Anyone have any problems putting a Velocity heatsink on a 13.5 pro motor? Can't rotate it so it fits in my car. Can't get it off either. Everything is brand new.

Yep, Once it's on it's on.
Mine is so tight I think if I wanted to take it off I would have to cut it. :cry:
You could try useing a heat gun. Need to get really hot.
Good Luck Richard

maybe try some ky to get it off lol

I'm thinking guys need to start using a SILICONE Plating Grease or something when using these...(LIke a DC3 or 4 maybe) or like a silicone diff lube.

Hearing lots of guys with the same concern...and have even seen where motors have been sent back to NOVAK to have them deal with the issue.

I had no problem with MINE on the first motor I used it on...but couldn't get it ON the 2nd motor..and ended up eggshaping the heat sink and throwing it away.

(I wonder how a CLIP ON one would be...)

I had the same issue with mine so when I finally got it off, I took a dremel with a sanding drum and kept lightly sanding the anodizing off the inside until I could slide it on and rotate it. I still kept it snug but with a little effort I can rotate it or take it off.

Good Idea Lohrr1

When I installed mine onto my 13.5, I used ArticSilver thermal compound to help transfer the heat faster. I wished I would have sanded just a little off something, it was a tight fit. During the whole process, I was worried about damaging my brand new motor.

As for design changes, could the heatsink be designed like a clamp with just a slit cut into the middle of the heatsink and two clamping bolts hold it tight?

I don't use one, nor have I ever tried one,
but has anyone tried cutting a slot in it?

...I didn't cut a slot, but thought about the same thing...

The material is thick enough I think it would probably work decent.

With Randy Smith (Big Boys Toys) having upper pod plates for most of the NEWER style cars, they will stay in place w/o any problem I believe.

Heat Gun and a very thick set of gloves, I used gardener gloves. I put my motor in a small vise and tightened her down incrementally, and it worked O.K. Just have to be patient or it would be easy to wreck alot of stuff. Ones things for sure, that heat sink should transfer 100%. Randy at BigBoyToys makes great motor top plates to work with the heatsink.

I really don't think using the heatsink is really needed for anything but the bigger power motors like the 5.5 to 3.5. We are running the 10.5 with 6 cells and with the new rotor motor temps are around 130.

on our outdoor, medium sized tracks we see upward of 160 with 4cell/10.5 during the summer, similar on the velodromes.

I came off last weekend about 150-155 and the air temp was in the cool Low 60's.

...one of MY curiousities <sp> is HOW HIGH/TALL can you really gear one of these...IF you take the HEAT issue away. (Do we run a bank of FANS and Electric motor coolers?)

Personally I think the heat sink may cause more damage after the run. The car is not moving any cooler air over the heat sink and the motor will heat up even more and stay hotter longer. Heat has always been an issue for any electric motors.

I start off a run with my motor around 25F and have rarely ever reached 130F. I usually see a drop off in speed if I gear too high. Although for bigger tracks like velos and such this may be a needed item because you can take advantage of the large airflow during a race. Most tracks around here tend to be less than 120ft running line and are inside (60-70F). The heatsinks tended to be more of a weight issue with very little performance advantage.

Most tracks around here tend to be less than 120ft running line and are inside (60-70F). The heatsinks tended to be more of a weight issue with very little performance advantage.


I can see that...where we rarely worry too much about weight (and most of us run HEAVY)

Personally I think the heat sink may cause more damage after the run. The car is not moving any cooler air over the heat sink and the motor will heat up even more and stay hotter longer.
I don't think airflow from the car moving is necessary
for the heatsink to be effective.
It still has more surface area exposed to ambient air, after the run..
Not sure how much air is actually "flowing" around it in the car any way..
I haven't seen a heat issue indoors with a 10.5..
Seems like this may be more of an issue racing outside in 90* weather. :confused:

A hot heatsink alone creates its own airflow. Heat Rises last time I check on Earth.

I assume the heatsink is an extruded bar that is cut and milled to perfection, but could fins be cross cut also like on some CPU coolers. I remember my P133(Pentium 133mHz)processor had a fanless cooler that had 3" tall square spikes about 3/16" wide and tappered to 1/8" at top. It increases the surface area, reduces mass and the heat sink will no longer be a directional heatsink when not using the fan. On pan cars, buggies/trucks, belt driven sedans the motor is horizontal to movement of the car. This means the first fin blocks airflow. Crosscut heatsinks could take advantage airflow from anydirection!