In the purest sense, every machine needs pure air, water, fuel, hydraulic and engine oil. Given the amount of contaminants in the air, and everywhere else, keeping a machine ‘clean’ is usually achieved by having a filter of some sort in the system.

What’s a filter?

Filters are basically dirt or contaminant traps. They are designed to trap the contaminants before they do irreparable damage to whatever system they are entering – or already in.

Sometimes these contaminants are outside trying to get in – such as in the case of an inlet air filter on the air intake to an engine. In other cases, they are designed to catch small parts of components breaking down in a system – such as an engine oil filter catching small particles of the piston ring, or crank bearing breaking down.

The emergence of filters

Filters haven’t always been part of the protection package of a machine, or car for that matter. The first Holden 48-215 did not come with a filter fitted as standard. Likewise, European and American industrial equipment of the 50’s didn’t come with filters as standard. And when they did, they certainly weren’t up to the task of dealing with the heat, humidity and massive contaminant loading of the Australian bush. After time and many motors ruined by excess dust inhalation, or “dusted”, the mechanics cottoned on – maybe there was a better solution.

The first English industrial machines brought into Western Australia to build the infrastructure necessary to open up the north of the State came with primitive “oil bath” style air cleaners, which used a thin film of oil over a wide gauge wire mesh to stop dust from entering a motor. Alright in the Midlands of the UK, less so 200km north of Kalgoorlie in the middle of summer!

Wartime ingenuity

The expertise to fix this rapidly emerging problem came from the USA. In WW2 all American machines came equipped with military standard oil filters. There were two sizes named ‘Junior’ and ‘Senior’ and all equipment came with a combination or multiples of these two elements. Like so many things done during WW2 it was cutting edge and clever, yet devastatingly simple. Many American filters brands got their start in WW2, or soon after, and as such so many of the initial aftermarket applications of filters came from American manufacturers.

Australia was not to be left out though. In much the same way as the USA there was a lot of expertise honed in war time that was put to use to fix these filtration related problems. Remember that 48-215 without an oil filter – there was soon an aftermarket oil filtration available to remedy that.

Post war development

The end of World War 2 marked the start of a massive period of growth and innovation. The main filter types that we know today were all invented and refined in the post war years.

Dry type paper air cleaners, spin on oil filters and pleated cartridge liquid filters are all products of this period. So many of the legacy brands that are no longer powers in the industry were at the forefront of this development. There is some conjecture around who invented what and when amongst the American Brands.

Locally, Ryco Filters were at the forefront of the industry. Their Z9 and Z10 elements were the first Australian made mass produced spin-on filters in the late 1950s. These filters are still made today, although unfortunately not in Australia.

Filters of today / modern filters

Today, whilst there has been innovation, the same basic filter types still exist and flourish – dry type paper air filters, spin on filters and pleated cartridge style liquid filters. Within each subset there have been many attempts to improve the basic design, but they are generally just tinkering at the edges.

Air filters have gone from having metal end caps with a rubber seal to plastisol rubber moulded endcaps to proprietary stacked pleat elements like the Donaldson Powercore. Spin on oil filters have similarly changed at the edges, but not in basic form. Innovations such as combined full flow/bypass elements and high efficiency filtration have changed the internals but not the basic form. Pleated filters have gone from having metal endcaps, to moulded plastic. Some specialist hydraulic oil filters have done away with the internal element core completely. In terms of efficiency it is now commonplace to have a hydraulic oil filter that is able to remove 99.9% of contaminants that are 1 micron or larger, or 1/50th the diameter of an average human hair.

Final Thoughts

The old adage goes that if something isn’t broke then you don’t need to fix it. This holds true for filters. Whilst the efficiency has changed over the years and they have become easier to install, the filters of today at least outwardly resemble their predecessors from the 1950s. The other thing that hasn’t changed is that they still need to keep the fluids, and air in your machine as clean as possible.