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Another Oil ?

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Your first indication will be in the circular label on the back of the bottle, or sometimes the front, that shows the API grade. If it bears the words "energy conserving", avoid it.

Otherwise, it's hard to know, because after all, lower friction is what anyone would want from an oil, right? So, marketing types are always ready to slap some little phrase like "reduced friction" on the label, but does that mean the oil is bad?

As I see it, you have three options. The first is to study the subject until you understand it as a chemical engineer does. Then you can gather and analyze the appropriate information from data sheets and decide about your oil based on that.

No? Well, then, there's option two, in which you take the experiences of people who have used various brands and grades of oil themselves and follow their recommendations. This works, but it has its limitations.

The third way is to assemble a set of qualifying indicators that can be read from the label or otherwise found and evaluate an oil based on them. In general, you want 3 basic things: good wear protection, compatibility with your wet clutch, and excellent shear stability so that the transmission won't crush the viscosity out of the oil in the first two hours.

So, if I have to go and find an alternative to the oil I usually use, here's what I look for. First, it should be a good high quality synthetic. There are a lot of advantages to modern synthetics, but one of the most important to me is that they are made from base oils that have a very high viscosity index. That means that the viscosity changes less with heat than simple dino oil, and requires less chemical modification to behave as a multigrade. That in turn means that the viscosity of the oil will be harder to break down. Another good indication of shear stability is a ratio between the high and low viscosity of no more than 4 to 1, as in a 10w-40. This can be achieved in a good synthetic with very little modification to the base oil, and means that the viscosity will be more difficult to break down than it would in a 5w-40.

Next, I look for the older API grades of SG or SH. These may be difficult to locate, but they are still carried on some commercial oils carrying grades of CF or higher (I think Rotella T Syn has it). SJ is not necessarily bad, but it may not have the high levels of zinc and phosphorus based wear prevention additives that exist in SG/SH oils. SL and SM oils are almost all EC.

The one thing you can find on a label that will absolutely tell you the oil is suitable for wet clutches is the JASO (Japanese Automotive Standards Organization) grade of MA. This indicates that the oil is essentially an API SG/SH oilby default, probably at least a CF as well, even though it may be marked as an SJ, and will work with your clutch. There is also a JASO MB, which is NOT for wet clutch applications, and should only be used for engines like the CRF's, where the clutch is isolated.

Hope that helps.

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