Originally Posted By: fdcg27
Your uncle may have impressed this upon you, but I don't think you'll find much agreement among knowledgeable owners of older vehicles.
The oil is intended to suspend debris too small to be caught by the oil filter, and some current Japanese OEM oil filters are little more than rock catchers.
Any really large debris will end up in the bottom of the pan or be caught by the screen on the pickup.
Detergent oil will not caused increased wear.
I'll put it to you this way.
If this were my engine, I'd not be using non-detergent oil.
The sludge doesn't just build up where you can easily get to it.
Better oils are a major, maybe the major reason that engines live longer today than they ever could when the OP's stovebolt six was new.
Agreed, oils have come a long way since those old six bangers came out, but so have motors themselves. The difference here is between carbs and fuel injection, between electronic ignition and points and condenser, between a pressurized oil system and the old splash system, (at least my 58 still had the "dippers."). Metals alloys are better and clearances are much tighter.
I do find it interesting the rebuilder recommended a heavy oil while most modern engines recommend a light oil (5W20 for example). I would guess that if a 5W20 were used in this engine, it would consume the oil at a much higher rate. That tells me clearances are greater than a more modern engine and thus you would have more "blow by" and contamination of the oil which in turn would float around rather than settle.
In addition to my old '47 Case tractor, (which does have a filter), I also have a 1933 Case Model "C" tractor that my Dad and I rebuilt when I was a senior in High School. We've always run non-detergent and periodically pull the valve cover as well as remove the inspection plates on the pan, (there are two on either side) and clean the inside of the motor. In addition, the oil screen can be removed from the outside of the engine and according to the owners manual should be cleaned every 250 hours. It doesn't get much use other than shows and such, but stays pretty clean.
The motor on the truck I had had been rebuilt by my Uncle at 65,000 miles, (pretty common in those days). When I got it, it had 118,000 miles and burned about a quart of oil every 500 miles. I would be curious to see if the rebuilt 235 would go longer with detergent oil.
I know you disagree and that's cool, but I'm a firm believer in using the oil the motor was designed to use - just my humble two cents worth
