1916-1923 Packard Twin Six


The 1920 Twin Six limo was a somber looking machine because it had no brass trim, and only a bit of shiny hardware. See more classic car pictures.
©Nicky Wright.

Packard built its early success as the standard American luxury car with the four-cylinder Thirty of 1907-1912 and the mighty Six of 1912-1915. But the model that really cemented Packard's reputation as a make of the highest rank was the 1916-1923 Packard Twin Six, which one-upped Cadillac's 1915 V-8 with four more cylinders and lasted with relatively few changes for eight years: a remarkably long run.

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In three series between 1916 and 1923, Packard built slightly more than 35,000 Twins, including numerous chassis for custom bodies. The Twin Six was the chief reason why, when the wealthy ordered a custom-bodied car, they tended to choose a Packard chassis.

Jesse Vincent, Packard's chief engineer, liked the 12-cylinder layout for three reasons: performance, smoothness, and silence. "A six-cylinder motor is theoretically in absolutely perfect balance," he wrote. "This is because the vibratory forces due to the rise and fall of one piston are neutralized by equal and opposite forces due to another...Now it is only possible to cancel out forces in this way if they are tied together strongly."

This meant a heavy crankcase and crankshaft and a rigid flywheel. But a Twelve or "Twin Six," Vincent continued, would provide the same rigidity and smoothness with less piston, crankcase, flywheel, and crankshaft weight -- and provide more horsepower and torque, to boot. He preferred a V-12 to a V-8 because a V-8 would require a wider frame, larger turning radius, and more complicated steering gear.

The Twin Six engine duly embodied the above principles, with two banks of L-head cylinders set at a 60-degree angle (versus 90 degrees in Cadillac's V-8). This allowed accessories to be bolted just below the frame, where they were protected from road hazards, while keeping the valves accessible.

Delivering 85 horsepower at 3,000 rpm, a bore and stroke at 3.00 × 5.00 inches resulted in a displacement of 424 cubic inches. Rockers were eliminated, with a separate cam for each valve, and all valves were located inboard of the cylinder blocks. A short, light crankshaft ran in three main bearings.

Vincent proclaimed that torque was "50 percent better than it would have been with a V-8, and 100 percent better than the Packard Six. Six impulses per crankshaft revolution blend together so closely as to make it absolutely impossible to distinguish any pause between impulses, even at very low engine speeds...The only thing I can liken it to is the action of steam."

For more on the 1916-1917 Packard Twin Six, continue to the next page.

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1916-1917 Packard Twin Six

With 12 cylinders and a 3.00 x 5.00-inch bore x stroke, displacement of the L-head Twin Six came to 424.1 cid. In 1920, it was rated at 90 bhp at 2,600 rpm and was cast in two blocks of six cylinders each.
With 12 cylinders and a 3.00 x 5.00-inch bore x stroke, displacement of the L-head Twin Six came to 424.1 cid. In 1920, it was rated at 90 bhp at 2,600 rpm and was cast in two blocks of six cylinders each.
©Nicky Wright

Other 1916-1917 Packard Twin Six features were less radical, having been evolved on the previous 1912-1915 Six, including many items we still find on cars today: ignition was supplied by a generator-charged storage battery; an ignition timer and distributor were fitted, with separate circuit breaker and distributor for each bank of six cylinders; the starter and lights were electric; the rear axle had spiral-bevel gears; cooling was by water pump; and the carburetor was located between the two banks of cylinders.

Bodies, on two different wheelbases, were up to date and offered in wide varieties, both closed and open. All Twins were expensive, but closed cars involved a lot more assembly work: while the touring, phaeton, and runabout listed at $2,750, the $3,700 coupe was the cheapest closed model and the Imperial Limousine cost nearly $5,000. Such figures represented small fortunes in 1916, yet to the Packard clientele they seemed amazing because they were hundreds less than the previous Six.

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The introduction of the 1916 Packard Twin Six on May 1, 1915 was the greatest single announcement in Packard's history to date. Testing one, The Automobile (a British motoring magazine) declared that it met Vincent's three design criteria: "No vibration was perceptible up to a road speed of well over 60 mph and the motor is hardly audible even at full revolutions...there is no sense of effort whatever in opening up from 3 mph in high gear...it was easy to accelerate from 3 mph to 30 mph in 12 seconds and on second speed in a much shorter time."

Demand for Twins was brisk and Packard's workforce increased 50 percent to nearly 11,000 in order to meet it. The factory on Detroit's Grand Boulevard underwent a $1.5 million expansion and now covered over 100 acres. In 1917, Frank Eastman, wry editor of the company's house organ, quipped: "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 announced (all previous models being 1916s). Designated the Second Series 2-25 for the short wheelbase car (2-35 for the long), the Twin Six was little changed except in cooling; "In place of the water being expelled from the forward ends of the cylinder blocks, the gas intake manifold has been cored out to permit all water from the cylinder jackets to be circulated through it and thence to the radiator through a single tube."

New also were detachable cylinder heads, "to insure a more perfect machining of the combustion chamber"; a faster running generator; a higher 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 -- another portent of the future. The Second Series looked lower, with its smaller wheels and deeper chassis.

Like its predecessor, the Second Series lasted a year. To read about the Third Series of Packard Twin Six, continue to the next page.

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

This 1920 Twin Six sports a shiny Motometer cap atop the radiator.
This 1920 Twin Six sports a shiny Motometer cap atop the radiator.
©Nicky Wright

In the summer of 1917 Packard announced the 3-25 and 3-35 models, which would comprise the third and final series and cover the 1918, 1919, 1920, 1921, 1922, 1923 Packard Twin Six, ushering in numerous body changes as the upright bodies of the Teens evolved to the sleeker, lower shapes of the Twenties.

Mechanical changes included a redesigned electrical system, improved heads for better breathing and cooling, and the "Fuelizer" intake manifold to help vaporize inlet gases with the help of its own spark plug. The ball-end gear lever was shifted to the center of the floor, where it would remain until the column shift in the late Thirties.

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The frame was tapered slightly and the wheelbase increased; horsepower was now 90. Custom bodies began to appear for the first time: a coupelet, limousine, brougham, and landaulet by Derham; limousines by Caffrey and Judkins; a runabout and cabriolet by Fleetwood. From these the glittering array of custom-bodied Packards evolved during the later Twenties and Thirties.

Packard owners loved their Twin Sixes, sometimes to extremes. An oil-rich Osage Indian chief bought a custom-bodied 3-35, smashed it an hour after taking delivery, and telephoned the dealer for an immediate replacement. Czar Nicholas II of Russia owned a Twin Six with the front wheels replaced by skis for winter work.

In 1921, Warren Harding used a Twin to become the first president to motor to his inauguration. In Japan, mechanics took the first car imported on a joy ride, ditched it in the moat of the Imperial Palace, and were fined for disturbing the royal goldfish -- but the Emperor soon had one himself.

A lot of Twin Sixes are still around, because they were built to last. Many years later, an owner of a Twin Six he'd owned since new wrote the company: "It has twelve cylinders but I only need four. The rest of them came with the engine and just let 'em run. The starter starts and the generator gens and the battery bats and the brakes brake and the seats seat and the top tops and the lights light. It will go from .001 mph to 75 on the same high gear, I love my old bus."

To find specifications for the First Series of Packard Twin Sixes, continue to the next page.

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1916 Packard Twin Six Specifications

The Packard Twin Six limo carried a single spare tire upright at the rear; the vertical tubes seen at both the front and rear were vibration dampers.
The Packard Twin Six limo carried a single spare tire upright at the rear; the vertical tubes seen at both the front and rear were vibration dampers.
©Nicky Wright

When Cadillac introduced its V-8 for 1915, Packard responded by one-upping Cadillac with its 1916 Twin Six. Find specifications for the 1916 Packard Twin Six below:

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

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

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

Frame: 6-inch-deep channel section pressed steel

Brakes: Mechanical, internal expanding, external contracting, rear wheels only, 262-square-inch swept area

Wheelbase (in.): 125.0 and 135.0

Track (in.): 56

Weight (pounds): 3,910-4,715

Top speed: 70-75 mph

Production: 7,746 (model year)

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