Outer Limits 4x4 Board

I want to get my rear pinion angle clearance up higher and instead of running a DC and having the the pinion point to the T/case can you run the pinion like this (pic) the pinion to shaft angle is same as the out put to shaft angle

Doesn't work!

I tried it myself. Apparently it's only good for low speeds and/or light wall shafts. A soon as you have a heavy walled shaft, you'll get bad vibes.

To put it into perspective, I couldn't get over 40km/h with my uni angles like that!

Yes, as long as the angles are equal, the output shaft and pinion do not have to be parallel.

Watch out for lack of oil to the front pinion bearing. Keep a good eye on the temp until you are happy there are no issues. Or maybe make a slinger up that will bolt to the carrier using one of the crown wheel bolts.

Edit: Beebee posted while I was typing. I was not talking from personal experience, so his comments have more weight.

Try it if you want, and report back, but according to the theory, the driving shaft (ie, your output shaft at the transfer) and the driven shaft (on the diff) must be parallel. Otherwise, the rotation becomes "jerky."

What happens with a universal joint is that the driveshaft (the middle shaft in the system) rotates faster or slower depending on where it is in the rotation, because a universal joint is does not transfer rotational speed in a perfectly uniform way. In other words, if your output shaft at the transfer is rotating at a constant speed, the driveshaft will actually be rotating at a fluctuating speed - a little bit faster, a little bit slower, during every rotation.

When the driven shaft and the driving shaft are parallel, and the universals are lined up together, the two universals compensate for each other's jerkiness.

See here: http://en.wikipedia.org/wiki/Universal_joint

ps I too am not talking from personal experience, although you can play with a universal joint yourself and see that the rotation is not perfectly transmitted. That's why there are always two.

Jason

I might just run a DC it`s not that much differance from that pick

but can you run that sort of angle with a cv driveshaft?

Rhett wrote:but can you run that sort of angle with a cv driveshaft?

You will need to run 2 DC (double cardon/cv joint)
all you need is 1 a run the pinion angle straight inline to the shaft

www.cvcoupling.com/

try this on for size
local boys up here figured this out.

doesn't address your problem but worth a look

Chad

4sum4 wrote:I want to get my rear pinion angle clearance up higher and instead of running a DC and having the the pinion point to the T/case can you run the pinion like this (pic) the pinion to shaft angle is same as the out put to shaft angle

correct me if im wrong but to run a setup correctly in this configuration the pinion would have to point straight up 90 deg to output shaft(tail shaft at 45 deg)??????? isnt that the same as the pinion and output shaft being parralel???Im not sure!!(limited by unis anyhow)

as picured: no it wont work. difference in uni angle

thinking out loud

you can run it like that if you do run a cv at the output end but as stated the bearing in the pinion would not get oil.

Chad

Yes it will work and work well It is called BROKEN BACK pinion set up. My old Mk was set up this way and it never had a viabration problem.. You can have no more than 5 deg difference in uni angles! so on set up have the angles set up on the shy side say 3 deg then on wind up of torque you may get to 5 deg if you get a little viabration on heavy acceleration so be it. If your not running decent spring packs you may need an anti wrap bar. Runnung this way is good on swb vehicles to avoid big tailshaft angles. and to avoid excesive uni joint wear. I did probably 40000kays on mine without having to change uni's once. By the way the crownwheel throws oil forward onto the pinion bearing again never had a problem,

DR Frankenstine wrote:Yes it will work and work well It is called BROKEN BACK pinion set up. My old Mk was set up this way and it never had a viabration problem.. You can have no more than 5 deg difference in uni angles! so on set up have the angles set up on the shy side say 3 deg then on wind up of torque you may get to 5 deg if you get a little viabration on heavy acceleration so be it. If your not running decent spring packs you may need an anti wrap bar. Runnung this way is good on swb vehicles to avoid big tailshaft angles. and to avoid excesive uni joint wear. I did probably 40000kays on mine without having to change uni's once. By the way the crownwheel throws oil forward onto the pinion bearing again never had a problem,

Yer, I read about this after my post. Apparently it puts more strain on the slip joint but that's the only problem, and it is the stock layout for some older landrovers.

Interesting option.

I`ll be going about 80kph at max at that will be about 4-5 times a year,the rest of the time I`ll be at 30-40kph
I`m not overly bothered about vibration just worried about weak points

Some info on the broken back set up described by Dr F:



(The middle one is the broken back design.)

http://www.pirate4x4.com/tech/billavist ... ndex2.html

You still need to get the angles matched. Remember to tell people you're happy with your broken back setup, not your Brokeback setup!

ahh yes it all make sense now.

Broken back??? is the same as a H block in a cardinal joint used in a swivel hub.

i was told that uni's angles work best between 1 - 8 degrease

just a bit of info i was given once

with ur originall set up she aint goin to work, u will bend shafts or slip joints, i found out the hard way, i had my pinion up about 7 degrees to high, was having endless probs untill i droped it down, now its all sweet.

bazooked wrote:with ur originall set up she aint goin to work, u will bend shafts or slip joints, i found out the hard way, i had my pinion up about 7 degrees to high, was having endless probs untill i droped it down, now its all sweet.

Yea look I agree the pinion is probably a bit high but all depends on where the transfer output is located. To overcome this problem just lower the transfer mounts down an inch or two

bazooked wrote:with ur originall set up she aint goin to work, u will bend shafts or slip joints, i found out the hard way, i had my pinion up about 7 degrees to high, was having endless probs untill i droped it down, now its all sweet.

Yea look I agree the pinion is probably a bit high but all depends on where the transfer output is located. To overcome this problem just lower the transfer mounts down an inch or two

bazooked wrote:with ur originall set up she aint goin to work, u will bend shafts or slip joints, i found out the hard way, i had my pinion up about 7 degrees to high, was having endless probs untill i droped it down, now its all sweet.

Yea look I agree the pinion is probably a bit high but all depends on where the transfer output is located. To overcome this problem just lower the transfer mounts down an inch or two

Uni angles are funny things! As I said, mine was terrible with the "broken back" setup. I ended up with a double carden at the transfer and a std uni at the diff. However, with the pinion flange set up at a perfect 90 deg to the shaft, I get unacceptable vibrations.....however, point the diff up another 3deg, and the vibrations are all but eliminated! Work that out!!

Something that I failed to mention is that my driveshaft probably weighs in at around 15-20kg so there's a bit of rotating mass there