ŠKODA 1100 OHC Coupé: Restored to its former glory

ŠKODA 1100 OHC Coupé: Restored to its former glory

ŠKODA WORLD HERITAGE

Only two units of the ŠKODA 1100 OHC Coupé racing car from 1959 were made and neither survived in their complete original condition. But the car is now back on the road, thanks to the professionals at the ŠKODA Museum and the ŠKODA prototype construction Centre.

7. 2. 2022

The 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 and 1960. The escalation of the Cold War meant that these two cars never even ventured beyond the borders of the then Czechoslovakia. But that wasn’t the end of the car’s troubles.

Even the domestic career of this elegant and agile car with a unladen weight of just 555 kg ended prematurely. Changes in technical regulations and a general decline in the up to 1,100 cc racing category forced its demise. As was customary at the time, the two cars were consequently sold to private buyers in 1966, resulting in the two coupés being modified for use on the roads – and meeting a similar fate.

Crashes are no obstacle!

The first owner of the unit that has just been restored was Hanuš Hrabánek, the father of Michal Hrabánek, the current director of ŠKODA Motorsport. Hrabánek Sr. replaced the 1100’s OHC engine with the 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 other owner crashed his coupé 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 crashed car was dismantled. The rear axle with gearbox and distributor went to the National Technical Museum in Prague, from which the ŠKODA Museum acquired it 15 years ago. The car’s chassis – the frame with the front axle, brakes, pedals and other small parts – survived in a Czech private collection, from where the ŠKODA Museum bought it 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 other of the two ŠKODA 1100 OHC Coupés produced was our family car for two years,” says Michal Velebný, the ŠKODA Museum’s restoration workshop coordinator, of his encounter with the unique car. “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 1300 OHV engine from the OCTAVIA model series. As our family grew, the coupé had to give way to a more practical family car, a ŠKODA 1000 MB.” We should mention that this coupé was also crashed – and 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.

ŠKODA 1100 OHC

A pair of open-top spiders with a fibreglass body developed since 1956 met a better fate than the two ŠKODA 1100 OHC Coupés. Both the spiders have survived: the first is one of the top attractions at the ŠKODA Museum in Mladá Boleslav, while the second is used by ŠKODA UK to promote the Czech car brand. 

The ŠKODA 1100 OHC racing car made its debut on Sunday 29 June 1958 at a race called the Mladá Boleslav Circuit. The open-top ŠKODA 1100 OHC, type 968, was developed for endurance racing on circuits.

Joint effort

One crucial step on the long road to the car’s restoration came when the experts from the ŠKODA Museum’s restoration workshop joined forces with the professionals from the ŠKODA’s prototype construction centre, whose official name is the EGV department. The know-how acquired from restoring the open-top version of the ŠKODA 1100 OHC and deploying it in vintage racing events came in very handy. 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, have been preserved in the ŠKODA Archive.

By the end of 2015, the restorers had already completed the chassis with a newly made radiator, fuel tank and other elements, and 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 shares with ŠKODA production cars of the time. The coupe’s outer door handles, for example, correspond to the ŠKODA 1200 “Sedan”; some of the switches and the switchbox proved their worth in the ŠKODA 440 “Spartak” and OCTAVIA; the three-spoke steering wheel covered in black plastic references the pre-war ŠKODA POPULAR bestseller – and we could list many more parts like that.

From two panel beaters to 3D

The toughest nut to crack was the reconstruction of the aluminium bodywork, designed in the late 1950s by Jaroslav Kindl, a ŠKODA designer. Back then, carpenters created a wooden mock-up based on Kindl’s drawings, and a team of panel beaters then hammered out the aluminium panels by hand according to the mock-up. Each applied his own inventiveness and taste, so the left half of the body was somewhat different in shape from the right, with an example being the way the edges of the bumpers are rounded.

This was a headache: how should they unify the car and modify shapes or proportions that do not look natural when the drawing is turned into 3D reality or differ from the form evidenced by 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 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, confronting the surviving photographs with the drawing documentation and the 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 red 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 hidden from view, again so that they all matched the period documentation.

Colour of the original

The body was made from 0.8 mm and 1.0 mm thick aluminium sheets. They 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 creators opted for anodised aluminium, on whose etched surface they applied the paint by electrolysis. In particularly stressed areas, however, such as the rivets and the front of the car, the finish was not very durable. The restorers respected historical development: as evidenced by surviving period photographs, in mid-1962 both coupés were given a red paint job

The demanding process of professionally restoring the 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. Even though they used techniques and modern technologies applied in the construction of ŠKODA cars in the 21st century, 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 the subsequent fate of salvaged components. And the result is impressive.

“You could say that the unique ŠKODA 1100 OHC Coupé has returned to its birthplace. The staff at the ŠKODA Museum and our team from the EGV department have managed to combine traditional methods with today’s advanced technology, digitising historical drawings from the ŠKODA Archive and leveraging the available period photo documentation. We then created a virtual model and produced several 3D models based on that. By the way, the modifications to the body shape took dozens of hours. The actual reconstruction of the car body was already underway in the prototype construction workshops. Our predecessors built the original racing cars in one of these workshops, at the Česany site in Mladá Boleslav, in 1959,” concluded ŠKODA prototype construction specialist Martin Kadlec.

ŠKODA 1100 OHC Coupé (1959) - technical specifications

Unlike the earlier ŠKODA SPORT and SUPERSPORT types, the 110 OHC Coupé is not built on a backbone chassis frame adopted - albeit with modifications - from mass production. The car is based on a lightweight yet rigid frame of super-strength thin-walled tubes. The front wheels are connected to a trapezoid made of pairs of superimposed triangular arms, with an effective trailer-arm wishbone axle system at the rear. Instead of the leaf spring bundles used on production ŠKODAs at the time, the designers opted for space-saving and lighter torsion bars.

The stripped-down original ŠKODA 1100 OHC Coupé 

By placing the engine behind the front axle and the five-speed gearbox behind the rear “axle”, a favourable weight distribution was achieved, with 48 per cent of the weight on the driving wheels when the car was empty and an almost ideal 50.3 per cent balance with a 75kg racer at the wheel.

The technically advanced and also visually appealing power unit – a naturally aerated an 1100 CC engine under the low front bonnet - is also worthy of note. It shares its aluminium block and crankcase with the classic 40-horsepower Š 440 “Spartak”, but the two camshafts in the head, driven by a reliable gear train with its own lubrication circuit, help to more than double the power output. Modified combustion chambers increase the compression ratio to 9.3:1, and some of the interesting features that improve both fuel mixture combustion and operational reliability include two mutually independent ignition systems - the German Bosch dynamo and Swiss Scintilla Vertex magnetos.

ŠKODA 1100 OHC Coupé: engine diagram

Delivering a peak output of 92 hp (67.7 kW) at 7,700 rpm and able to sustain up to 8,500 rpm for short periods, the engine’s cooling system is sized for racing circuits. Based on the fixed gear ratio, which was modified to offer a range of 3.73-5.25:1 to suit the character of the racetracks of the day, the open-top car could reach speeds of up to 200 km/h.

The naturally aspirated 1100 cc engine: technically advanced and visually attractive