Scrumpy's madforce brushless conversion

[barnetbasher]

I really wanted to, but the spur is poking over the top of the chassis...and the chassis plate is so full of holes now and diff/motor mount screws in the way, it seemed logical the way I have done it (okay not very neat though!)

space the centre diff away from the motor plate...problem solvedededed...

 

i'll head out to the man cave in a bit and look at the shock stockpile !

[scrumpy jack]

space the centre diff away from the motor plate...problem solvedededed...

 

i'll head out to the man cave in a bit and look at the shock stockpile !

With all due respect Amigo..no way am I doing that! I would have to shim equal amounts under both motor mount and diff tower thing, also doing so will be adding more stuff to it that will shift and move about under power. I can live with the pinion poking above slightly (and it took ages to cut the hole  ) I could get the battery further back, just would have to raise it slightly so it misses the spur (about 5mm at most) This is what it's all about though, build, test, learn from mistakes, then re-fix and re-build and hope your eyebrows don't get burnt in the process!

[Tug]

I would definitely look at raising and moving the tray, that's a lot of weight up front.

[scrumpy jack]

I do  however have a nice big piece of 4mm ali sheet sitting under my motorcycle kickstand at the moment (gravel drive, use it so it won't fall over!) so tempted to cut a whole new motor plate from that...extend it possibly as well 

[scrumpy jack]

I would definitely look at raising and moving the tray, that's a lot of weight up front.

quite a bit of motor at the back though. okay I'm going to take it out and see what happens! will get some video. balance wise I only think it's a touch heavier over the front. It's a madforce anyway, ill be luck if it stays on the wheels!!!

best put the ESC back in  again then 

[barnetbasher]

Yeah..give it a run out....if it works...job done...any madforce is always going to be barn door stylee ! part of the charm !

[scrumpy jack]

It works! slight smell of burning electronics... I did big beans through a puddle mind,,, So I'm very impressed ! lame you tube film to follow...

[Tug]

At least you've bothered to film it, unlike some.

[barnetbasher]

oi !

[scrumpy jack]

sorry no video yet, my camera has died  Although I've run into a few teething problems, first one being when setting off from standstill the truck was making a terrible grinding noise and not moving until I gave it more throttle. I managed to trace the problem to the centre diff, I pulled it apart and discovered a few of the teeth on the spider gears were a little mashed and must of been skipping over the bevel gears. whilst I was at it I thought I would check out the front and rear diffs as well..ah now I thought I had put in extra savage spider gears, but alas theres only the standard 2 spider setup in both front and rear diff. I must of been thinking about an old savage I put gears in or I've gone bonkers   So I have just received a bunch of gears in the post to replace the centre diff gears and add the extra 2 spider gears in front and rear diffs. What oil should I bung in the diffs? baring in mind I can probably only afford 2 bottles of oil at the moment!  

[scrumpy jack]

Today I had a few bits come through the post from China. I got some lipo straps and a lipo checker/beeper thingy. I striped out all the diffs and installed the extra spider gears in the front and rear. I also replaced the knackard gears in the centre diff and filled it with 100,000 diff oil. I've not tested it under power yet, but the drive train sounds a lot smother just by pushing it forwards and backwards, hopefully that has sorted the issues out.

 

[scrumpy jack]

so after spending most of a day rebuilding diffs, it appears I still have a horrid grinding noise when setting off from a standstill  some thing is slipping somewhere...all new gears in centre diff and front and rear diffs re-built. At a loss now, I have been reading about 'cogging' with electric motors, wondering if its that? will stick a small pinion on and see if that does anything to help. I'm a bit stumped here lads, throw in some words of wisdom please!

[scrumpy jack]

Okay fitted a smaller pinion, its less pronounced but still grinds. Had a good look at what's happening- it appears the spur is spining yet not putting drive to the centre axles, which suggests to me the bevel gears are slipping...but I just put in a brand new set including the spider gears as well? 

[Tug]

Shims ahoy!

[scrumpy jack]

behind the bevel gears? I tried adding thicker shims to the spider gears, then the thing wouldn't turn at all!

Damn if thats the case, I think I've just rounded off a few more bevel gears 

[Tug]

Oopsie, where's barnetbasher when you need him.

[scrumpy jack]

Oopsie, where's barnetbasher when you need him.

funnily enough I'm just writing an e-mail to him  not that your second best Tug, and I think your probably right- there must be a bevel gear thats not engaging properly. Damn going to have to open it again, and I filled it with 100,000 oil....that stuffs like golden syrup!!! 

Edited March 6, 2014 by scrumpy jack

[scrumpy jack]

this problem only just happens when I add enough throttle to engage the motor, once it gets above a little more it will engage and and be fine...

[Nitroholic]

Are you using a Hyper 7 centre diff....

 

If so....I would guess the worst wear is on the spur gear end. I replaced the hyper gear there with one from a Savage. It's fractionally deeper, and takes up enough slack without gumming up the works

[scrumpy jack]

Are you using a Hyper 7 centre diff....

 

If so....I would guess the worst wear is on the spur gear end. I replaced the hyper gear there with one from a Savage. It's fractionally deeper, and takes up enough slack without gumming up the works

I'm using a trophy centre gear...but have replaced the whole internals with savage gears...have it apart now and there appears to be no wear on any of the gears at all?! very strange...

[scrumpy jack]

sounds odd, but I'm going to try it without the big blue gasket seal..savages don't have these and it's nearly 2mm thick...which could be causing the problem. will report back when I have it screwed back together!

[scrumpy jack]

okay bad plan..its impossible to move now!

[scrumpy jack]

re-built the centre diff..it's perfect, whatever the issues it's definably not this! 

[Mr. Doktor]

I need a video to examine the patient! It could be either the "cogging" or some internal shim issue.

What shims do you use?

I have just built a trophy CD with savage gears.

I used 1x 0,1 mm thick shim behind the front and rear bevel gear and 1x 0,5mm thick shim behind each of the smaller gears and it is just right. Actually almost too tight, but still OK.

Edited March 6, 2014 by Mr. Doktor

[scrumpy jack]

Ok Really gone to town on the mad force now and brought some much need new shocks-Hyper 7 ones to be precise. the mad force uses rear buggy size shocks (125mm) problem was I could never find to sets of rear shocks at the same time without paying silly money. I stumbled on an ebay seller who was selling 5 pairs of new rear bigbore hyper shocks for the princely sum of

Edited March 13, 2014 by scrumpy jack