Good convo. I just recently retired a 49 216 that had approx 123k miles on it. I got it when it had 99k on it, pulled the head and had it rebuilt and put 23K miles on it before retiring it. I knew the original owner and know that the dealer installed bypass oil filter was installed before he took delivery of it when it was brand new.
The bottom end looks exactly like you'd expect an old engine that primarily ran non-detergent oil to look. In the attached pic you can see the difference in condition and oil deposits between the original bottom end and the rebuilt and refinished original head. Non-detergent oil doesn't suspend the debris it deposits it onto the stationary parts of the internals, namely the side walls and the bottom of the oil pan. Thats why crud builds up and you want to drain the oil when it's hot inorder to get as much of the debris out as possible.
Long story short, when you observe the pic you'll see the blocks pushrod gallery sidewall is coated with old oil debris/crud/ byproducts even tho the engine ran a bypass oil filter since new. After I got it running I ran detergent 15w40 oil and thats primarily why the head looks so clean when compared to the block.
So will a bypass oil filter keep a stovebolt engine from developing sludge? In my scenerio it didn't.
Oil gallery pic with pan removedGood luck
Dave
P.S. I forgot to add that the pic is when I removed the side pan last year with approx 22K miles on it to change out the leaking gasket. So the head coloration in the pic is after approx 22K miles.
