RC10Talk - The Net's Largest Vintage R/C Community

I’ve been working on this for a while and think I’ve hit upon a design that will work.

I want to replace the original Stealth transmission’s ball differential with a B4 (5,6) style gear diff to remedy the outdrive availability problem and to reduce or eliminate the need for frequent transmission maintenance.

The goal was to incorporate a B4 style 52 tooth diff with a Stealth transmission while retaining as many Stealth parts as possible, minimizing the extent of modifications to original parts and make something that looks similar to the original transmission. I’ll be running the B4 gear diff but I reckon these cases should accommodate the 52t ball diff as well (assuming the bearing sizes are the same).
The only modification that is necessary is to the motor plate; the rear lower trans screw must be relocated higher to clear the larger diff gear. The assembled transmission is 2.7mm taller than the original so a spacer block is needed between the top of the bulkhead and the trans brace plate. The motor plate sits higher and is rotated slightly (3.1 degrees actually) so that the rear chassis screw holes will align. This means that the motor will reside about 1.8mm higher in the chassis; not ideal but holding the motor and plate to their original locations would have required the idler gear be shifted even farther forward and the relocation of other motor plate screws and I wanted to minimize the number of modifications to original parts.
Before sending these cases off to Shapeways for printing, the plan is to make some functional prototypes to confirm gear mesh and screw hole locations and to perform some running tests. I can machine these cases in the shop from some blocks of PVC that I have lying around. I’ve used this material for a variety of projects including a transfer case for one of the crawlers and it seems to be holding up fine so far.
Feedback, comments, critiques, etc. are always welcome. Please let me know what you think about this?

Looks great to me! I still need to order a third test from
Shaoeways to get the holes the right diameter. You did exactly what I did- rotate the motor plate and raise the brace. One thing I struggled with was the motor plate holes since mine used all b6 driver train. I ended up screwing the motor plate to the right side case half and used separate screws to hold the case together.

Sorry Jeff, I didn't know... was this posted somewhere? I remember the very slick 3-gear in a 6-gear case you did a while back but I wasn't aware that you've done the 52t diff gear swap.
And you've gotten the left side slipper adjustment - I was thinking about that as well. I have no clue what B6 drive train looks like so I need to do some research on that. Are you using a 26t idler gear?

Well, at the very least you've confirmed that idea isn't crazy. Thank you.

I’m glad to see someone else doing this- I don’t have the time and it’s something that would sell for sure. I don’t recall the idler teeth but it’s all b6. I did a couple different setups, and also modded them in case we wanted to run 4wd. I just never got around to finishing any of it. I don’t think I posted it anywhere on here. One thing you might consider is making hubs like I did that bolt on and use b6 axles and wheels. They have to be pretty chunky for those big bearings. Then you have an all-b6 drivetrain

Attached a few pics. Some were just for fun- like the one with the windows so I can see the gear mesh

That's great info, thanks for posting Jeff.
That's also a great suggestion regarding the hub mods to accommodate B6 axles. I will definitely move ahead with that one as well but right now I just want to focus on the gear diff mod because I'm tired of rebuilding ball diffs every dozen runs.

I nearly forgot the main reason for raising the motor plate. With a larger diff gear, this also raises the outdrives and this will cause interference with the motor plate if it isn't raised accordingly.

That printed trans case with windows is pretty clever. How about printing an entirely transparent case? Wouldn't that be cool!!

Before I send these case halves to Shapeways, could you please provide some advice on getting the bearing bore sizes right? Do they tend to shrink by some known percentage on Shapeways' prints? Otherwise, I've considered modeling a simple test plate to send to Shapeways with a range of bearing bore sizes in order to establish the shrinkage. Any help here would be greatly appreciated. Thanks again.

Funny you mention that about making a gauge to have printed- that was exactly my thought as I’m tired of spending a month of waiting and $25-35 on failed prints. Mine have ended up loose in the bore, but I’ll have to find the case and measure it to be sure how far. The last one was probably usable but well oversized compared to my home prints. I’ll let you know when I dig it up. This highly probable move to Idaho is going to get in the way

GoMachV wrote: ↑Mon Sep 07, 2020 12:53 am ........This highly probable move to Idaho is going to get in the way

Moving sux the big one. At least the physical moving all your junk part of it. Hopefully none of your cool stuff gets lost or damaged. You seem to have alot of cool stuff. I think everyone here has alot of cool stuff though.

Keep going with this. There will be a good demand for something like this for sure. Especially if you can offer the case so that someone could spend less money than what it costs for two aftermarket stealth outdrives to get a modern gear diff.

If anyone is willing to share the files I can get willspeed to produce these in cnc ali

GoMachV wrote: ↑Mon Sep 07, 2020 12:53 am Funny you mention that about making a gauge to have printed- that was exactly my thought as I’m tired of spending a month of waiting and $25-35 on failed prints. Mine have ended up loose in the bore, but I’ll have to find the case and measure it to be sure how far. The last one was probably usable but well oversized compared to my home prints. I’ll let you know when I dig it up. This highly probable move to Idaho is going to get in the way

No worries Jeff. I understand the move comes first.
I've gone back to you're earlier post where you've indicated that you were working to get those hole sizes correct. Sorry I missed that the first time.
Anyway, I'll move ahead with a test gauge print and report the findings here and hopefully this will save everyone's time and money with future projects. I'll probably order the test print in the standard nylon and alternate materials since shrinkage could vary with other types of plastic.
Thanks for taking time to post your info. This has been extremely helpful!

Doug

Now this is one really sweet project!
All the benefits of the B6 style trans without having to cobble the goldpans chassis.
Very clever indeed.

Chuck

radioactivity wrote: ↑Mon Sep 07, 2020 11:37 am Doug

Now this is one really sweet project!
All the benefits of the B6 style trans without having to cobble the goldpans chassis.
Very clever indeed.

Chuck

Thank you Chuck however the accolades should go to Jeff since it's his design that uses B6 internals.
For my part, I just want a Stealth case that will accommodate my B4 gear diff. If it happens to accept B6 internals then that's just an added benefit.
As I've indicated before, I have zero interest in the commercial side of the hobby. I'll support Jeff any way I can but this is his baby to sell.
I've posted my work here hoping to gain some technical feedback from the very knowledgeable members here such as yourself.

Headling wrote: ↑Mon Sep 07, 2020 8:44 am If anyone is willing to share the files I can get willspeed to produce these in cnc ali

Thank you for that link. I'll keep Willspeed in mind for some other RC related projects.
For what it's worth, I can't speak for Jeff but I'm really not interested in an aluminum Stealth case for this project. Although aluminum would be superior to printed nylon in just about every respect, I really want my case to resemble the original as much as possible. I've even considered painting or dying the 3d prints to closely match the color of AE's molded nylon. Yeah, it seems a little crazy but it's what I want.
But thank you again for the link, I'll likely reach out to them on another project soon.

Ok fair enough Doug, I’ve got Will looking at a stealth with B6 parts and layshaft etc but won’t be an overnight project as he is busy with his day job