differance between oils.
09-16-2007, 09:21 AM
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differance between oils.
What is the differance between a multi grade synthetic oil and a streight grade synthetic motor oil .? What are the advantage and disadvantage of each in a marine eingne.? I have been using a streight grade 40 W oil for 200 hrs. would changing to a synthetic cause me a problem.? I have been thinking about a streight 40 W synthetic oil. I have a 1999-502 cid 500 HP eingine.
09-16-2007, 11:29 AM
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mobil 1 15 w 50 is a good oli. primarily multi viscos oils are eaier to circulate at start up when you need thin oil, and then turns to the sturdier or thicker viscos oil when it reaches operating temp. hense the 2 designations 15 w 50. single grade maintains the same viscos all the time. theoreticly.
09-17-2007, 12:05 PM
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A multi viscosity oil is an oil that meets two different SAE oil grades at two different temps. Those temps are 0 degrees F and 210 F. A straight weight only meets one SAE grade. If the straight weight is a 10w oil it meets the grade at 0, if it is an SAE 40 it meets the grade at 210. The "W" stands for winter.
When you use a 20W50 oil, it will offer the flow properties of a 20W oil at 0f and the flow properties of an SAE 50 at 210.
ALL OILS THIN WITH HEAT. A multi vis oil thins less. The thinning is more controlled due to the polymer that is added to the oil. A SAE 50 is alot thinner than a 20w because they are tested at two different temps. A SAE 50 is a lot thicker than a 20w at 0 but that is not the temp it is qualified at.
So in response to your question, you can change to a synthetic 15w/20w-50 with no problen and because the oil meets a 50 grade at 210 it will offer more film strength than your SAE 40.
Ken
When you use a 20W50 oil, it will offer the flow properties of a 20W oil at 0f and the flow properties of an SAE 50 at 210.
ALL OILS THIN WITH HEAT. A multi vis oil thins less. The thinning is more controlled due to the polymer that is added to the oil. A SAE 50 is alot thinner than a 20w because they are tested at two different temps. A SAE 50 is a lot thicker than a 20w at 0 but that is not the temp it is qualified at.
So in response to your question, you can change to a synthetic 15w/20w-50 with no problen and because the oil meets a 50 grade at 210 it will offer more film strength than your SAE 40.
Ken
