Engine History: Alfa Romeo Twin Cam Four – A Pioneer, And As Beautiful As The Cars It Powered

(first posted 12/1/2013)    Alfa has always been known and loved for their engines as well as all the rest of their seductive qualities. Perhaps even more so than the others, although given the superbly beautiful bodies and their typically fine handling, that may be a subject of endless debate. But what isn’t in question is the fact that the classic Alfa twin cam engine essentially pioneered the popular adoption of what is now under the hood of even the cheapest econo-box.

But once upon a time, a DOHC alloy engine in a relatively affordable car was almost unheard of. And such a beautiful one at that. So let’s have a little meditation on one of the most significant engine milestones in automotive history, and how this engine became the model upon which all modern engines are based on.

The basic hemi-head/pent roof DOHC configuration has of course come to dominate the modern automobile engine (with a few notable exceptions). And although it’s only been in the last two decades that it’s been adopted wholesale, at least for smaller engines, the classic configuration goes back quite a ways, to the early days of the car, or racing car, to be precise.

There’s a bit of a question as to who exactly built it first, but there’s no doubt that the 1912 Peugeot racing engines designed by Ernest Henry first combined not only the DOHC hemi-head, but also four valves per cylinder. These legendary L3 (3 liter) and L76 (7.6 liter) engines instantly dominated the Grand Prix scene, and were just as instantly and universally copied.

This Peugeot gP8 engine from 1914 shows all the classic essentials, including its still-exposed valve springs. And by 1914, Alfa also had its first DOHC racing engine.

Alfa Romeo Giulietta_Sprint_Front_1image: bringatrailer.com


Fast forward to 1954, and Alfa’s new Giulietta. The superbly designed (by Bertone’s Franco Scaglione) Sprint coupe arrived in late 1954.

alfa romeo_giulietta_berlina_1

The Berlina sedan followed in the spring of 1955. These sporty cars were the true pioneers of what has become a huge segment, dominated later by the BMWs like the 2002 and 3 Series.

Alfa Romeo Giulietta Spider

And Pininfarina’s addition to the trio, the Spider, is a milestone car by any measure. Stylistically, the Spider set the template for the modern sports car for decades to come. Next to a 1955 Corvette, the Spider looks like it’s almost from a decade later.

The Giulietta rocked the automotive world, offering a level of performance, design, handling and Italian flair for an unbeatable value.

At a time when flatheads were still all-too prevalent, and pushr0d OHV engines were still hot stuff, at least in some quarters, Alfa graced the Giulietta with an engine that looked straight out of a racing car: alloy block, and DOHC hemi head. The 1954 Giulietta Sprint made 65 hp from 1290cc at an almost unheard of 6000 rpm (for a production street car). In 1954, the Porsche 356 still came with a standard 1100cc pushrod engine making 46 hp at 4000 rpm, and the highest output optional engine was the 1500 Super, making 70 hp. The Porsche, especially the Super, was considerably more expensive.

The Alfa DOHC four was built for forty years, with displacement and power steadily increasing. In 1962, the classic 1570 cc version arrived, and powered two of the most-loved Alfas ever, the Giulia Sprint coupe and Duetto Spider. And in 1968, the 1779cc version appeared in the 1750 GTV. The final size of 1962cc arrived in 1971. There was no more room, but twin spark heads appeared towards the end of its life, as well as some flirtation with turbocharging.

There wasn’t room in the heads for four valves, so that would take a new generation of Alfa fours, but the classic four is a meditation in engine perfection, at least from a visual aspect. This one was awaiting installation in a restored car, but I forgot to ask what size it was. Doesn’t really matter. There is a symmetry and perfection in its architecture that can’t really be improved upon, and I was lost in my veneration. Good thing the floor was so clean, that I could get on my knees and do that properly.