Car Restoration Projects
Skoda’s restored racing Coupé
Development of Škoda 1100 OHC racing cars began in Mladá Boleslav in the spring of 1956. The initial pair of open-top cars was followed by two Coupés at the turn of 1959/60, but escalation of the Cold War meant that these two cars were destined to remain inside the borders of then-Czechoslovakia.
Early racing Sport model with production-car backbone chassis
Unlike the earlier Škoda Sport and Supersport racers, the 1100 OHC Coupé was not built on a backbone chassis frame that was modified from mass production vehicles. The Coupé had a lightweight, rigid frame of super-strength, thin-walled tubes.
The front wheels were connected to a trapezoid made of pairs of superimposed triangular arms, with a trailing-arm wishbone axle system at the rear. Instead of the leaf springs used on production Škodas at the time, the designers opted for lighter torsion bars.
Coupe chassis showing offset engine and rear-mounted transmissions and brakes
Large-diameter finned brake drums were fitted outboard up front and inboard at the rear.
The result was an agile car with a unladen weight of just 555kg.
Even the domestic career of this racer ended prematurely, because of changes in technical regulations and a loss of interest in the under-1100cc racing category.
Twin-cam 1100cc engine
Consequently, the two cars were sold to private buyers in 1966, resulting in the two Coupés being modified for use on the roads. Both cars met a similar fate.
The first owner of the featured car that has just been restored by Škoda was Hanuš Hrabánek, the father of Michal Hrabánek, the current director of Škoda Motorsport.
Hrabánek Sr replaced the 1100’s OHC engine with a more practical OHV, four-cylinder from a Felicia cabriolet. The removed racing engine was put on display at the Škoda Academy in Mladá Boleslav.
The owner of the second Coupé crashed it into a pillar in a motorway underpass near Mladá Boleslav. The driver made a lucky escape from the wreck through a hole in the perspex rear windscreen, but the car caught fire.
The wrecked car was dismantled. The rear axle, gearbox and prop shaft went to the National Technical Museum in Prague, from where the Škoda Museum acquired it 15 years ago.
The car’s chassis, front axle, brakes, pedals and other small parts survived in a Czech private collection, from where the Škoda Museum bought them in 2014.
The mechanical components showed relatively little wear and tear, as the car only took part in five races in its short career.
“The second of the two Škoda 1100 OHC Coupés was our family car for two years,” said Michal Velebný, the Škoda Museum’s restoration workshop coordinator.
“My father, Dušan Velebný, later head of the company’s testing workshop, bought this unique car in 1966, but by then it had already been fitted with a racing 1300cc OHV engine from the Octavia series.
As our family grew, the coupé had to give way to a more practical family car.”
Unfortunately, this Coupé was also crashed – more than once – by its later owners.
Several non-original bodies of various designs were then successively mounted on its frame and the car took part in hill climb races, among other adventures. It is preserved in incomplete form in a Czech private collection.
The resto process
One crucial step on the long road to our featured car’s restoration came when the experts from the Škoda Museum’s restoration workshop joined forces with the professionals from Škoda’s prototype construction centre.
Know-how acquired from restoring the open-top version of the Škoda 1100 OHC and deploying it in vintage racing events also came in very handy.
Fortunately, almost all of the original technical documentation, for the cabriolet and the coupé versions, including all section diagrams and a drawing showing the construction of the individual groups, had been preserved in the Škoda Archive.
By the end of 2015, the restorers had completed the chassis rebuild, incorporating a newly made radiator, fuel tank and other elements. The engine and gearbox had also been thoroughly refurbished.
It’s a good thing the restorers could scour the shelves in the museum’s workshop for a number of smaller components that the racing model shared with Škoda production cars of the time.
The coupe’s outer door handles, for example, were from the Škoda 1200 Sedan; some of the switches were developed for the Škoda 440 Spartak and Octavia; the three-spoke steering wheel, covered in black plastic, was from the pre-War Škoda Popular best seller and there were many more shared parts.
The hardest task was to reconstruct the aluminium bodywork that had been designed in the late 1950s by Jaroslav Kindl, a Škoda designer.
The original craftsmen
Back then, carpenters created a wooden mock-up, based on Kindl’s drawings and a team of panel beaters hammered out the aluminium panels by hand. Each artisan applied his own inventiveness and taste, so the left half of the body was slightly different in shape from the right, with an example being the way the edges of the bumpers are rounded.
This was a headache for the restorers: how should they modify shapes or proportions that do not look natural when the drawing is turned into 3D, or that differ from the evidence of surviving period photographs?
A substantial part of the work was transferred to the Škoda prototype construction centre: it was these specialists’ predecessors who had built the original coupé, after all.
Scanning the drawings to 1:1 scale gave rise to a grid of 3D curves covered with surfaces. Checking and correcting the shapes of individual elements, such as the rear lights, took dozens of hours.
Experts from the Škoda Museum contributed a number of tips and comments, comparing the surviving photographs with the drawing documentation and a 3D model created using CAD (Computer-Aided Design) technology.
In the virtual studio, the coupé could be viewed from every conceivable angle, to find out what adjustments were necessary. Scale models were then created for the next phase of shape verification: first a simpler one without radii, then a more accurate one.
That was followed by 1:1 scale models of the front and rear body corner cutouts. After the external body shapes were given the definitive stamp of approval, Škoda engineers designed the bulkheads, wheel arches and other elements, so that they all matched the period documentation.
The body was made from 0.8mm and 1.0mm aluminium sheets that were beaten into shape, welded and riveted by hand, just as they were more than 60 years ago.
The only thing left to do was to determine the colour of the body paint. Both Coupés were originally blue and their finishers had opted for anodised aluminium, on whose etched surface they applied the paint by electrolysis.
In particularly stressed areas, however, such as on rivets and at the front of the car, the finish was not very durable, so, in mid-1962, both coupés were given a red paint job.
The demanding process of professionally restoring a racing car, when only its chassis had survived intact, would not have been possible without the combined experience of the Škoda Museum staff and the contemporary prototype construction experts.
Although they used 21st century techniques and technologies, they tried to adopt their predecessors’ thought processes. They tried to make the reborn Škoda 1100 OHC Coupé as faithful as possible to its original form, overcoming difficulties caused by a series of conversions, crashes and salvaged components. The result is impressive.
By placing the right-offset engine behind the front axle and the five-speed gearbox behind the rear axle, a favourable weight distribution was achieved, with 48 percent of the weight on the driving wheels when the car was empty and an almost ideal 50:50 balance with a 75kg driver in the LHD seat.
The technically advanced and visually appealing1100 CC engine under the low bonnet is also worthy of note. It shared its aluminium block and crankcase with the classic 40 horsepower Škoda 440 Spartak, but twin overhead camshafts, driven by a gear train with its own lubrication circuit, helped to more than double the original power output.
Racing pistons increased the compression ratio to 9.3:1 and two mutually independent ignition systems – German Bosch dynamo and Swiss Scintilla Vertex magnetos – supplied the spark plugs.
Weber DCOE side-draft carburettors fed in the racing fuel.
Delivering a peak output of 92bhp (67.7kW) at 7700rpm and able to sustain up to 8500 rpm for short periods, the engine had a tiny cooling system, sized for racing circuit speeds.
A choice of final drive ratios – 3.73 – 5.25:1 – were fitted to suit individual racetracks and the open-top versions could achieve 200km/h.