Driveline Angles!

[78zlt1]

I have studied Petes' Excellent web Page and read the forums till my eyes bleed, so I think I understand , but just looking for verification.

 

I first made Ron Tylers famous Diff mount , installed urethane bushings in the mustache bar and installed the diff. The engine/tranny (95 LT1/T56) was installed using the JTR mounts, and a jack holding up the tranny ,(havent made the tranny crossmember yet)

 

The Diff shaft's center is 3/4" from center towards the pass side,

I Located the center of the tranny shaft so it is also 3/4" from center towards the pass side.

 

I didnt modify the mustache bar urethane bushings and used the top washers also.

 

So I took some measurements and layed them out to see what I had,

And this is what I got...

 

So my forward and aft operating angles are .789 degrees each and my Trans/diff operating angle is 0 degrees?

 

I'm just cant believe everything lined up the first time, without alot of modifications to do. maybe i got lucky

 

 

 

 

[Cal Poly Zmanaustin]

Nice work. Very Impressive.

[buZy]

Yes looks good!

Last time I did this the one looking down from the top of the car (vert) was very hard to measure paralell compared to the side view (horz) shown in your drawing. How did you do it exactlly? Just 3/4 over and its paralell to the pinion shaft using JTR mounts? I just ask as my car is not JTR mounted.

[78zlt1]

The way I measure the verticle offset of the transmission shaft and the Diff flange is not difficult , When I installed my front frame rails and my subframe connectors I made a jig so that they are parrallel both horizontally and vertically to each other and the car , So I can use the subframe as a datum to take measurements. I center a yardstick between the subframes and use a square to find the offset.

This picture will explain it better.

 

 

the 24 inch mark is the centerline of the car

 

 

I also measured the crank pulley and it is also 3/4" offset to the pass side.

So I know the engine is parallel to the cars centerline.

 

I use those Dial angle gauges to find my angles, they seem to be acurate to .5 degrees.

 

Transmission angle:

 

 

Diff angle:

 

[buZy]

Very nice! You got it for sure. Thanks for sharing the information.

Brian

[zguy36]

So output shaft of the tranny is coaxial with the input of the differential? This is not good to have both shafts on the same axis. This makes it so that the needles in the u-joints will never turn, which will wear them out faster and make them weaker. (Each needle wears a tiny groove in the race since they don't rotate making a stress concentration and a breaking area) Ideally, you want a couple of degrees angle for each u-joint to take up,but still have both shafts parallel.

[alternativez2003]

OK, so maybe an uninformed question: Why are your engine's and drivetrain's centerline not on the car's centerline? I'm in the middle of aligning mine and don't want to screw things up. I figured everything should be centered. I appreciate this thread, very informative. What was "Pete's webpage" that you referred to? Thanks

[kcelectronics]

How much driveline angle is right for my application?

Thats a loaded question. The best answer is....the least amount of driveline or u-joint angle is the best amount of angle. Try to achieve the least amount of u-joint angle but don't make it less than 1 degree. A little known fact about u-joints is that they require about 1 degree of operating angle to get the needle bearings rotating. If they do not rotate they will fail. Too much angle will also cause them to fail. The type of rear suspension also plays a big part in setting the angles as well as the engine/transmission angle. Leaf spring cars have a need for more downward pinion angle due to spring wrap-up while coil spring cars control the situation better. Hard acceleration as in the case of a drag race car requires a different setting than a street driven car. Traction bars, ladder bars, 4 links, independent rears all have special needs and requirements.

[78zlt1]

Thanks zguy36 , So should I lower the diff .5 deg and raise the tranny .5 deg? that would keep it parallel but increase my ujoint angles, I'll try that and see what I get.

 

alternativez2003 Pete Paraska's Page has a wealth of information , its at

http://alteredz.com/ read it all very good stuff.

 

As for having the driveline on the centerline , Do you mean the horizontally or vertically? Horizontally (up/down) you could but you'd have to raise the diff or lower the engine/tranny , but that would decrease the ujoint angles more which is bad as zguy36 & kcelectronics said. as for vertically (left/right) I dont think you can .... the R200 input shaft is offset 3/4 inch towards the pass side, the JTR mounts also shift the engine/tranny 3/4 inch to the pass side to line up with the diff. I didnt measure but I'm sure the stock engine was offset the same amount.

[alternativez2003]

Thanks for Pete's Page and the centering comments. Actually I meant vertically, left/right. So you are aligning your engine to the diff which is off-centered? I am replacing everything with a BMW drivetrain which was centered in the original car, so I was planning to center it vertically in the Z. I got alarmed when I saw your post, that there might be some reason, even particular to the Z, for aligning off center. Also the bimmer driveshaft is a two piece with a center bearing, so setting up the horizontal diff angles is flexible. So, I think I will continue on my plan, but I have appreciated your information and the comments you have generated on the subject. Every bit of information is helpful to getting the job done right. What engine are you using? Maybe I missed that somewhere. Good luck with yours. Nice precision work.