kgw51gmc,
The main purpose of detergent in motor oil is to keep contaminants in suspension until you drain the oil. This is why the oil gets black and skunky...it full of junk.
A detergent oil does have a limited ability to scour internal parts, although as stated above, this is secondary. The general line of thinking is that when a rig was run on non-detergent oil, it should stay on that diet..Grandpa's theory!
If I wanted to switch to a detergent oil, I would do exactly as you have outlined above, although maybe not as many/often changes.
If you were to ask if this would lead to more oil consumption on the motor, my answer would be maybe, or maybe not.
A reasonable question would be whether the gunk in the engine from all these year of non-detergent oil is what is sealing the rings and making the motor tight.
If it were my engine, I think I would change to a oil that was more available, and offered a little more protection..a modern multigrade detergent oil.
You will probably find a million different viewpoints on this subject depending on who you talk to. Use your common sense and you will prevail.
Stuart
