Alfa Romeo Alfetta Type 158/9

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Alfa Romeo Alfetta Type 158/9

Alfa Romeo

Alfa Romeo Type 158/9 Alfetta

1937 - 1952
Straight 8
313 kW / 420 bhp
4 spd. man
Top Speed:
Number Built:
5 star
Alfa Romeo Type 158/9 Alfetta
Reviewed by Unique Cars and Parts
Our Rating: 5

The Triumph of the Italian Colors

Turn the clock back to 1938. The Germans were unbeatable in Grand Prix racing, a bitter fact to their nominal allies, the financially outclassed Italians. Helpless but not hopeless in the big 3-litre league, they made the best of Maserati's brilliance in 1500cc voiturette racing and drew courage from overt fantasies by the press which continued to brag about "The triumph of the Italian colours, always, when challenged by foreign machines."

On the last day of July 1938, a new red car made its debut in the Coppa Ciano for 1500cc cars at Livorno. Its straight-8 engine was straightforward, elegant and would have looked at home in any good sports machine. Its road-holding and handling were also brilliant and, with 145 kW (195 bhp) under the hood, the late Emilio Villoresi ran away with the race. Biondetti finished second in an identical Alfa Romeo. The beloved four-cylinder Maseratis were rendered obsolete at the drop of the starter's flag and it was clear to one and all that something full of portent had happened even though Marazza's Maserati took third place ahead of Severi's Alfa.

The Littorale

The motoring journal Littorale proclaimed, "Why should we not see in these little 1500s the fertile gem of a great new Italian racing car? It is not since today that we have argued that only a completely fresh start can bring us important racing victories. The victorious debut of this Alfa 1500 could be a direct confirmation of this." Of the four new Alfas in contention only E. Villoresi and Severi managed to finish in the money once more, with a 1-2 win at Monza.

The 1939 season began with another defeat for Alfa when Lang and Caracciola ran away with the GP of Tripoli in the one and only appearance of the 1.5-litre W-165 Mercedes-Benz. And then the Alfa sweep of victories began. Giuseppe Farina won the Coppa Ciano, Biondetti won the Coppa Acerbo and Farina won at Berne. Unfortunately these successes were not scored in the European Championship. The Alfas were competing in the special 1500cc formula class that was established by the Italians when it became apparent that the 3-litre Type 308 Alfa and the 8-CTF Maserati built for the 1938 GP formula could not compete with the Mercedes-Benz and Auto Union teams that were being heavily subsidised by the government of Nazi Germany.

The Italian Love For Motorsport

By 1940 Grand Prix racing was a peacetime memory but the Italians managed to stage the Tripoli GP one more time. Giuseppe Farina was the winner. In his Alfa voiturette he bettered Lang's record, set with a 1.5-litre Mercedes-Benz the previous year. The war clouds then drew across Europe and the 158s were hidden to await happier times. At the end of the war in 1945, Italy's industrial facilities were sadly depleted and it was only through the Italians' great love for the sport that motor racing was organised again as quickly as it was. The 1946 season was both pathetic and ridiculous as races were held for battered relics of random displacement which had survived the war years in barns and under haystacks. Giuseppe Farina and Wimille had a crack at the GP of St Cloud at Paris but both retired with clutch spline shaft failures.

But then Farina won the GP of Geneva and Varzi and Trossi won the last two big races of the season, at Turin and Milan. The real saga of the Alfetta had begun. In 1947 the cars were improved and won the GP of Switzerland at Berne (Wimille), the GP of Europe at Spa (Wimille), the GP of Bari (Varzi) and the GP of Italy at Milan (Trossi). In '48 it was the GP of Europe at Berne (Trossi) and the GP of Torino (Wimille) and the GP of Monza (Wimille). Alfa abstained from racing in 1949 but improved its cars so effectively that in 1950 it started in 11 Grands Prix and won 11, while Farina won the world's championship for drivers. The following year, 1951, Alfa's six victories gave Fangio his first world's championship. And thenAlfa retired in from Formula 1 racing.

Created for One Formula, Dominating Another

The Alfetta was unique among race cars. Its 14-year life span, war or no war, was more than remarkable. The fact that it was created for a lesser formula but came to dominate the maximum formula is remarkable too. There is the history of its amazing development from 180 bhp to over three times that figure. There is its still unmatched power output per unit of piston area. And there is its racing record of 36 first places in classic events. As Laurence Pomeroy has pointed out, Bugatti comes closest to matching this performance with 21 wins for its Types 35B and C and for the related Type 39.

Something which never has been told is that the Alfetta's staggering impact on history was achieved with a total of just nine engines, all of which were built during the first four years of its long life. And, also never told, four of these engines raced with fractured crankcases from 1939 until the end. The car was conceived quite modestly when Alfa Romeo decided in early 1937 to attack the voiturette class with an independently sprung chassis with straight-8 engine, supercharged and capable of developing around 190 bhp. Scuderia Ferrari in Modena still was functioning as Alfa's sub-contractor for racing activities and it was there that engineer Gioachino Colombo was sent by his chief, Orazio Satta, from Alfa in Milan to design the new machine and to supervise its construction. Colombo had worked under lano at Alfa since 1924 and thoroughbred racing machinery was his meat, as the racing world was eventually to discover.

Alfa Corse

Although the new 158/9's cylinder liners and single-stage superchargers were made by Alfa in Milan, the first four engines and chassis were built in Modena during late 1937 and the first half of 1938. Then Alfa created its own separate racing department, which it named Alfa Corse. Alfa bought out the assets of Scuderia Ferrari and hired Ing. Ferrari to direct the new department. Thus the whole project and staff were moved to Milan. This is important to clarify since previous reports of where and when the cars were built are often contradictory.

At this point the new car was christened the Alfa Corse 158, the first two numerals standing for the displacement and the last for the number of cylinders. Its more popular name, Alfetta (meaning little Alfa), was conferred on it gradually by a public which had not forgotten the original Alfetta, the little 1500-cc supercharged sports car which lano (with Colombo) had created for Alfa Romeo back in 1927. The nomenclature of the Type 159 was coined just to distinguish it from the original 158 specifications.

Colombo's engine for the new monoposto was classifically Alfa but with many subtle differences and some major ones. Unlike previous Alfa eights, which had their gear towers running up the centre of the engine; the 158 gears were at the front in order to get the shortest and stiffest possible crankshaft. Its twin overhead camshafts had five bearings each instead of three and its steel cylinder liners were threaded into the upper portion of the two aluminium block castings. Each of the cam covers was a one-piece casting and, contrary to some of the published information, the cylinder heads were integral with the blocks.

The main bearings of the 2-4-2. crankshaft were of bronze, lined with babbitt and so were the rod bearings. The crankcase and sump were Elektron (magnesium) castings. The water jacketing of the cylinder blocks was cored to provide large windows which put the cooling fluid in direct contact with the steel sleeves, and coolant was fed to the block via an eight-port manifold at its base. The crankshaft weighed only 10 kg (24 lb) but was machined from a 79 kg (176 lb) forged billet of chrome nickel steel. The Type 158 engine, complete, weighed 164 kg (363 lb). The clutch was in unit with the engine and consisted of four aluminium alloy discs on the driveshaft and four steel discs on the crank. The one-piece driveshaft employed no universal joints; it was connected to clutch shaft and transmission shaft by means of male and female gears which meshed like splines.

The transmission was in unit with the final drive, was without synchronisation and had four speeds forward and the usual reverse. The driveshaft passed very low beneath the driver due to a double-reduction final drive which consisted of a low-mounted, permanent ring and pinion and, above, a set of spur gears which could be changed to vary the overall drive ratio. A ZF limited-slip differential was used and lubrication of the transaxle unit was served by its own oil pump.

The First Alfetta Frame

The first Alfetta frame of 1937 consisted of very flat steel tubes 1.5 mm (0.06 in.) in wall thickness, 23 mm (0.877 in.) wide and 121 mm (4.80 in.) high. From the second chassis onward the tube width was increased to 35 mm (1.38 in.). The engine and final drive housing also doubled as cross members, the whole assembly, when bolted together, making an adequately rigid frame. Suspension was by trailing links at the front and by swing axles at the rear. These were, of course, enclosed in housings and their inboard U-joints were of the American Chrysler pot-type. Six-leaf transverse springs were used fore and aft; vertical wheel travel was 96 mm (3.86 in.) at the front and 124 mm (4.92 in.) at the rear. Each wheel was snubbed by one piston type and one friction type shock absorber and ride characteristics were variable over a wide range by means of shock adjustment of 192 I (42% gals).

This was the car that, with a single-stage Roots blower delivering 17.65 psi boost, produced an initial 134 kW (180 bhp) at 7000 rpm on the Scuderia Ferrari dynamometer and 145 kW (195 bhp) in time for the historic Coppa Ciano of 1938. Each race taught its lessons and was a new laboratory for experiment that yielded results both good and bad. At first there was a single exhaust system but this was changed in 1939 to a dual system with one manifold and tailpipe serving cylinders 1, 2, 7 and 8 while the other served the four central cylinders. Then it was gradually learned that the two manifolds feeding into a single pipe gave the best performance for fast circuits while the full dual system was best for mixed circuits.

It was during this early period that the one real weak point of this engine manifested itself. The bearing caps were held in the magnesium crankcase by two short bolts each. Directly above them were the short hold-down bolts for the cylinder blocks. It was between the ends of these upper and lower bolts that each of the original four crank-cases developed large and serious cracks. Colombo pleaded for new castings in which he could run big single bolts from cap to block and thus eliminate the possibility of repetition of this failure. But this was never a large-budget operation and his management told him to make the best of what he had, which he did. He drilled the cracked cases, installed the new through-bolts, and in this patched-up form the engine went on to develop ever-higher output for another dozen years. And of course no one ever knew.

A Year Of Automotive Perfection

1939 was really the year of the perfection of the 158. As output and rpm continued to rise, the limitations of the plain rod bearings became precisely defined: beyond 7200 rpm they simply washed out. The remedy was found in needle bearings, which embodied some interesting touches. There were "big" needles which alternated with ones which were 0.0008 in. smaller. The smaller ones had blunt ends because they acted as guides between rod and crankshaft and their ends were chamfered for oil flow. The larger needles had radiused ends for the same purpose and the microscopic difference in diameter between the two provided perfect clearance for oil film. These bearings and the through-bolts put an end to the Alfetta's lower-end troubles and the top end never was significantly changed, except for one major change to the cooling system.

The Mercedes-Benz win at Tripoli in 1939 was brilliant, but to the men of the Alfetta it was a victory by their own default, one they believed might have been theirs. It triggered the change which Colombo considers to be the most important in the development of the 158. By now the output of the engine was pushing 178 kW (240 bhp) but nothing had been done to compensate for the inevitable increase in heat rejected to the coolant. This, plus the fact that early May in Tripoli was scarcely balmy, sent three of the four Alfettas boiling into their pits. Only by staying well under 7000 revs was Emilio Villoresi able to trudge home in third place behind the victorious W-165s.

The first corrective measure was to increase the cooling system's cap pressure from 4 to 17.6 psi, but this was a minor detail. The big change was the drilling of the cylinder heads and the installation of a coolant manifold with a pressure outlet for every combustion chamber, while still retaining the manifold at the base of the blocks. No Alfetta suffered from overheating again. The cars were in their pre-war form when they first raced at Paris in 1946, and both were forced to retire with clutch problems. But in less than six weeks the entire stable was renovated and a major change was tried on the engines of two cars. Farina's and Varzi's Alfettas were equipped with two-stage blowers that gave them an output of 189 kW (254 bhp) at 7500 rpm.

The GP of Geneva

Giuseppe Farina won the GP of Geneva, Trossi and Wimille finished second and third in single-stage blown 158s, and Achille Varzi placed seventh. That was on July 21 and by September 1st (the GP of Turin) all the Alfetta engines had been equipped with two-stage superchargers. The Alfetta's were the uncontested victors there and at Milan a month later, the concluding event of the season. During the winter before the 1947 season, the volume of the low-pressure blower was increased and the intake system improved to the point where engine output was raised to 230 kW (310 bhp) at 7500 rpm. This stage of tune was called the 158/47 but existing competition did not warrant its use that season. It was kept in reserve and the cars campaigned with 1946-type blowers and detail improvements which raised output to 205 kW (275 bhp) at 7500 rpm. This was enough to let them dominate the four events in which they competed in 1947.

The 1948 Alfettas, running in 1947 tune, placed first, second and fourth in the GP of Europe at Berne. Then, on July 18, the Type 158/47 engine was introduced at the GP of France at Reims. The greater power output demanded more fuel and a supplementary fuel tank was installed to the right of the driver, matching the oil reservoir to his left. The chassis was lowered slightly, the magnetos were driven off the front of the camshafts, and refinements were made in the air-intake. Originally a large air horn had delivered air to the blower from a low position near the front of the car. This resulted in the aspiration of dust and grit, rapid blower wear and even jamming. Then the air horn was turned around and pointed toward the firewall, with some improvement in this problem. In the 158/47 the air horn was brought through the firewall, where it drew air directly from a shutter in the cowl.

Opening the Blower Under Instruction

This shutter had been a cockpit-cooling feature of the bodywork from the very beginning and so the change went unnoticed by all but Alfa's racing team, which thought that the "forced" air thus delivered to the blowers at high speed added as much as 18 kW (25 bhp) to the engine's output. Something else that went unnoticed was the fact that after this change Alfettas always started a race with these shutters closed. Usually after two laps a white flag would be waved as each car passed the Alfa pits and this was the signal for the driver to open the blower-intake shutter. The reason for this was that it had been learned from hard experience that during the first couple of laps of any race great quantities of rubber particles were thrown from brand new tyres. This was of no significance to the unsupercharged competition but it had been known to cause jamming of the Alfettas' blowers.

Two-Stage Supercharging

Supercharging the Alfetta engine began very humbly, with the single-stage Roots blower delivering only 7.1 psi boost. This was gradually increased to a high of 19.9 psi. At this point the discharge temperature was 130 deg C (266 deg F) and 110 bhp was required to drive the blower. In its final two-stage form the low-pressure blower delivered 11.4 psi, with a discharge temperature of 32 deg C (89.6 deg F). The high-pressure blower had a discharge pressure of 48.3 psi, a discharge temperature of only 82 deg C (179.6 deg F) and power consumption of the two blowers combined was only 100 kW (135 bhp) - a good illustration of the advantages of two-stage supercharging. In its Type 159 form the Alfetta developed the highest output per unit of piston area in the entire history of racing engines.

During the 1948 season three of Alfa's finest drivers lost their lives: Varzi, in practice in an Alfetta; Trossi, due to illness; and Wimille, killed early in 1949 in a Simca race car in Argentina. The loss to Alfa was tremendous and was a rrtajor cause of the factory's abstention from racing in 1949. Instead it used this interval to perfect the Alfetta still more and increased its output from the previous year's 230 kW (310 bhp) to 260 kW (350 bhp) at 8500 rpm. But it was not until March of 1950 that Alfa announced that it would participate in the grandes epreuves for the FIA World Championship. Meanwhile, Colombo had been back in Modena, designing the Formula One 1500cc Ferrari V-12. During the Alfa Corse changeover in 1938 Enzo had insisted on a clause in the contract which provided that, in the event of war in Europe, his plant would be returned to him, as it was.

The Alfetta made its first appearance of the 1950 season at the GP of San Remo in April. There was just one of the 158/47s entered and Juan Manuel Fangio passed all three of the Ferrari V-12 challengers in the 14th lap, showing that the old machine still was a match for all comers. It was during that memorable season that Alfettas contested eleven GP events and won them all and Dr Nino Farina won the World's Championship for drivers. For 1951 the Alfetta was modified still further and was re-christened the Type 159. There were no significant changes to the engine, which had now been pushed to deliver 312 kW (420 hp) on the dyno at 9600 rpm. Interestingly enough, Colombo (who returned to Alfa in 1951) never had to redesign the valve springs, which exerted the same pressures as they had 14 years and 2600 rpm ago. But he did prune 23 grams from the weight of each valve.

Swing Axle to de Dion Suspension

The big change in the Type 159 was the switch from swing axle independent rear suspension to a de Dion rear axle with centrally located de Dion tube. This change was dictated by the loads imposed by the ever-increasing speed of the car - now right at the edge of 320 km/h (200 mph) - and by its increasing weight as greater loads of fuel had to be carried to match the engine's increasingly ravenous fuel consumption - now not even 3.2 km/gallon. In the 159 what had been the oil reservoir at the driver's left was commandeered as yet another fuel tank and the oil reservoir was under the cowl.

It was in this car that Fangio won his first World Championship after a season-long, neck-and-neck duel with the 4.5-litre unblown Ferrari. The championship was a toss-up between Fangio and Ascari after Alfa's loss to Ferrari at Monza. Ferrari's hope to run without refueling stops, his unfortunate choice of tyres and Colombo's shrewd preparations for the final race of the season, the Pena Rhina GP, Barcelona, were crucial. But there was another change made in the 159 which has not been reported before; this was an increase in the wall thickness of the frame tubes to 1.9 mm (0.079 in) and the addition of 25 mm (1 in) cantilever tubes high above both the frame rails. This gave the Alfetta a new level of rigidity and roadholding and it was sorely needed on this very fast and far-from-smooth course. The cantilever frame was used on that one occasion, the one which gave Fangio his first world championship.

After this race Corrado Millanta was quoted as saying: "I have written that the small supercharged engine is to be considered at the end of its career. In the light of what happened at Monza and Barcelona, it is no longer possible to hold this view. It can only be said that some kind of an equilibrium exists. Technically one may still hold to the former beliefs, but after the Barcelona race no one is able, in all fairness, to predict the results of next year's racing." Alfa had no lack of faith in the basic Alfetta design, nor had Colombo, but both knew that the development of the 14-year-old car had passed the point of diminishing returns and that it would have to be radically reconceived.

1500cc Developing 313 Kilowatts On The Dyno

The engine was now yielding 313 kW (420 bhp) on the dyno, plus another estimated 18 kW (25 bhp) due to dynamic charging of the blowers at speed. The two blowers, however, consumed 100 kW (135 bhp) at full revs, meaning that the little 1479-cm3 engine actually was delivering 432 kW (580 bhp) even if only 268 kW (360 bhp) reached the driving wheels. This output demanded proportional fuel capacity and weight. The 159 weighed 1079 kg (2380 lb) with driver and ready to go and, even dry, it had become heavier than the original 158 by 260 kg (575 lb). Acceleration, handling and tyre wear all suffered. And there was a severe braking problem. The fuel pumped to the engine by blower inertia forced the drivers of the Type 159 to back off for turns hundreds of metres earlier than their competition.

The most graphic and dramatic illustrations of dimishing returns for the Alfetta were there for all to see in its performance record. At Monza in 1947 the 158's best lap time was 1 min 57 sec. Four years later the Type 159 - with 316 kW (425 bhp) against 167 kW (225 bhp) - managed to get around the same course in 1.51. Two hundred horsepower in order to gain six seconds! This was not the way to go, and everyone knew it. Colombo prepared a complete redesign of the car in the interest of generally improved performance. This included reducing dyno output from 313 to 223 kW (420 to 300 bhp), dry weight from 757 to 519 kg (1670 to 1145 lb) and fuel capacity from 299 to 179 litres (65 to 39 gal). The two stage blowers were scaled down proportionately.

Great Car, Great Drivers, Durable Mechanicals

Alfa had been receiving financial support from the Italian government for its racing activities, which did so much to raise the prestige of Italian technology abroad. The grant for 1951 had been a reputed 100 million lire - about $130,000 at today's rates. Now they asked for 500 million with which to build five new cars and maintain a stable of four drivers throughout the 1952 Formula One season. The grant was denied and there the Alfetta died. The reasons for the Alfetta's success were many. The design was excellent, an extension of the know-how of the winningest marque in Grand Prix racing history. Alfa had its pick of great drivers and its team management was generally very good.

Colombo himself felt that the greatest single factor in the mechanical performance of the cars was the taking of no chances with the durability of components. Crankshafts and blowers were replaced at the end of each season. New connecting rods were installed after every six races. After every four races all cylinder liners, pistons and roller bearings were replaced. And whether they needed it or not the transmission and rear-end gears were thrown away after every race, while the same old nine blocks and crankcases just went on forever.

Fangio leads Giuseppe Farina in another Alfetta Type 159. Behind them are Ascara and Gonzalex in Ferraris. The photo is from the 1951 Barcelona GP, which Farina would win. At this stage, the 1500cc Alfetta was producing a staggering 316 kW at 9300 rpm, using a de Dion rear axle.
Juan Manuel Fangio in the Type 159 Alfa Romeo
Juan Manuel Fangio in the Type 159 Alfa Romeo.

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