I have been chasing down and fixing small oil leaks on the 4,5,6 side and have it mostly fixed, but I got to thinking about the orientation of the oil distribution tube in the camshaft housings and decided to pull the intake valve covers and take a look.
Glad I did as I found I had the oil distribution tube on the 4,5,6 cam tower 180 degrees out of alignment - when I was assembling cam towers I got one of them wrong. When you have the oil feed fitting and the oil plug out of the cam tower as I had during engine rebuild, the oil distribution tube can rotate freely by hand.
An oil drip would form at the bottom of the exhaust valve cover at the #6 end:
Incorrect oil tube orientation on the 4,5,6 cam tower - the 2 visible holes should be pointing at the camshaft lobes not at the valve cover:
Correct oil tube orientation on the 1,2,3 cam tower, notice the hole pointing at the rocker arm oil lube hole:
This photo, if you look closely at the scratchy mirror image, shows the oil feed / alignment thru hole visible at both the oil feed and oil plug holes in the cam tower. The oil plug has a pointed end that fits into the thru hole at the end of the oil distribution tube and locks the orientation of the oil feed tube so oil goes where it is supposed to:
I rotated the oil distribution lube to the correct orientation in the 4,5,6 cam tower and re-installed the oil plug at the back end (# 6) of the cam tower to lock the oil distribution tube orientation, then I re-installed the oil feed fitting at the front end (# 4) of the cam tower and re-attached the oil feed line. Then I re-installed the intake valve covers and spark plug wires.
I'll see if not having oil sprayed at the inside of the 4,5,6 valve cover has any effect on my last small oil leak. And clearly having the oil sprayed at the correct locations on the 4,5,6 camshaft lobes and rocker arms will promote longer life.
Living and learning.