Tailshaft Angles (3 Viewers)

[frankenyota]

I have a rear 60 series diff, 60 series rear springs with a H55 5 speed in my '71 FJ40 and l'm setting up my rear tailshaft.
I made a rear tailshaft to suit from the rear 60 series tailshaft which is 530mm long ( Not sure what factory lengths are)
I have a tailshaft slope angle of 13 Degrees and transfer and diff angles of 5 degrees for a parallel tailsahft set up, which gives the uni working angle of 8 degrees. ( Too much)
The tailshaft unis binds up when lifted on the hoist and i think 8 degrees is too much working angle for the uni.
So i would like to run a unparalleled or broken back tailshaft set up.
This would give me a tailshaft angle of 8.5 degrees tailshaft slope, transfer 5 degrees and rear diff set to 10 degrees up and allow for 2 degrees lift under cruise, acceleration.
This would give me good working angles for the uni joints at 3.5 degrees.
Has anyone else run a set up like this in there FJ40?
Picture in middle is the un parallel set up

 

[Mace]

pics would help..

 

[frankenyota]

 

[frankenyota]

 

[65swb45]

It looks like your rear diff is already pointed ABOVE the centerline of the driveshaft. That is not a good thing on an LC, as the pinion torques upwards under load. The second illustration in your chart is not applicable to setting drivelines on a 40.

Best

Mark

 

[frankenyota]

The pictures are of the set up of a unparalleled shaft, the uni joints are at a much better angle then normal set up.
What are the main concerns running this set up?
Lack of oil to the pinion bearing?
Just looking at all options before i go to a CV style shaft, which can get expensive.

 

[65swb45]

Have you researched the FAQ on pinion angles?

Never mind. If your driveshaft is binding on the lift with that angle, you definitely will need a CV.

 

[Mace]

I'm missing how that driveshaft can be binding.

 

[frankenyota]

When lifted on a two post hoist the tailshaft cannot be rotated, even with some clearancing.
I know thats with both wheels at droop, maybe it will clear on flex with only one wheel down?
Did a search and most are worried about starving the front pinion bearing of oil and overfill the rear diff to compensate.
With a CV style shaft the pinion will still be rotated up to 7 degrees?
Is 8 degrees too much of an ask for the uni joints?

 

[65swb45]

We are obviously not talking the same language. Driveshafts can definitely handle more extreme angles to the numbers you are throwing around.

 

[frankenyota]

Whats the maximum operating angles for land cruiser universal joints?
From what i have read it should be around 3 degrees?
I had 9 degrees on my dual cab hilux and had to go with a CV style shaft to fix the vibration.

 

[frankenyota]

Just looking for some advice before i burn the spring perches in, then realise i have bad vibrations and then have to move the perches and change the set up. Want to get it right the first time.

Cheers Matt

 

[Mace]

Can you take a pic of the driveshaft at full droop and binding?
Cruiser driveshafts can flex quite a bit without binding. And sprung.under trucks aren't known for max flex.

 

[frankenyota]

No pictures of the uni binding, will do the parallel set up and flex it and see if it binds. Then get some pictures of it on the hoist at full droop.
I am guessing the short length of the shaft. The springs would be 2" lifted plus extended shackles should give about 3 " l guess, so not huge.
Heading off to work tonite for a few weeks.
I will do some more searching for maximum operating angles on cruiser uni joints.
Thanks for feed back so far.
Matt

 

[Fast Eddy]

You need equal angles unless you switch the front joint to a CV.

 

[shawnfj40]

Thats nothing a double cardin will not eliminate. You would just aim the pinion flange directly at the output flange for the transfer case, add a double C and your done.

 

[Splangy]

Thats nothing a double cardin will not eliminate. You would just aim the pinion flange directly at the output flange for the transfer case, add a double C and your done.

Or he could just set his pinion angle to work with his existing driveshaft and save a lot of time and money. I can't see how anything could possibly be binding with that setup.

 

[65swb45]

Or he could just set his pinion angle to work with his existing driveshaft and save a lot of time and money. I can't see how anything could possibly be binding with that setup.

Agree with @Splangy. In the unlikely event there is binding at full droop with pinion angle properly set, a limiting strap is still a lot cheaper than a CV.

 

[Mace]

Well

 

[shawnfj40]

Agreed, it is hard to beat setting up the proper angle.