Scorpion 4x4 Build project

[Dadio]

Front gearbox mounting milled out , just off the mill so its not all prettyfied yet.

[Mr. ED]

What's that black cylinder in the center of the hinge bar for?

[Dadio]

What's that black cylinder in the center of the hinge bar for?

Because the front track was too wide i shortened the hinge bar by first milling a flat on the middle of the bar ,then cutting it in the middle and shortening the bar , the cylinder is a sleeve with two grub screws to re connect the bar at exactly the same alignment , I've seen a similar old school mod done to increase the front track so it's not my idea or out of place .

[rccars4sal]

Thats looking very nice! I always wanted to do the same thing, but never even tried. Your solutions are top notch and seem like they should work great.

[Dadio]

Thanks , next i have to shoehorn some steering in there , should be interesting .I'm really pleased that so far the body sits in place without issue , as i said before its got to look like a scorpion when its finished or it will be turned back to a 2wd .

[Mr. ED]

What's that black cylinder in the center of the hinge bar for?

Because the front track was too wide i shortened the hinge bar by first milling a flat on the middle of the bar ,then cutting it in the middle and shortening the bar , the cylinder is a sleeve with two grub screws to re connect the bar at exactly the same alignment , I've seen a similar old school mod done to increase the front track so it's not my idea or out of place .

I see. I did more or less the same not too long ago: Turning a diff into a solid axle.

[Dadio]

I may have run into a glitch , i just extended one drive shaft and test fitted it , now because the steering hub is forward of the diff out drive cup when the suspension is compressed it bottoms out the shaft in the diff out drive and the hub axle cup , in order to have the shaft short enough not to bind up it is not very far in when the suspension is extended .
The ideal solution in a to move the gearbox forward but there's not much further i can get it , maybe 1-2mm at most and then it starts to protrude under the front of the chassis , next choice would be to redesign the king pins so they bring the hubs back but that could cause odd effects on the geometry .
Third choice is to deepen the diff out drive cups a few millimeters and use the spring in the cup method to push the shaft into the hub axle cup more , i think this is going to be my first choice to try , i could just live with the issue and limit the steering angle but i think the spring solution should be enough .

[Mr. ED]

Sliding axles?

[Dadio]

I'm not sure I'd have space for sliding axles, there's very little clearance of the shock and shock tower ,I'd rather not use cvj's as they are too modern ...... I remember my old hotshot was forever spitting out front drive shafts so maybe it's a good vintage problem and shows how well I've made a true vintage design

[Phin]

Have you considered making new chassis rails that lower the kick-up and extend the wheelbase? Both would free up room in front of the tub. Lowering the kick-up would shift the front suspension beam down and forward and might allow you to flip your transmission case around. Also, as the front arms would become more parallel to the ground, the front shocks could be stood up to be more vertical...which would increase clearance for the front drive shafts.

[Dadio]

Changing the kick angle and extending the chassis are interesting idea's but i do want it to look visibly like a Scorpion , i think I'd rather build a new gearbox and move the screw from the front bottom corner so the gearbox could more closely follow the profile of the diff ,this would allow the gearbox to move 3-4mm forward , more imediatly I've decided to make a new pair of king pins that are off set and move the wheels 3-4mm backwards , I'm hoping it won't make any visible impact or any wierd geometry problems .

[Dadio]

I started making the offset king pins today , I've done the lath work cutting the shaft that goes through the lower suspension arm and the thread on the end .
Tomorrow I'll get them on the mill and finish them off , I'm aiming to get 3mm offset and move the axle back 3mm , this will mean the axle is in front of the diff with the suspension extended and behind the diff with full compression rather than parallel at full compression and forward at full extension , hope that makes sense .

[Dadio]

After experimenting with the drive shaft length I've redesigned the king pins to have an offset moving the wheel back 3mm , this gives the correct end float with the driveshaft .The new kingpin is at the top of the first picture.

[Mr. ED]

Dude, you're skilled and well equiped ...
Ok, that sounds dubious. Take it the right way please.

[Dadio]

I was lucky enough to be able to afford a basic lath/mill combination machine a few years ago , not a CNC machine but a by eye and by hand machine , some people loose hours on computer games , i lose hours on my mill or lath , it's fine for making a couple of pieces but it's no quicker to make the second than the first so it's no good for doing a production run of parts , mostly i make WW2 replica custom airsoft guns but as I'm into cars again it gives me more flexibility to make stuff than a black and decker drill and a dremmel , but I'd always stress that for any project the best tools are imagination and time , mostly time really as any builder of custom stuff will tell you .So far the new king pins have taken 4 hours to make and the second one has yet to go on the mill at all so is just a piece of 15mm bar that's turned down to 4mm on one end and threaded so it probably needs another hour or two and then you have to remember that the first two king pins took that amount of time as well , so time , mostly time