[JasonB]

The 1520 will fit into the stock flux with a little bit of effort.

Step 1: The castle motors are 2mm bigger in diameter due to the fins, so you will need to sand down inside of motor mounts. I didn't take pictures of this step, but there is another post somewhere with pictures of this step. First thing to do here is slide the mount onto the end of the 1520 motor and scribe a very thin line around where the fins touch the mount with a hobby knife. This will show you exactly how much material must be removed. Then chuck up a ~1" sanding drum in your drill/ drill press and make several full passes around the inside of the mount, gradually removing material until you approach the scribe line. When you start to touch the line, do a test fit and then very gradually sand off more until you get a perfect snug fit. If you want to skip this step, GCM has done the work for you and sells a set of mounts that have already been milled to the correct size.

Step 2: Install the motor without the pinion and leave all the hardware a little loose so that you can slide the motor front to back in the mounts and side to side in the slots. Slide the motor all the way forward until the motor shaft is just touching the transmission box, then back it off ½ mm so it will not rub. Then lock the motor down in the mounts, but leave the mounts loose in the slots.

Step 3: Use the sanding drum to take off about 2mm of material from the part of the TVP that is preventing the motor from sliding all the way to the end of the stops. Just take off a little bit at a time until you have full adjustment. Shown below is a picture of a stock TVP next to the one I sanded down.


Step 4: Notch the battery box mount. Just need to take off about 1mm or so.

Step 5: Mount the pinion on the motor backwards, line it up with the spur and lock it down. With this mod, there will be no front to back motor adjustment, but if the pinion is aligned correctly and loctited down, this adjustment is never needed.

Step 6: Put it back together and enjoy your bigger badder motor! I love the 1520, it runs cool, gives a little more run time, and has more torque. I have run it hard in the sand for 15 min straight and could still hold my thumb on the motor. Never temped it over 130 deg.