In my column entitled “Altering Oil Desire”, I reevaluated my long-held convictions for recommending mineral-based oil over artificial. Whereas writing the article, it occurred to me that I ought to have a look at oil filters extra carefully and with an open thoughts.
Filters are an integral a part of the oil cycle in an engine. If I have been altering my thoughts about what lubricant to advocate, I must also reevaluate my oil filter suggestions.
Automotive oil filters fall into two classes, full-flow and bypass. Bypass oil filters take about 10 % of the oil pumped from the sump, filter it after which return it to the sump whereas the remaining 90 % is delivered to the lubricated parts.
Full-flow oil filters filter one hundred pc of the oil pumped earlier than it continues on to the lubricated surfaces. It might sound that the full-flow filter can be the most effective oil filter, although that’s not essentially true. Every has its virtues and vices.
No Oil Filter
Early automobile engines didn’t make use of oil filters. The forerunner to grease filtration was mesh and display strainers. I don’t take into account display or mesh to be an efficient filter. There have been automobiles manufactured via the late Nineteen Sixties that didn’t have oil filters in any respect. (Anybody have a Nineteen Sixties-model Volkswagen or Fiat?)
The primary VW I noticed with an oil filter was the water-cooled VW Rabbit in 1975. The VW Tremendous Beetle had a full-flow filter after 1972 till manufacturing stopped in 1980. There was additionally a full-flow filter on the 1975 VW sedan and the 1980 VW convertible.
Bypass Oil Filters
Bypass oil filters have been the primary oil filters on automobiles. They’ve been put in on automobiles and light-weight vehicles because the early Nineteen Twenties. Ernest Sweetland launched the primary fashionable oil filter which promised “pure oil later” … so named as a result of it was positioned between the pump and the sump, and it promised to ship the pure oil later to the bearing surfaces.1
The filter was a heavy metallic case; inside was a sequence of metallic plates with twill weave materials round every plate. A sight glass let the person know when the oil move dwindled to a trickle. At this level the entire filter unit, case, sight glass, plates and twill materials had to get replaced. This was the start of the Purolator oil filter firm.
Mr. Sweetland’s filter was improved by introducing substitute cotton fiber filtration within the late Nineteen Thirties, which may very well be modified with out changing the entire filter unit. Nonetheless, it remained a bypass oil filter, the place 90 % of the oil was despatched to the engine unfiltered.
So long as the oil contamination charges have been low and the oil was modified steadily, the bearings had some affordable life expectation. Most automotive oil filters have been the bypass-type till the mid-Nineteen Forties.
In a earlier column, I wrote that 45 years in the past an engine might run 100,000 miles earlier than needing an overhaul (Equipment Lubrication, July-August 2001). All of the engine required was care and protracted upkeep. In that age of $2,000-cars and oil costing $0.25 per quart, oil filtration strategies and schedules have been doing a fiscally accountable job.
By 1950, most new automobiles have been constructed with full-flow filters. The elevated use of full-flow oil filters accompanied a lower in bypass filter utility.
Full-flow Oil Filters
What was the reasoning for the shift to full-flow filters? It’s easy – all of the oil, not the ten % of bypass norms, was filtered earlier than it was despatched to the oil gallery. Ideally, we wish to see particles considerably smaller than 5 microns trapped by the oil filter, nevertheless, there are sometimes value and efficiency trade-offs with finer filtration.
Judging a filter solely by its micron-size trapping capability has its limitations. My barbeque grill will filter 5 microns; a couple of five-micron particles will catch on the grill as fluid passes over.
The SAE HS806 customary makes use of each a single-pass take a look at and a multipass take a look at, assessing dirt-holding, contaminant capability in grams, and effectivity based mostly on weight. The effectivity of the filter is set by weight solely via gravimetric measurement of the filtered take a look at liquid. Typical numbers for cellulose paper filter components are 85 % (single-pass) and 80 % (multipass).
The SAE J1858 take a look at gives each particle counting and gravimetric measurement to measure dirt-holding capability and seize effectivity. Precise counts of contaminant particles by dimension are obtained each 10 minutes, each upstream (earlier than the filter) and downstream (after the filter), for analysis.
From this information, a filtration ratio and seize effectivity above completely different contaminant particle sizes could be decided in addition to dirt-holding capability and strain drop as a operate of time. Typical numbers for paper aspect filters are 40 % seize effectivity at 10 microns, 60 % at 20 microns, 93 % at 30 microns, and 97 % at 40 microns.
Oil filter design is considerably of a balancing act between particulate dimension, filter medium, floor space of filter medium and oil strain. The finer the filter medium, the shorter a filter’s lifespan earlier than it begins to point out strain drop and the oil filter bypass valve is opened.
Nonetheless, new artificial filter media and pleating configurations have managed to beat a few of these drawbacks. We have now the capability to filter out particles smaller than wanted (lower than two microns) to guard the oil between bearing surfaces, however figuring out the correct stability generally is a actual puzzle.
The unique full-flow filters have been housed in heavy canisters. The aspect was modified, the canister was cleaned, and a brand new sealing ring was put in. In about 1955, nevertheless, the full-flow filter as we acknowledge it at present was launched. Inside a couple of years, nearly all automobiles featured the present-day disposable, spin-on filter with a light-weight canister and its personal sealing ring.
Selecting a Filter – Full-flow or Bypass
Bypass filters usually are not new to the automotive setting. They have been the primary filters put in on automobiles, however have since been changed by full-flow filters on nearly one hundred pc of the brand new automobiles manufactured at present. I’m, nevertheless going to vote for each forms of filters; every stands out in sure situations. Ford Motor not too long ago introduced that it’s equipping its 2005 E Collection with bypass filtration.
I’m an enormous advocate of oil coolers to assist ease the burden on the lubricant. Vehicles last more with oil coolers. Vehicles last more with higher filtration and well timed oil and filter modifications. Vehicles last more with cleaner oil. The trucking business is forward of the auto business on recognizing the significance of cleaner oil.
There may be, within the trucking business, an affordable expectation of 500,000 miles between main overhauls. Why the lengthy interval? Truck producers use each bypass and full-flow filters, oil coolers and transmission coolers. In brief, they use all of it and have the outcomes to justify their expenditure. A million miles between overhauls is not uncommon within the trucking business.
With the substitute value of my spouse’s 1998 Buick Park Avenue approaching $35,000 I have to make that automobile final so long as I can. Any fairly priced gadget that will lengthen its life past 200,000 miles (it’s at present at 88,000 miles) is of curiosity, and is financially helpful to me. Among the advertisers in ML make or promote bypass filters for contemporary cars.
There at the moment are oil filter models commercially accessible for passenger automobiles that make use of each the bypass and full-flow filters. I’ve discovered a neat place underneath the hood of the Park Avenue to mount the manifold and filters. I believe I’ll test the scale one final time and buy one.
Any grime that will get previous the air filter enters the engine, turning into the enemy of all lubricated parts. This makes the oil filter’s job tougher. To fight such put on, change your air filter repeatedly. “PCV System – A Breath of Recent Air” (Equipment Lubrication, September-October 2001) discusses sustaining the PCV system. If broken, it may be one other supply of engine injury.