with the NiMH so it could heat itself up quicker too.

 

I literally just ordered this yesterday: ebay.com

I'm not using the fan; I'm splitting the heat sinks apart so one sink goes on my dt-02, one goes on my dt-03. I'll see how it goes!

 

[alvinlwh 5895]

10 hours ago, SlideWRX said:

I literally just ordered this yesterday: ebay.com

I'm not using the fan; I'm splitting the heat sinks apart so one sink goes on my dt-02, one goes on my dt-03. I'll see how it goes!

Well, I have another problem, some 540s will not work due too too short a shaft (so she says!). 

From what I have on hand, it seems that the closed bell end ones (silver can, ST) will not work while the open ONES (RZ, GT) will, and I don't think I can fit a heatsink on an open bell end motor... I don't really want to risk melting another open bell end motor (previous one was OK to melt as it was 10 years old and badly trashed and rusted) as they tends to be expensive. 

 

[alvinlwh 5895]

Little update, not the DT-02, I have yet to put the 550 that ad456 gave me in. 

Last week, I took a TT-01 (R) out with a 18T motor and 25T pinion with 58T spur out. Buring hot. I swapped out with a 45T motor with 28T pinion and 55T spur and it did not get as hot. 

[alvinlwh 5895]

@ad456 installed. Will test it on Friday and update on how it goes.

 

[alvinlwh 5895]

Update: tested the car with the 550 @ad456 gave me and I LOVE IT! It is a 15T one but being a 550, not that fast but the torque! The HB wheelies! In fact it was so mad that I did not have a chance to run it hard to test the temperature as this happened...

The car rolled and flipped so much within 5 minutes that the turnbuckles just pulled right out. Put it together again and the same happened less than 5 minutes later. Put it together again and took a more gentle drive (turn) up and down the football field at full throttle. It did get quite warm but not burning hot. Never had the car upright enough to do a flat out test for 30 minutes. 

On 7/17/2022 at 12:40 AM, SlideWRX said:

I literally just ordered this yesterday: ebay.com

I'm not using the fan; I'm splitting the heat sinks apart so one sink goes on my dt-02, one goes on my dt-03. I'll see how it goes!

I have the same idea with this, perhaps fitting just one heat sink to the motor. 

https://a.aliexpress.com/_vPiQKT