And the culprit is . . . Cam Seals:







Lessons learned:
1. Don't assume. I've "learned" this lesson multiple times. I still do it anyway.
2. Oil travels. It can appear to be coming from somewhere completely unrelated to the real source. In this case, oil dribbling from above was being caught by the slanted intersection of the block and oil pump and following that junction directly to the front, driver's side of the engine. Looked for all the world like a leak from the oil pump (the oil pump is not leaking at all, thankfully).
3. That UV dye stuff is awesome.
4. Curly got the reverse Murphy's Law working for me with the engine pull vibes. That's the only way I can explain getting lucky like this.

 

Dammit. Damn you.

You described a lot more oil than that.

 

at least that's easier than pulling the engine.

 

FWIW, I thought you had it nailed. Plus, no guarantee that an oil leak from the pump won't eventually develop. But I don't need to pull the engine right now, thank goodness.

 

So is it the seal or do the ends of the caps not have any RTV othem?

 

It sure does.

Several years ago, I had a problem with oil winding up on the top of the valve cover, down in the well around the spark plug holes.

It was coming from the head gasket.

 

Swapped the seals last night. Drove to work this AM (about 40 minutes at highway speeds) and everything is dry.

I can't really figure it out though. The caps were properly torqued (150in-lbs) and had black RTV in the right place. I disassembled, cleaned up, hit the cap mating surfaces just a touch with some emory cloth (making sure there were no burrs), and reassembled with new seals. I guess the seals that were in there were somehow defective -- but I'll be darned if I can see why. They were new, same dimensions as the replacements I put in, yada, yada.

???

Well, at least everything is working and dry. I hate mysteries.

 

How in the ??????

Joe invented anti-gravity!!! You need to replicate that.

 

I have utterly no idea.

I replaced damn near every other seal in the engine first. Even got around to finally removing the CAS, tracking down the blocking cap for that hole from an NB engine, and slathering the **** out of it with RTV. Nothing made a difference.

When I pulled the head, both it and the block were still straight, but the area at the extreme rear of the gasket where unpressurized oil drains down out of the head seemed to have degraded somewhat. Popped in a new gasket and that magically fixed the problem.

I can only assume that there are some bizarre air currents going on under the hood while in motion.

 

were they installed properly to start? I had my cams out once and when I refit the caps, I didn't install them properly and had the same oil leak. I just popped the caps, and place them back in fully and retorqued and away I went.

 

Don't know. They were pre-installed with the crate engine. They looked like they were fully seated.

One of life's mysteries. Like oil travel.

 

Just a bit of follow-up. I remembered that I had posted pictures of my new oil pump here:

https://www.miataturbo.net/diy-turbo...d-70274/page2/

It turns out that it did not have an O-ring groove. So, a gasket-only assembly is correct in this case.

New engine continues to be clean and dry.