Modified Grand Daddy Build

Econdron

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Just go with a 1” steel flex proof axle. The parts to fit it are way cheaper and easier to get. Also it is more than strong enough!
Hindsight is 20/20! All the components I currently have were meant for a 1-1/4" axle. Except maybe the wheel hubs. It won't take long to turn down the ends and key the axle, but if we end up building another one, I'll most likely go with a 1" axle.
 

Econdron

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Lower frame is complete, we made the rear engine frame and the suspension arms the wheels will mount to (neither are pictured).

Also milled the keyway for the wheel hubs. Unfortunately, while cleaning up the axle on the lathe, I really messed up. I had the lathe spinning way too fast while drilling my center hole for the live center with about 4' of unsupported length flapping around behind the lathe head, which unfortunately bent the axle right in the center. It's bent on a sharp line. It's not horrible, but when laid out on a flat surface, the two ends are touching the table and over the 60" length there's about .75" of a gap in the center. I have a shop press with a pretty large V-Die, I think I can correct the axle by manually bending it back to be straight there. How big of a deal is it for the axle to be perfectly straight? Would it help to put a third axle bearing right in the center of the go kart? Obviously not the way it is right now, after I try to bend it back to straight. Who knows, maybe it will come out perfect after I try to correct it! But I doubt it...
 

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panchothedog

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Third bearing almost sounds like a good idea of you are trying to save that piece. Problem with it having a bow in it ( regardless of how slight ) is that the sprocket will perform as though it were out of round. Chain tension would constantly fluctuate. Probably saveable if you can get the center bearing DEAD
On.
 

Denny

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With that much length even if you did not bend the axle using 4 bearings would not be a bad idea. I have my doubts about you getting the axle straight enough to run true, but good luck anyways. You may end up wearing out chains, bearings and sprockets rather quickly.
 

Econdron

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With that much length even if you did not bend the axle using 4 bearings would not be a bad idea. I have my doubts about you getting the axle straight enough to run true, but good luck anyways. You may end up wearing out chains, bearings and sprockets rather quickly.
It still needs to be cut to size, final axle length is 51.5", with the bearings being on ~33" centers. I'm try and straighten it today and see how it goes.
 

Econdron

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Well maybe partly laziness, but I decided to just order a 1-1/4" keyed steel shaft. I realize the shaft a lot of imbalance while on the lathe, but I also so how easily it bent with the imbalance being the only load on the shaft. So I'm thinking I'll add a third bearing, and the steel shaft will hopefully keep everything running true.

Now any advice on keeping the axle from rusting?
 

BaconBitRacing

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Well maybe partly laziness, but I decided to just order a 1-1/4" keyed steel shaft. I realize the shaft a lot of imbalance while on the lathe, but I also so how easily it bent with the imbalance being the only load on the shaft. So I'm thinking I'll add a third bearing, and the steel shaft will hopefully keep everything running true.

Now any advice on keeping the axle from rusting?
Not lazy, smart. maybe grease or oil? someone who knows more than I will surely help you.
 

panchothedog

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A very LIGHT coating of grease and you're good. Denny, I always thought
Anti-seize was for the threads on the end of bolts. Plus it comes in little tiny tubes. Maybe I 'm thinking of something else.
 

Econdron

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Working on the front end yesterday and today. Looks a little crude right now, but we're just test fitting everything before we take the time to clean everything up. The tie rods definitely need to be extended about 3-4" each side. That should be pretty simple though. Also need to figure out some kind of mounting bracket for the rack and pinion. Thinking either some kind of a clamp, or there are two screws in the center of the rack and pinion, we might make a small bracket and use some longer screws to screw it in through those holes.

I've been reading a little about the ackermann angle, seems the simplest solution is to cut the tie rod mounting bracket off the spindle and weld it back on at an angle, pointing the center of the rear axle. Does this only improve the tire life or is there a noticeable performance feel change when you incorporate the ackermann angle?
 

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TNThomas

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Working on the front end yesterday and today. Looks a little crude right now, but we're just test fitting everything before we take the time to clean everything up. The tie rods definitely need to be extended about 3-4" each side. That should be pretty simple though. Also need to figure out some kind of mounting bracket for the rack and pinion. Thinking either some kind of a clamp, or there are two screws in the center of the rack and pinion, we might make a small bracket and use some longer screws to screw it in through those holes.

I've been reading a little about the ackermann angle, seems the simplest solution is to cut the tie rod mounting bracket off the spindle and weld it back on at an angle, pointing the center of the rear axle. Does this only improve the tire life or is there a noticeable performance feel change when you incorporate the ackermann angle?
Good job widening the box and A- arm angles. In hindsight I would have done the same thing. Looking good. I am building a not too terribly different Grand daddy than yours, and I found a good set of monroe shocks for the front/back, if you want any info let me know and I can send part numbers over. You probably already know this, but yours will be bigger/heavier than the buold plans, and most of thr go kart shicks might be a little soft.

Also, the Ackermam will help prolong life, and just reduce issues with steering as the tires can adjust to different sized "circles" they are turning on.

Your moving fast, looks good!
 

Denny

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Oh, the wonders of the world you will unlock by adding in Ackerman! You will be able to do wonderful things like turn while driving on grass or gravel. Reduced understeer, less tire wear. A whole magical world awaits you. If you don’t believe me don’t build it in and see how much you hate the kart that won’t turn then!
 

Econdron

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Good job widening the box and A- arm angles. In hindsight I would have done the same thing. Looking good. I am building a not too terribly different Grand daddy than yours, and I found a good set of monroe shocks for the front/back, if you want any info let me know and I can send part numbers over. You probably already know this, but yours will be bigger/heavier than the buold plans, and most of thr go kart shicks might be a little soft.

Also, the Ackermam will help prolong life, and just reduce issues with steering as the tires can adjust to different sized "circles" they are turning on.

Your moving fast, looks good!
I have the front springs on, if anything they almost feel pretty stiff. I'm not sure what the right amount of "spring" should be, but if I stand and bounce on the front end, they compress maybe halfway? I believe the springs I purchased had a 600 pound rating.

The attached pictures are progress from yesterday, the axle is coming in today so hopefully we'll start getting the back end put together. Might even have a drivable go kart by the end of the week!
 

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BaconBitRacing

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I have the front springs on, if anything they almost feel pretty stiff. I'm not sure what the right amount of "spring" should be, but if I stand and bounce on the front end, they compress maybe halfway? I believe the springs I purchased had a 600 pound rating.

The attached pictures are progress from yesterday, the axle is coming in today so hopefully we'll start getting the back end put together. Might even have a drivable go kart by the end of the week!
Looking good! Guys at the shop enjoying it?
 

Econdron

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Sorry for the long delay, we had some sickness rolling through the shop and we've picked up a bit, so not a whole lot of progress. But the last couple days we've been able to get back going on this. The torque converter has been really confusing... I would appreciate if you guys could take some detailed looks at the photos and see if you see anything that is going to be problematic or just doesn't look right.

Right now, we're just trying to hook up everything, make sure it works as expected and no major changes need to be made, then we're going to clean everything up and finish the "roll cage".

Bleeding the brakes right now, then we'll take it for a test spin.
 

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Bansil

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Looks good, in 28 years working in a machine shop, I have seen 1 person badly hurt, a top box destroyed and smashed and a kia motor fan housing explode by too much stock sticking out of the back of lathes...0 to 2000 rpm is quick :eek:

Stay safe and I wish I worked for you and changed platforms and build Karts and bikes !!
 

panchothedog

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I don't know where you got that small sprocket, but you have the shop to make it right. I'm sure your kart will run as is, but having a small drive sprocket sitting
out on the end of the jack shaft like that is going to tear the Hell out of the bearings in the mounting plate, and possibly bend the shaft itself, depending on the load placed on it. The sprocket should sit between the plate and the driven clutch. I have never seen one with such a long shoulder on it. The shoulder should be 1/4" on each side of the sprocket. This will push the driven clutch out on the jack shaft about another inch. You might not have enough crankshaft length to slide the driver outwards 1" . The fix is to turn the driver around 180 degrees. Flip it so the bell end is in towards the engine. It will run exactly the same. The belt is the same angle on both sides, so it makes no difference. I have a nice high powered kart sitting in my side yard with the exact same 40 series converter on it, set up as I have explained. It won't last long as you have it set up in the picture you posted.
 
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