By Tim Suddard
Jul 1, 2011
|
Triumph
| Posted in
Restoration & Renovation
| From the July 2010 issue
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A strong foundation is vital for just about anything, from a home to a relationship to a vintage race car. Our Triumph GT6+—the 1969 SCCA national champion winner campaigned by the legendary Group 44 Inc.—now had a revitalized body and fresh coat of paint. Next we needed to redo the entire chassis and suspension. While this would be a demanding ground-up restoration, we did have a few things working in our favor. For one, the GT6+ is not a unibody car. Like the open-topped Spitfire and the earlier GT6, the GT6+ has a separate frame that is simply bolted to the body. Undo a dozen or so bolts, disconnect the brake lines and steering linkage, and you can simply lift the body from the chassis.
Also helping our crusade was the fact that our body and frame were both relatively solid. Yes, we had a lot of cleaning and restoration ahead of us, but we wouldn’t be forced to recreate sections of the car that had rusted away.
If the car had been rusty, we would have taken an additional step: Brace the body before separating it from the chassis. This would have ensured that the mounting holes lined up after all of the restoration work was finished.
Once we lifted the body from the chassis, we stripped all four suspension corners. Our policy is to keep subassemblies intact for as long as possible, as this saves space in the shop and aids reassembly. Although GT6s are simple cars that we’ve had a lot of experience with, we followed our usual plan with this project. There was a method to our demolition work, too. We lubricated all fasteners before undoing them. We also took plenty of photos; when the time comes to reassemble the car, we’ll have plenty of information on how things go together.
We even counted the number of alignment shims used at each end of the car. We plan to do a real alignment later on, but this will give us a good starting point when we reassemble the car.
Our frame came back from the powder coater looking brand new. From there we could start reassembling the rest of the suspension.
Once our frame was clean, we could see that it was solid, straight and true. Other than a few minor issues that needed touching up with a welder and grinder, it was ready to be sandblasted and refinished. Then came a big question: powder coat or paint? From a finish standpoint, our powder coater’s black semigloss looks just like the paint that Group 44 Inc. originally used.
However, some say that powder coating can hide cracks in the frame and therefore shouldn’t be used on a race car. In this instance, though, we believed the durability and look of the finish offset this potential problem. Why totally restore a car if it’s going to look beat after six months of use? Plus, we won’t exactly be campaigning this car every month for the next 20 years. The plan is to race it a few times per year—if that.
Another advantage to powder coating: It can be very inexpensive. The total cost to powder coat our GT6+, including the frame plus many suspension components, came to less than $500. That price even included sand blasting the frame. We blasted most of the smaller components ourselves to control costs and quality, but the frame was simply too big to fit into our bead blasting cabinet.
Before powder coating, we checked all of our critical components for cracks and trueness. Except for a couple of suspect suspension mounting points that we strengthened, every piece we removed from the car was in good shape.
One final word about powder coating: A good powder coater will know to plug thread holes, bearing surfaces and the like. If they skip this important step, the powder coating will materially alter clearances. That means the very durable finish will have to be painstakingly removed from threads, bearing surfaces, and other areas with critical dimensions. Skip the headache and make sure they plug the holes.
We didn’t just hope that our old suspension parts were still good—we evaluated each component using a dye-check kit sourced from Goodson Tools & Supplies.
Once our frame and suspension components came back from the powder coater, we began the reassembly process. Since we left many of the subassemblies together, each one could be tackled individually.
We didn’t want to make radical changes during this step. In its day, this car was good enough to win almost every race it entered, including the SCCA Runoffs. Our goal was to simply preserve history as much as possible.
To ensure that the original parts were still safe for track use, we checked all critical components with an inexpensive, simple-to-use dye-check kit sourced from Goodson Tools & Supplies. This kit lists for $46.99 and includes a special cleaner plus the dye penetrant and a developer. It can be used to check both aluminum and cast-iron pieces.
We started up front with the steering rack, carefully cleaning and inspecting everything before reassembling the unit with new tie rod ends and boots sourced from SpitBits. Once renewed, we attached the rack to two aluminum mounts fabricated by Group 44 Inc. This upgrade eliminated the play allowed by the original rubber mount.
From there, we carefully inspected the front hubs—and uncovered a bit of a mystery. Our car wore aluminum hubs when we purchased it, and we assumed that they had been added later in the car’s life. We replaced them with a set of stock cast-iron units.
Turns out we made a mistake. Mike Downs, who drove and prepared the car in 1969, eventually produced a photo that showed the car wearing the aluminum hubs. This is why we don’t throw away anything during a restoration. We retrieved the aluminum hubs from our parts box so we could clean, inspect and install them.
We can only assume that Group 44 Inc. team member Brian Fuerstenau created these pieces. They were obviously handmade, and the late Fuerstenau was a masterful fabricator. He also served as crew chief when this car was first assembled.
Upon further investigation, we realized how these hubs work. They were machined to move the 6-inch-wide race wheels inward—about an inch per side—for better fender clearance. The hubs also take a stock GT6+ wheel bearing.
The front coil springs that came on the car are of unknown origin, but they’re beefier than stock GT6+ springs. We retained them along with the obviously aftermarket front anti-roll bar.
Among the tricks found in the suspension are custom bronze A-arm bushings. While certainly not great for street use, these bushings eliminate suspension compliance.
Group 44 Inc. added this adjuster to the rear transverse leaf spring. The piece aids corner weighting by allowing the assembly to move from side to side. Trick stuff today, but amazing for 1969.
After redoing the front suspension, our attention turned to the rear of the car. Unlike the front suspension, the rear features a single transverse leaf spring that also acts as the upper control arms. A pair of traditional lower control arms and trailing arms wrap up the setup.
Group 44 Inc. made some modifications within the SCCA rules. The biggest change involved replacing the less-than-durable Rotoflex couplings with sturdier halfshafts and U-joints sourced from a TR6.
Other changes from stock are a bit more subtle, including a few that involve the rear leaf spring. While it appears similar to the standard GT6+ piece, the spring on our car features noticeably thicker leaves. We decided to retain it since it obviously worked well for the team.
Because the spring moves around a bit and has tight clearances between the leaves, we decided to forgo the powder coating on this piece. We began the arduous task of disassembling the spring so we could bead blast and paint the individual leaves before reassembling the unit.
This uprated leaf spring also features a clever centering device that allowed the team to dial in the car’s corner weights more accurately. The team basically engineered in some adjustment so the spring could be moved slightly from side to side.
The spring also features spherical bearings at each end instead of the simple rubber bushings found on the mass-produced GT6+. These bearings allow for adjustability at the spring ends and eliminate binding. The lower control arms are stock Triumph pieces, but we noticed that someone had heated and bent them. Lanky Foushee explains that this was a simple and inexpensive way to gain negative camber.
To get even more negative camber, the team also replaced the inner and outer lower control arm bushings with offset bronze pieces. Each one can be locked in place with a hidden set-screw found underneath the grease fittings. Again, there’s a reason why Group 44 Inc. won so many races. This is the most sophisticated Triumph suspension setup we have ever seen; the fact that it was built in 1969 is outstanding.
Vintage Racing Services rebuilt our differential, locked the gears, and installed a 4.11:1 final drive ratio.
The differential and axles again featured a mix of standard components and Group 44 Inc. improvements. We kept to our mission of rejuvenating things as necessary without erasing any special work done by the team.
The differential itself is a stock GT6+ unit fitted with 4.11:1 final drive—significantly shorter than the stock 3.27:1 ratio. To keep one wheel from slipping, the spider gears were welded together, a measure commonly taken with race cars. Instead of using the standard Triumph rubber differential mount bushings, Fuerstenau also fabricated aluminum mounts to take any flex out of the system.
So far, this setup and gear ratio has worked well for us at Road Atlanta, Laguna Seca and Roebling Road. Were we to run Daytona, however, we may want to try the 3.89:1 ratio found in a Spitfire.
The halfshafts are from a Triumph TR250 or early TR6. The bolt holes were modified slightly to fit the GT6+ differential, while the GT6 and TR6 use the same centering ring. Both cars use a standard sleeve and shim arrangement to get between 0.002 and 0.005 inch of end float where the stub axle meets the bearing. Some extra clearance was needed to clear these TR6 halfshafts at full droop. As far as we can tell, the frame was heated and bent slightly to make it work.
The suspension uprights came from a GT6+, but they were machined to fit different stub axles. Lanky Foushee claims that they’re modified Corvair axles, and they appear to be from a 1965-’69 model. The axles have been modified to accept the Triumph bolt pattern.
The backing plates are also GT6+ pieces. Somewhere along the way—presumably during the Group 44 Inc. era—they were drilled out to aid cooling and shed some weight. Finally, the trailing arms look to be standard GT6+ units that have received spherical bearings at each end for maximum adjustability.
Carbotech is one of just a few companies that can reline old brake pads and shoes with modern racing compounds.
Other than the master cylinders—we’ll get to them in a bit—the front and rear brakes are essentially stock Triumph GT6+ units. These were retained to comply with the 1969 rules, although teams could upgrade to better pads and shoes as well as braided steel brake lines.
We sourced new braided steel brake lines from SpitBits and ordered pads and shoes from Carbotech. We used their XP8 compound and have been very happy. This is a high-torque compound with a wide operating temperature range: 200 degrees to 1350 degrees Fahrenheit.
As promised, the compound has outstanding initial bite plus excellent modulation. Fade hasn’t been an issue, and dust has been minimal. We’ve always had good luck with Carbotech products, and they’re one of the few companies that offer race-ready compounds for brake shoes. We spent less than $200 to outfit the front end of the car.
Group 44 Inc. even modified the brake pedal. The whole assembly was lengthened, presumably to aid heel-and-toe driving, while the fulcrum was relocated.
The master cylinders for the clutch and brake still remain somewhat of a mystery. Early pictures of our car clearly show it wearing the stock GT6+ master cylinders.
When we purchased the car, it featured a beautifully made metal plate that reinforces the firewall area and also houses three period-correct Girling master cylinders—two for the brakes and one for the clutch. A balance bar between the front and rear brake master cylinders can be used to adjust brake bias. Both the front and rear master cylinders feature a 5/8-inch bore. Foushee told us that this setup is original, and it looks like those found on slightly later Group 44 Inc. cars.
Our theory: The team raced for at least part of the 1970 season with the stock master cylinder setup before switching to the updated arrangement. The change was made either out of necessity or in accordance with a rule change.
Regardless of how and when this master cylinder setup appeared, it’s obvious that it was built by Group 44 Inc. Plus, the setup is done well and maximizes a key part of the car. We decided to keep it.
A modified brake pedal hangs from that master cylinder arrangement. The team first lengthened the pedal an inch to aid heel-and-toe downshifting. To offset the resulting increased leverage, they raised the fulcrum by about half an inch.
After some confusion surrounding tires and wheels, we eventually found the correct answer: American Racing Libre wheels wrapped with Goodyear race tires.
Even though Lanky Foushee didn’t become crew chief until 1970—the year after our car scored its big win—he still had some insight into our car’s tires and wheels.
He said that the team ran 13x6-inch American Racing Libre magnesium wheels in the rain and Minilites in the dry. The wheels always had 3.875 inches of offset up front and 3.5 inches in the rear. We were confused, as all of our photos of the car showed it on the Libres, including the shots of its 1969 ARRC win. These photos were all from dry-weather contests, too. However, the car came to us with Minilites and, if not original, they were old. Which wheels to use?
Nearly three years after we bought the car, a former owner helped us answer that question. He produced a photo of the car taken late in the 1970 season: It clearly showed the car on seemingly the same set of Minilites that we had stowed away in our attic. Obviously the Minilites that came with our car were original, but we needed a set of Libres; we found a set and restored them. We’ll keep the Minilites for backup wheels.
We mounted a set of 5.00 x 13-in. Goodyear Sports Car Special tires onto those Libres—Group 44 Inc. was sponsored by the tire company in its heyday. The rubber came from SascoSports, a leading supplier of vintage race tires. Had we known that this tire model was soon to be discontinued, we would have purchased a couple more sets. We are now searching for a replacement tire.
Our tires and wheels are surrounded by bashed-in wheel wells. We figured this was done intentionally, and Foushee confirmed our suspicions. Group 44 Inc. worked with Goodyear to develop larger tires for the car that would increase its top speed at fast tracks like Daytona. Looking back, we’re glad we didn’t fix these dents during the body redo.
Our painted body could finally be lowered onto our totally rejuvenated suspension. Now we’re making some real progress.
Finally, we could reunite the restored body with the chassis, turning our project into a roller. Since we plan to work on exact alignment specs later, we just left the toe and camber at zero. These benign alignment settings will also make the car easy to roll around the shop. Once the car is at speed, we can take advantage of those Group 44 Inc. tricks.
Next, we’ll get into the car’s drivetrain. Part of that process includes building a real vintage race engine.
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