There's an old adage that pretty well sums it up- - - - - -"Oil is cheaper than engine parts!" We changed oil in the race engines once a week, and used the oil we drained out in our daily drivers. Of course, one of our sponsors was the local gasoline/oil/diesel fuel distributor and he dropped off a case of Valvoline racing oil about twice a month.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!