Reversing ZF axle shafts

are you speaking of the half shafts.
I though the larger diameter was towards the upright?

The large part of the output shaft is closer to the ZF like the bottom picture.

The bigger part of the shaft is closer to the ZF.

the top is the unaltered scan.
the lower is my cut/paste with Paint

The few that I have looked at are like the bottom diagram and the picture I posted.

Many of us have switched the half shafts as you describe to gain a bit more clearance for the exhaust pipes.

I have never experienced nor heard of any downside or problems associated with this change.

Larry

I had done a search and didn't come up with anything, but it is good to hear that from somebody that had done it.

Larry, I am considering it for the exhaust clearance, just like you stated.

Thanks

Since I purchased my car all apart I don't know which orientation is stock. Assuming the big end is heavier, having it outboard will increase the un-sprung weight of those corners a little. Every time we add big brakes or bigger/heavier wheel/tire combos we do the same. These are undesirable consequences of our mods. Mike

As stated, the largest portion is nearest the ZF. I would surmise that the larger end U-joint with the larger tube would withstand the greater torque nearest the transaxle.
As importantly, the two shafts should be aligned with the inscribed arrows pointing at one another to assure the U-joints are "in-phase".

Theoretically, if the small OD portion is outboard, there may be a tiny bit of unsprung-weight advantage, which even pro-racers will not notice. But as mentioned, making a little more large OD exhaust pipe clearance is more important, and that may be either way on some Panteras. Whichever yields clunk-free driving is desirable!

could it be possible the larger OD of the HOLLOW end looks heavier than the smaller OD solid end?

using fish scale, my dirty half shaft with flanges weights 22 lbs (+/- 1/2 resolution)

supporting one end flange and then weighing the other with the shaft level had both ends at 11 lbs. (the length set to old wear marks)

Thanks guys for the replies. I had thought about the unsprung weight as a potential issue but wasn't sure if it would make that much difference.

quote:

Originally posted by jimmym:
Thanks guys for the replies. I had thought about the unsprung weight as a potential issue but wasn't sure if it would make that much difference.

It doesn't matter one way or the other. In fact it doesn't matter very much adding unsprung weight even on a race car. It's unavoidable and whatever changes you make you need to learn to live with.

It's almost just academic.

Probably the Pantera with the best unsprung weight vs. performance potential is a completely stock one with the skinny tires and smallest wheels.

Virtually everything you can do to the car for better braking and handling will increase that unsprung weight.

I wouldn't worry about reversing the axles. It's a drop in the bucket.

Thanks Doug. You make a great point. Any change that adds weight(wheels, brakes) in that area would have an effect over the original narrow wheels and tires.

I agree with Doug & Jack...

The only real reason to do this is for exhaust clearance. I went to larger diameter pipes, and the swap-around was required, as well as a large number of suspension swings (shocks and tires removed) to verify clearance.


Rocky

Just to add some fuel to the discussion; CV axles are much thinner than the half shafts, if clearance is a concern you could always upgrade!

quote:

Originally posted by Joules:
... CV axles are much thinner than the half shafts, if clearance is a concern you could always ...

As I read I was expecting " ...take a lathe cut to provide extra."

quote:

Originally posted by Rocky:
I agree with Doug & Jack...

The only real reason to do this is for exhaust clearance. I went to larger diameter pipes, and the swap-around was required, as well as a large number of suspension swings (shocks and tires removed) to verify clearance.


Rocky

That is the main reason why I am considering doing this. I would like to run a 3" exhaust to the mufflers. I had also thought about compressing the round pipe to oval pipe at the half shaft for fitment.
The third option was converting it to a CV joint. Dennis at Pantera Performance offers a couple of different options for this setup. One uses an adapter and the other one doesn't. With his setup and his optional heavy duty axles he estimated about 4" of exhaust clearance.

This is a picture of the CV kit Scott sells with the Wilkinson exhaust which I think is 2-1/2". As you can see the issue is the exhaust kisses the swaybar.

Steve

And to add to the frustration, all exhaust are not the same, slip joints between headers and rear section are more forgiving, but often getting everything to work correct is challenge. I have had to physically cut and re-weld a brand new Ansa exhaust to get the muffler tips straight.

There's always 180's!

Julian

Like Steve, I have the 2 1/2" pipes. My buddy modified the collectors on my headers, and then ran larger diameter pipes to the stock ANSAs.

ANSA -1 Build

Anyway - if you are going even bigger, it's going to be tight. You may have to follow Julian's advice on the 180s!

Good Luck.

Rocky

The CV joints from Scott is a very good addition. More room and much less vibration. You don't realize how much you have until you go with the CV's.

quote:

Originally posted by Rocky:
Like Steve, I have the 2 1/2" pipes. My buddy modified the collectors on my headers, and then ran larger diameter pipes to the stock ANSAs.

ANSA -1 Build

Anyway - if you are going even bigger, it's going to be tight. You may have to follow Julian's advice on the 180s!

Good Luck.

Rocky

This is not intended as a criticism but Precision Proformance already has built 2" primary tube with 3-1/2" collectors for the Pantera.

I have no idea how well they fit the application though. A smaller axle assembly might be required?

IF you ask me, the tubes show the typical "bluing" of the stainless tubing.

Ceramic doesn't do that ALTHOUGH it can dull in spots due to the heat.

These are PIM's. They seem to have addressed the collector JUST a bit differently?

If your particular Pantera simply cannot provide enough exhaust pipe clearance around halfshafts and/or antiswaybars, consider that one of the car magazines (I think) ran a series of tests on various exhaust systems using a SBC mounted on an engine dyno. After the usual small gains & losses from the different headers & muffler systems was recorded, sort of as a joke, one of the participants asked if small dents had any effect.

So they whacked one header pipe with a dull ax, producing a dent that was about 30% of the tube dia. The next dyno run showed NO MEASURABLE EFFECT from the visible restriction. Getting into it, they eventually smashed ALL 8 of the header tubes; still no effect on power even when one tube was nearly pinched off.

If you accept their results, adding small dents in the pipes to clear unavoidable metal-to-metal contact around our rear suspension will likely not slow down your next WOT Silver State run much if at all....

Thanks for the pictures guys. Nice looking exhaust Rocky. This picture is one Dennis from Pantera Performance sent me. Estimated ~4" of clearance with the CV joint set up.

That is a picture with the suspension hanging. You need to measure it with it fully compressed.

It should be less then the static distance from the hub connection at the ZF that shows now.

You only need something like 2-1/2".


The original Ansa pipes I took off of the car were dimpled on one side for the axles. Just the one side. I don't remember which AND they were 2-1/4" pipes.

I'm skeptical of 4" but with that new kind of axle I doubt a 2-1/2" will have any issue.

Unless you were going for a race car, a 3" pipe only adds more noise to the exhaust.

2-1/2" is more manageable sound wise. 3" is going to sound like an open unmuffled exhaust.


Talking about unsprung weight? Look at the mass of that 1-1/4" vented brake rotor? That I do not understand considering the puny size of those motorcycle rear calipers? What's that about?

quote:

Originally posted by PanteraDoug:

Talking about unsprung weight? Look at the mass of that 1-1/4" vented brake rotor? That I do not understand considering the puny size of those motorcycle rear calipers? What's that about?

That is probably the e-brake.

quote:

Originally posted by Husker:

quote:

Originally posted by PanteraDoug:

Talking about unsprung weight? Look at the mass of that 1-1/4" vented brake rotor? That I do not understand considering the puny size of those motorcycle rear calipers? What's that about?

That is probably the e-brake.

You are probably right but look at the braided line running to it. Is that a hydraulic hand brake?

The e-brake caliper is a mechanical kart style you can see the actuator arm and the bracket for the cable housing, it's not hooked up in the photo.

I think the braided hydraulic line likely goes to the main caliper.

Julian

The calipers on the top of the picture is p-brake, I have the same, cable not attached yet in the picture. They don't weight much, alu