(PROJECT) Rupp Dart restomod

[Raywelder]

I love sandblasting.
Well doing it sucks, but the result is awesome

 

[Fast Eddie]

NICE pictures, keep em coming!!!!

Thanks Briggs. You know I will!!

I love sandblasting.
Well doing it sucks, but the result is awesome

I couldn't agree more. I learned a while ago that there's just some things you hire out.

 

[Fast Eddie]

Cranks came back today. A special thanks to my boy Tim and his crew over on "the West side" for whittlin' these fine chunks of steel for me. IOU all big-time!

BEFORE

AND AFTER

Next up, get the short blocks back together. Waiting (more like delaying) to order clutches and carbs. Can't find any rebuilt carbs, but my timeframe is getting shorter.

More updates soon...

EDIT: 100th post-yea!

 

[BriggsTwins]

this thing will sound neat

 

[anderkart]

Nice, looking good man.

 

[Fast Eddie]

Frame and steering updates

Hello all,

Thanks for the kind words guys.

Got a little done over the Holidays. Added some reinforcements for the rear frame section. Rupp frames have a tendency to snap just behind the seat. These extensions (when gusseted) should eliminate any possibility.

Also wrapped up the steering. I think I may need to crisscross the tie rods to minimize the Ackerman. These tie rods are off a snowmobile I diced up a while ago...they just happen to fit. Used 1.25" 1/8 wall on the upper and lower steering shaft supports so I could run bearings. Didn't turn out too bad.

That's all for now. More updates to follow.

BTW, any suggestions on the Ackerman steering? The arms are just tacked to the steering rod.

 

[Ken]

Are the arms on the spindle turned inward to create true Ackerman-effect steering? I understand they are to both point to the center of the rear axle which will give the desired result.

Nice metalwork on the steering mechanism, by the way. It's a work of art well beyond anything I will be attempting with my Rupp. I don't possess a welder, much less the knowledge of how to use one so I will be outsourcing any work mine may need. Hence my wallet will be my guide...

Great job overall and I'm enjoying seeing its progress!

 

[Fast Eddie]

Thanks for the props Ken. No the spindle arms point straight back. They're the stock spindles switched from side-to-side. They need to angle inward?

Metalwork doesn't seem that hard at all. I'm using a 110 flux core Mig and some HF angle and die grinders. I'm experienced in fine carpentry so that definately helps...but this is my first metal fab project ever.

 

[freakboy]

if you take a peice of string and go from the top of the king pin and to the center of the rear axle you bend the spindle arm to follow the string and drill a hole on there were the string is. then that should do it.

 

[Fast Eddie]

if you take a peice of string and go from the top of the king pin and to the center of the rear axle you bend the spindle arm to follow the string and drill a hole on there were the string is. then that should do it.

Thanks man. Current spindle arms just barely clear the front gussets anyways. I can raise them up now for more clearance.

Should I crisscross the tie rods? (LH tie rod to RH steering arm and vise-versa)

 

[freakboy]

no i wouldnt crisscross them id keep em on the same sides.

 

[Fast Eddie]

I did a little more research and here's what I found. There are two ways to achieve Ackerman angle. One is to angle the spindle arms towards the center of the rear axle as you have explained. The other option is to mount the inner tie rod ends in two different locations as I have done.

Here is an informative LINK I found describing the two options.

The biggest difference I can see is with option A, your Ackerman angle is static. Whereas option B, the angle is dynamic (meaning the angle becomes more extreme the further you turn the wheel). Is this right? At what angle/distance do I place the inner tie rod mounting points? If this is correct, I would rather do option B instead of cutting into my spindles. Any input is appreciated.

 

[Ken]

Nice article! But would the tie rods mounting to the steering shaft in two separate holes like you did also work when the pitman arms are in front as originally done on the Rupp? (as opposed to rear mounting like yours.) My concern is that my live axle kart with no Ackerman would plow terribly.

 

[Ken]

OK, hypothetical question: On a steering setup with the pitman arms pointing to the rear, the tie rod attachment piece points downward. On my kart with the pitmans facing forward, the attachment piece points up. Therefore, in my case, if I use the attachment piece with two holes, shouldn't I cross-mount the tie rods to achieve some Ackerman-effect?

And Eddie, I see the holes for your pedals. Won't they will cause interference between the drivers leg and the tie rods?

 

[Fast Eddie]

OK, hypothetical question: On a steering setup with the pitman arms pointing to the rear, the tie rod attachment piece points downward. On my kart with the pitmans facing forward, the attachment piece points up. Therefore, in my case, if I use the attachment piece with two holes, shouldn't I cross-mount the tie rods to achieve some Ackerman-effect?

And Eddie, I see the holes for your pedals. Won't they will cause interference between the drivers leg and the tie rods?

If you're stayin with the correct front-steer setup for Rupps, then you'd be running one tie rod from the steering shaft to the spindle, and one long tie rod running from spindle to spindle. No Ackerman possible. If you run that shaft I mentioned in my PM, you only have one mounting point anyways. I'd just run narrow width front tires and let 'er plow a little.

As for the pedals, I'm using ones similar to AnderKarts new ride (see project log) where they extend out in front of the front axle centerline, out of the way of the steering.

 

[nerfo]

Actually, if a kart has a drag link/tie rod set up, where the tie rod runs from spindle to spindle and the drag link runs from pitman arm to one spindle arm, proper ackerman geometry is still doable, but it has to be set with steering arms coming off the spindles at the proper angle (center of king pin to center of rear axle... this has been beat to death now.) And if your steering arms come off the front of your spindles, then it's the same angle, just faces the front of the kart, not the rear. This type of setup has been used on solid axle vehicles (i.e. straight axle 4x4's) for years. The ackerman is not adjustable with this set up, but really, as long as it's dialed in with the wheel base in mind, there shouldn't ever be a NEED to adjust this. Ticky stuff!

 

[dpaxson]

Nice article! But would the tie rods mounting to the steering shaft in two separate holes like you did also work when the pitman arms are in front as originally done on the Rupp? (as opposed to rear mounting like yours.) My concern is that my live axle kart with no Ackerman would plow terribly.

you're right. it would achieve the same effect as having the tie rods separated on a downward facing pitman arm set up

 

[Fast Eddie]

Actually, if a kart has a drag link/tie rod set up, where the tie rod runs from spindle to spindle and the drag link runs from pitman arm to one spindle arm, proper ackerman geometry is still doable, but it has to be set with steering arms coming off the spindles at the proper angle (center of king pin to center of rear axle... this has been beat to death now.) And if your steering arms come off the front of your spindles, then it's the same angle, just faces the front of the kart, not the rear. This type of setup has been used on solid axle vehicles (i.e. straight axle 4x4's) for years. The ackerman is not adjustable with this set up, but really, as long as it's dialed in with the wheel base in mind, there shouldn't ever be a NEED to adjust this. Ticky stuff!

The issue in Ken's situation is he needs to set up a steering system with minimal welding or fabrication. Changing steering arm angle may not be an option for him.

 

[Ken]

All interesting possibilities, but I think I'll be using the two-pitman setup like Fast Eddie, but facing up. With the spindles remaining straight, I believe if I cross-mount the tie rods (Left rod to right pitman and right rod to the left pitman) I will achieve a desired Ackerman-effect. I just need to mathematically figure the angle of the two pitman arms before I weld it. (see image)

 

[nerfo]

Fast Eddie - Oops! I try to pay close attention to early posts so I can TRY to avoid making mistakes like that! Heh, whoopsie!

But I really like this "split pitman" idea for achieving the desired ackerman! As far as mathematically figuring that out... I would love to hear what you come up with! I noticed the snazzy spindles I welded on today do not have any provisions for ackerman either, so this sounds like it might be right up my alley... either that, or I'm going to modify the steering arms coming off the spindles so I can put rod ends in the correct place.

Frankly, I don't know why I'm bothered by this... I'm building a yard/fun kart that's never EVER going to see a track... let alone much turning on pavement. I think because I'm aware of it, I have to make sure it's correct, otherwise it'll bug me.