RC10 four wheel drive project

[vsefiream]

I posted in the Jammin Jay four wheel drive prototype thread that I have a few ideas about how I plan to attempt a modern four wheel RC10 conversion.
If you are a collector, this won't be of much interest I'm sure. But if you like to bash and 4wd sounds like fun you might just be interested.
I have been kicking this idea around a little bit for various reasons after dabbling in 1/8 scale. I looked for an MIP kit and I about fell over when I heard the price. So I started poking around with spare parts I have from other vehicles, other brands and I think I have a basis to start with.
It will be a design similar to the MIP with a cogged belt driven off the stock diff to the front end. There will be a couple major differences. First I plan on using a single diff in the front without a gearbox. the reduction will be accomplished in the pulleys to match rear wheel speed. Secondly I plan on running the belt as low as possible and using two 1s Lipo packs in saddle configuration. The front end parts will be the big change. I only intend to use the stock RC10T front kick and the rest of the front suspension will be from a donor vehicle. The rims will ride on 12mm hex for a wide variety of choices.
I should have something to display in this thread in about two weeks. Once I do I am sure a number of people will catch on. If it proves durable and easy to setup I will share my parts list. If not, I will deny any of this ever happened
Overall this should be cheap and reliable, that's the goal.
I have chosen Christmas as my deadline.
I would love to hear opinions and ideas on execution. Pics of MIP kits/parts would be appreciated. Specificly the diff shaft.
Thanks guys!!

[tiger1]

looking forward to see this interesting vehicle!

[RC104ever]

I'm very intrigued - can't wait to see what you have in mind! I have to say I would love something that I can bash with my B44 based on a goldie.

[Phin]

Also looking forward to seeing what you've got planned.

I'm in the parts gathering stages of a WOIN 4wd build myself. My plan is to use a SC10 4x4 inner slipper hub (coupled) to run a belt off the the top shaft to a set of two pulleys towards the front of the car that will shift a second belt to the front diff or one way. Similar to how the Schumacher Cat SX2 is set up except with a gearbox in the rear instead of 3rd belt. I would like to go straight from the rear top shaft to the front axle but I don't know of an existing front axle that would be the right dimensions.

I'll be using a mid-engine oval conversion chassis as my base instead of a tub.

[vintage88]

Here are some pics ill post any pics u need of my car but i would like to know
More on this plan of yours

[vsefiream]

Just wanted to update this thread. I have been busy with ~8 cars I am trying to turn over on ebay to fund the 4wd project. They have been time consuming and burning up cash in their own right. I think my 12/25 deadline is not even remotely possible. However I have been working through ideas and researching some possibilties:

I have been kicking around the following ideas on drivetrain:

Belt: I have researched belts a lot mainly because of the MIP kit being "the" existing platform. I can put a belt drive together fairly easily, it's the front trans that is the tough part. A lot of currently produced cars use belt drive. Most of them use the same type of belt. Most use a central diff and belt driven diffs. Belt diffs are easy to come by without a trans of any sort. I am still trying to figure out if I can gear it down enough to eliminate a need for a front trans and just use a diff. Problem with this is as I try to gear down the front, the pulley size needs to increase. This makes for a larger front pulley/diff assembly in a car that has little room to begin with. Moving the front plate forward may help.

Mid motor: This is a very common setup on 1/8 nd some 1/10 4wd cars. I kind of like the idea of throwing two diffs, a mid mounted trans and dog bones or drive shafts in between. I think this has a lot of promise because of the available parts and simplicity Plus I can balance the weight a little better. I haven't spent as much time researching this option but on the other hand these parts are much easier to find.

Shaft: Like the Traxxas Slash and Stampede 4x4. I have not spent much time on this drivetrain but it's still on the back burner.

Optima: Crazy idea just because the parts are not easily or cheaply had. However I heard of this and thought I'd through it out for an honorable mention. I hear that some people have cut off the front section of the Kyosho Optima and replaced the RC10's front nose plate with the severed Optima front end. Sounds interesting but not too practical.

The hardest part of this conversion is the front suspension setup. My goal is to use cheap readily available parts ie Traxxas stuff. Traxxas parts are everywhere and RPM makes some good stuff. I have a Traxxas a-arm and steering setup that looks like it will work with a little modification.

I should have the beginings of a prototype comming together after Thanksgiving as parts are comming in the mail. I hope to have a picture or two in the next post.

If anybody is interested in collaberating on this project please feel free to contact me. I look forward to having some fun with this project!

[jwscab]

If I was tackling this (and have thought about it already) I would go with the following setup:

modify the stealth trans with an external shaft just like the MIP system. You can't run the front diff directly from the idler because it spinning in the wrong direction(you need another gear interface to change direction). Take a stealth case, and trim off the upper section so that it's just the diff and idler, and add another shaft just like the rear idler. pick a pulley you like and get two of them, the ratio is 1:1.

use a gold tub, and fab a custom nose plate to mount the stealth trans, and front arm mounts for an associated B44. Use B44 front cvd's/c-chubs/steering blocks, etc. Add whatever bulkheads and braces are necessary to get a shock tower mounted, and the nose reinforced. Maybe mold a small lexan or soda bottle cover for the hole in the front trans you can glue into place.

[vsefiream]

Thanks Jwscab. I'm glad you contributed, the counter rotation of the idler would have bit me for sure. I like the B44 parts idea. I have been stuck thinking traxxas parts just because my kids have a couple Traxas vehicles and I have a ton of spares. But The B44 parts are redily available, fairly priced and a great idea. The creidt will be yours if I go that route.

Thanks!

[Phin]

I think it's better to run a rear pulley off the top shaft rather than the idler as you can connect everything with belts and pulleys that spin in the same direction and are easier to space out properly. Gears in a transmission need to have the correct mesh making it a more complicated build.

Take a look at Georg Kotzinger's custom B4 4wd: http://www.oople.com/rc/photos/euros2010/day2/

He runs a pulley behind the slipper on the top shaft directly to a one-way up front. He makes enough room for the rear pulley by cutting off the part of the B4 case where the bearing is installed. With the old stealth case you can either try to fit a pulley between the motor plate and trans case with longer spacers or go the route the SC10 4x4 does and mount the motor plate flush to the stealth case using really short spacers.

I've considered a few ways to mount a pulley to the back of a slipper. The first is to use an SC10 4x4 coupled slipper on a B4 top shaft. The non-coupled SC10 4x4 slipper probably won't work since it's made for a metric sized top shaft. The other method is to use a pulley that's held on by a drive pin and drill a hole in the top shaft for the pin. There's several pulleys you can use from other cars that are set up with a slot for a pin.

If the coupled slipper works you can use the SC10's pulleys but you would have to put a center shaft up towards the front of the car that has a front SC10 4x4 pulley to connect to the rear trans and a smaller pulley that connects to the front diff or one-way. The front and rear SC10 pulleys would have a 1:1 ratio or be used for overdrive, while the inner front pulley and the front axle pulley would match the FDR of the rear transmission. The inner pulley can be positioned where it needs to be on the center shaft to align with the front axle so it makes finding an axle that works a little easier.

If you use a pinned pulley you can either use a center shaft like you would with the SC10 pulleys or you can try to find a front axle that's the right length to run a belt directly to it from the rear top shaft. Finding one a front axle like that is going to be tricky though. I have a one-way on order that I'm hoping will work (and was cheap enough to take a shot at) but if it doesn't I'll be going for a center shaft.

For a 2.25 trans you can go for a 12t center pulley and a 27t front axle pulley or a 16t center pulley and a 36t front axle pulley. The 16t/36t combo is nice because there's several options to choose from (Tamiya, 3racing, Hot Bodies/HPI) but the 12t/27t combo uses smaller diameter pulleys and should be a little easier to fit in the front.

I don't know what the pitch is of the SC10 belts but most touring cars use 3mm belts. That only really makes finding the right pulleys easier though. Belts will probably have to be custom ordered.

Haven't picked up B44 castor blocks to try mounting them onto RC10 arms yet....hoping they fit and don't push out the front track out wider than is legal.

Once I have the front axle and steering knuckles figured out I'll start looking for CVDs/Unis.

[Phin]

One more thing....I still hold that the easiest way to build a 4wd RC10 is to recreate a TM belt drive transmission in the rear and a TM direct drive trans in the front using modern diffs/pulleys from a touring car. Simple CF or Alum. plates connected to the chassis with L brackets that sit under the front and rear arm mounts.

The suggestions I mentioned in the above post are just what I've been thinking about building.

Edit: TPS should've been Track Master.

[GoMachV]

If going mid motor, a rc10gt gearbox has enough room for a hex adapter to a brake disk between the slipper and case, remove that and there is room for a pulley

If going off a stock stealth box, going off the top shaft makes a lot of sense as it will keep the modifying to a minimum. It is also less efficient.

So now is a good time to come up with a game plan. Here are some things "I" would consider. First, who is buying this? Do they want a nostolgic representation of a 4wd rc10? Something that "could have been"? Handmade parts instead of B44 parts will be expensive but era correct.

Truly, if you want a 4wd rc10 you probably want it for the retro aspect, but using traxxas parts kills that. If you go B44 parts your better off just buying a B44 as you won't compete with its efficiency and design. Rc10's aren't really "cheap" so you probably wouldn't convert one because its cheaper than a B44.

Not trying to be a downer, just making sure you have an idea of your audience and a direction for the design.

I'm in the planning/drawing stages of an era correct 6 gear version. It will not be efficient and it will not be pretty.....but that's how the conversions were bitd.

[jwscab]

the original poster said he wanted to build a modern 4wd rc10, ergo my suggestions. If you really want 4wd, you can just buy a B44, but I think this is more of a 'I can do this' type of build. 4wd conversions are a compromise at best, and it boggles the mind that the MIP kit is really worth as much as it is. Truly it's just a nostalgia based demand. As I've said before, for the price you pay for an MIP kit, you could easily have someone machine up the relative simple parts that can't be substituted with a modern equivalent, ie, the diff parts and front trans case.

[vsefiream]

As I've said before, for the price you pay for an MIP kit, you could easily have someone machine up the relative simple parts that can't be substituted with a modern equivalent, ie, the diff parts and front trans case.

I guess the target audience/market is myself and anybody else interested along the way. I'm doing this simply because I enjoy vintage RC10's but really like 4wd after owning a Stampede 4wd and an Ofna 9.5. I cannot be the only one as it's been done and is still being talked about.
I think if anybody else is interested in this kit it will be for bashing/racing. I'm not concerned with era correctness but more so on parts availability so anybody can go out and easily reproduce this. I do like the idea of keeping the car all associated but I'm not against using any other manufacturers parts.
Durability is my primary goal as it's going to be jumped/crashed etc. I would love it to be as efficient as a modern car but that will remain to be seen.
I had thought about making a simple belt trans similar to the trackmaster. It wouldn't be all that difficult and it would give the project a little more flexability. It's just not readily available. However that doesn't mean something easily fabricated would be ruled out. The 3mm high grip style belts and pulleys are available through various places like robot parts shops etc. Pulleys and belts are available in a wide range of sizes as well as RC specific parts like a pulley diff.
Great ideas guys please keep them comming. I have ordered a b44 front bulkhead to test that out, pics when it arrives.

Thanks for the link Phin, any conversion info is appreciated.

Everybody please continue to contribute ideas as this will keep the project moving forward with less hiccups and expensive mistakes.

[GoMachV]

If your target then is bashing and general having fun action, you need to keep in mind that rc10 stealth parts have become harder to find recently, so using them will end up costing more in the build. This is where traxxas is your friend, as well as anything you could scab from newer associated cars.

Like I said, just trying to make sure you are thinking about these things. Working in a high performance shop has taught me that people rarely plan properly and it ends up both costing more and with a compromise at the end when the goals are not set in the beginning. Since you have a goal, you are going down the right path.

That link that phin posted with the 4wd B4 is damn cool!

[Phin]

... As I've said before, for the price you pay for an MIP kit, you could easily have someone machine up the relative simple parts that can't be substituted with a modern equivalent, ie, the diff parts and front trans case.

I've said the same myself but to extend on the substitution of modern equivalent parts...if I can find a part that exists for a modern car that is essentially designed the same as a part that I could've found or had machined back in the day, then I see no problem using that modern part.

Pulleys, belts, diffs, one-ways are all things that were available in the '90s and design-wise are no different than parts made today.

And using CVDs, arm mounts, and steering parts from a B44 is no different from what RC10 owners have to do to run modern wheels.