Finally built my top force evo

[no1trancefan]

Finally built with a bz super motor. Managed to throw away the undercowl in error during the build so need to add one of those.

I'm not sure if i havent set enough tension on the differentials? On test drive, it gains pace but seems as though slipping a lot. How would i know if the tension is right if i rebuild the differentials? To trial and error will have to keep taking the whole thing apart.

 

Hope someone can help thanks

[no1trancefan]

[Anthroxoid]

Go back to the diff build page in the instructions and note how the two sides are compressed together and adjustable. I put one of these together a few months ago and I’ve already forgotten. I’d like to say that you can stick an Allen key in one side and turn a tire to increase plate pressure. If I’m thinking of one of my other cars then the worst case would be opening one side of a suspension arm in order to tighten the assembly from inside the diff cup. Most designers tried to avoid that maintenance hassle for the user so there’s likely a way to just jam one side up the side with the exposed cross pin head and then rotate the opposing tire (righty tighty).
 

The diff should feel smooth when it’s tightened down, but not slip like that so you can adjust in the field. Sometimes it’s recommended to bottom out (tighten all the way) the diff then back up a half turn as a starting point, though get it reasonably tight for starters as it’ll break in and lose a little bit of tension after a bit of running, then take a little bit of tightening. Some of your grease under the pressure plates will also have been squeezed out if you didn’t break in the diffs on the bench, so there’s naturally a touch too little pressure on the plates now. Should stay reliable for a good while when setup correctly. Nice model 😎

[sosidge]

Pressure in these diffs is set with the spring washers. Effectively they are not adjustable. The bolt should be fully tightened (take care not to overdo it as the pressure plates are aluminium and prone to stripping).

[Anthroxoid]

43 minutes ago, sosidge said:

Pressure in these diffs is set with the spring washers. Effectively they are not adjustable. The bolt should be fully tightened (take care not to overdo it as the pressure plates are aluminium and prone to stripping).

This motivated me to go grab a pdf of the manual. I’m guessing that the pressure washers were not stacked correctly. Please note that this stack of parts creates the spring tension for compressing the stack of plates on either side of the ball diff spur gear. It is also possible to over or under tighten part MA3 thus leaving the stack too loose or causing incessant wear on the plates via over tightening. In short, it’s adjustable:

 

Note the paragraph bottom right. There are a few ways to build these incorrectly.

 

[no1trancefan]

Hi guys, came back to it rebuilt the diffs from scratch.

 

I tried putting a 19t on the bz motor read somewhere it runs better. however, im still having massive issues, on of the gears is too big to fit in the gearbox, when it runs when suspsended in air, the wheels turn but as soon as it is on the ground i only have reverse. i must be doing something majorly wrong as ive rebuild this thing about 4 times now over months. ive uploaded some links which i hope may assist.  

Items Shared on 7-9-2024

 

I have redone the links above as one thanks