need advise on my method of driveshaft angle

[love-my-V8-280Z]

I just installed a new drive shaft on my 280Z with a LT1 T56.

I did some studying from archives and found I need about 1 degree of angle.

Now I installed the drive shaft and the Transmission cross bar.

I placed a level on the solid steel slab under the dif, I think it’s just a skid plate. I level this point by adjusting the car stands.

Now with the car level, I adjusted the distance between the transmission and the cross member until the drive shaft was also level.. Now if I just add the 1 degree of adjustment to the transmission by shimming the cross member don't think this should work?

Thanks, guys I would not have been able to do this project with out this site..

[John Scott]

The drive shaft can be at an angle from top to bottom or left to right. What is critical is a PARALLEL match, on the VERTICAL plane, engine and rear should be square to eachother as well. Use an angle finder, cheap at sears or other. Place on the face of the differential pinion flange mounting surface and then the rear of the transmission. You need to set angle finder just outside the output shaft, or on another flat surface such as pan, as long as it is parallel to centerline of transmission. Also easy to do with just the yokes in place before you start measuring for driveshaft length. Measure against the outside of yokes in vertical position. I prefer the machined surfaces for more accurate measuring. 85/95, 90/90, 91/89, whatever, angles should = 180 degrees. 1 or less degree, I believe is what you are looking for. Perfectly phased is ideal unless engine and trans are exactly in line on all planes. Not likely. Some consider having a slightly lower pinion angle to compensate under power, since pinion raises under torque. Most diddle with the angle of the differential. In my swap I shimmed the trans crossmemeber 1/4" to attain 0 0n my finder, use solid rear mount. Suprisingly quiet and no bad vibes at any speed. John

[mark]

Geart ingo John. How about moving this to Petes FAQ page?

[love-my-V8-280Z]

John,

Thanks, but I don't understand it. I have read other comments close to the same..Dont' you think the way I explained it will work?

What I don't understand is What is critical is a PARALLEL match, on the VERTICAL plane.

Ok, tell me if I got it, I need to make sure the transmission is level in the up and down movment, so that it is level with the dif.

I understand the side to side movement of the trans is not important, Also did I understand you right, you used steel to fill in the gap between the trans and the trans support? I was going to user a rubber disk the thickness I needed to get the level I need to match the trans with the dif...

Thanks for your input

[Pop N Wood]

Your way of doing it isn't going to work. Side to side means just as much as the verticel plane.

 

Best way I can think of it is draw a straight line out of the transmission shaft and a second out of the diff yoke. Line up the trans and diff so these two lines point straight into each other. this is zero angle. Now tilt the front of the engine down a half degree and the back of the diff up a half degree. The two lines will be perfectly parrallel (the exact same distance apart all along the line). This is 1° of drive shaft angle. You can also move the engine and (or diff) sideways by and inch or two. As long as it doesn't twist, the two lines will still be parrallel giving you a good drive shaft angle.

 

What you want is the angle between the transmission output shaft and the drive shaft to be exactly the same angle (but in the opposite direction) as the angle between the drive shaft and the diff yoke. That way the angle at the back U joint cancels out the angle at the front.

[love-my-V8-280Z]

Got it! It’s hard to understand when talking parrallel and vertical.

The way you explained tipping the engine and the differential made it easy to understand. I have no misunderstandings about the issue now..

Thanks Again...

[American]

If I understand this correctly, 1-3 are ok but number 4 is not?

 

[love-my-V8-280Z]

Is this looking at them from the side or the top?

[American]

Sorry.. from the side.

[John Scott]

If I understand this correctly' date=' 1-3 are ok but number 4 is not?

 

[img']http://www.sporttwin.com/280z/transdif.jpg[/img]

Yes. From over head view, similarly, engine can be offset left or right as long as the centerline is parallel to the centerline of the differential. John

[VRJoe]

There are two angles to be aware of:

 

1) the VERTICLE angle - the angle the drive shaft slopes between the trans and the diff.

 

2) the HORIZONTAL angle - the amount of difference LEFT - RIGHT between the trans and the diff.

 

The two angles work together and must be added using good old trig (and you thought you'd never use it after the last test in high school).

 

Here's one link that may help The Driveshaft shop

 

And Another Street Rodder

 

Also note that 1 degree is the MINIMUM, I forget how high you can go. I had a good conversation with the guys at Denny's Driveshaft about this. I did all my calculations quite a while ago and they were in tolerance.

 

You must make the measurement from the flange, not the bottom of the diff or the bottom of the trans.

 

I thought I sent you a description of the way I calculated mine a while back, I should be able to find it again if you need it.

 

- Joe

[Pop N Wood]

Is this looking at them from the side or the top?

 

Actually for the drive shaft it doesn't matter. You need to look at it from two different angles to get the total 3D view. Basically what VRJoe is saying

 

For the half shafts, your diff had better be lined up parrallel to the wheel, like 1 and 3, or your half shaft angles will be wrong. This means your engine centerline must be parrallel to the diff and wheels.

[Guest nitr0x99]

i agree!

[love-my-V8-280Z]

I will get a angle finder and get it figured out over the holiday weekend,

Thanks again.