Drive line question

[Guest Lenny]

In order to more easily redo my wiring, I've removed all the couling going down the center. This also allows me to completely redo my parking brake. While looking at things, I wondered why the front two piece drive shaft couldn't be converted into one long shaft. This eliminates the center u-joint and the carrier bearing along with it's bracket. Looks to me like a cleaner design and probably another 7 or 8 pounds of weight savings. Not being a car guy, is there any reason I shouldn't be considering this. It's fairly easy to do other then it may be a little more difficult to install the shaft. It may require sliding the front diff forward. Any thoughts anybody.

Lenny

[Kinarfi]

Post a photo, I tried to find one I had taken but couldn't, I'm thinking mine is a single with just the carrier bearing, but I'm probably wrong and will verify & photo later when I get moving.

Kinarfi

[Guest Lenny]

Post a photo, I tried to find one I had taken but couldn't, I'm thinking mine is a single with just the carrier bearing, but I'm probably wrong and will verify & photo later when I get moving.

Kinarfi

It's pretty much a straight through shot to the front. I see no reason for the two piece except for installation reasons. I'll bet the carrier bearing, it's bracket and the extra U-joint are at least 10 pounds. As you can see in this photo, I tore out the parking brake handle bracket (3 pounds) and the battery box (4 pounds). The rear bracket for the parking brake master cylinder is also out (5 pounds), not shown. This will all get replaced differently with a couple of pounds of aluminum. Like Jeanne said, I'm on a biggest looser missiion.

,

Lenny

[rocmoc]

I believe it was done for ease of installation which may have not been the case. A one piece should work fine, trans & diff locations are fitted! JMHO!

rocmoc n AZ/Mexico

[ksimpsy]

It would be nice to have a one piece shaft. has anyone watched it while driving? It wobbles erratically i assume because of the poorly fitted slip yoke.

[Guest Lenny]

It would be nice to have a one piece shaft. has anyone watched it while driving? It wobbles erratically i assume because of the poorly fitted slip yoke.

Good point Ksimpsy. Were getting away with it now but it would be more noticable without the center carrier bearing to steady the center. I'm sure that is part of the viabrations we feel now. I'll take a close look at that when converting to a single shaft. Maybe I can split the spleened collar at the u-joint and put a hefty clamping collar around it to eliminate the movement. I'll have to put some thought into it. Thanks

Lenny

[ksimpsy]

I was thinking a person could do it by using two shafts, one inside the other. this is the way all pto shafts are on farm equiptment and they work fine at high speeds. the tolerance between the two shafts are alot closer and are just a square or pentaganal shaft and once you grease it it takes up the slop if there was any. this should be easy to have built at any drive line shop. another thought about the steady bearing is that it keeps it from wobbeling in the tranmisson and maybe with that long of a unsupported shaft it may want to wobbel extra and snap the shaft in the tranny off like rocmoc had.

Just a thought

Kevin

[Kinarfi]

I was thinking a person could do it by using two shafts, one inside the other. this is the way all pto shafts are on farm equiptment and they work fine at high speeds. the tolerance between the two shafts are alot closer and are just a square or pentaganal shaft and once you grease it it takes up the slop if there was any. this should be easy to have built at any drive line shop. another thought about the steady bearing is that it keeps it from wobbeling in the tranmisson and maybe with that long of a unsupported shaft it may want to wobbel extra and snap the shaft in the tranny off like rocmoc had.

Just a thought

Kevin

After you get the two parts of the drive shaft that slide together you'll need to pin them so they can't collapse any at all, a circlip wouldn't work because if you bump something, the weight of the drive shaft could cause the circlip to let it slide back and disengage. You could use splines or even round tube inside round tube and pinned into place. Take a look at how long drive shafts in cars and truck are. A larger diameter of thinner steel may save some weight and still have the strength needed and if the alignment is proper you could use industrial motor coupling instead of U joints or even just the splines.

Just another thought

Kinarfi

[Guest Lenny]

I have a complete metal working machine shop in my extra garage so I really don't have to go outside to have any work done which gives me a lot of flexibility and save a lot of money. Here is what I have found so far. I have removed the front driveshaft with it's support structure. It weighted in at 29 pounds. After looking it over, it wouldn't be hard to just weld a peice of tubing in the middle. it could be machined to tightly fit over the existing shaft so it can slide on for say 4" over each end. However I just happen to have a front CV drive axel out of who knows that I found along side of the road one day. I don't let stuff like that go, I put in in inventory for possible use some day. Well, it turns out that its axel shaft is slightly larger then the rear CV drive shaft, shaft. I checked test welds on both of the CV bells, it's shaft and the u-joints on the removed drive shaft. They weld good without enbrittlement and the 3/16" dia by 3/16" tall bumps I welded on then wouldn't chisel off without cutting through the weld itself. So I feel comfortable in welding any of the parts without problems. The shaft of the CV axel is .990" diameter. I have a peice of DOM tubing that is 1-1/4" OD by 1.005" ID. I figute by slight knurling on the CV shaft I can bring it up to the 1.005" plus a little for a tight fit for centering. I do have to check the DOM tubing for torsional strength yet to see if it will hold but I think it is going to be OK. I will slide it onto the the CV shaft 5" on each end. The DOM will have probably 20 to 30, 1/4" diameter holes in the first 5" of each end for welding. This way, I can never build too much heat at any one point and it will stay straight and centered If I spread the welding over time. I also will have to cut the ends off the existing U-joints and weld them to the CV bells to fit the Diff and trans shafts. When I'm done, I'll check it for staightness and adjust if necessary. I don't have the equipment to check it's balance but will hope for the best. Still thinking if there is a way I can do that myself in house. I can always take it back out and bring it into a shop to balance it I find it is a problem. The new shaft will be 14 pounds giving a 15 pound weight savings over the old. I'll follow up after It's done with pics. I also plan on running a piece of 1-1/2" PVC pipe from the rear to the front to run wires through. That way I can have easy access to them and if I ever need to run additional wires, I can do so easily. Running wires from rear to front now is a pain.

Lenny

[rocmoc]

Kinarfi, I snapped the shaft off because I abused it at Moab. My failure not the Trooper's.

Lenny, don't forget the driveline should be balanced IMHO. The few times I have had drivelines built for race cars or hot rods, I always had the new driveshaft balanced.

rocmoc n AZ/Mexico

[Kinarfi]

Lenny, after your done, put it in your lathe and spin it slowly watching to see if it needs balancing.

kinarfi

[rocmoc]

Helps but will not catch thickness irregularities in the inside of the tube. Take it to a driveline shop and have them balance it.

rocmoc n AZ/Mexico

[Kinarfi]

What I meant was that if you spin it and it vibrates the machinery, it's out of balance, if smooth, it may be ok

[rocmoc]

Duhhh, I thought you wanted him to turn/smooth it in the lathe. Boy did that one go over my head. LOL! Take care!

rocmoc n AZ/Mexico

[Guest Lenny]

I will spin it in the lathe when done like you said Kinarfi. I'll also use it for checking straightness and adjusting that if necessary. I guess i better have it balanced. Will just need to find someone that can do it. I've checked the torque values of the tubing and for that matter the CV's shaft, both the Joyner's rear driveshaft and the new one I'm using and they are are Ok but there isn't much leaveway in torsional strength surplus in any of it. I assumed that the CV shafts are of alloy steel has between 80k and 95k pounds per square inch tensile strength with 35k to 51k yeild strength as this is what the automotive industry requires. The DOM tubing shows at 63.8K tensile and 51K yeild. The stock front drive shaft is aprox. 2-1/2 times stronger then it needs to be. Here is the way I looked at it. Checking the Chery engine site, their hightest torque 1100cc 4 cylinder engine produces 98 newton meters of torque. This converts to 69.8 foot pounds of torque. The transmission I beleive has a 5.24:1 low gear ratio so 69.8 x 5.24 = 366 foot pounds of torque at the driveshafts. This is only when the engine is reving probably near 5000 RPMs and putting out max torque. I'm thinking that the max pull on the drivetrain is when your in a tight spot and need to gun the engine and work the clutch to get moving or if your already moving and spinning and catch traction. In either case, the engine is more then likely reving at somewhat less then the 5000 RPMs so the torque output values are lower and probably substantially. If I assume that for example I'm backing up a steep slope and all the torque goes to the front wheels because the back wheels are on something slippery or weightless, then the front shaft has to take all of the 366 foot pounds of torque. The tubing I'm planning on using will hold 530 foot pounds of torque before it would fail. Now if I figure that my supercharger is going to add 50% more torque to the 366, I'll be putting out 549 foot pounds of torque at the drive shaft. Again this would be at high RPMs which probably don't come into play when in tight spots. And again this is putting everything on the front and putting nothing on the rear which is also hard to acheive. That said, I think I'm OK but I do wish I had a bit more leaveway. I'd be happy with say being able to hold 800 foot pounds of torque but my tubing is as strong as the existing rear CV driveshaft shaft so I'm letting myself accept that. If it has been holding then this should. Also under full torque, the tubing will torsion aprox 18 degrees so it acts as a big cushoning spring to inpact. The last thing I'm going to look at is to see if I can align the trans output shaft to line up nearly perfectly with the front diff input shaft and hold it there reliably. If so, I think I'm going to eliminate the CVs all together. This not only makes the whole thing easier to build but saves probably another 3-4 pounds and as a bonus, I can use a different tubing (1.25" OD x 5/8" ID DOM tubing which I also have and my strength goes up to the 800 foot pounds I prefer. Also the chances of a straight through shaft being out of balance goes way down and at the 1-1/4" diameter, slight misbalances that colse to the center will be much harder to feel.

I know that a lot of the forum readers aren't interested in all this detail. It is more information then you need. There are a few readers out thers that like to be very methodical and will probably enjoy seeing how I looked at this. I know Kinarfi, Rocmoc, Brostar, Ksimpsy, Flatbed if he is still alive and others will get a kick out of it. Also by throwing this out, they can put their dollars worth of thoughts in. After all, it's when I get over confident and cocky that someone puts me on the canvis and that's when I learn the best. I forget a lot of stuff but those things that get shoved in my face, get remembered best.

Lenny

[brostar]

One thing to watch out for is the physics for sure, or put it finer, "flex". A two piece drive shaft will sort out any flex better than a single between the axels & the transmission and if you are going to reduce the strength to save weight, it might not cope to well. 98 newton meters of torque will behave differently to a lighter single shaft off road. When you floor it with your supercharger, flex will come into play. Not much but over time only you will know how this will work out. The good news is you will still have the stock driveshaft and if one pops out in the middle of no where, you will still have 2WD to get yar home. That been said, I like the idea and would expect nothing less from you and if your happy with the above calculations (beyond me) then go for it. Added stress will be your enemy though.

Cheers Mike.

[brostar]

Forgot to add Lenny that if you go ahead with this project, try and replace the circlip with a ball bearing to secure the driveshaft in place. Like used on Walker ride-on lawn mowers. Just think of the advantage you would have with that. Not sure if counter weight is need as its right on the pivot gear. Food for thought anyway.

Cheers Mike.

[STIHLMAN]

It's been awhile since I have posted on this site,but would like to ask if anyone knows if the Joyner people are getting any of the information that these hard core Joyner ( trooper ) lovers ( smart,machine improving people are giving them )?????I would like to think from all this information that is given freely that some REALGOOD would come from it.

[STIHLMAN]

Lenny, or anyone ,,let me know when you have installed an automatic into one of these units.Please

[rocmoc]

Lenny, or anyone ,,let me know when you have installed an automatic into one of these units.Please

For rock crawling, I would love to have an auto. BUT the rest of the time, I love my stick!

rocmoc n AZ/Mexico