Upside-Down Indian: The 1937 Indian Four

The 1937 Indian Four has support despite the controversy surrounding it and its upside-down 4-cylinder design.

1937 Indian Four

1937 Indian Sport Four

Photo by Sedrick Mitchell

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Claimed power: 35hp @ 3,600rpm (est.)
Top speed: 90mph
Engine: 77.21ci (1,265cc) exhaust-over-inlet inline four, 2.75in x 3.25in bore and stroke
Weight (wet): 515lb (234kg)
Fuel capacity/MPG: 4gal (15ltr)/40-50mpg
Price then/now: NA/$25,000-$50,000

Was this the bike that killed Indian? Some enthusiasts say that when Indian brought out its still-controversial “upside-down” 4-cylinder design in 1936, the Springfield, Massachusetts, firm started down the slippery slope to failure. 1936 was the same year Harley-Davidson introduced its iconic Knucklehead, a stylish motorcycle with a look that still resonates today, while the “upside-down” Four faded from view.

The idea that the redesigned Four hurt Indian is held by no less than the AMA Motorcycle Hall of Fame, which, in its summation of the model, said, “It was the answer to a question no one had asked: What was wrong with the Indian Four of the 1930s? As it turned out, very little. But that didn’t stop Indian engineers from ‘improving’ the design in 1936. And in the process, building one of the company’s biggest flops.”

Frank Westfall, an expert on American inline fours and the owner of our feature bike, disagrees — and most emphatically. “The ‘36 and ‘37 Indian Fours had a lot more power. The 1927-1935 Fours were dogs. Dave Holzerland is an Indian Four expert, and his 1935 Four is in top running order, but when I am riding my Henderson on a run with him, I have to pull over and wait. The Henderson — built in the Twenties — is faster than the Indian Four built in the Thirties.”

Frank has support from other Indian Four fans. “Red” Fred Johansen, Antique Motorcycle Club of America director, has no fewer than three 1937 Indian Fours, and thinks they are perfectly fine motorcycles. “They are supposed to overheat in hot weather, but that’s an old wives’ tale — they don’t. They were the Gold Wing of their day. They are comfortable and will go all day long. If one passes you, you will hear their sound — like a herd of bumblebees or a small airplane going by. There’s nothing like it.”

The Indian Four was based on the Ace, a popular motorcycle designed by William Henderson in 1919. The Ace was powered by an inlet-over-exhaust inline 4-cylinder engine, with chain final drive. It was smooth and fast, but the company that built it had suffered serious setbacks. Henderson was killed in an accident in December 1922, and the company’s financial management was worse than hopeless — a not uncommon problem in the Roaring Twenties. After two separate reorganizations, the patents and remaining stock for Ace were bought by Indian in early 1927.

Indian gets an Ace

In the 1920s, Indian’s management was not much better than Ace’s. At one time one of the largest motorcycle companies in the world, Indian had been run by professional management types and financiers since World War I. These administrators were much more interested in short-term gain than the long-term viability of the company. In the 1920s, some executives were effectively embezzling funds. Even before the stock market crash of 1929, Indian had repeated cash flow problems and was on cash-only status with many suppliers.

Yet while Indian’s management may have been suspect, the company’s engineers were top notch, and passionate about the company’s product. Charles B. Franklin, the designer of the Sport Scout and the Indian Chief, was the head of Indian’s engineering department. Arthur Lemon, chief engineer for the Ace after the death of Henderson, had been hired by Indian when it bought Ace, and was put in charge of developing the newly acquired model.

At first, besides painting it red and changing the tires and fenders, Indian did not make major changes to the Ace. In August 1928, the Ace engine was bolted into a single-downtube frame modeled after the frame of Indian’s successful 101 Scout. The Scout-type frame didn’t work well with the Four engine, lending excessive vibration, and was quickly replaced by a double-downtube frame. Although this frame didn’t vibrate like the Scout frame, it was considerably heavier and slowed the bike.

Indian’s first major change to the engine was made in May 1929. The Ace three-bearing crankshaft was replaced by a chrome nickel five-bearing shaft, which was stiffer and more reliable over the long haul — and heavier. Henderson’s Ace, a light, speedy thoroughbred, was being turned into a Clydesdale. The reason was the prospect of police sales. Indian was competing with Henderson for the motorcycle cop market, and reliability was an important selling point.

Following the onset of the Great Depression, Henderson pulled out of the motorcycle market in 1931. No one had money at that point to buy motorcycles — or anything else. Indian had been bought by E. Paul DuPont a year before, but was still saddled with debt and bad investments left over from the atrocious management of the 1920s.

By 1935 things were looking up, and Indian decided to revamp the Four engine. The engineers involved in the revamp were a new group, as Arthur Lemon had left to start his own business in Michigan and Charles B. Franklin had died, way too young at only 52, several years before.

The problem Indian was trying to solve was heat dissipation. With top-end lubrication not really well understood, available lubricants a long way from perfection and contemporary metal alloys for cylinder heads a study in shortcomings, Indian’s engineers tried their best with what was available.

The new Four

When it was introduced in late 1935 as a 1936 model, Indian claimed the new Four was the fastest bike it had ever built. Frank Westfall states that there was possibly a 20 percent improvement in horsepower and an increase in usable rpm range, rising from 2,800-3,000rpm to 3,500-3,600rpm. Jerry Hatfield, an antique motorcycle expert and author, states that the 1935 and earlier Indian Fours put out about 30 horsepower and were good for about 75mph, and the 1936-37 Fours had 35 horses on tap and could manage 80mph. Red Fred says that his 1937 Four is a good, comfy ride up to 80mph.

The engine configuration was unusual. Before 1936, all American inline fours were either flathead designs with side-by-side valves or an inlet-over-exhaust valve configuration, with the intake on top of the cylinder and the exhaust on the side in the cylinder. The 1936 Four had the exhaust valves, and hence the exhaust pipes, on the top of the engine, with the intake plumbed up and under the cylinder head, making it an exhaust-over-inlet design. This arrangement, along with a new updraft Marvel carburetor, spawned the nickname “upside-down” Four.

Unfortunately, Indian’s engineers did not consider the rider when designing the new engine. “If you are riding the bike and wearing shorts on a hot day there is a problem,” Frank says. The new design much improved the dissipation of heat, a goal of Indian’s engineers, but it put the four hot exhaust valves and the header pipe much too close to the rider’s leg. Early 1936 models had a small heat shield and exposed exhaust valve gear and stems. The heat shield was quickly found to be inadequate, and by the end of the year the exhaust valve gear was enclosed and the heat shield enlarged.

Other features of the bike included a recirculating oiling system (standard on Indians since 1933) and a leaf spring front end, which riders appraise as providing as good or better handling than the more familiar coil spring fork designs of the era. Harley riders derided the new bike as ugly, and supposedly coined the model’s nickname.

Gary Stark of Starklite Cycles, a specialist dealer in classic Indians and parts for them, says the Marvel carburetor was not always reliable and the engine would overheat. Red Fred disagrees. He says the Marvel carburetor is reliable if set up correctly, but that it is complicated and delicate. There were also complaints about the heat that came off the engine from the motor officers who had to ride the bike all day in any weather. In any event, in 1939 the resale price for a 1936 or 1937 “upside-down” Four was the same or less than the same year 45-cubic-inch Sport Scout twin.

In 1937, Indian changed to twin Zenith carburetors and dual aluminum manifolds to carry mix to the 4-cylinder. According to Indian expert Jerry Hatfield, the added complexity didn’t make the bike more powerful or any faster, although the Zeniths may have been less problematic. Red Fred thinks the Zeniths are actually harder to set up, as they have to be in sync, while Frank Westfall says the twin carb setup makes for a peppier engine. Other new features were a new headlight with high and low beams, and chrome exhaust pipes and mufflers. The new features did not halt the catcalls from the Harley crowd, or complaints about the heat from the engine.

Behind the scenes, Indian engineers were at work revising the Four’s engine. For 1938 and later model Indian Fours, the intake valves went back on top and the exhaust valves off to the side in standard F-head configuration, putting the exhaust manifold down low instead of up high. They were not only beautiful, but rugged, fast and smooth, and have proven a timeless design. Enthusiastic owners still go touring on them.

Frank’s Four

One person who has probably put as many miles on American fours as anyone living today is Frank Westfall, an enthusiast with a penchant for adventure. To date, he has participated in five cross-country rallies, all on pre-World War II American-built fours. Frank started collecting American motorcycles back when you could get them for next to nothing, and he put together an interesting collection of machinery. Now that prewar American iron has become valuable and collectible, Frank trades bikes he has for bikes he wants. Some time ago, Frank acquired a 1928 Harley-Davidson factory hill climber. The Harley museum found out he had it and offered him three bikes, including this 1937 Indian Four, in trade.

In typical Westfall fashion, Frank reserved judgment on his upside-down Indian until he took it out for a ride with some other riders and their bikes and discovered “it could pull on a KJ Henderson,” a benchmark American four in Frank’s eye. Despite the age and value of these machines, Frank does not like to ride slow or avoid mud puddles. His evaluation: “It’s a nice, low-slung four with a low center of gravity. It handles better than a lot of modern bikes.”

He continues: “The brakes are adequate — if adjusted properly — for today’s roads, but understand that I am not going that fast [Note: “not that fast” for Frank is staying at the speed limit]. You have an investment in a bike like this, you are going to cruise, not race.

“It takes regular gas. Low octane is higher octane than was available when the bike was built. It doesn’t like high ethanol gas, so you have to be a little careful where you gas it up. It uses straight 50 weight oil, or 60 weight if it is hot out. If the motor is set up right, it can use synthetic oil. You have to break in the motor first, because if you build a motor and run synthetic, the motor will not break in. You have to do a thousand miles on the rebuild first, then use synthetics.”

On that note, Frank says that frequent oil changes are key to reliable running. When he participates in cross country rallies like the Cannonball run, he changes the oil every night. Otherwise, oil changes happen between 500 and 1,000 miles. “The more changes the better — it’s cheap insurance.”

One of the selling points of the Four was easy starting, and it is still easier to prod a Four into life than most other kickstart bikes. “Full throttle, full choke. Turn the key off and give it a full kick; that gets the gas in the carb. Turn the key back on, give it a little choke if it is cold and kick. Fours always start on the first or second kick, if the magneto is in good shape. Live by the mag, die by the mag. The mag has to be good,” Frank says.

That’s a little more work than the average rider is used to, but Frank says it’s easy and so worth it. “They are a gentleman’s ride no matter how you slice it. They are a lot of fun, and so damned smooth — it’s a Four!” MC