Greetings . . .

John, I love the way you remind us what the 'old school' intended . . . and you'll get no argument from me. And I think I can help with the logic part.

Modern motor oils contain all kinds of additives, including detergents that emulsify water and suspend dirt. They are in fact formulated to be filtered.

But these old engines were designed to run a non-detergent oil. These oils weren't formulated at all - "straight 20 weight" or "straight 30" oils simply deposit the dirt in the pan - which the local mechanic would scrape during routine maintenance.

So I agree with John. Heck with the filter. Just change the oil more often.

But I run modern oil in my 216 and change it every 1000 miles. Because the service interval in the manual assumes "straight weight oil" and that dirt is being deposited in the pan as opposed to suspended.

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