AuthorTopic: Drive line angle  (Read 4591 times)

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Offline hotrodharley

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Drive line angle
« on: April 25, 2018, 09:04:34 PM »
Building a pro street rat rod truck..with 33x21.5×15 M/T tires on rear..this puts my pinion on rear end very high off ground..can there be a angle on drive line where the u joint at rear end is higher then u joint at trans..way it is now is the drive shaft goes up from trans to rear end..example is u joint at trans is 10" up from ground and u joint at rear end is 14" up from ground.

Offline hotwheels

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Re: Drive line angle
« Reply #1 on: April 26, 2018, 08:43:18 AM »
Basically you need to take a level and go straight out from the center cup of the tranny yoke and to the same from the rear end. Where the center of the drive line is, make sure the distances are equal. You may have to adjust the pinion angle up or down to try an get the distances to be equal. If that makes sense...
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Offline lowboy

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Re: Drive line angle
« Reply #2 on: April 26, 2018, 02:15:04 PM »
I bought a cheapo magnetic angle finder to do the bugs. It's not correct but it's close. I don't notice a difference from the stock to current angles. It still runs the legal speed limit plus 1 mph  :o ;D ;D ;D
life is a ride where you slide into heaven sideways on 4 flats blown motor saying Thank you God what a ride!!!!!

Offline lowboy

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Re: Drive line angle
« Reply #3 on: April 26, 2018, 02:38:48 PM »
Took me a while but I found this video for you.
life is a ride where you slide into heaven sideways on 4 flats blown motor saying Thank you God what a ride!!!!!

Offline Ratty51F1

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Re: Drive line angle
« Reply #4 on: July 14, 2019, 10:47:23 AM »
I did what lowboy did Picked up a couple different magnetic/digital ones from summit that's been a Big help as the one I had with a needle pointer I had to crank my head to see it in confined spaces

The internet is full of opinions some informed some I'm sure not, even supposed magazine experts seem to be at odds which is confusing the heck out of me at the moment

Most agree at least 1/2 degree difference at each end of the drive shaft to "work" the grease in the U-joints is needed ...I get that

With my F1 on the ground/suspension loaded and temporarily mocked up I have......

Engine/trans 4 degrees  (which puts the carb mounting surface at 0 degrees/level)[using Holley Sniper anyway so not really an issue]

driveshaft 3 degrees

rear end 2.5 degrees

That leaves me at a 1 degree difference for the front u joint & a 1/2 degree on the rear u joint

This is the first time I've done this and want to get it right the first time(who doesn't) I know I tend to over think things ALOT but like I said who wants to go back and redo when you have the time to do it right!?

Anyone with some experience  on this want to comment please do

THANKS and Sorry for the Hijack  ::)

« Last Edit: July 14, 2019, 11:10:58 AM by Ratty51F1 »

Offline lowboy

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Re: Drive line angle
« Reply #5 on: July 14, 2019, 07:14:18 PM »
sometimes I wonder if the angle is all that critical. Seen some 4x4 jacked up trucks running some off the wall angles
life is a ride where you slide into heaven sideways on 4 flats blown motor saying Thank you God what a ride!!!!!

Offline Blackwater

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Re: Drive line angle
« Reply #6 on: July 15, 2019, 06:41:11 AM »
For optimum U-joint life, angle is, if not critical, at least important. Some of those jacked up 4X4s will have spare U-joints in the glove box or tool box at all times!! Some even carry a spare drive shaft and a lot of them only put the front shaft in when they go off road!!

One thing I've learned is that so long as the joint doesn't get TOO much angle, and so long as it isn't spun too fast, you can get by with some pretty odd configurations. Getting pinion angles adjusted properly can help, but remember that what you do on one end directly effects what happens on the other end.  If you take angle out at the pinion when the shaft runs downhill from the out put to the third member, it will take angle out at the other end as well, but IF your driveshaft runs UPHILL, the angle increases on one end as you decrease it on the other!  Don't rule out the double joint configuration on either or both ends. It's a little bulky and it's ugly as hell, but it can get you around some pretty radical angles, safely.
« Last Edit: June 30, 2021, 09:21:15 PM by Blackwater »
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Offline Ratty51F1

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Re: Drive line angle
« Reply #7 on: July 15, 2019, 04:58:36 PM »
In the photo hotwheels posted is the same American power train is using in their paperwork I have, they state the optimum angles at rest are equal and opposite 2.5 degrees just like in the pic, from my understanding under Full power you want the whole combo to "straighten out" to transmit that power with minimum drag.... yes Spicer recommends .5 degree for grease/bearing movement but we are talking FULL power ... your not there that often(some more than others  8) )

I know the rear end yoke rises under power and will align with the driveshaft BUT I've never really paid attention to what the engine does under  power except that it rolls a bit to the passenger side because of the crank rotation but does does the tailshaft of the trans tilt Downward under full throttle?
it must under their equations

BTW here is SPICER's calculator comes in handy

https://spicerparts.com/calculators/driveline-operating-angle-calculator

Offline just old

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Re: Drive line angle
« Reply #8 on: July 16, 2019, 07:21:02 AM »
I only no on my 2 it comes to about 7 degrees I don't no were I found that but that is what I used

Offline Blackwater

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Re: Drive line angle
« Reply #9 on: July 21, 2019, 07:35:22 PM »
NO!  In general, the transmission output shaft normally remains stationary.  The change in angle at the output end results from the rise and fall of the third member.  As the rear axle rotates upward in relationship to the output of the transmission, the angle at both ends changes in corresponding amounts.

In the instance where the transmission output is lower than the input to the rear end, where the axle rotation would INCREASE the U-joint angle when power is applied, it would probably be advantageous to use a two piece drive shaft. 
Never use a minor caliber bullet on a major caliber adversary!!

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