The Stovebolt Site Forums The Shop Area Engine Shop By pass oil filter question

Way back when they were... you can't take today's methodology and apply it to 50+ years ago.

At the time... you didn't filter oil, you threw it out. Saying bypass filters on a Cumming diesel have anything to do with a car motor in the 40's 50's is comparing apples to watermelons.

I posted the specs.... the bypass filters of the time (Fram C4s) offered LESS filtration as a PH8A full flow filter today. Media technology of the time was nowhere near what we have today. Although the 50's DID invent the Frantz toilet paper filter that is like today with AMSOIL filters... sure they are available, but not production standard because you threw out the oil.. you didn't try and filter it.

As for OPs question typically you would change NOT change the filter ever oil change, from my specific manual:

OIL FILTER. Every 1,000 miles, when engine is drained remove
drain plug from oil filter to drain oil and sediment in filter.
Every 6,000 miles, remove filter element (par. 81). Clean inside of
shell with clean rag and install new element (par. 81). Run engine
a few minutes and check oil level. Add oil to bring crankcase oil
level up to "FULL" mark on gage. [sic]

The Chevvy S-6 filter decals state:

Change the filter when the oil on the dipstick appears dark.

I would let it go at least till every other oil change. The size of the element can hold a LOT of debris. But you WILL want to drain and clean the filter body every oil change to remove debris that would have settles out to the bottom of the filter.