[Rich-L79]

I was reading a book the other day about Trans-Am racing. One team's main car was down so they built a '64 Tempest and it actually was moderately competitive even though it was a bit larger than other cars in the series at the time such as Firebirds, Camaros, Mustangs and Javelins. The owner of the Tempest was quoted as stating that later in life he tore into the Tempest only to find it had been modified by Herb Adams in a special Pontiac project which helped explain why the car handled so well. What he found is that the Adams' engineers had found a way to dial two degrees of negative camber into the rear axle which really helped plant the car in turns.

How could you build negative camber into a solid axle? I would assume you would basically bend the axle housing tubes two degrees vertically to accomplish this. BUT, wouldn't doing so cause trouble where the axle shafts mate with the differential thus causing premature mechanical failure at that location?

 

[tunedbytad]

My 96 Impala is fairly rear camber happy for a solid axle car
and is very fast in the croners yet under performs for its mods
vs it's contemperaries on the Impala Forum at the 60' mark at the drags.

When I made our diff
I paid attent to trying to keep it straight during the whole project.
using laser levels, plumb, and sighting it like a rifle.
not too high tech but better tan not paying any atten.

The steer ahead and toe of the 4 link is really the most important thing.
The mounting points seems to have the most influence on that IMHO.

Note
our elco has .3 camber in the rear
My Impala .7 camber in the rear. and is very NICE!!!
go figure

http://www.chevelles.com/forums/showpost.php?p=2561141&postcount=5

 

[dave_silva]

How could you build negative camber into a solid axle? I would assume you would basically bend the axle housing tubes two degrees vertically to accomplish this. BUT, wouldn't doing so cause trouble where the axle shafts mate with the differential thus causing premature mechanical failure at that location?

Some guys at our track (circle) that dont run full floaters have done this, it will put wear on the center section and bearings, but I was suprised how long it would run before they had an issue. They will put a few blocks under the housing while it is in the car, and then heat the tube until it stops on the blocks.

Full floaters 9" do have cambered rear ends that have crowns (like those allen wrenches that have the one end that has a crown to tilt it) on the axle at the drive plate. Only the drive plate is cambered, not the tube, thus no damage or loading.

 

[Rich-L79]

Ha! And to think we spent all that time in the welding shop welding the axle tubes to the center unit of the 12-bolt for the wagon while trying our hardest to keep it as straight as possible!

 

[JWagner]

When I worked for Dana, I was somewhat surprised to learn that some of their axles had the bores for the axle tubes in the carrier set .020 off from the differential centerline. The thinking was that when the weight of the vehicle was put on the axle, the wheel ends would come into alignment with the differential.

 

[Keith Tedford]

I think that you will find that the NASCAR boys play the same game to some extent.

 

[72ragtop]

I think those early Tempests had a transaxle, not unlike a Corvair, as I remember. Jim.

 

[Rich-L79]

I think those early Tempests had a transaxle, not unlike a Corvair, as I remember. Jim.

Prior to '64 yes, starting in '64 it was another full-frame, front-engine, rear solid axle a-body just like the Chevelle. I have one sitting in my shop right next to the wagon project (a '64 GTO).

 

[Derek69SS]

Herb Adams' book "Chassis Engineering" has a chapter about heating axle tubes to add camber. I thought about doing it to my 12-bolt but decided against it for 2 reasons... #1 being resale of the housing, and #2 being that it would have a significant impact on drag-racing traction. While I don't drag race very often, I still like to know what it can do. Tire wear is another factor, but that didn't really weigh in for my situation. He stated how much camber you could do in a stock type Ford 9" without eating bearings, and it was something like 0.5deg IIRC.

 

[Gary U]

I think that you will find that the NASCAR boys play the same game to some extent.

I've consulted (regarding a product that my company makes for them) with several NASCAR teams. Not only do they run camber in the rear, they also run a good amount of toe - especially now with the COT. Rough on the axle/drive plate.

 

[93Polo]

Some guys at our track (circle) that dont run full floaters have done this, it will put wear on the center section and bearings, but I was suprised how long it would run before they had an issue. They will put a few blocks under the housing while it is in the car, and then heat the tube until it stops on the blocks.

A local Speedshop used to run an SCCA A Sedan 3rd gen. He actually used straps to further try to stretch the axle. They also went to the track with an extra rear end.