Outcast 8s Outcast/Kraton Differential Shims?

[djrahbee]

I'm looking for something like the shim kits for the 6s models. The 6s kit thick shims that go under the sun gear work great! I've been stripping gears in the last 3 8s diffs I rebuilt. Nothing I have will fit over the drive cup shaft. When the 6s diffs are shimmed properly the outdrive cup shaft sits perfectly flush with the top of the sun gear. I noticed after rebuilding the 8s diffs that wasn't the case. Tried thicker fluid too btw.

Any 8s guys have suggestions?? I can use my calipers and find something online but hoping there was a "go to" fix.

 

[Hammer Down]

what diff cups are you using?

 

[djrahbee]

what diff cups are you using?

I went to vitavon cups and the shimming and spacing with the gears is slightly different. I burnt through a brand new set of their "hardened" steel gears.

I went to vitavon cups and the shimming and spacing with the gears is slightly different. I burnt through a brand new set of their "hardened" steel gears.

Also I forgot to mention that the vitavon gears don't have those square notchy things on the sun gears...? I can take a pic if needed.

 

[Hammer Down]

Maybe contact vitavon since it’s their stuff that’s out of tolerance.
The only time I blasted the guts was due to my stock cups exploding or screws sheering off the metal arrma cups. Otherwise they held up great. I don’t have an hands on experience with the Vitavon ones though. Sorry

 

[djrahbee]

Maybe contact vitavon since it’s their stuff that’s out of tolerance.
The only time I blasted the guts was due to my stock cups exploding or screws sheering off the metal arrma cups. Otherwise they held up great. I don’t have an hands on experience with the Vitavon ones though. Sorry

It's all good any feedback is helpful. I haven't had a chance to pull it apart this time but the rear diff was grinding bad. Maybe...the loctite didn't hold and the screws on the diff backed out The stock diffs on my OC were bullet proof until recently. I previously blew apart the stocker diff cup on the K8 which is why I had the vitavon ones on hand. I hate diff struggles!

I hesitate to mention this but here it goes. I have the punch turned all the way up but think I have good trigger control and I'm not just straight gunning. But it seems like the diff issues arose after I turned the punch up. I like the punch up for more air control.

 

[SrC]

Be more conservative with Punch. How I fly with most of my RC's
You answered your question I think.

 

[djrahbee]

Be more conservative with Punch. How I fly with most of my RC's
You answered your question I think

All my rigs are turnt up, it's the only one giving me problems. But it also has the heaviest tires
The 8s rigs are a different beast fo sho!

 

[Hammer Down]

Also I forgot to mention that the vitavon gears don't have those square notchy things on the sun gears...? I can take a pic if needed.

Idk what purpose they serve… The Vitavon’s don’t have them?

 

[djrahbee]

View attachment 300793
Idk what purpose they serve… The Vitavon’s don’t have them?

Correct. Not sure either. Maybe to help move the fluid around??

 

[Hammer Down]

You have a pic of the ground beef? Just curious what they look like.

 

[djrahbee]

You have a pic of the ground beef? Just curious what they look like.

These are the vitavons, new vs not. I think I put stock gears back into a vitvon case this last time. But haven't opened it yet. Was too bummed this evening to mess with it.

 

[Hammer Down]

Are the satellite gears chewed up too?

 

[djrahbee]

Are the planetary gears chewed up too?

Not like that. You can feel burs on the ends of the teeth though and at that point think they're no good. I think if it's shimmed better it'll fix it.

 

[Hammer Down]

You think they’re too loose? Like the satellite gears aren’t engaging the sun gears enough? You thinking of adding a shim behind the sun gear?

You probably don’t have one of each (vitavon set, and stock set) to assemble dry and compare play/backlash on the out drives. That’s the only way I can think of off the top of my head to help diagnose the issue.

 

[djrahbee]

You probably don’t have one of each

Nah but thinking about getting a stock take off diff from ebay and experimenting. I just want some shim options first. I'll probably just have to figure something else out. Unless some other 8s guys see this later. Thanks for the help!
I'm about to hit the sack

You think they’re too loose? Like the planetary gears aren’t engaging the sun gears enough? You thinking of adding a shim behind the sun gear?

Yes!

 

[Hammer Down]

Nah but thinking about getting a stock take off diff from ebay and experimenting. I just want some shim options first. I'll probably just have to figure something else out. Unless some other 8s guys see this later. Thanks for the help!
I'm about to hit the sack

Yes!

Best of luck Homie! It’s tough being a pioneer in this type of destruction.

I’ll be watching to see what you come up with.

 

[djsarma]

Vitavon just released some shims for under the sun gear. Same thickness as stock at 0.5mm but they are much wider to support the full area of the gear. I used these with the vitavon v2 diff cup and stock arrma internal gears and the mesh is perfect. I can just slightly feel each tooth engage when its all buttoned up so its on the tighter side but still smooth.

I also had the vitavon hardened steel internal sun and crown gears and they locked up the diff once it was put together, yours seem too loose so it seems theres a large variance in their tolerance. At one point i used the vitavon suns with the stock crowns as i though it was an upgrade, it worked fine but the vitavons wore down vs 0 wear on the stockers in just a few packs.

https://www.ebay.com/itm/2851765584...n821lq6tdk&var=&widget_ver=artemis&media=COPY

 

[djrahbee]

Vitavon just released some shims for under the sun gear

Wow...I'm glad you saw this! You know what's strange, I hit up vitavon and asked about the gears stripping easily, if there was a solution, and they just apologized and sent me a new set of gears. I think there is huge language barrier. I'll email them and ask them to send some shims. A dollar is nothing but the 2 weeks shipping sucks! Any chance there's a place in the states that would have these shuims??

Thanks for the info!

 

[djsarma]

The only vitavon suppliers here in the US i know of are rcjuice and exocagedrc, i checked and they don't have them unfortunately.