Those chronic straight-eights
The editor enlarges on the theory of Lord Montagu’s that the craze for the straight-eight engine led several British car manufacturers into bankruptcy.
In his excellent study of motoring’s “Lost Causes” in the book of that name published by Cassell & Co. in 1960, Lord Montagu of Beaulieu put forth the theory that it was the obsession to have a straight-eight model in their range that had sent several British motor manufacturers to the bankruptcy courts. “The straight-eight”, said His Lordship, “stalks like some sinister skeleton through the story of the Lost Causes.” Lord Montagu went on to remark that Cecil Clutton, in his earlier book “The Vintage Motor Car Pocketbook”, had drawn a fascinating parallel between the incidence of the small “six” and the intervention of the Official Receiver, but that while no one would refute the element of truth in this thesis, he felt that there was a far closer relation between the eight-in-line engine and financial disaster. This is a line of thought which has long interested me and I now propose to enlarge on it.
Lord Montagu quoted those unfortunate straight-eights as the Belsize, Beverley-Barnes, Burney, Arrol-Aster, Hampton, etc. He also remarked that the last engines evolved by Lanchester, Hillman and Sunbeam as independent entities were of this type, and that eight cylinders did nothing to enhance the bank-balances of Alvis, Triumph and Wolseley.
Before we go further it is necessary to consider why the straight-eight came into being during the vintage years. There is no doubt that it was used for sporting purposes very successfully by Alfa Romeo, Bugatti, Maserati and others. It was a period when higher powers were required to keep performance reasonable on improving roads and with heavier bodywork, when long bonnets were thought to indicate status and speed, and when smooth-running was beginning to be both a salesman’s talking point and a desirable aspect of the private owner’s assessment. One might have thought that engineers would have been content with six cylinders, especially for the smaller-capacity power units. But some of them insisted on aping racing car practice in having the smallest possible cylinder area for a given swept-volume. It might have been thought, too, that some designers were anxious to follow an American lead, but with smaller engines. But if this was so, they were imitating other “lost causes”, because as Lord Montagu reminds us, of the “Big-Three” in the USA at that time only Chrysler listed an eight-cylinder car in the vintage years. Nevertheless, aided by we sinners the motoring writers, who even today persist in keeping buyers’ eyes on maximum speed when this factor of performance is unlawful away from certain German autobahns, the eight-in-line flared up for a decade or more before dying out like a spent roman candle, and it was certainly very evident on the Continent, in the vintage and just-post-vintage era. Let us, then, look more closely at this straight-eight craze….
By 1921, influenced by the use of such engines for racing (Ballot, Talbot-Darracq, Duesenberg, and by 1922 Bugatti) the pundits were advocating such multi-cylinder configurations for ordinary cars, reminding those who would listen of such early eight-in-line engines as 1902 40 h.p. CGV, the 1907 80 h.p. Weigel, and the Bugatti and other war-time aero-engines. The vee-eight had, of course, been successfully pioneered for catalogue cars by Rolls-Royce, De Dion Bouton and Cadillac, before 1914. So why the in-line? Well, the width of a 90º vee-eight engine, in the days when this had to be accommodated in a chassis frame the fore-part of which had to be narrow to provide a reasonable steering lock where half-elliptic springs restricted the pivotal angle of the front wheels, was against it, whereas today, when this vee layout is always used for eight-cylinder engines, the universal use of i.f.s. and the leniency of unit construction from the space aspect, has killed this objection. (Reducing the angle of the vee spoiled engine balance.) Another point was that in the 1920s bonnets were getting longer and higher every year, for the sake of styling appearance, and this suited an inline, but not a vee, configuration. Then there was the problem of the crankpins. If a vee engine was to gain the maximum benefit from its compact dimensions lengthwise, it was necessary to put two con.-rods on a common journal, or link auxiliary rods to master rods and the bearings of those days did not make this an attractive engineering aspect. Accessibility of sparking-plugs and other components was poor, too, in most vee-cylinder layouts.
So the eight-in-line naturally had its eager advocates. The Autocar had a long Editorial devoted to the subject as early as April 1921, in which it stressed how racing improved the touring-car, and how the straight-eight motor might reduce loads on the gearbox and back-axle by “its more regular torque”, so that these components could be lighter, that because of smaller cylinders and practically no flywheel the “eight” could be lower in the chassis, giving a lower c.-of-g. without loss of ground-clearance, that acceleration was improved, and lower tyre wear and lower internal stresses were other multi-cylinder advantages. But it did query why the vee-eight was not the better way of having these amenities, as it could be lighter, had a more amenable crankshaft length, was more compact, and better balanced than the in-line-eight.
It is indeed rather difficult to see the appeal, at that time (or maybe at any other), of the eight-inline for touring cars, as distinct from racing cars seeking maximum power and efficiency from a restricted capacity (3-litre, then 2-litre) ruling. If the four-pot job was comparatively rough, particularly in the period prior to the rubber engine-mountings pioneered by Chrysler and Citroen, the six-cylinder engine was not; it had good balance factors which the eight could not materially improve upon. Moreover, as one authority was pointing out at this time, where reliability was concerned there were two more sparking-plugs, four (or in a racing engine eight) more valves, and extra pistons, piston-rings and bearings to go wrong, with the luxury of eight pots. In the 1970s, when we neither decoke nor rebore our engines and take them very much for granted during the life of a car, these reliability arguments are no longer valid. But in the early 1920s they were; it was a fact that many people felt safe with a “four”, although a “twin” was seen to lose half its power if one cylinder went out, a “single” to die completely.
The problems with an eight-in-line were torsional vibrations from the necessarily long crankshaft, and how best to carburate its widely spaced cylinders. They were considerable, but perhaps the fear of changing gear which possessed many drivers at the time made the smooth torque of the eight seem worthwhile if this enabled a driver to hold onto top gear for most of a journey. By the mid-1920s all the for-and-against arguments broke out again, although it might have been thought that they were of mostly academic interest, inasmuch as a mere 3% of the cars on the British market in 1923 had eight-cylinder engines and these had increased to only 3.8% by 1925, to 5% by 1926. Nevertheless, in 1925 at least 18 well-known makes in this country, Europe and America were available with eight cylinders. At a time when large power units were still popular, the benefits of a multiplicity of cylinders from the viewpoint of the light weight of the reciprocating parts may have been valid outside the racing tracks and circuits, although this could hardly be justified in the case of Mathis, who made an overhead-camshaft in-line-eight of 1,720 c.c., with cylinders of 60 x 76 mm. Nor was Voisin’s straight-twelve absolutely necessary, I would have thought!
There were different design methods as these in-line-eights went onto the drawing-board. The crankshaft could be arranged as two four-cylinder cranks set at right angles, or as a four-cylinder crankshaft with two-pot cranks attached at 90° to the ends of it. The former layout was less effective from the balance aspect, because the rocking-couple of a four-cylinder engine was duplicated, and also magnified by the length of the crankshaft. But it was easier to carburate. In both engines torsional crankshaft vibration was present unless a very stiff shaft was used and efficient carburation of the 2-4-2 crank layout was difficult, especially as engine speeds had increased over the years from around 2,000 r.p.m, to closer to 3,000 r.p.m. Twin carburetters, each one feeding four cylinders, were usual but some designers preferred one carburetter, either arranged to feed a manifold that divided to supply two separate four-cylinder inlet-pipes, or two manifolds, one feeding the inner-four, the other the outer-four cylinders.
In the larger or more sporting cars four carburetters might be employed, each usually supplying two adjacent siamesed cylinders through external branch-pipes. Carburation headaches apart, there were two other crank-throw arrangements then in use. That of the 2-litre Bugatti, for instance, in which cranks 1 and 3 were at 180° to 2 and 4, cranks 5 and 6 likewise to 7 and 8, but with Nos. 1, 2, 3, and 4 at right angles to Nos. 5, 6, 7 and 8, as in the other 4-4 layout. Another arrangement was that in which cranks 1 and 8 were at 180° to 2 and 7, cranks 3 and 6 likewise to 4 and 5, but with Nos. 1, 2, 3 and 4 at right angles to Nos. 5, 6, 7 and 8. I have an idea that Parry Thomas used yet another computation for his 1½-litre straight-eight “flat-iron” racing engine. The conventional 4-4 crankshaft was used by Beverley-Barnes, Isotta-Fraschini, Locomobile and Panhard-Levassor (and Ballot on the 1921 racing cars), the 2-4-2 layout by Hupmobile, Jordan, Packard and Wolseley, to instance how designers failed to agree over the basis of eight-in-line engineering. Apropos of this, I recall that amusing motoring journalist, Edgar Duffield, when he was writing in praise of the 1929 24.2 h.p. Marmon Roosevelt, remarking that it was “a real eight, not a doubled-four, or a six with two extra cylinders soldered on to whichever end happened to come handiest”. (So it seems that Marmon used an unusual crankshaft style; it had a “high-frequency modulator”, a polite term for a vibration-damper, which Duffield said smoothed out a faint engine tremor at just about 35 m.p.h., presumably in top gear.*) Apart from torsional crankshaft vibration to which the in-line-eight could be prone, one racing engine lost five b.h.p. on the test-bed, which was traced to the ignition-timing being affected by torsional vibration of the long camshaft due to magneto drag, cured by substituting coil ignition, so Louis Coatalen of STD was no fool when he adopted Delco-Remy coil ignition for his lengthy racing engines …
These different crank and carburation systems led to a variety of firing-orders, which I will list as follows:
The above are used with 2-4-2 crankshafts
The above are used with 4-4 crankshafts
The divergent ideas prevailing in mid-1925 can be appreciated when it is seen that Beverley-Barnes used firing-order (B), Bugatti (F), Isotta-Fraschini and Jordan (D), but Panhard-Levassor and Packard an order apparently all their own, and I believe Parry Thomas used a different firing-order for his racing Leyland-Thomas engines than he had for the original Leyland Eight.
There was a divergence of opinion, too, as to how many main bearings should support the long crankshafts of these eight-in-line engines. Bugatti got away with using only three, for his first model of this kind, Hupmobile, Jordan, Marmon and Locomobile and the later Hillman had five-bearing shafts, but Beverley-Barnes, Isotta-Fraschine, Packard, Panhard-Levassor went the whole hog with nine bearings, each. (And later Wolseley used ten, its o.h camshaft driven by a vertical shaft between the pairs of cylinders.) At this time such engines developed from the 35 b.h.p. from the minute Mathis to the 135 b.h.p. at 2,500 r.p.m. of the 7.4-litre Isotta-Fraschini. Hupmobile were proclaiming the merits of the inline over the vee-eight, a Mr. Strickland was an advocate of the latter layout, if eight cylinders were justified at all, and Warwick Wright, who sold straight-eight Stutz cars in this country, called fours “only fit for trucks”.
Even with what we now term the vintage years running out, the eight-in-line engine was very much in the news, although only 8% of cars on the British market had that number of pots. The advent of things like the Lanchester vibration-damper and the dual carburetter had helped to smooth out some of the difficulties confronting its designers. The 2-4-2 crankshaft had largely ousted the 4-4 from popularity. Less expensive straight-eights such as the 18 h.p. Hillman and 21-60 h.p. Wolseley had made their debut, and renowned companies like Sunbeam, with 30 h.p. and 35 h.p. models, and Renault, had become eight-cylinder conscious. Of the firing orders available, which were decided by both carburation and vibrationary considerations, that which I previously listed as (D) was used by Hillman, Lanchester, for their very fine overhead-camshaft straight-eight, Packard, Stutz, the single-sleeve-valve Arrol-Aster, Bianchi, Moon, Studebaker and Mercedes-Benz, but the new Wolseley had a firing order of 1,3,7,4,8,6,2,5, (with an in-line engine the orders are easy to read, taking the front cylinder as No. 1).
As to induction, double manifolding, inner feeding the paired-cylinders 2 and 3, 4 and 5, the outer piping 1 and 2, 7 and 8, all fed by a single updraught carburetter, was seen on the new Hillman, with Arrol-Aster using a similar arrangement, but with an aluminium manifold having separate ports for each pot. Mercedes-Benz did it differently, with one carburetter on the n/s feeding through the cylinder block to a straight manifold and separate ports on the o/s and with the complication of a driver-controlled hot-spot. Stutz had the system in which a single carburetter fed into a manifold leading to two “four-cylinder” manifolds within the cylinder block, Bianchi and Studebaker opted for a complexity of piping where a single “gas-works” fed up into an external inlet pipe and then to the two four-cylinder-branches that supplied siamesed ports, but Lanchester did it differently again, a duplex carburetter feeding the aforesaid three external supply pipes, supplying eight ports. Isotta-Fraschini continued to go for two carburetters, the outside dual manifolds with long risers supplying the siamesed ports, and Moon had the long-outer, shorter inner manifolding, all external, with paired ports, and elaborate balance-piping. The dual carburetter enabled each of the separate manifolds to be fed as from its own gas-works. This was a system liked by the Amilcar, Ballot, Beverley-Barnes, and Renault engineers.
By 1930 the eight had ousted the six-cylinder power unit by 46 to 42. The breakdown by makes of straight-eights then available was:
Graham Paige (2)
Stutz Black Hawk
De Dion Bouton
(The figures in brackets show the total number of models of each make, when more than one was made, with straight-eight engines, listed in 1930.)
From then on the vee-eight began to oust the straight-eight from its lead in the multi-cylinder stakes. Henry Ford, who like Henry Royce, had refused to have anything to do with eight-cylinder engines in the beginning, made that great breakthrough in 1932 when his skilled foundrymen contrived to make a vee-eight cylinder block and crankcase as a one-piece iron casting (Ford could also cast instead of forged steel crankshafts), enabling the inexpensive Ford V8 (“V8” is, I think, still a Ford copyright symbol) to make its debut. Scintillating performance thus came within the reach of ordinary car buyers, allied to eight-cylinder smoothness and good low-speed torque, at first in cars that were rather too quick for their chassis. Today the vee-eight is the only form of eight-pot power plant on the market, universal in America but used here only by Rolls-Royce, Aston Martin and Rover (discounting hybrids). For which I am grateful, because it enables me to enjoy the satisfaction which only a good multi-cylinder engine can give, behind the wheel of a Rover 3500.
* * *
Before concluding this discourse I thought I would try to discover what those straight-eight cars castigated by Lord Montagu were like on the road. This isn’t easy, either because they were produced in such small numbers, or were so bad, that no-one seems to have tested them. However, in 1925 The Autocar took out a 3.9-litre o.h.c. Beverley-Barnes, manufactured by the London firm which made nothing else but straight-eights all through its chequered existence. The car’s chassis was praised and in spite of a heavy Vanden Plas saloon-limousine body 0-50 m.p.h. took 15 sec. in top gear, eight seconds in second, on the 3-speed box. But the tester reported that there were vibration-periods at 45 and 55 m.p.h., in top and at corresponding speeds in the lower gears, trying to excuse them by saying these top-gear speeds “are considerably higher than the average driver on British roads would wish to maintain!” The 75 x 112 mm. engine was “distinctly noisy” at these speeds and “not really quiet throughout its range”. It was also sensitive to ignition settings and gave a jerky action when picking up from 10 m.p.h., in spite of two carburetters (which gave 15 m.p.g.) and presumably a 2-4-2 crankshaft. The gear-change was stiff, making quiet changes difficult, and the brakes needed considerable force and displayed too much lost motion, as of cables stretching; it needed 157 feet to stop the car from 40 m.p.h. The tester, in fact, praised the bodywork more than the car and it is perhaps not difficult to see why the Beverley-Barnes failed, even when priced at only £1,250 in this form, with a radiator like a Rolls-Royce.
Of the other eights referred to in the bankruptcy context by Lord Montagu, the Lanchester was a very fine car and its demise can be put down to company rather than mechanical shortcomings. But neither of the two straight-eight Sunbeams (4.8 and 5.4-litre) earned the acclaim of the Wolverhampton company’s sixes, and Georges Roesch’s compact 4½-litre eight-inline Sunbeam engine never got into production. I can find no tests of the Belsize or Hampton eights but The Autocar tried the 2.6-litre 63 x 105 mm. straight-eight Hillman. However, this was at a time when it was not very critical. It did observe, though, that the improved 1931 Vortic saloon, good for nearly 70 m.p.h., was smoother than the previous eight-cylinder Hillman model, was more lively, and its central gear-change easier than the older car’s right-hand one, which incidentally had achieved only 16 m.p.g. and 57 m.p.h. in Segrave saloon guise. Of this £355 Hillman The Times was more critical, saying the carburation or manifolding was suspect at low speeds. The same source found the 21-60 Wolseley’s engine “beautifully silky” but the springing poor.
The Alvis and Triumph straight-eights were very specialised sporting cars, which are outside the general run of those we are discussing, but it is easy to see how the less well-contrived and constructed cars of this kind failed, and as Lord Montagu says, all too often took their makers with them. The 21-60 (2.6-litre) and 32-80 (4-litre) o.h.c. Wolseleys were complicated propositions and only Daimler made a go of the in-line-eight, with various versions (3.7, 4.6 and 3.9-litres) culminating in the 5.4-litre DE-36 which remained in production until 1953. But even Daimler went over to vee-eights eventually, leading on to a return to the existing twelve-cylinder or “Double-Six”; and who could ask for a smoother, quieter motor car than this? – W. B.
* But Arthur Judge and P. M. Heidi advocated the 2-4-1 crank, which Heidi called “the proper arrangement”.