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Recent content by Xtrema

  1. Xtrema

    Engine friction data at low temperature

    The different oil viscosity grades winter rating define how thick the oil is at a certain cold temperature. The oil can be no thicker than XXXX at YY temperature in this test, called the Brookfield viscosity test. So, you can be assured that the engine will turn over more slowly with a 15W...
  2. Xtrema

    Engine Oil Standard Attributes

    It would be difficult to set up a test program in house for the tests referenced above. There are outside test houses that can perform "Used Oil Analysis." Many of these are allied with suppliers of high-zoot engine oil like Amsoil. www.bobistheoilguy.com is a site frequented by both oil...
  3. Xtrema

    SAE oil viscosity vs. Centipoise

    Viscosity grades are simply a range of possible thicknesses of an oil. You could think of them as you might the tolerance on a resistor labeled 1000 ohms. Would you be surprised that one resistor was 990 and another was 1010 ohms? It's the same kind of thing. Oils with the same SAE weight...
  4. Xtrema

    Hypoid Gear Teeth Relative Velocity

    Given a typical hypoid gear rear axle for a passenger vehicle, a pinion rotational speed, and basic gear dimensions, how do I calculate the tooth-to-tooth relative velocity of a pair of mating points on the teeth?
  5. Xtrema

    NOx Reduction Techniques

    If you choose exhaust gas recirculation, you are attempting to prevent NOx from forming in the cylinder. By transferring some of the combustion heat to inert recirculated exhaust gas, you keep the N2 and O2 from splitting into radicals that want to join each other. It is effective, but can...
  6. Xtrema

    Which oil or grease will work the best?

    Regarding a special lubricant, you might consider a hybrid approach. Use a widely-available lubricant, purchased on site. Send a small quantity of an additive known as "anti-oxidant" for the end user to blend with the standard lubricant. The quantity of anti-oxidant needed will be so small...
  7. Xtrema

    Which oil or grease will work the best?

    I like your approach of a single low viscosity motor oil. With regard to your 2-stroke oil idea, Bel-Ray makes great motorcycle oil. I don't know if they distribute worldwide.
  8. Xtrema

    Which oil or grease will work the best?

    My first reaction was surprise that one nylon-filled bearing wore and the other didn't. Are the bearings sufficient for the applied loads at the high temperature zone? 400 F for any sump oil is quite high. Varnish and carbon are sure signs of oil oxidation. A custom lubricant might be in...
  9. Xtrema

    friction reduction in ring and pinion

    Many folks try synthetic racing rear axle lubricant like Royal Purple or Redline.
  10. Xtrema

    0 Degree Pinion Offset

    Did you call Dana? Mack Truck? Randy's Ring and Pinion?
  11. Xtrema

    Increasing Gear Durability

    You may want to consider high performance lubricants to increase film thickness, decrease temperature, and enhance shock loading of the gear teeth.
  12. Xtrema

    Oil Filter Bypass Valve -- How Long Before It Opens?

    Thank you. I'll check for non-combination valve on my Mobil 1 filter and my K&N filter. My filter is mounted vertically with the cup up, threads at top.
  13. Xtrema

    Two stroke oils - corrosion resistance

    What corrosion test did you perform?
  14. Xtrema

    unloaders on refrigeration compressors

    Call a Copeland Corporation application engineer. They make and sell both types of compressors and know the answers. Refrigeration load does change, especially in grocery stores. For example, all the opening and closing of reach-in cases occurs during peak human traffic times, and overnight...
  15. Xtrema

    Engine cooling

    Casting an engine block requires that wall thicknesses be controlled to minimize distortion upon casting cooling. A thick section next to a thin section can distort dimensionally. Cast iron costs money, so adding iron to fill a jacket would be a financial penalty. Heat transfer is a function...

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