After the broken springs and finally getting the carb running just right, I decided to change the
oil. After pulling the drain plug, I noticed some black "fuzz" on the end of the magnetic plug. Then after draining the
oil I noticed some tiny silver metallic dust sized particles in the
oil. They appeared silver rather than copper. There were no particles larger than what I would describe as dust. They could not be felt by rolling between my fingers. I was in a hurry so I didn't do anything else. I replaced the plug, put on a new filter, then poured in new oil. I am beating my head against the wall with this thing. I've only put about 500 miles on it since the new motor two years ago.
Possibilities I can think of:
1 - bearings. I am using 10W-30 Castro Dino oil. I have a High Volume pump. I get >70 psi when cold, 40 psi warm idle, >70 psi when warm and over 2000 rpm. I *should* have enough oil pressure/flow to protect the bearings. The mains were lined and honed with the ARP studs at the local machine shop. I don't recall the bearing clearances, but they were within the "normal" range recommended by the book I was using for reference.
2 - spring residue. I had two broken springs. One of them was fractured into five separate pieces. Perhaps some of this material made its way down into the pan. I thought that all the spring material was there, but perhaps...
3 - Normal "break-in". Although I have roller lifters and rockers, perhaps what I am seeing is just normal initial wear of this essentially new motor. None of the material is palpable, only visible. Now that I finally have it running well it may just go away (hopefully).
4 - Other failure. Anything. Bad lifter, damaged cam/bearing, piston, ring, head, valve guide. Distributor gear looks fine.
I really don't want to tear this thing apart. I finally got it running after the failed EFI attempt, broken springs, and carb adjustments. No leaks. Starts quickly, idles and runs well once warmed up. Compression testing is good. Leak down testing is good. I guess I'll run it for a bit, drain the oil, send a used oil analysis, cut open the filter, etc. If it still has metal, I'll take off the pan and check the main and rod bearings.
If I end up taking off the pan, I'll probably switch back to a normal volume oil pump. I thought about switching to 0W-20 oil to increase oil flow and decrease oil pressure, but don't think that is a smart choice.
Any other thoughts?