Technical Drive train angles on ..an option to correct??

Each joint needs to be at least 1 degree different than the last and no more than 3 degrees between the first and last. I can email you an easy I use driveline calculator Monday when I am back at work if it would help. N


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The top image in the first illustration and the bottom of the second are both OK.

 

Couple of years ago I contacted the guy who made that prop shaft video and asked if he could do a demonstration with the angles like the top/bottom drawings, just to demonstrate, but he never got back to me.

The basic physics suggest it works perfectly well, but as suspension moves vertically the angles will alter vastly in relation to each other, as opposed to staying the same with the conventional set up.

 

Crawl under a Land Rover, an early one, and tell me you don't see the bottom one.

 

Oh yeah, I remember that. I just wasn't sure how the angled joints make the shaft accelerate faster, once or twice each rotation.

 

I don't mean to hijack thread but I'm having some trouble and would like help also.
Now I'm trying to get the right angles between the transmission and the rear end but I'm now quite getting it. I read all the posts a few times but for some reason I'm not there yet. I ran stringers to check the angles. I have the ****** down 3 degree and the rear end up looks like 7-9 so the bottom stringer from the rear end crosses the upper one from the ****** 3/4 s of the way toward the back of the ******. I don't want to tack weld the spring pads until i'm sure its right. Should I point the rear end down? and how much?
I would appreciate some input ty.

 

I will try to explain how my brain sees the angles the best.

the end result of what you build,.. is having both U-joints working at the same but opposing angles.

Some guys get confused using an angle finder that needs to be turned around when going from the pinion yoke face, and then go to the trans output face.

I keep my head straight by seeing what the front of motor is; so if the motor is "up" 3 degrees, then the pinion shaft also needs to "up" be 3 degrees. That makes a "two joint shaft" have same U-joint angles.

depending on the build style like say a RR with belly laying on the ground, the driveshaft can run uphill as you go to the rear. Or a high ch***is that has the driveshaft running downhill to the rear. Does not matter, as long as both joint angles match.

I hope I explained it well enough.

.

 

Ok. that is more helpful ty. I want to keep the engine angle at 3 point down in the back. So I need to flip the degree gauge on the rear end now?

 

Can I suggest a better/more accurate place for the angle finder gauge?

You are on a rough casting surface that may not be the true angle of the pinion shaft.

I would remove those 4 u-joint bolts and the two straps. Now rotate the flange so that one cup seat is at true top, and the other cap seat is at the bottom. See if your angle finder base can reach to the two flat surfaces of where the straps sit. If not, put the gauge base right where the u-joint caps sit. This will give you a honest reading of the pinion angle.

So, I see the car up on blocks and soft tire, whatnot. If you read the motor angle a long time ago, then double check it at the same day you set the pinion angle to weld it up.

One thing after rotating the rear end housing to get your degrees, now run something to both u-joint centers, to try to measure the working angle of the joint. Perfection is 3 Degree to keep grease flowing under the needle bearings in the cups, and that is also a good angle that is not too severe to cause vibrations.

There are online charts that give the maximum angle, if you measure the distance between both joints, but I don't see a severe angle in your pics.

If you are under 3 on the joint angles, report back and let us know. You can go less, a bit.

 

All that matters is ,,,,
The working angles are fairly equal.
This information is reflected every where but it's like they played the Telephone game and everyone adds their own personal spin and states it differently.

Below is an ilistration of what's typical on a lifted vehicle.
You'll note that the output shaft and the rear end are at Zero in this illustration.


Ok this^^^^ is a lifted vehicle headed off to the left of your screen.
If you flipped it like this
(Ignore the shifter and stick it on top)
Now it's a lowered vehicle headed off to the right of your screen.
Lowered With a A belly s****ing stance and a big *** Z in the rear frame rear and wheels into the Windows
Get it?

The operating angle or "the working angle" is clearly pointed out between the Two thick arrows. It's simply a relationship between the driveshaft's attidute and the U joint, that's all there is too it.

Here's the rub- you really can't get an accurate measurement on the driveshaft's angle or attidute without the drive shaft. So enter the confusion and nonsense and nincompoopery of the 3* up and 3* down when setting things up. That means NOTHING!!!!
However It could work great if your driveshaft angle falls on the realm of acceptable.

Take a careful and discriminate look at this famous pic already posted.
Really pic it apart. Look at the details, the bolt holes, the perspective lines on the bell housing, the math. The eloquent explanation,,,
Lots of work to help you out


All the way till you get to here-


Typical scenario for a hot rod stance, drive shaft running up towards rear.

That engine is not 3* down, but the text says it is. Oops mistake here for sure.
Did the enlightened goof on the text and math or goof on the graphic? The others are set at 3*. And again the rear is set at zero for illustration but text say something different.
Set yours up like its drawn and you'll have no troubles, set it up like it says and you could be in trouble.


So let's say this next pic is a top view of a set up with a perfectly level drivetrain. Everything 100% straight thru from the side with an off set pinion
...........TOP VIEW ........

Here all is well and there's not one iota of 3* up -turnaround - 3*down BS. The engine is at zero, the drive shaft is level and the rear end is at zero but the offset pinion or engine moved over for steering clearance creates the working angles. Why does that matter? Because !!!! You need to measure the angles in a 360* plane, monkey around in the same driveline with both 3* up down and an offset pinion and your calculations are off, maybe enough to send you chasing vibrations till the cows come home.



If you were to tell anybody who's familiar with measurements, angles, trajectories or fabrication or blueprints to draw you something or to build you something and used the exact words "3 degrees down and 3 degrees up" you'd get this.

 

As far as my Bostonhemi's reply I made, he said his motor IS already set up at 3degrees.

That is the reason my comments said 3 degrees, and my other reference to 3 degrees was the "optimum" U-joint working angle.

So if I was the target for your reprimand, look for someone else.

I also said run something between the two joints to get the working angle of the joints. I sure as **** can get an angle reading WITHOUT a driveshaft, and plenty of others do as well.

That can be misleading to someone asking for help. All that matters is correct and matching working angles. Working angle "max angle specs" change with driveshaft lengths. A shorty shaft can't handle a max angle spec for a long shaft.

Sorry to vent, but seems to me that I need to
.

 

None of that was directed to you.

I am unaware of shaft length having any effect on altering the Max angle the ujoint itself can handle. I'd like to see that info if it's available.
However the driveshaft length does play quite well into the diameter, and strength and how safe rpm that it can spin.






Here's a chart that shows how the angles relate to drive shaft speed




this chart shows life expectancy of the ujoint drops as the working angle increases.


Here's just a little bit on how compound angles are calculated to get the "true" working unjoint angle. Anyone who's moved an engine for clearance or running an offset pinion should be interested in this.




Mabe you can help me out on the driveshaft angle thing- getting the accurate and correct angle of it without the drive shaft. During set up and fabrication, The rear end is located but pinion angle is not set, so as it rolls up and down obtaining the best and correct pinion angle it's also changing the drive shaft angle as the pinion raises or lowers. Equally, as the tail of the Trans goes up and down that changes the angle of the drive shaft. The length of the drive shaft yoke stick out changes the driveshaft length and the length changes the drive shaft angle as well. Can you get close? Sure I've done it dozens of times. Does it result in matching working angles u joint angles? I'd say fairly equal is the best I've managed but that seems to be more than close enough. From the above chart, once the working angle gets above 3* just 1/2 of one degree drops the Rpms by 500. Kinda ****s if the engine will Run hard