RETURN OF A CHAMPION
article: Gary Anderson • Nate Lander
images: Mercedes-Benz Classic Center, Daimler Archives, Richard Simonds, Gary Anderson
Where better to test and tune a stunning tribute to a famed 1957 300SLS than on a historic circuit where it competed during its championship-winning season?
One day late last September as a busy crew of automotive roustabouts set up portable facilities for an upcoming AMG Driving Academy event at Mazda Raceway Laguna Seca, a giant car transporter pulled slowly into the sleeping paddock, attended by a small swarm of support vehicles. With a hydraulic whine, the transporter’s tail ramp lowered and a distinctive green 300SL Roadster with a stubby racing windscreen and chrome rollover bar was unloaded, checked and rolled into pit lane.
Someone with a good eye for vintage racing cars might have noticed that – except for the color – the vehicle appeared to be a perfect replica of a Mercedes-Benz that was raced at Laguna Seca and other U.S. tracks in 1957 by esteemed sports car ace Paul O’Shea.
The story behind the story
Two men standing nearby as the car was carefully unloaded from the bright orange transporter – Michael Kunz, director of the Mercedes-Benz Classic Center in Irvine, California, and well-known classic-car enthusiast Bruce Ianelli – could easily explain the resemblance to the O’Shea roadster and the reason it was at Laguna Seca on that otherwise-quiet Friday.
The story began several years earlier during the Colorado Grand classic car tour, when the two men shared the cockpit of a well-tuned 300SL Roadster from the Classic Center’s collection. Over the course of the five-day event, Ianelli became intoxicated by the epic song of the roadster’s full-throated roar at high speed and the purring lullaby of the 6-cylinder engine idling through little towns along the route. He wondered if the Classic Center might build him a roadster with the performance of their current car, but made somehow more distinctive and unique.
Kunz told Ianelli how in 1955 and 1956, Paul O’Shea had scored more points than any other driver in SCCA races behind the wheel of a C-Production 300SL Gullwing. Both years he had been named U.S. Sports Car Champion by the motorsports writers association. In 1957, Mercedes-Benz, looking for publicity in the United States for its growing brand, had supported O’Shea in Sports Car Club of America competition by building a racing version of the new 300SL roadster for him (see Artifact, page 6).
Kunz then proposed that the Classic Center undertake technical and historical research into the long-lost Mercedes-Benz built for O’Shea. The team in Irvine would then find a suitable 300SL Roadster donor vehicle and restore it as closely as possible to the appearance and performance of the O’Shea car as a tribute to the original. Ianelli agreed immediately.
A 1957 photograph of Paul O’Shea with his new 300SLS.
Michael Kunz (on left), director of the Mercedes-Benz Classic Center, Irvine, with Bruce Ianelli, who commissioned the 300SLS tribute.
Unloading the car at Mazda Raceway Laguna Seca on test day morning.
Researching the O’Shea car
Project director Nate Lander soon began digging into the background of the O’Shea car, exploring the Daimler Archives, and an extensive set of photographs at the online Revs Institute gallery of the Collier Collection in Florida. One fact quickly became clear: The two cars constructed by the Mercedes-Benz racing department had been incredible sleepers. There were only minor differences from the production model on the outside – of the sort that might be true of any roadster prepped for weekend races – but under the hood and beneath the DB180 silver-grey metallic paint, the changes were significant.
A low racing windscreen was substituted for production glass while a distinctive cooling duct was added to the cockpit cowl; a neat tonneau covered the passenger seat, with matching trim enclosing the cockpit. Lightweight racing seats replaced the leather-trimmed originals. A rollover bar and racing seatbelts were installed, and a detachable wood-rimmed racing steering wheel replaced the stock Mercedes-Benz part.
Almost everything that wasn’t necessary was removed from the exterior as well. Obviously, the soft top and frame were gone, as were door handles, fuel-filler door, trunk and glove-box lock. The trunk and hood were now secured by quick-release race fittings. Front and rear bumpers had disappeared, as had all related brackets and hardware; the mounting holes had been filled and painted. Blank aluminum discs replaced the headlamps; with all SCCA races held during daytime, headlights were deemed superfluous.
Exterior body alterations ranged from the subtle to the imperceptible. The lower rear body panels were integrated into the main body – as on the Gullwing coupe – eliminating trim moldings at the rear of the car. Instead of a mix of steel and aluminum panels, all body panels were aluminum. The pair of cars had individual custom-fabricated aerodynamic belly pans extending from front to rear. Peeking inside the cockpit, it was obvious that the door glass – as well as all related guides, regulators and mechanisms to operate the side windows – had vanished.
All was not stock in the engine compartment, either. As soon as the roadster was fired up, the exhaust tips extending out from the rocker panels on the left side of the body announced loudly that this special machine was running open pipes without mufflers. For increased cooling, the front inner-grille mesh resembled that of the Gullwings.
Opening the hood, anyone used to seeing a cast-aluminum intake manifold would have been surprised to find a sheet-aluminum intake manifold – reducing engine weight by 10 pounds – though the fuel-injection fitting was still at the front of the manifold.
According to the plans, the intake manifold throats were 70mm longer than stock. The cast-iron engine block was replaced with an aluminum block, resulting in a dramatic reduction in weight. Within the engine, everything had been built to racing tolerances, with custom weight-matched pistons and connecting rods fitted, and all passages tested and ground to optimize air flow.
According to the final build sheet, the aluminum engine would produce 235 horsepower, 20 more than the stock engine’s 215. The finished vehicle weighed in at a mere 1,985 pounds compared with the production car’s 2,932 pounds, offering a dramatic power-to-weight ratio improvement. It was no wonder that the factory identified the special roadster as the 300SLS, for “Super-light Sport.”
Only two cars were ever built to these specifications, rather than the 150 units required by the SCCA for homologation as a production car. This meant that O’Shea had to race in the D-Modified sports-car class for the 1957 season. Mercedes-Benz did not view this as an issue; most other marques, such as Jaguar, were running modified versions of their production cars, so the advertising impact would still be considerable.
Period photographs of the 300SLS provided key guidance during the planning and construction of the Paul O’Shea Tribute Car.
Nate Lander assesses the roadster’s handling out on track.
The Classic Center’s traveling workshop van offered support from pit lane.
The tribute car’s engine was rebuilt to closely match the appearance and performance of the competition original.
Shakedown laps offered a unique chance to test the roadster in track conditions, make minor adjustments on the fly and highlight desired refinements.
Creating the tribute car
Research in hand, the Classic Center soon located an early-production roadster, hidden away on a North Carolina farm and not driven for over 30 years. Company records indicated it was the 44th car built during the first year of 300SL Roadster production. Over a period of 18 months at the Classic Center, the roadster was disassembled and then restored back to the appearance of the O’Shea car.
The original steel body was retained, as well as the donor car’s aluminum doors, hood and trunk. Reproducing the distinctive belly pans remains a project for the future. Although aluminum blanking plates cover the headlights, there are in fact operational headlamps under the easily removable covers. Turn signals and warning lights remain functional for night driving.
On the other hand, just as with the original machine, there is no weatherproofing – no windows and no soft top – so foul-weather gear will be the order of the day on long-distance tours.
In a major departure from the original objective of visually duplicating the O’Shea car, Ianelli and the restoration team made the deliberate decision to paint the roadster in very attractive production-correct Tundra Green (DB178) instead of the original silver-grey, thus there could never be any confusion that this is a restoration of the actual Paul O’Shea car.
A great deal of labor was expended rebuilding the engine to closely match the original power unit’s character and ability. In addition to fabricating the distinctive intake manifold, the Classic Center team completely balanced and blueprinted the engine and installed higher-compression pistons.
When all the work was completed, the tribute car weighed in 325 pounds less than a production roadster, or about half of the weight reduction of the O’Shea original. Nevertheless, that was sufficient that lowering springs and mounts had to be installed to bring the car back into engineering spec for alignment and suspension settings.
Superb interior details of the newly built roadster closely follow the cockpit appointments of the 1957 racecar.as
Track testing in 1957
As soon as Mercedes-Benz completed construction of the two 300SLS racing specials in early April 1957, the machines were taken to the Hockenheimring for testing and final tuning under racing manager Alfred Neubauer’s supervision. After Neubauer’s approval, the vehicles were shipped by sea to New York, then immediately transported to Lime Rock racetrack in Connecticut so that O’Shea could familiarize himself with the SLS’s handling and performance. Though the Mercedes-Benz service engineer assigned to tend the roadsters stated, “the car was not fully driven to the limit,” O’Shea was easily able to better the practice times of the competing Jaguars.
A camera truck recorded the car’s hot laps.
The 1957 Mercedes-Benz 300SLS Paul O’Shea Tribute salutes a colorful period of American racing.
Track testing 60 years later
Finally, the Classic Center’s work was finished. In preparation for a poetic rendezvous with the past, the tribute roadster was trucked from Irvine to Laguna Seca, familiar stomping ground of the O’Shea car 60 years earlier. The visit – timed to coincide with an empty track while preparations were underway for a forthcoming AMG Driving Academy event – would allow project leader Nate Lander to put the Tundra Green machine through its high-speed paces on the historic track to expose any hidden mechanical issues cloaked during static checks back in the Classic Center shop and test runs on a dynamometer.
By the end of the day, with a camera truck following the roadster to record the occasion, Lander had made some changes – such as rejetting the fuel injection – and put together a punch list of items to resolve before delivering the car to Ianelli. These included altering the rear-end gearing to allow lower engine rpm when cruising at highway speeds, and additional refinement of the ignition system. Overall, Lander reported that the car was remarkably agile on the track. The power-to-weight ratio increased the roadster’s response when accelerating out of corners, and the weight and suspension changes made a big difference to handling and stability on acceleration.
Then and now
O’Shea competed in 22 SCCA races during 1957. He dominated the D-modified class, earning an overwhelming 11,400 points, more than any other SCCA driver that season, and – for the third year in a row – was voted U.S. Sports Car Champion by the North American motorsport media. However, back in Stuttgart, Mercedes-Benz withdrew from racing at the end of that season. The SLS disappeared.
Ianelli says the Paul O’Shea Tribute car will next be used in a business course at his daughter’s college, rekindling the memory of those exciting postwar entrepreneurial years at Mercedes-Benz, when the company supported customer racing cars to promote the marque, just as it is now doing again with GT4s at tracks around the world.
Specifications
1957 Mercedes-Benz 300SLS Paul O’Shea Tribute
TYPE: Two-door, two-passenger track-prepared roadster
ENGINE: M198 2,996cc, Inline 6-cylinder, Bosch fuel injection, dry-sump lubrication
TRANSMISSION: 4-speed manual
HORSEPOWER: 260 at 4,500 rpm (SAE) TORQUE: 275 lb-ft at 2,600 rpm (Estimates)
WHEELBASE: 94.5in CURB WEIGHT: 2,812 lb
FUEL EFFICIENCY: 10 mpg (est)
PERFORMANCE: Zero-60 mph 7.5 sec TOP SPEED: 135 mph (4.11:1) 160 mph (3.25:1)