I have not found anything online yet mentioning a leak in the same location, but maybe my search-fu is weak today. Thoughts?

 

Does it go away when driving and/or smoke constantly? Might be exhaust condensation leaking past the stud.

 

When you removed the A/C compressor bracket, did you replace the long bolt which goes in through the front and retains the end of the oil pump against the block?

 

Curly, this is definitely oil, see the closer pic below. Edit: and no smoke, just popped under the hood today to see if there were any leaks...130 miles on the fresh build, haven't checked in a couple of days and found this.

Joe, I think have the correct hole plugged up. The one below it is threaded deep inside, though. Either way, the leak is starting up high.

 

Cam seals puking? Look behind the valve cover right in front of that bolt.

I'm not crazy, that's the forward lower corner of your exhaust flange right?

 

Oil leaks are mysterious beasts.

After much head-scratching, and the replacement of many seals, I finally traced the oil that was pooling in the valley where the spark plug wires go to a leaky CAS seal. There was little sign of oil leakage on the back of the engine, most of it traveled up and forward.

 

Isn't the oil cap and breather pipe on the valve cover right above that?

 

valve stem seals(s)
or blowby from rings not seated

 

Correct location, no oil whatsoever anywhere forward or above this location. Every seal in the motor was replaced in the build, not that I couldn't have screwed one up, but there's no oil seeping out from behind the covers anywhere or across the top of the water pump.

Yep, nothing leaking above this point.

New valve stem seals. And the alternative is not what I want to hear! Brand new rings, no oil peeing out anywhere else, but I guess I could have screwed up a stem seal or this cylinder could be screwed.

I'm guessing a compression test would reveal incorrectly seated rings?

 

Eo2k had almost exact same symptom on his 949 cnc head with new stem seals. They installed them wrong

 

Well I'll take that any day over an incorrectly installed control ring/improperly seated ring. Is there an oil drain behind that stud? That was going to be my first and best wish

 

Good thing you posted that diagram with the oil pump bolt. I removed the AC bracket to put a custom motor mount there! I will have to replace that bolt.

 

While I can't say with certainty that it's your problem, check the bolts again. This one is the usual suspect:



My recollection is that after removing the bracket, you have to buy a shorter bolt (or shim the stock one out with washers) to get it to tighten.

 

Probably valve stem seals. Use a mirror and look under all the other cylinders in that area, see if any others are wet with oil.

Pulling the turbo manifold and look in the ports, of they're oily it's valve stem seals.

 

Thanks for the follow up, guys. I'll likely pull the manifold off and have a look at what's going on in the runners.

 

Thanks for for taking well-focused sharp images.