Oil and Filtration Made Simple
By: Douglas Brooks
I have seen so many things that were working, but worn so badly when I looked at them I have said, “That is impossible.” Several times we have torn down a CAT® D9 or D8 transmission with the planetary bearing completely chewed up, spit out, and the shaft they ride on worn half into with a half mile of clearance in the clutch pack ring, and they were still running. Take this same transmission put $20,000 in new parts, install it - put a nick in a 50 cent oil ring and it won't move out of its tracks. I have seen a few good old boys build a 350-Chevy motor in a mud hole, using parts from four or five junk motors, and drive it for years. I have seen people spend thousands of dollars and the motor break before they get it out of their nice shop.
Over the years I have learned that most men (I will exclude any women who are mechanics or machinists because I am totally positive that I do not have a clue what they think) hate to take advice or read the instructions. This is caused by how God designed our brain and we have no control over this condition. Show a man what’s wrong and he can fix it. There lies the problem. Sometimes it is hard to figure out what’s broke, or if we find the broke part, just what caused it to break. I change the oil in my truck because I know after a while it gets dirty and if I don’t change it my engine will wear out. But I changed oil like I should and it still wore out, so as my kids say, Aduh, what’s the point. Everyone has heard about the guy with 150,000 miles on his truck or car and has only changed the oil twice.
Points of pressure are how I am going to share my opinion with you, and as you know, in polite terms, opinions are like what we sit on and everyone has one. If you sit down on a nail sticking through a wood church pew and slide to the other end, you will leave a trail. But if you reduce the point of pressure by removing the nail, you can sit down and slide without leaving a path of cloth and body parts torn loose by the point of pressure (nail). Point is, if you have a fat _ _ _ it will spread out and be flat against the flat polished wood church pew and you can slide back and forth quite easily and not cause any damage. This is my theory in hydraulics (or any machine) - keep it as big and flat and smooth as possible, keep out the nails and rocks that would create any point of pressure and it will last a really long time. We have a patent pending on our port plate and process of re-cutting original port plates to let them remain flat as they warm up. And a flat @ is less than .0000116, which is 11.6 millionths, which we measure with light reflection. We also found out, after we got these parts that flat, that new oil is not filtered - it is only run through a 50-micron screen and has stuff in it that damages parts. So now we filter the new oil with a special filter before we use it for assembly or refill the machine. A standard engine or hydraulic filter is only rated to stop stuff bigger than 20 micron and not less than 10 micron; but, that is not absolute so you may get stuff bigger than 20 micron. Stuff damages the parts so that’s the reason we use a special filter to filter all our oil used for assembly, refill, and in our test bench.
My first memories of filtering oil was on my new 1966 Honda 90cc motorcycle when I was 14 years old. The Honda had a small dish-like plate about 2 - 3 inches in diameter with ribs on the outside lip. It bolted to the end of the crankshaft and oil came through the center and was filtered by the centrifugal method which made the particles in the oil sling to the outside lip. When you changed oil you simply scraped out the layer of blackish-gray material on the outer lip, which was about the consistency of dried cake icing, and you were ready to ride again.
I could give you all kinds of stories from my years of experience and all the scientific data and papers to support what I am about to tell you, but what you want to hear is something you have seen. You also want to hear what I or you can do that will help, is it easy to do and is it cheap.
So have you ever wondered why, if you have a filter, you need to change your oil because it’s dirty? Or maybe a better question is, "why does my filter not work?” If it worked, the only reason to change the oil is if it was worn out and, scientifically speaking, oil does not wear out. You can destroy oil with too much heat (change its molecular structure), dilute it with water, dirt or whatever and make it bad, but a good filter would fix that.
Oil film, oil slick, or floating on oil -- Spray some WD-40 on a tile floor at Wal-Mart and watch the lawyers get happy. But if you gave everybody golf shoes with the real sharp little spikes, they would cut through the WD-40 film and dig into the tile and make the lawyers sad. Or you could sprinkle a little sand over the WD-40 and that would work to make them sad also. Now, if you had a big pile of thick wheel-bearing grease on the floor, the small sprinkling of sand that fixed the WD-40 would not affect the grease, but the golf shoes would still work to keep you upright.
Take two pieces of clean flat glass, the bottom piece is round, one inch thick and 12 inches in diameter and the top piece is round, one inch thick and 4 inches in diameter. Spray WD-40 on them and place them together with the WD-40 in the middle. If there is nothing in the WD-40 and there is no dust on the glass, there will be no scratches when you slide the top piece around. The WD-40 is all over the 12 inch piece and between the two pieces of glass. Put a 2 lb. weight on the 4 inch piece of glass and it moves around with no scratches and floats on the film. Now pour sand over it. As you move around the 4 inch piece with the weight, it will now push most of the sand off the 12 inch piece and only the sand dust, which is the same size or smaller than the thickness of the WD-40, will be under the 4 inch piece. But as the small particles of sand displace the WD-40 it will start to cut the glass. This makes more particles and soon the glass is a haze. The filters that come on most hydraulics and engines do a good job of getting the sand that fell off the glass, but do little about the sand dust between the glass that wears and destroys the two pieces.
Studies that I have read state that 90% of wear is caused by contaminates 5-micron and smaller. This would indicate that the oil film, under pressure and heat, reduces to 5-micron or less. The special filter we use filters below 5-microns. Multi-grade oil like 15/40 pours like a 15wt when cold and as it warms up takes on the viscosity of 40wt. Straight 30wt pours like 30wt when cold and decreases in viscosity as it warms up. It is best to run the highest multi-viscosity oil you can that will flow in the clearance of your running parts and not create too much heat caused by the turbulence of the thick oil. Extra filtration below 5-micron, the right oil, and keeping the temperature below 180° F can more than double the life of some machinery transmissions, hydraulics and engines.
It doesn’t take a rocket scientist to figure out that a big Caterpillar or small car engine, when it is at 180° to 200° pushing a big pile of dirt or running down the road at 70 mph, puts a whole lot more pressure on its parts and creates smaller places than those two pieces of glass. Visualize a bowling alley that is so flat and smooth that it looks like a mirror but is made of steel. Then imagine a steel bowling ball so smooth it looks like a mirror. Now we take motor oil that is run through a regular filter and put it on the alley. Roll the ball; you know the point of contact is extremely small. As the ball is rolling you will see the path in the oil behind it, but what you cannot see is that particles in the oil, bigger than the thickness of the film under the contact point, are moved to each side. But the particles that are the same size, or smaller than the thickness of the oil film, will go under the ball and then displace the oil. If it is abrasive enough it will wear on the ball and the alley.