FEATURE ARTICLES

First in Filtration: From Canister Oil Filters to Spin-Ons

By John Gunnell

Early automobiles did not have any sort of oil filtration system and many cars well into the '60s offered oil filters only as an extra-cost option. It was common to change oil every 500-2,000 miles. Later, when drilled crankshafts and pressure lubrication systems became common, some kind of oil filtration was necessary in order to protect the oil pump from damage and wear. Early filter designs were often crude set ups using steel wool, wire mesh or metal screens placed in the oil pump intake. Many designs were cleanable and reusable.

The first modern oil filter was introduced in 1923. Ernest Sweetland invented the device and called it the Purolator. The company's trade name was written as "PUROLATOR" and was a combination of the words. Purolator later used the slogan "First in the Field of Filtering" with full honesty.

The original Purolator was incorporated into a car's oiling system after the oil pump and before the oil flowed into the engine bearings. It featured an upright series of seven twill weave cloth-covered, perforated plates encased in a heavy-duty cast canister. It also had a sight feed glass on one side, enabling the owner to see the oil flow and change the filter when the flow slowed to a trickle.

James A. Abeles saw enough potential in the Purolator to convert a New York City garage into a company called Motor Improvements Inc. His firm was developed primarily to manufacture Purolator oil filtration systems.

The Maxwell-Chalmers company also saw promise in this new product, installing a Purolator on a Maxwell automobile, which was test-driven on a round-trip from Detroit to the West Coast in 1924. The longer oil drain intervals, cleaner oil and reduced engine wear offered by the Purolator ensured endorsement by the automotive industry. The "oil cleaners" soon became standard on many popular automobiles of the day, including Studebaker, Pierce-Arrow, Hupmobile, Peerless, Cadillac, Oakland, Gardner, Moon, Jordan, Buick and Dodge.

Over the years, innovations in oil filter technology continued. In the late 1930s, cotton waste material was introduced as filtration media, providing the first replaceable filters. Woven fabrics were also used in some filter designs.

Prior to 1943, most oil filters were of the by-pass variety, only filtering about 10 percent of the oil at a time. The first full-flow oil filter that cleaned 100 percent of the oil, was introduced in 1943 and became common by 1946.

As disposable filters became the norm and interest in saving production costs increased, materials such as pleated paper and cellulose became the filtration media materials of choice. They are still widely used in today's oil filters.

In 1949, Purolator Products, Inc., had facilities in Newark, N.J. and Windsor, Ontario, Canada. At that time, the company offered a range of different oil filters that fit cars and trucks from a 1931 LaSalle up to most new 1949 models, either as original equipment replacements or retrofit installations.

The OE replacements were mostly Purolator N or T Series models, while most of the install kits used the latest P-Series Micronic canisters and elements. Filters in the P-900 series were used in applications previously serviced by the N-1600 and N-1900 series. A heavy-duty model called the P-3000, designed for vehicles with crankcases holding over 25 qts. of oil, used two filter elements.

In non-OE applications, the filter size recommendations were based on the crankcase capacity of the vehicle being retro-fitted. All N-1500 and P-700 series Purolators were recommended for crankcase capacities of 6 quarts or less. All N-1900 and P-900 models were for 6-14-qt. Crankcases. Vehicles with 14-25-qt. Crankcases were suited to N-2900 and P-2900 filters. Finally, vehicles with crankcases of 25 qts. or more were best suited to N-3000 and P-3000 filters.

In 1949, Purolator also developed a new Wing-Nut Type Micronic Filter that allowed motorists or mechanics to check the filter element as quickly and easily as checking oil. This design required no tools to unscrew the wing nut on top and lift off the cover. The P-40 filter inside came out with the cover so it could be checked for muck. These filters were in the P-400-W series and all used the same filter element. They were recommended for Chrysler Corp. cars and trucks.

Purolator did a good job of promoting the Wing-Nut Top as a "money maker." A 1949 trade ad claimed that the new P-40 Purolator Micronic Refill had "5 times the filtering area of old-style filters" and "removed 290% more sludge." Savvy mechanics knew that the P-40 trapped more sludge and was easily removable by whipping out the dirty filter each time a customer drove in. "This muck in an oil filter can mean money in your pocket!" said the ad's headline in bold type. "Show it to your customers for more Purolator sales."

WIX invented the easily detachable 'spin-on' filter in 1954. Automotive historian Matt Joseph believes Chrysler may have been first to use them. This subsequently became the prevalent design, though not always standard equipment. This type of filter is used almost exclusively in modern cars and in recent years, has gained use in heavy-duty vehicles. Spin-on filters made cartridge-type filters that had to be placed in a special canister.

During 1950s, the use of oil filters on cars varied. As early as 1953, a full-flow oil filter was listed as standard equipment for Lincoln V-8s, but a canister type oil filter was optional equipment on the 1956 Ford. The 1957 Mercury included a spin-on oil filter at no extra cost. All 1958 Buicks came with an oil filter. However, if you bought a 1959 Chevrolet, the car and engine you ordered determined whether you would get an oil filter and what type it would be.

Chevrolets with the Hi-Thrift 6 engine offered a by-pass type oil filter as an extra-cost option. A full-flow oil filter was optional at extra-cost on 1959 Chevrolets with V-8 engines, unless the car had Rochester fuel injection. In that case the full-flow filter was standard. If you ordered a car with a special 348-cid "Turbo Thrust" V-8, the installation of an oil filter was optional, but mandatory.

By the early 1960s, there were dozens of different oil filtration system designs and a myriad of trade names. You could find goofy ads in pulp magazines offering magnetic filters, "Snow Cone" shaped filters, bronze filters and others. But in a practical sense, at that time there were two basic types of practical, mass-produced oil filter materials: cotton waste and activated clay.

Detergent oils had come into use by 1961 and, as most hobbyists know, these tended to break down the sludge deposits that Purolator used to count on to sell Wing-Nut filters. Detergent oil would hold these dirt particles in suspension and, if everything went right, the cotton-waste type filter would allow only microscopic particles to pass through it. In theory, at least, the filter would snag any sludge that was large enough to hurt the engine.

In contrast, the activated clay filter would take out just about every bit of dirt. In fact, it would sometimes leave the oil looking clean enough to scare a lab tester. One problem with activated clay filters is that they would also filter out some expensive oil additives. Cotton-waste filters did a good job of keeping the engine safe, as long as the motorists changed filters every 6,000 to 8,000 miles.