[mason71]

Hello,

Working on my rear suspension I realized the pinion on my rear-end housing is offset by 2.75". This throws my drive shaft angles out much further than I was hoping.

I plan to run a 3.5" aluminum drive shaft.

As photoed the engine and transmission are pointed down in the back at 3* (carburetor base level) and the pinion is pointed down 1*. With the tape measure stretched across the span it reads 8*.

Are these angles too high even with such a short drive shaft?

Should I bring up the engine and transmission (carburetor base off level)?

Am I going to need to source a equal distance rear-end?

Thanks for any help!

 

[mason71]

more pictures

 

[123pugsy]

Here's a great guide for driveline angles from Spicer.

 

[timothale]

drive line angles

The center lines of the crankshaft and the rear end pinion must be paralled in both up and down and left to right. I didn't read the spicer posts again but I think they have a chart to compute the actual angle using both the up and down and side to side numbers. When I first looked at the 2003 Ford GT (modern version of the old GT 40) the drive shafts run offstet front to back. looked weird since I was used to looking at corvette and Jag rears. AS long as you don't get too radical it should work just fine. A lot of jacked up 4 X 4 trucks have high U joint wear because of excessive angles they run.If your trans is too close to the ground on a Z ed frame You can raise the trans up and then buy carb mount wedges, They are used a lot on boats. If you are running multiple carbs it might require a regular spacer and a wedge to get the linkages to work best.

 

[timothale]

good frame

Your frame looks good, and you used Fish Plates on the Z's One sugestion is to Have a removable center piece of your crosmember so you can drop the trans out easier. The first couple of T 's I built I had to take off the body to get the trans out.

 

[NEW INTERIORS]

When I set all mine up.. I put the carb base level, That will have the trans down 3*, Then I set the pinion 3* up..

Now if it's for the track, I will set the pinion level.. When setting it up this way, Sometimes it will look funny and you will think something isn't right,, But it work's.. Good luck..

And as far as the side to side.. Some cars came with the drive shaft off center..

 

[mason71]

Thanks for the tips, keep them coming. I really don't want to source another rear end, I have worked hard on this one. I swapped the gears, ground off the factory brackets, and got a really good deal on it.

My trans tunnel will be removable so I will service the trans through the interior.

 

[NEW INTERIORS]

you should be able to make what you have work..

 

[123pugsy]

Hello,

Working on my rear suspension I realized the pinion on my rear-end housing is offset by 2.75". This throws my drive shaft angles out much further than I was hoping.

I plan to run a 3.5" aluminum drive shaft.

As photoed the engine and transmission are pointed down in the back at 3* (carburetor base level) and the pinion is pointed down 1*. With the tape measure stretched across the span it reads 8*.

Are these angles too high even with such a short drive shaft?

Should I bring up the engine and transmission (carburetor base off level)?

Am I going to need to source a equal distance rear-end?

Thanks for any help!

First thing you need to do is get the pinion up to 3*. The angles need to be the same.

That 8* you have with the pinion down 1* will be more when the angles are the same. (pinion up).

If it stayed at 8* less 3* is 5* angle. They recommend 3* to be optimal but 5* may be OK.

But, with your pinion down 1* and rotating it up to 3*, the angle will end up more than 5*.

The suggestion about lifting the tranny up seems like the best way to go.

 

[cliff tate]

drive line angle

read the dana artical. it claims aslong as both face angles ar within 5dg tpparalel you ar ok.you do not toline up the output of the engine eith the diff,you need the out put face to be with in 5dg max of input of diff.the diff input can be3or 4 in left or right of engine.the alighn ment should be measured withwheels on the ground weight. look at the older ford vans,the diff input is way over to 1 side,also look at 4x4s that ar lifted,they ar a bit to radical. you can get a magnetic degree gauge for unde20.00 that is all you need. the engine center line must be paralel with the diff. but up down sidways ok if face angles within the 5dg

 

[NEW INTERIORS]

read the dana artical. it claims aslong as both face angles ar within 5dg tpparalel you ar ok.you do not toline up the output of the engine eith the diff,you need the out put face to be with in 5dg max of input of diff.the diff input can be3or 4 in left or right of engine.the alighn ment should be measured withwheels on the ground weight. look at the older ford vans,the diff input is way over to 1 side,also look at 4x4s that ar lifted,they ar a bit to radical. you can get a magnetic degree gauge for unde20.00 that is all you need. the engine center line must be paralel with the diff. but up down sidways ok if face angles within the 5dg

I think he has a magnetic degree gauge.. Take a look at his pictures..

 

[cdminter59]

Here is another article from Inland. Empire.http://www.iedls.com/asp/admin/getFile.asp?RID=5&TID=28&FN=PDF

 

[123pugsy]

Nice article. Pinion and driveshaft the same angle and angle of driveshaft to pinion/tranny yoke no more than 3 degrees.

Looks like the OP has some adjustments to make.

 

[mason71]

Thanks for the tips guys, after doing some more measuring I realized the net over head offset is more like 1.25" due to the fact that my engine and transmission is not perfectly centered.

After bringing up my transmission and reducing my angles as most as possible I'm hoping for the best.

 

[prostreet6t9]

What are you doing for the rear suspension? Have you thought about bringing the whole rear end housing down?

Do you have a suspension you could mock up to get a true ride height?

 

[NEW INTERIORS]

I still feel you won't have the problem some say you will.. Not enough to cause a problem..:nono:

 

[123pugsy]

Randy's probably right. He's built a bunch of chassis.

Just hate to see you finish and then have an annoying vibration. ain:

 

[prostreet6t9]

I still feel you won't have the problem some say you will.. Not enough to cause a problem..:nono:

Not arguing with ya Randy It may very well work just fine.

Once a year the Spicer rep stops by and we get Certified "not sure if that means anything" Certified in what I'm not sure lol.

The Rep brings in a stanture mocked up with a 2ft D/L with 2 joints in it that you can change the angles at will. I have to say that little tool changed some of my thinking about angles. In post#2 Pic #1 the diff looks about 2" higher than the center line. Just a Idea... Trying to iron out those gremlins can be a pain.

 

[NEW INTERIORS]

I have had some with a good bit of angle on them with no problems... Look at most of the 4x4's with way more angle on them... And the u-joints don't go out like some say... I had a 1979 4x4 blazer and it was very high,, I could not touch the roof standing on side of it.. And I'm 6'... Never had problems with u-joints.. So I would tack everything in place at ride height and spin the back wheels with the drive shaft hooked up and see how it feels.. But from what I see.. I would build it.. I don't see it being that bad from the pictures..

 

[mason71]

I emailed Dennys Driveshafts and he felt like I would have some issues especially with the shorter than normal shaft.

I am going to raise my transmission to help reduce my angles as much as possible. Here is our conversion:

Denny: With short driveshafts it is very important to have everything inline and no offset at all.

You will need to install a rear end that has the pinion in exactly the right place to allow for a straight line from pinion to trans.

Me: While measuring a little more I realized the over head net difference is more like 1.25" due to my engine and transmission being mounted offset.

I am planning to go ahead and use this rear end. I was thinking about bringing the transmission up to decrease the driveshaft angle.

Any thoughts? Thanks!

Denny: Get your angles as little as possible so the total amount of offset will not cause too bad of a vibration. Technically you should have vibration with that short shaft and compound angle. You might get lucky and the offset may not react so badly.