Driveshaft to yoke angles

[deckofficer]

I had the Track T up on the lift yesterday (wheel lift so angles same as on the road) to check for how I will be swapping a T56 Magnum for my Muncie M20. Knowing that I will have to shorten the driveshaft, I looked at the current yoke to driveshaft angles and was disappointed to see that already is maxed out to the point of small indentions on the yoke collar where the u-joint cap sleeve would hit during the rebound from an uneven road surface. Since I will have to shorten my driveshaft 4", this will increase the angle way past acceptable. My question is, will (2) sections of driveshaft and (1) more u-joint work? I figure it will cut down whatever angle the shorter driveshaft creates by a factor of 2. Any thoughts?

http://i1236.photobucket.com/albums/ff452/deckofficer/DSC012081014x760.jpg

Bob

 

[deckofficer]

Let me answer my own stupid question, no it won't work. Didn't even give consideration to the fact that the splined tranny output shaft is designed for fore and aft travel as needed by suspension travel. I guess if I want that 6 speed, I'll have to redo engine mounts and a differant tranny mount was needed too.

 

[Lee_in_KC]

Bob, you have a Jag rear-end, don't you? The differential is hard-mounted to the frame, so "suspension travel" should not be affecting your driveshaft angle. It should be constant. That should mean that you can get away with a little more U-joint angle as you don't have to allow for the differential moving up and down with the suspension.

I have a Jag in my T. My driveshart appears to be a little shorter than yours and I have a couple more degrees of angle. I have absolutely no problems with my driveshaft or U-joints.

 

[GAB]

It also looks like you are using the stock Jag companion flange on the pinion with a u-joint yoke bolted to that. You might want to check out a Spicer part number 2-4-2821X yoke that fits the Jag pinion and might give you more length to your driveshaft. Not a lot but every little bit might help.

 

[Ted Brown]

If you are going to shorten the shaft, you can turn the yokes 90 degrees to each other, this allows for much more angle without any binding... They also make a special U Joint for off road use, half the unit sticks out maybe 1/4" off center, to allow for more sever angle... I have a pic somewhere, I'll look for it and maybe a part number if you would like?

 

[deckofficer]

Bob, you have a Jag rear-end, don't you? The differential is hard-mounted to the frame, so "suspension travel" should not be affecting your driveshaft angle. It should be constant. That should mean that you can get away with a little more U-joint angle as you don't have to allow for the differential moving up and down with the suspension.

I have a Jag in my T. My driveshart appears to be a little shorter than yours and I have a couple more degrees of angle. I have absolutely no problems with my driveshaft or U-joints.

Lee,

You are 100% correct. What I meant to say was the sliding arrangement of the yoke on the tranny spline, though it doesn't move now because the rear is mounted to the frame, it would slide with a 2nd added articulation, i.e. putting in one more u-joint and having two really short driveshafts going from the trans to the rear end. The picture I posted was taken before I was considering the 6 speed. Next time I have it on the lift I will take detailed pictures of the clearance at the u-joints, post them here, then ask for suggestions. A lot of the guys on the forum have "been there, done that" and just would prefer doing things right because of using other's experiance.

Bob

 

[Whiplash]

Hi Bob and sorry I can't give you any info on the driveshaft but I was always told that one needs the offset angles on the driveshaft for the universals to work correctly. But what does concern me is the fact that you guys doen't seem to worry about a driveshaft safety hoop mounted towards the front of the shaft for safety reasons. By law down here all vehicles have to have a safety hoop no more tham 6" from the front of the driveshaft. And yes I have had a driveshaft give up the job out on the open road in one of my street machines and it is not nice.

 

[Screaming Metal]

If you are going to shorten the shaft, you can turn the yokes 90 degrees to each other, this allows for much more angle without any binding... They also make a special U Joint for off road use, half the unit sticks out maybe 1/4" off center, to allow for more sever angle... I have a pic somewhere, I'll look for it and maybe a part number if you would like?

Teds right, the 90 degree turn of the u-joint will allow more angle without 'camming'. Could always go the CV route....

 

[deckofficer]

Thanks guys,

90 degrees it will be and I'll start researching the off road yokes that Ted mentioned. Whiplash, I'm with you about driveshaft loops because if mine was to fail at the rear end, that unrestricted driveshaft would literally beat me in the butt.

Bob

 

[fluidfloyd]

deckofficer,

All drive line experts will tell you to keep the ujoint trunions in phase and at equal angles to the engine/pinion centerline. If the engine is 2 degrees down then the pinion should be 2 degrees up. In your case it appears your pinion is fixed and non adjustable. One solution is the use of a double cardan type setup. This is very popular with the off road crowd that have high lift vehicles. It was also used in some of the earlier Linclons due to long wheelbases and long driveshafts. The link below will show you several ways to solve your problem. In your case (as in the OEM Lincolns) you can put the double joint on the pinion end. There are a number of good shops that specialize in off road shafts and can be found by doing a google search. I have used this method several times on hotrods that were built with rear pionions that had been installed incorrectly. This was usually a cheaper and quicker fix then cutting the suspension brackets loose and realigning them. Most of these guys have online tech sheets and toll free phone numbers. Hope this will help you out.

George

BTW: Nice looking car!

http://www.4xshaft.com/index.html

 

[Ted Brown]

In that last site they show the Super flex U joint... $60 each...

Tom Wood’s Custom Drive Shafts Inc. is pleased to announce and introduce our new and exclusive“Super-Flex”[sup]TM[/sup] Universal Joint in both 1310 and 1350 series. Both joint sizes are considerably stronger than the Toyota joint and do not require any “special” flanges for the transfer case or differential.

​

 

[deckofficer]

George and Ted,

Thanks for the link, I checked out the double cardan shorty CV type shaft used in CJ5's for I'm assuming the front axle on a 4X4. Questions are 2,

1.) will this CV shaft handle the torque? I'm 516 lbs/ft @ 2800 rpms X an almost 3 to 1 1st gear ratio
2.) With a CV in combination with the splined output trans shaft, what keeps the whole assy from shifting for and aft?

Bob

 

[fluidfloyd]

George and Ted,

Thanks for the link, I checked out the double cardan shorty CV type shaft used in CJ5's for I'm assuming the front axle on a 4X4. Questions are 2,

1.) will this CV shaft handle the torque? I'm 516 lbs/ft @ 2800 rpms X an almost 3 to 1 1st gear ratio
2.) With a CV in combination with the splined output trans shaft, what keeps the whole assy from shifting for and aft?

Bob

Bob,

The Spicer Book show the following:

Series 1310 Maximum Driveshaft Torque: 1100 lb ft

Series 1350 Maximum Driveshaft Torguw: 2100 lb ft

Your numbers show 1548 lb ft at 2800 RPM after 3 to 1 first gear ratio. As your RPM increases your torque will usually decrease. Not knowing what tires you have and running a IRS setup I would think you'll slip the tires pretty quick. So by running the bigger 1350 joint you should be good to firewall it. I have added a link below that will give you the Spicer book in as a PDF document.

One other thought. I would stay away from any special type joints such as offset trounions or different diameter bearing cups that allow using a Ford to Chevy shaft/differential, etc. These are great for someone in a real need to mix-match parts. They are terrible if you're on the road and lose one in the middle of nowhere. Just a thought. Give one of the driveshaft guys a call and let them walk you through it. One more thing: If you have any doubts about the double cardan's strength just look at the rock climbing crazies. They have crazy angles and unbelievable low gear crawl ratios driven by hi torque engines. They twist axles, suspension piecies and even u-joints but that's their very meaning to exsist. If they don't break, bend or crash a rig at a climb then they have nothing to brag about Monday morning. They are the worst for punishing parts. You will have no problem. Hope this gives you something to think about. Have fun.

George
http://www.pirate4x4.com/tech/billa...Driveshaft engineering data - IJ900-02[1].pdf

 

[deckofficer]

George,

Thanks alot for all the good info. My peak torque is at 2800, so it falls off a bit from there. Are you suggesting a double carden CV driveshaft or just a plain driveshaft non CV? If CV, then question # 2. With the new 383 torque motor I just don't goose it in 1st. If road conditions allow it, I can roll on all the throttle in 2nd, so it does hook up very well. I use M/T Sportsman radials see picture.

Bob

 

[fluidfloyd]

Bob,

If you can adjust your pinion centerline so it will be parallel with the crank centerline then use what you have. If you have a big difference in angles then you should look at the double cardan joint. With a short shaft as yours I think you could get away with some misalignment in angles without a vibration problem. But with lots of driveline torque you relly should try to make it right. Being you have an idependant rear I would think it would be a major undertaking to change the pinion angle. I'd go the easy route. You can call for tech info from the shaft builders without buying one. If you decide to use the double cardan system you can probably have one built locally. As I've been out of town for the past year I don't have access to my shob library but a NAPA store should have all the yoke catalogs you need to find what vehicles ran those types of double joints. Then go to the wrecking yard or get your local driveshaft shop to order one. Hope this gets you out of trouble.

I don't want anyone to think I'm an expert on driveshafts/joints but I have been in the drag racing rear end business for over 30 years and I know how brutal this stuff can be. For now I have stepped away from that world and went into something a little bit different. Below are two links to the last car I built. This was a pure R&D project I took on several years ago. I did not build the body but my son and I built the entire chassis and suspension system and mounted the body one the first protype car as seen in the following video. Hope you enjoy it.

Damn that's a fine looking car!

George

http://www.jaylenosgarage.com/at-the-garage/sports-cars/scarab-replica/

Company website:

www.scarab-motorsports.com

 

[deckofficer]

George,

This forum has such diverse talent on board. I was duly impressed with the Scarab, a powerful and nimble light car, just what I am into. Mine weighs in at 1790 lbs full of fuel. Thanks very much, the 6 speed upgrade is back on. I will measure my current angles and get with the driveshaft shop armed with a little info on what is out there.

I'll keep you posted on the progress of the 6 speed install with pictures.

Bob

 

[Ted Brown]

To Bob or anyone that uses special parts, which covers a lot of folks, some times it is good to carry a spare, like points or late replacement ign. parts or U joints that not many parts houses carry in stock... When driving on a long out of state run, drive like your Granddad might drive, keep it all together, not acting like a kid and burn rubber all over the place, you may end up walking and taking your ride home in a box or trailer... you too, if all goes wrong... Drive safe PS, Bob, I wish you would either replace, or add leaves to that mono leaf front spring, as that is a safety hazard, another one of those not IF it will break, but a WHEN... I Just want to keep you in good health.