Scorpion 4x4 Build project
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Scorpion 4x4 Build project
As the title suggests this is a build project of a Kyosho Scorpion conversion to 4 wheel drive .
Aims
1 period possible with 1980's tech/parts
2 to keep it looking like a Scorpion cosmetically
3 to be functional ,not a shelf Queen
The plan is to use chain drive from the rear to the front , Optima front steering hubs and a front diff .
I've started by making a replacement for the front steering hub king pin , as standard the king pin passes through the steering hub but if fitting a driven hub I had to think of an alternative system . My solution is to have a king pin under the hub that passes through twin flanged bearings fitted it the pin that passes through the front suspension arm , I'll post up pictures tomorrow as it's way easier that way .
The first issue I've come across is that with a wheel fitted to test it's increased the front track to make the front wheel 10mm wider both sides than the back so I'm going to have to find ways to bring it in again , I think I can move each wheel 6mm inward so I've got another 4mm to go .
Here's pictures of the king pin arrangement and Optima steering hub installed .
this is a comparison of the stock steering hub and king pin next to the Optima hub and king pin .
hub installed
and view from front showing increased track .
there's surprisingly little slop ,at least comparable if not better than the stock king pin setup , hopefully the tiny flanged bearings don't wear out too quickly.
Aims
1 period possible with 1980's tech/parts
2 to keep it looking like a Scorpion cosmetically
3 to be functional ,not a shelf Queen
The plan is to use chain drive from the rear to the front , Optima front steering hubs and a front diff .
I've started by making a replacement for the front steering hub king pin , as standard the king pin passes through the steering hub but if fitting a driven hub I had to think of an alternative system . My solution is to have a king pin under the hub that passes through twin flanged bearings fitted it the pin that passes through the front suspension arm , I'll post up pictures tomorrow as it's way easier that way .
The first issue I've come across is that with a wheel fitted to test it's increased the front track to make the front wheel 10mm wider both sides than the back so I'm going to have to find ways to bring it in again , I think I can move each wheel 6mm inward so I've got another 4mm to go .
Here's pictures of the king pin arrangement and Optima steering hub installed .
this is a comparison of the stock steering hub and king pin next to the Optima hub and king pin .
hub installed
and view from front showing increased track .
there's surprisingly little slop ,at least comparable if not better than the stock king pin setup , hopefully the tiny flanged bearings don't wear out too quickly.
If a jobs not worth doing then its certainly not worth doing well.
A problem shared is a problem halved but an advantage shared is no advantage at all.
A problem shared is a problem halved but an advantage shared is no advantage at all.
- 1300GT
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Re: Scorpion 4x4 Build project
Off to a great start. That's a neat way to overcome the kingpin hub problem.
Are the front stub axles and 12mm hexes from the rere Scorpion?
If you don't mind a suggestion, to narrow the front track you could use Kyosho OT18 stub axles and corresponding 12mm hexes or the modern rere equivalent. You'd also need four 5x10 bearings. That's if you're going to run those wheels on the front. That'd bring the wheels back towards the centreline of the car a bit.
If you've already worked out a cure then ignore the above.
Are the front stub axles and 12mm hexes from the rere Scorpion?
If you don't mind a suggestion, to narrow the front track you could use Kyosho OT18 stub axles and corresponding 12mm hexes or the modern rere equivalent. You'd also need four 5x10 bearings. That's if you're going to run those wheels on the front. That'd bring the wheels back towards the centreline of the car a bit.
If you've already worked out a cure then ignore the above.
Chris.
Toys.............they are!
Toys.............they are!
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Re: Scorpion 4x4 Build project
Thanks I'll look up the parts you mentioned ,the hex wheel adapters were just laying around so I fitted them ,they are the re re ones ,I'd rather use the Scorpion rear tyres all round like you did on your SRB build but the offset would make the track even worse , ideally I'll shorten the front suspension hanger bar and bring the arms inward ,I'd rather not have to elongate the drive shafts but that alone won't be enough . I have another front suspension hanger bar that I'm going to mill a flat onto in the middle then cut in half ,make up a sleeve with grub screw's to re connect the two parts and make it adjustable in length , it's an old mod that was originally intended to increase the track but I'll do the reverse , the limiting factor being the shocks .
I can also bring the king pins in toward the suspension arms by 1.5mm , a little here a little there and I'm sure I can work it out .
I can also bring the king pins in toward the suspension arms by 1.5mm , a little here a little there and I'm sure I can work it out .
If a jobs not worth doing then its certainly not worth doing well.
A problem shared is a problem halved but an advantage shared is no advantage at all.
A problem shared is a problem halved but an advantage shared is no advantage at all.
- Mr. ED
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Re: Scorpion 4x4 Build project
http://www.rc10talk.com/viewtopic.php?f=48&t=5973
I did a similar thing to my ghost-rider front end to mount wheels with hexes in 2008. But your finish is way better with the bearings, and I never went 4wd.
Have fun with the project!
I did a similar thing to my ghost-rider front end to mount wheels with hexes in 2008. But your finish is way better with the bearings, and I never went 4wd.
Have fun with the project!
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Re: Scorpion 4x4 Build project
Ill have to have a look at your ghost rider ,thanks for the link.
Just made the new adjustable front suspension hanger , at the moment the servo saver fouls on the joining sleeve but that's kind of a mute point as it won't be there when I'm done as the front gearbox will be there ,I also modified the king pins to bring them in a bit ,overall it's about 5 or 6 mm narrower ,I've ordered the Optima front axles that 1300GT recommended as well to have a play with along with the stock rear drive washers . Sorry about the photo quality ,kids are on the PC so I can't use the digital camera and download decent pictures ,these were done from my tablet but you get the idea.
Just made the new adjustable front suspension hanger , at the moment the servo saver fouls on the joining sleeve but that's kind of a mute point as it won't be there when I'm done as the front gearbox will be there ,I also modified the king pins to bring them in a bit ,overall it's about 5 or 6 mm narrower ,I've ordered the Optima front axles that 1300GT recommended as well to have a play with along with the stock rear drive washers . Sorry about the photo quality ,kids are on the PC so I can't use the digital camera and download decent pictures ,these were done from my tablet but you get the idea.
If a jobs not worth doing then its certainly not worth doing well.
A problem shared is a problem halved but an advantage shared is no advantage at all.
A problem shared is a problem halved but an advantage shared is no advantage at all.
- Coelacanth
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Re: Scorpion 4x4 Build project
You've probably considered this, but since it looks like your front & rear tires are different diameter, with a 4WD, you'll want to make sure you're running same-size front & rear tires or you'll potentially have issues with your drivetrain gearing and/or diffs.
This is a very intriguing build so far, definitely not an easy project. Good work!
This is a very intriguing build so far, definitely not an easy project. Good work!
Completed projects: CYANide Onroad Optima | Zebra Gold Optima | Barney Optima | OptiMutt RWD Mid
Gallery - Coel's Stalls: Marui Galaxy & Shogun Resto-Mods | FrankenBuff AYK Buffalo | 1987 Buick GNX RC12L3
Gallery - Coel's Stalls: Marui Galaxy & Shogun Resto-Mods | FrankenBuff AYK Buffalo | 1987 Buick GNX RC12L3
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Re: Scorpion 4x4 Build project
Oh yes absolutely it will need matching diameter wheels front and rear , I just fitted those wheels up front to check the fit etc , there's no way I'm fitting modern yellow wheels up front and nice classic wheels at the rear ,Yuck ! Ideally I want to fit the Scorpion rear tyres and wheels all round or at the very least a more period correct looking wheel and tyre .Coelacanth wrote: ↑Mon Feb 13, 2017 10:42 am You've probably considered this, but since it looks like your front & rear tires are different diameter, with a 4WD, you'll want to make sure you're running same-size front & rear tires or you'll potentially have issues with your drivetrain gearing and/or diffs.
This is a very intriguing build so far, definitely not an easy project. Good work!
I want this to look like it came from the 1980's ideally not like a re re made race ready in 2017 , I'm having an argument with myself about the brushless motor that's currently fitted , I hate brushed motors but this will look wrong with a brushless motor .....
If a jobs not worth doing then its certainly not worth doing well.
A problem shared is a problem halved but an advantage shared is no advantage at all.
A problem shared is a problem halved but an advantage shared is no advantage at all.
- Mr. ED
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Re: Scorpion 4x4 Build project
Solution: Put one of those good old rubber covers over the moter. The only give-away will be that third wire... Oh, and perhaps the esc and receiver being several times smaller.
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Re: Scorpion 4x4 Build project
That's not a bad idea at all ,thanks , I'm not really too worried how it looks under the body , just externally .
While I'm waiting on the next batch of parts that hopefully bring the track in a bit I'll explain my transmition ideas .
Now much as 1300GT did I'll extend the axle for the gear that drives the diff , on the Scorpion that's the same axle as the slipper , I'll make an extended axle that I can fit a sprocket on for the chain , the front will have a gearbox again just like 1300GT,'s build with a diff gear and counter gear .
As mentioned at the beginning I want to keep it looking like a Scorpion and this leaves me with a problem , the battery is inline with where ideally the chain would go as is the steering servo , the servo can easily be transplanted to the right hand side of the tub where the servo would have been for a mechanical speed controller so that's nice and easy , the battery is more difficult , I have a choice of either going up and over or further to the left and have the chain run above the chassis rail and next to the battery , I'm kind of leaning toward the latter , moving the chain further left is not cosmetically as nice but it a lot easier to do .
While I'm waiting on the next batch of parts that hopefully bring the track in a bit I'll explain my transmition ideas .
Now much as 1300GT did I'll extend the axle for the gear that drives the diff , on the Scorpion that's the same axle as the slipper , I'll make an extended axle that I can fit a sprocket on for the chain , the front will have a gearbox again just like 1300GT,'s build with a diff gear and counter gear .
As mentioned at the beginning I want to keep it looking like a Scorpion and this leaves me with a problem , the battery is inline with where ideally the chain would go as is the steering servo , the servo can easily be transplanted to the right hand side of the tub where the servo would have been for a mechanical speed controller so that's nice and easy , the battery is more difficult , I have a choice of either going up and over or further to the left and have the chain run above the chassis rail and next to the battery , I'm kind of leaning toward the latter , moving the chain further left is not cosmetically as nice but it a lot easier to do .
If a jobs not worth doing then its certainly not worth doing well.
A problem shared is a problem halved but an advantage shared is no advantage at all.
A problem shared is a problem halved but an advantage shared is no advantage at all.
- Mr. ED
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Re: Scorpion 4x4 Build project
Would one of these low cg packs create enough clearance?
Or, maybe you can twist the battery? I mean keep it in the length, but have it resting on it's side instead of bottom.
Or, maybe you can twist the battery? I mean keep it in the length, but have it resting on it's side instead of bottom.
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Re: Scorpion 4x4 Build project
There's quite a few battery options that would help , the 2200 soft shell lipo's are lower and shorter , as it's fully enclosed it does not have to be a hard shell battery so long as the chain is kept well clear .
The advantage of running the chain over the chassis rail is that there's already a space for it in the tub and only the ends of the tub need cutting , running it over or through the battery compartment means considerably more chopping .
The advantage of running the chain over the chassis rail is that there's already a space for it in the tub and only the ends of the tub need cutting , running it over or through the battery compartment means considerably more chopping .
If a jobs not worth doing then its certainly not worth doing well.
A problem shared is a problem halved but an advantage shared is no advantage at all.
A problem shared is a problem halved but an advantage shared is no advantage at all.
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Re: Scorpion 4x4 Build project
I found time to modify the Optima front axles that arrived so they can take a standard 12mm hex ,fitted them and now the front track is 2 or 3 mm narrower than the rear YAY !
If a jobs not worth doing then its certainly not worth doing well.
A problem shared is a problem halved but an advantage shared is no advantage at all.
A problem shared is a problem halved but an advantage shared is no advantage at all.
- klavy69
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Re: Scorpion 4x4 Build project
thats lookin really nice! The front trackwidth was really throwing me off earlier in the thread so good to hear about the new offset
Todd
Todd
Peace and professionlism.....Kabunga signing off!!!
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Re: Scorpion 4x4 Build project
There's likely to be a number of minor issues to overcome during the build , I tend to leave them in the thread , it's a warts and all approach to how it's done , plus if you mention the problem then you get useful suggestions from other forum members , try not to let it put you off until I say it's finished , I'm hoping it terms out well but as Mythbusters always say "failure is always an option" .
One thing I'm not happy about is that it looks like I'm going to have to abandon using the stock rear wheels all round but use modern 2.2inch wheels , the steering hubs just clear with modern wheels but not with the stock rears ,I'll just have to find some nice looking 2.2inch modern wheels and tyres .
One thing I'm not happy about is that it looks like I'm going to have to abandon using the stock rear wheels all round but use modern 2.2inch wheels , the steering hubs just clear with modern wheels but not with the stock rears ,I'll just have to find some nice looking 2.2inch modern wheels and tyres .
If a jobs not worth doing then its certainly not worth doing well.
A problem shared is a problem halved but an advantage shared is no advantage at all.
A problem shared is a problem halved but an advantage shared is no advantage at all.
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