OK, so here's what I found so far... Fired it up again prior to the tear down and the knock sounded more like top end noise this time around. But still couldn't pinpoint the location. It is in an outdoor barn with tin walls that echo. ha
Then I drained the oil and found copper flakes. Removed the oil pan and found more copper flakes and noticed a small amount of coolant mixed into the oil. Removed the valve covers and found a sludge mixture of oil, some coolant, and grease, but no copper flakes. Removed the oil filters and found a bunch of copper flakes on top of the filters.
I never found any chunks of and type of metal. There was just an abundance of copper flakes. Didn't feel any obvious "unusual" movement in any of the components, ie. rods, push rods, valve springs, etc.
The coolant in the oil did not mix to the point of cloudiness as in most cases. The oil was still dark brown as is most used oil with no unusual smell. The coolant was staying separate, in little green beads mixed into or beading up on top of the surfaces with oil around it.
I've got my theories, but would love any input and suggestions that yall have to offer. Is a rebuild worth it? Or does anyone know where I can find a reasonably priced replacement? Oh yeah, the truck is a 1968 AM General M35A2 with the Continental LDT-465-1D. The motor was installed by Toole Army Depot in the mid 90's. The truck is parked at a friend's house about an hour away. So unfortunately, I cannot simply run outside and take a look at it. I'm planning on heading back out to work on it again this Sunday.
Thanks in advance for any helpful advice and words of wisdom.
- Jimmy Hank -