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Kyosho 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 . 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 . http://i1042.photobucket.com/albums/...pshhcv2nvk.jpg this is a comparison of the stock steering hub and king pin next to the Optima hub and king pin . http://i1042.photobucket.com/albums/...pse50an7ac.jpg hub installed http://i1042.photobucket.com/albums/...psmf5usqtp.jpg and view from front showing increased track . http://i1042.photobucket.com/albums/...pscjm2tmrb.jpg 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. |
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 some Optima front axles as well as they were recommended on another forum to help reduce the width . 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.
http://i1042.photobucket.com/albums/...psiww22qs5.jpg http://i1042.photobucket.com/albums/...pskxatxv3s.jpg |
Nice project dude....looking forward to more info etc :thumbsup:
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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 !
http://i1042.photobucket.com/albums/...pslrslbn7i.jpg http://i1042.photobucket.com/albums/...pspltkgraa.jpg http://i1042.photobucket.com/albums/...psaa43qujw.jpg |
Next instalment.
i got the chance to make another attempt at the extended rear lay shaft and this time it all went smoothly yay ! The shaft is over long right now but can be shortened to the correct length when i decide where the chain will run . The extended end for the sprocket has to be 4mm as that's the internal size of the bearing in the gearbox , the internal diameter of the sprocket is 6mm so I had to make a sleeve to fit between , the shaft may have to extend further than i'd like from the gearbox and if that's the way I go then I'll make up a support with a bearing in that can be secured to the side of the gearbox with either the diff cover plate screws or the motor support screws , again i might find a way to have it flush with the side of the gearbox ,in witch case i can shorted the shaft and sleeve . You might notice if you have a keen eye that there's no groove to fit the circlip that retains the shaft on the motor side of the gearbox , this function will be performed by the sleeve that goes between the shaft and sprocket , the sleeve is extended to butt up against the bearing in the gearbox , i did this because in was worried that a 4mm shaft extended that far might bend and having a groove cut into it would further reduce the diameter , the sleeve also helps to support the shaft and prevent it flexing . http://i1042.photobucket.com/albums/...pslx88arxn.jpg http://i1042.photobucket.com/albums/...psfw40ljrm.jpg http://i1042.photobucket.com/albums/...psg2z8nv4m.jpg http://i1042.photobucket.com/albums/...ps2srijafw.jpg http://i1042.photobucket.com/albums/...ps7ezdswwq.jpg http://i1042.photobucket.com/albums/...psut5pg7fz.jpg |
And the front Lay Shaft made up , again its over long and can be shortened later.
http://i1042.photobucket.com/albums/...ps3eha2phh.jpg http://i1042.photobucket.com/albums/...psif782dqs.jpg http://i1042.photobucket.com/albums/...psntjcnnnh.jpg |
Looking good , things are happening
😊 /iso |
yesterday I made up the centre part of the gear housing and flowed the edges , still needs more work but I'm pleased with it.
http://i1042.photobucket.com/albums/...psfyv5nzy9.jpg http://i1042.photobucket.com/albums/...ps1yuq08l0.jpg http://i1042.photobucket.com/albums/...psugdi1ckm.jpg |
Today i made up the mounting plate for the front gearbox , this replaces the original chassis plate that would support the servo saver and the cross bar that goes between chassis rails , it all fits in pretty well , i'll have to chop some of the front of the plastic tub to give clearance for the gearbox and for the chain but it should be possible to leave the battery compartment untouched .
http://i1042.photobucket.com/albums/...psvug66bqb.jpg http://i1042.photobucket.com/albums/...psxr4tfi1d.jpg http://i1042.photobucket.com/albums/...pscyknrwit.jpg |
I love this stuff!
Nothing like some properly executed, innovative engineering to sooth the soul. I dream of having the tools and knowledge to turn something old school back in to a competitive beast again. |
Thanks , i very much doubt it will be competitive in a modern race , I'd settle for a successful conversion and fun to drive.
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Great stuff. Will be following!
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Did a bit more cutting of the tub , its still a little rough round the edges but i think i have the clearance i need for the chain , i also cut the front under-plate so the gearbox fits into it and lowers the gearbox the 3 mm i needed , i might just get away without making new shock towers as there looks like enough clearance for the drive shafts , I'm going to have to extend the shafts about 10 mm but that's easy enough . One other thing on the list is to make up some guide pulleys and a tensioner .
http://i1042.photobucket.com/albums/...pshlsvjoqu.jpg http://i1042.photobucket.com/albums/...psnaqhvuyu.jpg http://i1042.photobucket.com/albums/...psqf9vtur0.jpg |
Front gearbox mounting milled out , just off the mill so its not all prettyfied yet.
http://i1042.photobucket.com/albums/...psb3gmfmdq.jpg http://i1042.photobucket.com/albums/...psodkrrlwl.jpg http://i1042.photobucket.com/albums/...ps44gwx9w2.jpg http://i1042.photobucket.com/albums/...psrxbxpbmz.jpg |
Rc porn, stunning
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Thanks , ive got to sort out the steering next .......should be interesting .
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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.
http://i1042.photobucket.com/albums/...pscxpbcz6i.jpg http://i1042.photobucket.com/albums/...pscjbox9xe.jpg |
Pictures of the finalised transmission ,drive shafts extended , chain guide pulleys fitted and chain length shortened, there's a second guide pulley up front but its kind of hidden , you can see the screw that it runs on in the side of the tub in the second picture also a scratch in the tub i'll have to clean up before painting:(.
http://i1042.photobucket.com/albums/...ps5a8ykmyt.jpg http://i1042.photobucket.com/albums/...psd3hdjkaf.jpg http://i1042.photobucket.com/albums/...ps87vjkgbc.jpg |
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