THE MODEL-A FORD
THE MODEL-A FORD
[There are so many Rolls-Royce cars about that they are almost commonplace and some of the interest in them is thereby diminished. At the opposite extreme the model-A Ford has become a rarity, and is worth restoring. This article by the model-A authority, Dr Paul R. Woudenberg of Long Beach, explains why and lists changes in specification down the four years this famous Ford was in production—ED.]
THE model-A Ford was in production just over four years and has been largely overshadowed by the legendary model-T. Recently the model-A has found new favour with American restorers and many now believe that it was the finest Ford ever produced. The model-A was the last Edwardian big four to be produced in America. With a bore of 3-4 in., and stroke of 41 in., it displaced 200.5 Cu. in., or just a little over 3.2 litres. The bore/stroke
ratio followed Ford’s early preference for a nearly ” square ” engine. Engine flexibility was of a very high order because of the small valves and narrow manifolding coupled with a heavy flywheel and a 4.2 to 1 compression ratio. A good engine with a retarded spark can idle below 150 r.p.m. On level ground the car will pull away from rest in top gear without too much fuss and can idle easily in top gear at s m.p.h.
In 1927, the engine originally produced 40 h.p., at 2,200 r.p.m. By 1932, in model-B form, output was upped to 5o h.p. This absurdly low figure from 3.2 litres suggests the possibility for development. A good many speed specialists developed overhead valve systems, such as C.ragar and Riley. A thoroughly developed Model-A could produce in the neighbourhood of too h.p., with rev, limits lifted to an incredible 6,000 r.p.m. In recent years with blowers and other modifications outputs have gone Still further. In 1961 at Bonneville, a B-engined Special exceeded 190 m.p.h.
It is probably just as well that no more than 40 b.h.p., was pulled from the engine in stock form, for the limiting factor was definitely in the bottom-end. Main bearing diameter was only ii• in., with rod big ends but i I in. Henry Ford liked a limber crankshaft which would follow block distortions. He certainly succeeded, for the crank is very limber at high speeds and has a strong tendency to whip out the babbit of the centre main bearing. Once the bearing clearance at the centre main opens up, the shaft usually becomes so flexible that breakage generally occurs. This sort of thing would begin to appear at speeds around 65 m.p.h. The modification of the B block in 1932 included larger bearings and counterweights on the shaft, which helped considerably.
The lubrication system included a small pump which lifted the oil to the valve chamber from whence it flowed by gravity through small holes to the main bearings. The rods were lubricated by splash. Sustained high speed running or hill-din-thing frequently allowed the bearings to squeeze away the oil cushion and I have drawn up after a good run with loud knocks at the rods. A few seconds idling generally brought things back to normal but sustained pressures would usually bring damage. All attempts at more h.p. begin with a pressure oil system to all crank bearings, the drilling of the shaft, for pressure being not unduly difficult.
A stock engine and a light roadster body could show a good turn of speed. A 3.7 axle ratio was used in 1928-29, along with 4.50 :. 21 tyres. Top speed when new approached 70 m.p.h. My own 1929 roadster will still do an occasional burst to 65, though the engine has now been bored out fOr its fourth and final time to 4 in., which adds a hit of urge. Cruising speed is easily around 45 to 5o m.p.h. The t930-31 model-A generally ran a 4.11 axle ratio along with 19-in. wheels and is a slower car, the engine having to work too hard to bring up a good top speed.
The chassis represents typical vintage practice. The side members have a maximum depth of 4 in., and were tapered toward the front. The frame had no diagonal bracing and it flexed sufficiently for Ford to reduce engine mounts from four to three in late 1928, . The springs were typical Ford transverse and were still. Houdaille shock-absorbers helped to further tighten the ‘car down. Cornering is good despite a high roll centre. Low polar inertia resulting from an engine well back on the chassis makes the car responsive and it steers relatively neutrally. 11’ the front spring sags the castor .angle increases; causing a change in handling something like oversteer. The model-A steering gave a measure of control unequalled since in American production. The steering ratio of ’28-’29 was
only it to 1. The dismal decline of Ford handling may be seen in the steady increase of this ratio. In 1930 it went to 13 to 1, in 1934 to 15 to 1, and in 1936 to 17 to 1. In 1936 Ford advertised so`,„ easier steering. This may have been true but the car was by now all but uncorrectable in any emergency situation. The early model-A’s are a delight to drive and steer with a precision and feel unknown to Americans until the large scale introduction of the M.G. after the war.
The transmission of the model-A is extraordinarily robust. Half-shaft failure is almost unknown. The differential design of 1927 persisted without major change through the VS series to 1948. It was also used in the Lincoln Zephyr and Continental series. By that time it was easily handling three times its original power rating. California dragsters still use these rear ends and run several hundred horsepower through them in brief spurts with no ill effects. ‘Die straddle-mounted pinions were absolutely reliable. The transmission used chrome alloy steel for conventional spur gears with ratios typical of Edwardian practice. Second gear was 54% and low gear 32% of high. These gears, sharpened over the years, produce a characteristic model-A transmission noise hut they rarely fracture. There have been cases where the bottom Of a model-A transmission case opened up in rough usage, allowing the oil to drain away. Apparently the transmission functions perfectly without any oil whatsoever. I know of one model-A which was run for four years with an absolutely dry transmission, due to a hole in the bottom. It was noisy but durable. The brakes were a sensational improvement over model-T — anything would have been! Brake effort was distributed 40% to
front wheels and 60% to rears. They were satisfactory When kept adjusted and in efficient condition.
The bodies of the model-A were designed under the supervision of Edsel Ford, Henry’s son. The ’28-’29 series show A pleasant resemblance to the L-series Lincoln. Ford pioneered all-steel construction and today the closed bodies show little deterioration with doors closing very smoothly on triple hinges and a rugged latch system. A two-door sedan weighed 2,375 lb.
In 1930 the bodies were changed and the model-A lost its spidery look. Chevrolet competition increased and Ford brought out a wonderful array of body styles, including a two-door sports phaeton, an odd convertible sedan with fixed windows, and a cute close-coupled Victoria, or two-door sedan.
In 1932, the model-B appeared with a synchromesh second gear and new engine mountings. It was a much-improved car and quite smooth hut the model-B was over-shadowed by the model18 VS. Since the price of the ” four ” was only Sto.00 below the VS, model for model, the model-B sold only in the absence of the VS. Passenger-car production of the model-B continued into 1933 for only about 9,000 units, out of a quarter million. Truck production of the model-B finally ended in 1934.
The model-A was the final statement of simplicity by Henry Ford. Non-adjustable valves, a carburetter assembled with one large bolt, a foolproof ignition system, and a gravity fuel flow all combined to Produce an exceptionally reliable car. Of the five million produced, perhaps to% may still be on the road and until very recent times it remained the last American car produced with an eye to durability, simplicity and economy.
The Model-A Club of America, formed in 1956, now has approximately 3,000 members who are busy restoring and preserving a splendid cross-section of these fine old cars. Model-As can still be purchased for less than $100.00 in running condition but spectacularly testified specimens have brought prices in the neighbourhood of $2,000.00. It would appear that once ,a Ford is able to survive its first 30 years, its chances for the next 30 are immeasurably improved.