Schaub Metalworks ROADSTER Part 1

Schaub Metalworks is all about tradition: Rebuilding old stuff the way it was built back in the day, always perfect and never disguised in bondo. Here’s the first part in a little series about Raphael’s personal 1932 Ford Roadster that we can hopefully see racing already this summer.

Schaub Metalworks is not just your ordinary body shop, where paint is king and filler is heavily used to conceal bad bodywork. Owner Raphael Schaub comes from restoring airplanes where half-baked implementations in most cases simply lead to death. He also applies this to anything he builds: If it ain’t perfect, it ain’t done.

Raphael doesn’t only have a phenomenal eye for proportions and what looks right on a vehicle, he also has the skills to make parts excactly how he imagines them and make them work they way they have to. Combining this with his awareness about the history of the automobile, he creates what today is called period-correct vehicles with having every little detail in mind.


We went by his shop lately to talk about his newest personal project, a very traditional Hot Rod. We’re going to make this a little series covering the whole process of Raphael building the car. We’re already looking forward to what’s new on the project when we get there next time.

The late 1931 Ford roadster body sits on a 1932 frame, those are all original pieces from back in the day and no reproduction parts. The car will have the original I-Beam axle up front and an all original 1932 Banjo axle in the rear. Still equipped with mechanical brakes, the car will feature nothing but pre WWII parts.

The powerplant is a 1937 Ford Flathead 21 Stud V8 engine that is equipped with a 1937 McCulloch Supercharger, that will be fed by one or two Stromberg 97 carburetors.


Since not everybody – including myself – is really knowledgeable about those rare old speed parts from the 30ies, we thought it would be a great idea to now tell you some of the history of the early McCulloch Superchargers and end the article with some photos showing you the current state of Raphael’s Roadster. We’re looking forward to going back to central Switzerland soon-ish to see what’s new on the build.

Robert Paxton McCulloch was a skilled engineering graduate from Stanford University who also inherited a considerable sum of money from his multi-millionaire grandfather. This gave him the financial freedom to indulge in his two passions: Boat racing and engineering. This eventually led him to set up the McCulloch Engineering Company in which he employed a team of engineers to develop engines and superchargers for aeronautical and automotive applications.

The first product of the McCulloch Engineering  Company was  a 2 stroke 60 cubic inch 90 HP racing engine. Another product developed at McCulloch Engineering was a centrifugal supercharger for the flathead Ford V8. The flathead Ford V8  was an enormously popular powerplant at the time, and a low cost centrifugal supercharger developed for this engine had potential for high sales. The resultant supercharger was belt driven, horizontally mounted between the standard intake manifold and carburetor and may well have been one of the first aftermarket blower systems produced.


This supercharger was manufactured and sold between 1937 and 1940 and was significantly different to the later McCulloch blow through centrifugal superchargers in that it was an inline unit, which compressed and mixed the fuel & air charge. It consisted of an impellor, which turned at six times the engine speed in the impellor housing, and was driven by a set of worm gears mounted on the drive shaft and rotor shaft. The worm gears were driven by a triple pulley mounted an input drive shaft driven from the crankshaft pulley using several belts and were initially lubricated using engine oil under pressure from the engines oil system. By revolving at high speed the impellor caused the fuel/air mixture to build up pressure, up to a maximum of four pounds, within the impellor housing as a result of centrifugal force, and the pressurized mixture was discharged into the inlet manifold.


A special three or four belt crank pulley was furnished for the Ford crankshaft, two new water pumps with three belt pulleys, as well as a set of matched belts, a belt idler pulley and a special air cleaner which was required due to the reduced clearance added by the supercharger.  The initial units, manufactured in 1937 and retailing for around $85, were designed to bolt onto the existing Ford and Mercury V8s which had the water pumps attached to the cylinder heads.  Continuous improvement by the McCulloch engineers resulted in a modified version being introduced in 1938, retailing for $125, and which was also engine oil lubricated via a supplied intake manifold, which contained all the necessary link ups required for the engine oil lubrication. These also appear to have been offered with in water jacketed and non water jacketed versions. In 1939/40 thermostatic control of the exhaust gas through the impellor housing was introduced, in order to promote a rapid warm up of the fuel/air charge output from the blower.schaub_roadster_05

McCulloch advertising of the period claimed a 38% increase in horsepower, better gas mileage, smoother performance and a longer engine life. More than 5’000 of the superchargers were sold during the late 30’s, but production was discontinued during the early 1940’s due to two reasons: The impeller for the supercharger, being gear driven, and being lubricated via the engine oil system which was often not changed as regularly as it should, had a tendency to become quite noisy with wear, and the blower, due to its fixed ratio of 6:1, produced no significant boost until high RPM was being achieved by the engine with boost levels being no more than 4 psi, even with radical reworking. These facts failed to impress the general public, and sales were low, although by the early 40’s this had become irrelevant as McCulloch was making superchargers for all purposes, and many thousands were manufactured for military equipment used during World War II. In fact McCullochs total sales in 1942 were $3 million, and the only larger manufacturer in the supercharger field at that time was General Motors.


The success of McCulloch Motors, and the restless nature of Bob McCulloch, resulted in him selling McCulloch Motors to Borg Warner in 1943 for 1 million dollars, which was subsequently invested in Pan American Airways stock. Six months later some of the stock was sold off and Bob McCulloch set up McCulloch Aviation Incorporated to manufacture 6’000 drone plane engines for the Air Force. As a result of this contract McCulloch felt that his future lay with featherweight two-cycle engines for industrial use, and given that it was time for a change, and his current manufacturing facilities were not suitable, McCulloch uprooted McCulloch Aviation and moved it to California.