Engine Excellence
by Dan Burger

Stare at the beauty. Admire the power. It's a 12-cylinder Packard.

What does an engine have to do to impress you? Breathe fire? Go forever? Run on tap water?

Great engine excite. They intrigue. They suck you in quicker that a fly on a four barrel. We recognize the truly great ones are precious commodities. There never seem to be enough of them to go around.

We habitually rate our favorites by their beastly qualities of raw horsepower and hair-raising speed. At times they are favored for their silky smoothness and velvet-glove knockout punch. Either way, don't you marvel at the ingenuity that mixes air and gasoline to produce pure pleasure?

You can probably rattle off the names and horsepower ratings of your favorite V8s, maybe some sixes and fours, too. How about the big guns? Some people say size doesn't count for much, but do you really believe it? One of the great eras for automobiles, the late 1920s and the 1930s, brought forth the V12 and V16 engines the likes of which we have never seen again. Because eight-cylinder engines were no longer the private domain of the most expensive cars, manufacturers pursued bigger dreams to put more distance between their fine products and provincial transportation.

Cadillac wanted to make sure no one misunderstood the difference between the privileged class and all others by introducing a V16 in 1930. Two years later there were V12s from Packard, Pierce-Arrow, Lincoln, Auburn, and Franklin. Marmon matched Cadillac with a V16. And Cadillac had added a V12. All of those companies also continued to fill their bread and butter cars with excellent, though less awe-inspiring, eight-cylinder engines.

If you have never examined these 12- and 16-cylinder engines, never listened to them run, or ridden in a car propelled by one, you are missing one of our hobby's great pleasures. There's engineering genius, brilliant design, and surprising achievements in each of them. Examining their construction, materials, and workmanship is an education. These were purpose-built engines on which lofty reputations were to be established. Most, not all, were worthy. Yet, when it comes to choosing one above all the others, I would have to make it the Packard.

This modified L-head engine is a masterpiece of engineering design and was built to fortress-like specifications. Low-end torque was magnificent. If you can coax a ride in one of these, your eyes will be opened to a different view of performance. The remarkable silence while at idle will cause you to lean closer to make sure you're not hearing what you think you should be. Packard liked to refer to its V12 as "the soft-spoken boss off the road."

You owe it to yourself to have a close-up look at a Packard 12.
What makes the Packard's V12 the valedictorian of a very prestigious class of engines? To begin with, there is the huge displacement. In its original form, with a bore of 3 7/16 inches and a stroke of 4 inches, displacement measured 445 cubic inches. It was rated at 160 horsepower, and more important, it could attain maximum torque at 1400 rpm. This was a clear advantage over most of the competition. It would pull 5,000-pound bodies like a Kenworth pulling a travel trailer. The engine demonstrates whipped-cream smooth pulling power in third gear, even from extremely low speeds. Once the V12 is in third gear, it can be driven without shifting until the car comes to a complete stop.

Displacement counts for a lot, but it is the refinements that make the Packard 12s stand apart from the others. At the head of that list is an extraordinary valvetrain. Usually the source of considerable engine noise, Packard hushed valve clatter with an intricately complex zero-lash, hydraulic, valve-silencing system. The system is a modification of the valvetrain Cadillac used in their V16. Modifications were required because the Cadillac was an overhead-valve engine and the Packard was a flathead. Rocker arms were necessary in the Packard engine because the valves were not in line with the camshaft. However, Packard made the most important change when it replaced Cadillac's bronze sleeves in the take-up mechanism and went to needle bearings on the cam rollers. This is a key to the engine's silent operation. The needle bearings reduced friction compared to a flat-tappet cam design. As a result, it takes very little effort to turn the V12 cam.

Another factor in Packard's pre-eminence was the induction system's efficient design. Of primary significance is the single downdraft Stromberg EE-3 carburetor - a 1 ½-inch, dual-throat design. This was a state-of-the-art carburetor that improved fuel vaporization at low, medium and high speeds - a capability that previous carburetor designs had trouble with. The EE-3 provided a perceivable difference in smooth operation. The Stromberg carb was not a Packard exclusive, but it worked exceedingly well in its induction system. Additionally, the manifolding on the Packard V12 rested between the cylinder banks and permitted a more efficient, free-flowing design. Exhaust ports are very short and straight, for instance. Compared to twin-carburetor designs that require synchronization and that work in conjunction with more convoluted manifolding, the Packard shines.

An important advantage that 12- and 16-cylinder engines had over engines with fewer cylinders was a smoothness derived from increasing the number of power impulses. In V-type engines the degree of bank between the two heads plays an important role in obtaining that optimum firing order and thereby reducing the impacts of the power impulses. On paper, a V12 with either a 60-degree or a 120-degree angle prevents the power impulses from synchronizing with the crankshaft rotation, decreasing the vibrations and enhancing smoothness. Making either of those options work within the confines of body and chassis requirements is a separate challenge. The V-12 Packards were built with 67-degree angles between the blocks. That was narrow enough to fit within the proposed frame and wide enough to accommodate the straightforward manifold that Packard knew would provide benefits of its own. Other 12-cylinder competitors had banks as narrow as 45 degrees (first-generation Cadillac V16, Lincoln and Auburn V12s) and as wide as 135 degrees (the second-generation Cadillac V16). To further diminish the effects of the power impulses, Packard had an excellent vibration damper that was for many years the industry standard others hoped to equal.

Compare the bottom ends of the 12- and 16-cylinder engines and Packard holds all the aces. The massive crankshaft is forged alloy carbon steel. It's strength exceeds all reasonable expectations. It is fully machined and counter-balanced. The main bearing journals and connecting rod journals overlap for increased rigidity. Connecting rods are constructed from chrome molybdenum steel of superior quality. The engines from 1935 to 1939 include precision insert bearings, capable of sustained high-speed operation. The thickness of the cylinder walls and the ample valve spacing were indicators of a well-conceived engine. The lubricating system featured a full-flow oil filter and an oil-temperature regulators for added protection and longer life. The cooling system was fully pressurized after 1933. All these advancements are evidence of why Packard's V12 stands out above the others.

The Packard V12 was essentially a hand-built engine and Packard paid more attention to the details when it came to meticulous assembly and quality materials. The precision that went into the engine was instrumental in making it quiet-running and powerful.

And we haven't even brought up the topics of body, paint and trim, and chassis refinements. Packard paid great dividends in those areas as well, offering status and prestige. The Packard V12s have been called "the Rolls Royce of American automobiles" and they deserve that comparison. This engine and this car were designed and built to last a lifetime.