My last blog on how autos have evolved since I started in the industry, got me thinking about other areas on vehicles that have become a lot better. Today I am going with the various filters in use today.
When I started in the industry, engine oil filters were almost non existent. I was working at a Ford de3aler in Toronto, and we installed a partial flow filter that Ford offered as an accessory. In those days it was common to change oil every thousand miles at the same time the chassis was greased. Hence the acronym LOF. No it was not some kind of thing one uses as texting. It means Lube, Oil, and Filter.
OK, so we started putting these partial flow filters on. The were a kind of cotton waste material, that fitted into a cup-like holder that could have the top removed, and the filter replaced. At the time oil was just oil, and we usually installed 30 weight oil, except in winter when we often put 10 weight oil in the engine. Believe it or not, there was even one non OEM oil filter that used a roll of toilet paper! All of these required frequent changing, since non of the oils or filters were very efficient. As the name implies, partial flow only filtered some of the oil, but over time it likely all got filtered. Crankcase venting at the time, was no more than a cap, and a draft tube below the car that would supposedly pull the oil fumes through the vented fill cap out into the air below the car,
Time went by, and that old partial flow model went to a full flow design. Great idea until the filter got too dirty to allow any flow, so a by-pass was built in, that would allow dirty oil to flow from the oil pump to the engine, rather than no oil at all. It worked pretty good too. This filter was a folded up paper design, and was a lot better in filtering oil, than a roll of toilet paper. This design lasted for some time, and was eventually replaced with the built in canister sealed unit. The spin on filter was born! It had the by-pass built in, and was a sealed unit.
Along about this time a better way of venting came along, PCV, or positive crankcase ventilation. Air was pulled into the engine through the crankcase where it picked up impurities and the resulting air mixture was burned in the engine. A result of all this was longer oil life since the acids and water were boiled off by engine heat and were eliminated in the combustion. About the same time something called multi-viscosity oil was developed. It started with 10W30 and eventually evolved into 5W30. This was oil that had all the properties of a 5W oil, (the W represented winter use) but had the stability of a 30 weight oil.
So, we have all the advantages of the 5W, and that offered easy starting at low temperatures and quick flowing in the engine reducing the old Cold Start up Wear and Tear. As the engine warmed up, the oil didn’t get any thinner as a straight 5W would, it got no thinner than a 30 weight oil would get at operating temperatures. So we now have the best of both worlds. Incidentally this type of oil also improved gas mileage, since engine friction was reduced as well!
The change in oils and engine management over the years has meant a number of things. Oil life has improved due to the ventilation, improved filters, engine temperatures are higher today, and oils themselves have gone through a lot of chemistry and last a lot longer. Most engines today will allow you to go a year maximum, or less depending on the oil life monitor built into a car today. There was a time not too long ago when the oil change interval was 90 days or 3000 miles. That is a thing of the past today, follow the recommendation of the oil life monitor. This has saved a huge amount of lubricating oil that was wasted at one time when the recommendation was every 1000 miles!
One more item regarding oil and the manufacturers recommendation. Today we have Synthetic oils around that have had a lot of additives put in as well as coming in many cases from oil sands. If you car calls for it, use it. It is worth the difference in price.
Air filters didn’t evolve quite the same way. The old standard was a rig that used a shredded metal product that looked a bit like an old Brillo pad. You washed it out in solvent and re-oiled it at every LOF! That was replaced with an improved rig called an Oil Bath Air Filter. The incoming air flow would pull oil up out of a reservoir into a wood fibre based media pad. The pad stopped a lot of junk from getting into the engine, while the oil got the smaller stuff. When the engine was shut down the oil would drain back into the reservoir and carry the dirt with it. These all were designed to keep dirt out of the engine. To give you some idea of how important this filter is, I saw one engine where the owner didn’t like his paper filter, so he took it out. The engine was absolute junk at 30,000 miles. The cylinder bore that should have no taper from top to bottom, was now tapered in his engine by an eighth of an inch! The cylinder bore was 1/8 inch wider at the top of the cylinder than it was at the bottom. I have also seen engines that have had proper air and oil filter maintenance with 300,000 miles where the engine showed little wear! The final part of the evolution in air intake filters was to use the same kind of filter paper technology as the oil filters.
One other area where a filter is located is in the automatic transmission. This is not an area that gets dirt coming in from the outside, but is designed to clean all the oil as it is used to shift gears, and so on, to be clean. An automatic can and will shed some metal particles as normal use wears away bearings and gear surfaces. No problem with that as such, as long as it stays out of the valve body, where clearances are very slight.
So there you have it, another continuous improvement, that has resulted in longer engine life, less cost maintenance, and a much lower oil usage and waste. I’ll think about some of he other areas and get a blog going on that. They don’t make ém like they used to! Good.
In the meantime, I am going to be away from my computer for a few days, so this will be my last blog until early February.