We stated last month that we were conducting a test of a Ford Ten “Prefect” saloon equipped with an A.75 Marshall supercharger by the North Downs Engineering Co. We can now reveal that this test covered 1,056 miles in a matter of five days and ranged from town driving to a long-distance night run in the teeth of the worst gale in living memory. Any suggestion that supercharging of utility type cars brings trouble in its train is dispelled when we say that in this mileage the only involuntary stops were those occasioned by dirt in a fuel line and by a short, circuit in the ignition system. The latter trouble happened when snow, driven by the gale, wetted the engine until the h.t. current “shorted” between the top, of the distributor and the supercharger inlet pipe. A chafed lead was found to be responsible and, as the car had covered 14,000 miles since the supercharger installation was fitted, can be excused. Otherwise, no mechanical troubles intervened and no belt tensioning or other work was required, although the Nordec-Ford was hard-driven throughout our thousand-miles test. About, a pint of water was added to the radiator, oil put in as required, while fuel consumption came out at approximately 28 m.p.g. On “Pool,” pinking occurred freely, but, did not appear to cause over-heating or other bothers.
The North Downs Engineering Co. has gone very thoroughly into this matter of supercharging ordinary cars. The Marshall Roots blower is perfectly reliable providing its nose bearings are properly lubricated. This is done by tapping the normal engine oil supply and feeding to the supercharger via an adjustable valve and a sight drip-feed. The latter can be inspected from time to time — a comforting assurance that oil is going where it should. Throughout our test, it always was. A single belt is used to drive the blower from a pulley ahead of that which carries the separate belt driving the dynamo and fan. An adjustable jockey pulley running on ball-bearings tensions the blower-drive belt. The supercharger runs at 1.21-times engine speed and with the existing downdraught carburetter, increases b.h.p. from 28 to 32.5 at 3,000 r.p.m. and from 29.5 to 37 at 3,500 r.p.m.
This power increase has the effect of improving top-gear acceleration or pick-up through the gears, to a marked degree. The sponsors of the Nordec-Ford rightly point out that to go beyond normal peak r.p.m. in the gears will accelerate wear and tear, and normally one changes up at 20 m.p.h. in bottom gear and at 30 m.p.h. in second. Even so, we had immense fun away from the traffic lights of the Kingston By-Pass, drivers of far more imposing cars being left standing by our insignificant looking, pressed-from-the sheet, automobile, (incidentally, this is not intended as a slight on the Ford, for it has proved its sturdy worth the world over and, mercifully, makes no pretence to be anything but a practical utility car). Not only does the supercharger installation enable one to indulge in tricks of this sort, but it materially improves top-gear acceleration from 45 m.p.h. upwards (at 2 lb/sq. in. boost) and enables hills to be climbed in top far faster than before. Consequently, this Nordec-Ford seemed just the job when a 200 mile night journey lay before us. It cruises easily at 50 all day, going up to 60 m.p.h. if required – incidentally, the speedometer appears to be almost accurate. There is a slight whine from the supercharger, nothing more. Starting from cold, and pulling away thereafter, is as easy as with the normal Ten, and so cool does the blower run that after a fast drive it is possible to rest one’s hand on it. Not once did we hear a protest from the blow-off valve.
How does this installation mate with the Ford Ten, as such? Well, we proved to our satisfaction the reliability of the outfit (special K.E. valves, over drive, etc. are available for Fords from the North Downs Eng. Co. if one wants to make doubly sure) and found that accessibility did not suffer unduly. The plugs are easily removed with a sensible plug-spanner, a sheet of rubber over the distributor top cured our short-circuit, and the fuel-pump primer is moderately easily reached — clean cuffs might suffer, but how often does the enthusiast consider such matters?
The Girling brakes are not only fully up to the car’s increased abilities, but work very nicely indeed while, with the divided-axle i.f.s. supplied by North Downs, the road-holding was also entirely adequate, assisted by Ford’s sensibly-geared steering.
The clutch was fierce unless dropped in, Alfa fashion, at zero revs., but this was hardly a fault to be blamed on the supercharger! Altogether this Nordec-Ford struck us as an excellent way of getting along, and incidentally, of getting maximum sustained urge for a £12 10s. annual tax. The Nordec installation also endows with individuality a car for which spares and service exist throughout the world. Most insurance companies ask no extra premium on the Nordec-Ford, while, as no radical alterations are entailed in installing the blower, this can be retained for use on a new car should the existing one be sold. On the car tested the air-cleaner was not coupled up to the carburetter intake, but normally this is in use, and obviates scoring of the blower rotors. Two extra gauges were fitted — an oil temperature thermometer, which never exceeded 40 deg. C., and a boost gauge, which went most fascinatingly up to 4lb.jsq. in. at a touch on the accelerator. It was possible to cruise just below 50 m.p.h. at zero boost, which should give maximum economy of fuel.
We did a standing 1/4 mile, two-up, in half-a-gale. in 29 sec. but did not have an opportunity to check the speedometer for further tests. However, we understand that the 0-50 m.p.h. acceleration time is improved by over 10 sec. when a Marshall supercharger is fitted, a truly useful gain. — W.B.