Just found a very old Gulf Supreme map of Maine and Quebec. It is interesting as it lists five different grades of their oil:
SUPREME MOTOR OIL--Medium
Too bad that no date is shown.
And no data ;-)
Ford recommended oil as shown below, corresponding to SAE 20W - 20. This is a "Light oil, which confusingly is referred to by Mobil as Arctic Heavy.
Here we go again.
When did Ford "recommend" that? SAE spec oil didn't exist during the Model T era.
Ken, Ford recommended a "medium light" oil in the owners manual that was included with every Model T.
Medium light was equivalent to what was called SAE 20 when the SAE specifications were standardized.
I'm not sure by any means, but I don't think multi grade oil was developed until many years after T production. Royce, where did you find that "light oil" corresponds to SAE 20w-20? Just curious. Dave
Tin Lizzie by Stern which is now reprinted,said sae #10 was the modern equivlent in 1955.Bud in Wheeler,Mi.
@ Roger (and David) - Ok, I misread Royce's wording. However, Ford published a specific viscosity for what oil should be used. The problem is that the viscosity method used back then is difficult to convert to modern SAE standards as an "equivalent". At best, it must be assumed the equivalent falls in a range somewhere between SAE 20 and below. Certainly no higher.
Those that are using diesel oil or 10W-50, etc. are robbing their engine of life.
How so?? Bud.
Ford referred to the viscosity as a "Light grade" of oil.
Neither of which is shown in your example.
What is Gargoyle Mobiloil "E" and White Star Extra Quality? I suspect these are light machine oils. There's a specific viscosity published but I can't locate it at the moment. It was covered in an old thread on this same subject.
In any case, any oil is better than no oil. People complain of noisy transmissions when using light oils. And I sure don't want to rehash bearing clearances. But heavier oil doesn't circulate as fast as the specified oil.