jag rear end in a t bucket

[itsed2]

Well if it wasnt for you all id never have gotten this far , ok I have the center pumpkin in and the housing were the drive shaft gose is pointing up about 2 to e inc,, what im asking is does it need to point out inline with the frame ? are can it tilt up a bit... please help Im at a loss... ( going nuts in tulsa okla) ..lol

 

[Aussie T]

G'day Mate
I'm Tim from downunda. I put a jag rear in my bucket and was equally confused. Do a Google search "driveline angles" and that will explain all you'll need to know. Basically tho looking from side view the centreline running through your crankshaft has to also be the same as your centreline running through your diff. They can however be above or below, but as long as the 2 lines are parallel. Sounds a bit like gobble de gook but if you look at the pics it'll make sense. In my bucket, I think the diff yoke was only about .5deg pointing up (thats in relation to the ground, the chassis is irrelevant) and the motor pointing down .5deg.

Check out my website for all the build pics sofar (still building but havent done much lately so havent updated website)
Aussie T's website

Aussie T (Tim)

 

[Gerry]

G'day Mate
I'm Tim from downunda. I put a jag rear in my bucket and was equally confused. Do a Google search "driveline angles" and that will explain all you'll need to know. Basically tho looking from side view the centreline running through your crankshaft has to also be the same as your centreline running through your diff. They can however be above or below, but as long as the 2 lines are parallel. Sounds a bit like gobble de gook but if you look at the pics it'll make sense. In my bucket, I think the diff yoke was only about .5deg pointing up (thats in relation to the ground, the chassis is irrelevant) and the motor pointing down .5deg.

Check out my website for all the build pics sofar (still building but havent done much lately so havent updated website)
Aussie T's website

Aussie T (Tim)

Be careful here guys. As far as I know the Jag IRS diff had a number of different angles on the top pad (mount). Also the diff points down at the front to encourage anti dive. Mine points down by 9 degrees.
Gerry

 

[Gerry]

Be careful here guys. As far as I know the Jag IRS diff had a number of different angles on the top pad (mount). Also the diff points down at the front to encourage anti dive. Mine points down by 9 degrees.
Gerry

Just thought that when I say down by 9 degrees... thats the angle of the pad (mount) at the top of the diff.
G

 

[Lee_in_KC]

The diff pad on my Jag ('77 XJ-6) is 5 degrees. I put 2 degrees in the mounting plate on the frame, leaving 3 degrees up on the pinion. This matches the 3 degrees down of the tranny output shaft. These degrees are all relative to the frame. My T chassis has a 3 degree rake, so my driveline sits level to the ground. I probably just confused everybody!

 

[Lee_in_KC]

Here are some CAD drawings of my set-up (done by GAB)...

 

[Aussie T]

Just to add another spanner in the works, the stabilizer bars in Lee's cad drawings reminded me.
The front mounting points are VERY critical. If they are not absolutely correct you WILL get binding as the suspension moves thru the arc up and down. I used mathmatics to calculate my points, then when fitted, took the springs off and checked for full movement up and down and no binding, so my calcs were good or I was just LUCKY, I'm betting it was more luck than anything :winkn:

Just giving you more to think about
Have fun, we're here to help.

Aussie T

 

[Lee_in_KC]

Very good point, Tim. The front pivot point of the stabilizer bars needs to be in the same axis as the inboard pivot shaft of the lower control arms (wishbones). A lower tech way to line them up would be to mount the differential in the frame, then mount the trunnions for the lower control arm pivot. Find a rod or dowel long enough to reach from the back of the diff to the back of the transmission crossmember and slide it through the bosses on the trunnion where the pivot shaft goes. Push it forward until it touches the crossmember, then mark that spot. That will be the attach point for the tabs shown in the CAD drawing above.

 

[putz]

If you are worried about drive angle after it is installed here is the answer a Tom Wood extreme angle joint that is offset just a little but still is balanced.They use these on high trucks and rock crawlers.

 

[Screaming Metal]

If you are worried about drive angle after it is installed here is the answer a Tom Wood extreme angle joint that is offset just a little but still is balanced.They use these on high trucks and rock crawlers.

And those are alot stronger than stock also!!!!

 

[Keeper]

I found this site is very helpful:

http://www.uk-hotrods.co.uk/v2/tech/jag_rear/tech_jag.php

This one as well:

http://home.bresnan.net/~dazed/JaguarIRS2.html

 

[itsed2]

G'day Mate
I'm Tim from downunda. I put a jag rear in my bucket and was equally confused. Do a Google search "driveline angles" and that will explain all you'll need to know. Basically tho looking from side view the centreline running through your crankshaft has to also be the same as your centreline running through your diff. They can however be above or below, but as long as the 2 lines are parallel. Sounds a bit like gobble de gook but if you look at the pics it'll make sense. In my bucket, I think the diff yoke was only about .5deg pointing up (thats in relation to the ground, the chassis is irrelevant) and the motor pointing down .5deg.

Check out my website for all the build pics sofar (still building but havent done much lately so havent updated website)
Aussie T's website

Aussie T (Tim)

Thanks your a reall help

 

[itsed2]

Well if it wasnt for you all id never have gotten this far , ok I have the center pumpkin in and the housing were the drive shaft gose is pointing up about 2 to e inc,, what im asking is does it need to point out inline with the frame ? are can it tilt up a bit... please help Im at a loss... ( going nuts in tulsa okla) ..lol

Gee thanks to all that helped its nice to get different views on this ,, again thanks and keep them coming

 

[Screaming Metal]

Well if it wasnt for you all id never have gotten this far , ok I have the center pumpkin in and the housing were the drive shaft gose is pointing up about 2 to e inc,, what im asking is does it need to point out inline with the frame ? are can it tilt up a bit... please help Im at a loss... ( going nuts in tulsa okla) ..lol
[/quote

The guys here have got ya covered, but I can tell your still a little mystified by the Geometry of it all. Lee gave you the math, just let me say something to kinda let you get your head around this.

You've heard all of us at one time or another talk about driveline geometry, pinion angles, setting such-an-such up. When your standing beside your car, if you had x-ray vision so you could see the trans, driveshaft, and rear, you'd notice that the driveshaft is slightly outta align with the trans. and rearend. This is the static position.
IF, you grab that driveshaft, and spin it, like it is in the car, as you move the rear and trans off axis, the more you go, the more 'camming' effect your gonna have, you gonna notice a slight vibration. More angle, more vibration.
Whenever you apply torque to your car, thru the drivetrain, things are not long static, motor mounts are twisting, rearend wrapup is occurring, and if everything is setup correctly, going down the road cruisin', THEN, your driveshaft, trans and rearend should be in alignment.

If your rear has 4.11 gears, that driveshaft and rearend yoke is singing along @ 4.11 turns per every revolution of that tire. Next time yur out on the highway, and your doing 60 mph or 70, look at the car next to you, and see how fast that wheel is rotating, multiply that X 4.11.....scary, isn't it! Just imagine a fairly heavy drag car running the 1/4 mile with 5.56 gears, thats the reason why they run driveshaft loops.

Some of the altereds and FC's we do, depending on whats going on, big blown all out hemi and all, they might run 3.90's and then you see them boil the tires off the line, think of the yoke rpm in these things. They don't realy have a driveshaft, so-to-speak, the rear trans yoke more or less bolts up to the rearend yoke....(we have diff. Terms, of course).

Our major enemy is vibration, the Motor is spinning at 9500+ rpm, rear gears are 3.90's there abouts, and your shooting for just barely slightly spin the wheels on takeoff...just enough to wrinkle the sidewall, putting all the power to the track. At that rpm, even the slightest vibration will destroy the whole drivetrain....Altered and FC drivers DO NOT LIKE things coming apart under their butts!!!! There's a big hunk of metal there to protect them, but they still don't like it.
Even in a light car going relatively mild road speeds like say 70 mph, if things aren't setup right, the potential for disaster is high. Even in my mild street cars, I ALWAYS run a driveshaft safety loop! Always check your driveshafts, and these things got weights welded onto them. If you loose a weight and have a littlebit of slack in a u-joint....its a big recipe for a whole lotta no fun!!!!!

Driveshafts in general are dangerous, the amount of abuse they take is staggering. And in a bucket the only thing you got between that whirling piece of steel and your butt is a thing piece of plywood and/or fiberglass. Whether you run a convential rear or a independent like a well setup jag that will bite the pavement even harder if setup correctly...always, I mean always run a driveshaft safety loop!!!!

Once you've ever seen a car thrown into the air by a front u-joint blowout, you'll never drive without one......

....STAY SAFE MY FRIENDS....