Let’s Talk V8

Terry Walker (From Winged Messenger, 2012


Cross-section of the R-R V8, Silver Shadow edition

An amazing number of people think that the Rolls-Royce/Bentley V8 engine introduced in 1959 was copied from a US V8 engine. After all, the logic goes, V8s are an American idea, right?


The 90 degree V8 layout was patented in 1902 by the French Antoinette company, builders of internal combustion engines, and was used in boats, and very soon in aircraft. Within a few years several other companies, including Rolls-Royce, had built 90 degree V8 engines for passenger cars. In fact, Rolls-Royce was the first Car company to catalogue a V8 passenger car. The first Rolls-Royce V8 was a side-valve of 3.5 litres, introduced in 1905. The cars it was intended to go into were commercial flops— the Legal Limit model, and the Invisible Engine model. This V8 had two camshafts, one on the outside of each bank of the V8. In this contemporary drawing, the carburettor, which was between the banks of the V8, has been omitted. The mysterious object to the front top right is the distributor, inside a waterproof cover.


The 3.5 litre V8 (Autocar, Nov 11 1905)

Shortly afterwards Rolls-Royce adopted its one-model policy in favour of the very successful and profitable 40-50 HP 7-litre side-valve six "Silver Ghost", and all the other cars (2cyl, 3 cyl, 4cyl, 30 hp six and V8) were dropped. Meanwhile, back in France, the V8 concept thrived. De Dion-Bouton, in particular, were captivated, and soon offered a range of V8 cars from 6.1 litres to a whopping 24 litres, right up until the Company went broke.

The V8 concept trickled across the Atlantic, and several luxury makers produced V8 engined cars— Cadillac, and Lincoln, in particular— after World War 1. The Lincoln side-valve engine was a curiosity, having a sixty degree instead of ninety degree angle, which resulted in a very distinctive exhaust note. In 1932, as is well known, Henry Ford came out with the V8 replacement for the Ford A’s 200 cubic inch in-line 4-cyl. This new monobloc flathead engine had a traumatic birth. Casting a monobloc V8 with sand cores, and with the cores at 45 degrees from vertical, encouraged the cores to shift, and for a while something like half of all castings had to be scrapped. However, Ford overcome that problem.

A problem they could never overcome was that of overheating. The Ford engine is that monstrosity, a cross-flow side-valve. The camshaft is of course in the centre of the Vee, and logically the valve chest is, too. But the exhaust manifold bolts to the block on the outside of the Vee. How do they do it? By casting long exhaust ports right through the block’s water jackets from one side to the other. The inevitable result is the red-hot exhaust “manifolds” are in effect inside the water jackets, heating the water. Ford radiators were enormous for that reason.

Through the pre-war years, Ford was the only producer of cheap V8s. The other few brands on sale with V8s were distinctly upmarket, notably Cadillac, while V16s were to be found at the very top end of the market.

After WW2, everything changed.

In Europe, high fuel taxes and steep licencing on big-engine cars pretty much shut down interest in V8s, because the only real advantage of a V8 was to cram a big engine in a small space, and no-one could afford big engines. In Europe four cylinders reigned supreme.

In the States, Chrysler and GM began introducing V8s as options, Chrysler with its famous Hemi, Cadillac with its equally famous wedge-head. However, these V8s were small, just 5.3 litres initally. (We tend to forget that the typical Detroit car of the early 1950s was under 4 litres; engines such as the Chev stove-bolt 6, the Ford side-valve V8, and the various permutations of the Chrysler/ Plymouth/ Dodge side-valve sixes were all under 4 litres!) The big-engine top-of-the-line models tended to be straight eights, giving that fashionable long bonnet.

In late 1953 Rolls-Royce chose to go ahead with an all-new engine, and handed the project to Jack Phillips, their head piston-engine designer. The new engine had to drop straight into the Silver Cloud, replacing the 4.9 litre inline six, and therefore had to be no heavier, and use the same radiator. He soon realised that the optimum layout would be a V8 of between 6 and 7 litres, and also realised that a cast-iron engine that size would be far too heavy. So the alloy pushrod V8 we know so well was born.

When the Rolls-Royce V8 was introduced in 1959 it was one of the largest V8 car engines anywhere in the world. It was also one of the very, very few aluminium V8 engines. And some of its key design details derived from the pre-war Phantom III V12, and the successful aviation V12s, including the wet cylinder-liner sealing system.

The Rolls-Royce V8, Silver Shadow edition. Note how many of the accessories are forward
of the cylinder heads, rather than beside them. The engine was originally
designed to fit into the long, narrow Silver Cloud engine bay.

In the early 1960s, Ford introduced the Mustang, the first muscle car. Today we think of them as huge fire-breathing V8s, but in fact a majority of the original Mustangs were six-cylinder cars with three speed manual, or auto gearboxes: the Falcon in a party frock. And the optional Ford V8 engine was typically tiny: a mere 4.2 litres, smaller than the Bentley Mk 6 engine! Of course, it rapidly bloated out, until it was eventually distended to 5.7 litres, but that was still smaller than the 6.25 litre Rolls-Royce V8 engine (later 6.75 litres).

But Detroit didn’t have the only V8s. The Czech Tatra, with its rear-mounted 2.5 litre air-cooled V8, was an oddity indeed. In the UK in the late 50s Daimler introduced two alloy V8s, a 4.5 litre hemi for the big cars, specially the Majestic Major, and a 2.5 litre alloy hemi V8 for the smaller cars. Both were designed by the man who designed the Norton ohc motorcycle engine. Then Jaguar took over Daimler, quietly dropped the Majestic Major and its 4.5 litre V8, but slotted 2.5 litre V8s into Jaguar Mark 2 body shells, making a very nice Daimler 250 saloon, lighter and better handling than the Jaguar 3.4 it was based on. In France Simca had its own Ford-based 2 litre side-valve V8 derived from the Ford V8-60, and Fiat offered the 2.5 litre Fiat 507 V8.

And of course through the 1960s, Grand Prix cars were predominately V8s— the little 1.5 litre Coventry Climax, later the Cosworth Ford 3.0 litre V8. Even Ferrari were running V8s from time to time.

When the short-lived muscle car era ended, Detroit returned to its more traditional sixes, although they are usually Vee 6s now. V8 engines remained, but only as high-cost top-of-the-line options. Even the mighty Mustang was downgraded from V8 to 4 cylinders for some years.

And all through these years, Rolls-Royce and Bentley sailed on unpeturbed with the 6.75 litre aluminium pushrod V8.

It was not until a year or so ago that the original Jack Phillips design was finally replaced with an all-new engine. Rolls-Royce and Bentley had by then seperated again, and now it is a Bentley engine. But it is still an aluminum pushrod V8. It has the same bore and stroke as the Phillips design, but is produced using the latest in block and head design and casting technology, which makes it physically a lot smaller and lighter than before. And still more powerful.

The all-new V8 retains pushrods, and the same bore and stroke as
the original engine, but is smaller, lighter, and far more powerful.