The Packard Twin Six, produced from 1916 to 1923, stands as a symbol of American automotive luxury and innovation.

Packard solidified its early reputation as the pinnacle of American luxury cars with its four-cylinder Thirty (1907-1912) and the powerful Six (1912-1915). However, it was the 1916-1923 Packard Twin Six that truly elevated the brand, surpassing Cadillac’s 1915 V-8 with its additional four cylinders and maintaining its relevance with minimal changes over eight years, an impressive feat.

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Over three distinct series from 1916 to 1923, Packard produced just over 35,000 Twin Six models, including many chassis for custom-built bodies. The Twin Six was the primary reason wealthy buyers often opted for a Packard chassis when ordering a custom-bodied car.

Jesse Vincent, Packard's chief engineer, had three main reasons for his preference for the 12-cylinder configuration: performance, smoothness, and quietness. He noted, "A six-cylinder motor is theoretically in perfect balance," explaining that the vibrations from one piston’s rise and fall are neutralized by equal and opposite forces from another piston... This perfect balance could only be achieved if the components were strongly linked together," he wrote.

This design required a robust crankcase and crankshaft, along with a solid flywheel. However, Vincent continued, a V-12 or "Twin Six" would offer the same rigidity and smoothness while reducing the weight of the pistons, crankcase, flywheel, and crankshaft—and simultaneously delivering greater horsepower and torque. He favored the V-12 over a V-8 since the latter would necessitate a wider frame, a larger turning radius, and more complex steering mechanisms.

The Twin Six engine followed these principles, featuring two banks of L-head cylinders set at a 60-degree angle, compared to the 90-degree angle of Cadillac's V-8. This design allowed accessories to be mounted just beneath the frame, offering protection from road hazards while keeping the valves easily accessible.

Generating 85 horsepower at 3,000 rpm, the engine's bore and stroke of 3.00 × 5.00 inches resulted in a displacement of 424 cubic inches. Rockers were eliminated in favor of separate cams for each valve, and all valves were placed inboard of the cylinder blocks. A short, lightweight crankshaft operated on three main bearings.

Vincent declared that the torque was "50 percent greater than it would have been with a V-8, and 100 percent greater than the Packard Six. Six impulses per crankshaft revolution merge so seamlessly that it's impossible to detect any pause between them, even at very low engine speeds... The closest comparison I can make is to the motion of steam."

To learn more about the 1916-1917 Packard Twin Six, continue to the next page.

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1916-1917 Packard Twin Six

The 1916-1917 Packard Twin Six incorporated many features evolved from the earlier 1912-1915 Six, with some components that are still in use on modern cars. These included ignition powered by a generator-charged storage battery, a timer and distributor with separate circuit breakers and distributors for each cylinder bank, electric starter and lights, spiral-bevel gears in the rear axle, water pump cooling, and a carburetor placed between the two cylinder banks.

The bodies, offered on two different wheelbases, were modern and came in a wide variety of open and closed designs. All Twin Six models were costly, with closed models requiring more assembly. While the touring, phaeton, and runabout were priced at $2,750, the coupe, the least expensive closed model, cost $3,700, and the Imperial Limousine nearly $5,000. These prices represented substantial sums in 1916, yet to Packard’s wealthy clientele, they seemed a bargain compared to the previous Six models.

The debut of the 1916 Packard Twin Six on May 1, 1915, was the most significant announcement in Packard's history up to that point. Testing by The Automobile (a British motoring magazine) confirmed that it met Jesse Vincent's three design goals: "No vibration was noticeable at road speeds exceeding 60 mph, and the engine was almost inaudible even at full revolutions... There was no effort required to accelerate from 3 mph in high gear... it accelerated smoothly from 3 mph to 30 mph in 12 seconds and even faster in second gear."

The demand for the Packard Twin Six was high, prompting a 50 percent increase in Packard's workforce to nearly 11,000 to keep up with production. The factory on Detroit’s Grand Boulevard expanded by $1.5 million, now covering over 100 acres. In 1917, Frank Eastman, the company's witty editor, remarked: "We build a good car and charge a good price for it... ask the man who owes for one."

In July 1916, the 1917 model was unveiled (with all prior models being classified as 1916s). Known as the Second Series 2-25 for the short-wheelbase version (2-35 for the long), the Twin Six saw little change apart from its cooling system: "Instead of expelling water from the forward ends of the cylinder blocks, the gas intake manifold was hollowed out to allow the water from the cylinder jackets to be circulated through it and sent to the radiator through a single tube."

Other updates included detachable cylinder heads, "to ensure a more accurate machining of the combustion chamber"; a faster-running generator; a higher-positioned carburetor to keep it away from the manifolds; a low-current distributor; a lighter-pressure foot brake; and a redesigned gear shift with a ball end — signaling a shift toward future designs. The Second Series had a lower profile, thanks to its smaller wheels and deeper chassis.

Like the model before it, the Second Series was only produced for a year. To learn more about the Third Series of the Packard Twin Six, continue to the next page.

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1918, 1919, 1920, 1921, 1922, 1923 Packard Twin Six

In the summer of 1917, Packard unveiled the 3-25 and 3-35 models, which would form the third and final series of the Packard Twin Six, covering the years 1918 through 1923. This new generation introduced several body style changes, as the more upright designs of the Teens evolved into the sleeker, lower profiles of the Twenties.

Mechanical improvements included a newly designed electrical system, enhanced cylinder heads for better airflow and cooling, and the innovative "Fuelizer" intake manifold, which utilized its own spark plug to assist in vaporizing the intake gases. The ball-end gear lever was relocated to the center of the floor, where it remained until the introduction of the column shift in the late 1930s.

The frame was slightly tapered, and the wheelbase was lengthened, bringing the horsepower to 90. For the first time, custom bodies were offered, including a coupelet, limousine, brougham, and landaulet by Derham; limousines by Caffrey and Judkins; and a runabout and cabriolet by Fleetwood. This marked the beginning of the custom-bodied Packards that would become a hallmark of the late Twenties and Thirties.

Packard owners were deeply devoted to their Twin Sixes, sometimes in extraordinary ways. An Osage Indian chief, rich from oil, purchased a custom-bodied 3-35, crashed it an hour after delivery, and immediately contacted the dealer for a replacement. Czar Nicholas II of Russia owned a Twin Six with skis replacing the front wheels for winter travel.

In 1921, Warren Harding drove a Twin Six to become the first president to attend his inauguration by car. In Japan, mechanics took the first imported car for a joyride, crashed it into the moat of the Imperial Palace, and were fined for disturbing the royal goldfish. The Emperor, however, soon acquired one himself.

Many Twin Sixes remain on the road today, as they were built to endure. Years later, one owner who had kept his Twin Six from new wrote to the company: "It has twelve cylinders but I only need four. The rest came with the engine and just let 'em run. The starter starts, the generator generates, the battery bats, the brakes brake, the seats seat, the top tops, and the lights light. It goes from .001 mph to 75 in the same high gear, I love my old bus."

For specifications related to the First Series of Packard Twin Sixes, please proceed to the next page.

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1916 Packard Twin Six Specifications

In response to Cadillac's introduction of its V-8 in 1915, Packard outdid Cadillac by unveiling its 1916 Twin Six. Below are the specifications for the 1916 Packard Twin Six:

Engine: L-head V-12, cast in two blocks, 424.1 cubic inches (3.00 × 5.00-inch bore × stroke), solid valve lifters, 3 main bearings, 85 horsepower @ 2,600 rpm

Transmission: 3-speed manual, selective sliding gear; multi-disc clutch

Suspension, front and rear: Solid axle, longitudinal semi-elliptic leaf springs

Frame: Pressed steel with a 6-inch deep channel section

Brakes: Mechanical, with internal expanding and external contracting systems, applied only to the rear wheels, offering a 262-square-inch swept area

Wheelbase (in.): Available in 125.0 and 135.0 inches

Track (in.): 56 inches

Weight (pounds): Ranges from 3,910 to 4,715 pounds

Top speed: Capable of reaching 70-75 mph

Production: A total of 7,746 units were produced for the model year

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