The Pontiac rear axle flange is different from the Chev one Steve, You may need a pair of the unobtanium versions.Quote:
Originally Posted by Steve Holmes
I know a guy who may be able to provide patterns.
Bruce.
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The Pontiac rear axle flange is different from the Chev one Steve, You may need a pair of the unobtanium versions.Quote:
Originally Posted by Steve Holmes
I know a guy who may be able to provide patterns.
Bruce.
Huh, why is nothing ever simple! What does your car have Bruce? I assume T/G made something in their shop?
If too many things were the same, where would the fun be for us rivet counters?
Viva la difference !!!!!!!
My car has rear caliper mount brackets whittled down from a big ass blocks of steel, with Pontiac 'D' (prototype) part numbers.Quote:
Originally Posted by Steve Holmes
I will take some pics.
Bruce
Attachment 43853
There is a bit of surface rust pitting on one, but this is what they look like. They use the Ford type bearing capture and have no C clip like the factory GM rear ends. The 4 bolts where they attach to the flange are different from the Chev bolt pattern.
Bruce.
Very true John. I have to remind myself sometimes that no matter what challenges I face, they pale in significance compared to what you had to go through in restoring the Monaro.Quote:
Originally Posted by John McKechnie
Thanks Bruce, these are fascinating. These are some bloody big clumps of metal.Quote:
Originally Posted by Bruce302
I note the Jon Ward/Jerry Titus Firebird is being correctly rebuilt, including the switching of rear end from Camaro to Firebird. I assume they'll face the same problems?
Last I saw, a couple of weeks back, the Ward/Titus Firebird was for sale and still in need of the correct restoration. Who ever does the final correct detail work will need these types of mounts. As far as I know the ones on my car are the only ones known to exist.Quote:
Originally Posted by Steve Holmes
I can't really see those posing too great an issue with CNC and someone who can draw this readily. I happen to know someone who does his stuff all day every day for XKSS, D types and similar. :)
Can you PM me please. we can get this project started.Quote:
Originally Posted by Oldfart
Bruce.
Done Bruce
Thanks Rhys.
Chassis:
Its common to see cars in New Zealand historic racing fitted with tractions bars. These are a pair of tubular bars that link the rear axle housing with the bodyshell. They attach to the axle housing at one end, and run forward of the axle and attach to the underside of the car at the other end. What these do is to basically tie the rear axle to the rest of the car to prevent axle hop and other undesirable behaviour under racing conditions.
However, in the Trans-Am series, most cars didn’t use this set-up. They weren’t allowed to. They had to use what was on the production car. In 1967, the Camaro teams suffered massively from axle hop. They tried various methods for overcoming this, and Chevrolet even made available a radius rod on the Camaro as a preventative measure. This was a single tubular bar that attached to the bottom of the passenger side rear axle and ran forward and attached to the vehicles underside. But it didn’t work. In fact, after persevering with the factory radius rod for much of the season, Penske racing found the car actually behaved better when they removed it.
One option a few teams tried was to fit traction bars from the Pontiac Firebird to their Camaros. In 1967, Pontiac Firebirds fitted with posi-traction had a pair of hefty box-section bars, much like the traction bars described above. Some Camaro teams in 1967 tried adding a Firebird traction bar on the drivers side, and retaining the factory radius rod on the passenger side, as can be seen from this original 1967 Trans-Am Camaro. Note the difference between the two bars in the photo.
Attachment 43872
However, GM engineers eventually came up with a fix for the problem, which was actually really simple. Beginning with 1968 Camaro and Firebird models, they staggering the rear shocks, mounting one behind the axle, and one in front of it. In 1967, both Camaros and Firebirds had both rear shocks mounted in front of the axle. The staggered set-up all but eliminated the axle hop. The below photo is of the John Ware 1968 Trans-Am Camaro. Note that it doesn't have any traction bars, but that the shocks are now staggered, unlike those in the photo above.
Attachment 43873
This was something I discovered after buying my car, and if I’d known, I likely would have tried to find a 1968 Firebird instead, as these also came with staggered rear shocks. But as you've probably gathered by now, I'm a bit of a slow learner. So I’ll need to convert my rear shock set-up to 1968 guise. I won’t run any traction bars. If the staggered shock set-up works, being able to do without traction bars will help keep the weight down.
Despite General Motors being a massive conglomerate, the Camaro Trans-Am race program was run on a shoestring by a small group of dedicated Chevrolet engineers who loved racing. And they came up with ingenious ways to retain manufacturing costs. One of these was to make the Camaro rear sway bar the exact same configuration as the front. The only difference being the diameter.
I’ve asked a couple of people their opinions on swaybay thickness, and have understandibly had a range of answers, from 25.5 – 27mm front, and 16 – 18mm rear. What I’ll do is purchase off-the-shelf swaybars, from Summit Racing or similar, that are as close to these numbers as I can get. That’ll help keep costs down. I do feel that areas such as swaybar thicknesses, and how they affect the behaviour of the car, making it an oversteering, understeering, or neutral car, is somewhat of an individual preference. Maybe some trial and error required.
Most teams in period used a Watts-link, as do most in historic racing. I’ll likely have a watts-link made, or may just purchase a Fays 2, which is an over-the-counter bolt-in system that costs US$695. That is, assuming it’ll fit the Firebird rear end.
I suspect in the best methods of cost cutting that both brackets are off the production line for the same side, so that one turned around became the "opposite" handed one. ie the right hand one for a front mount becomes a backward one on the left?
You could well be right Rhys!Quote:
Originally Posted by Oldfart
That sounds right, I heard of some H-M set ups that used the same RH spring carrier used on LH to stagger shocks.
Just need to check the staggered LH shock clearance to the diff housing while trying to fit to OEM shock top mount.
and the top mount is?Quote:
Originally Posted by Oldfart
Hi Steve,
Any more progress on the car?
Hi Paul I'm still only at the parts collecting and research stage.
Wheels and Tyres:
Wheels:
I don’t want to sound too much like an anorak by making this statement. But choosing the right wheels is hugely important for the look of any historic race car. In fact, I’d go as far as to say the decisions made in this area can make or break the look of the whole project.
The 1960s were a time of massive progress in motor racing. And that was no more the case than in the SCCA Trans-Am series. The Trans-Am quickly grew to become a massively successful and competitive series that was followed throughout the world, and whose influences were global. This wasn’t just a championship in which there was a manufacturer war between Ford, Chevrolet, etc. There were battles going on right throughout, including a tyre war between Goodyear and Firestone, a war between the oil brands, and even a war between the various specialist wheel manufacturers.
The first two years of the SCCA Trans-Am series were actually run to FIA Group 2 touring car regulations. It was only from 1968 that the SCCA started writing its own regulations. From 1968, the maximum wheel width allowed was 8 inches.
The Trans-Am series was very specific when it came to wheel choices, and wheel designs can be pin-pointed to certain years. So too, the various makes and model of car can be tied directly to the wheel styles that were the most popular choice for each year. The first season of the Trans-Am was 1966, and many cars were fitted with steel wheels, or factory alloys. However, for the really serious teams, ie, those with plenty of money, they could go to specialist companies such as American Racing, who produced their beautiful 5-spoke wheel commonly referred to today as the Torq Thrust.
In 1966, American Racing were a small cottage industry company, and produced wheels to order, usually with the customers name hand-punched into the centre of the wheel. And it was all pretty organic. I saw a great example of this a few years ago when visiting Nigel MacDonald, who owns the former Frank Bryant/Red Dawson 1967 Shelby Mustang. Nigel has managed to track down three of the original magnesium American Racing wheels that were ordered for his car when new. On one of the wheel centres, they’d made a spelling mistake when punching in name Frank Bryan Racing, misspelling Bryan with Byran.
Attachment 44188
Attachment 44187