It's worth repeating that while testing these turbos I removed the hose from the CCV(PCV), allowing it to vent directly to air. Therefore, elevated case pressure could not have been responsible for causing blow-by at the turbos' journal bearing. A Provent 200 has arrived to replace my similarly-functional but less-elegant DIY. I am going to tap the provent's vent-out into the 3" exhaust downpipe.
I'm going to water-cool the incoming Garrett ball-bearing turbo. That will leave the high/low oil-pressure supply/return ports at the block vacant:
- The High Pressure port can be used for mounting an Oil Pressure Sensor for a gauge.
- The Return Line's port can be dedicated to the Provent's oil drain line.

Question for the Brain Trust:
Which coolant line would it be best to intercept to install the feed and return to the turbo?
I am already stressing about the spectre of sudden coolant loss frying the turbo... maybe a separate coolant pressure gauge would provide comfort if not adequate warning.

Re gauges, thanks for your input.
It's a good idea to start a new thread on the subject.
Cheers

Many Thanks for coolant port-tap counsel, WW!!!
Re provent oil-return back-pressure, I purchased the check-valve at same time. Thanks for heads-up.
Re vacuum @ CCV, with the hose off there is plenty of vent-pressure even without any applied intake-vac. That makes it difficult for me to absorb that hosing it to the intake vac induces a 'crucial' reduction in case pressure.
Anyway, I'm going to tap a "Y" pointing downstream within the exh. downpipe to accept the provent vent-out line.
In theory, the higher-volume of the 3" exhaust passing around the smaller (5/8"?) pipe orifice should create some measure of venturi-effect vacuum, No?
IN theory yes, let us know how well it performs. And many on LOST have stated that anything over a 2.5" pipe is an overkill and waste? Not sure on this one!
Post-install, I'll grab a vac gauge to confirm. Given the effort/expense to mod, hope I'm right...

Thanks for the graphic, WW!

I back-drafted the link. It seems most concerns re the EHM were cold-climate based (= freezing). At least at my current latitude, that doesn't apply to me.
Anyway, I now have a Provent in-hand...

The "engineers designed for a slight vacuum applied to the CCV"...
Okay. Even absent frigid temps, my objective is to replicate that intake "slight vacuum" venturi effect except at the exhaust side. Hope it works.
If you have no CAT and a free flowing muffler to prevent any back pressure, in theory your exhaust negative pressure device should function adequately.

However, I maintain that blow-by at a NEW turbo should not pivot on the addition of that "slight vacuum". Especially with the CCV blowing wide-open with no hose attached? No Way. Not Acceptable.
I totally agree with this statement.

This Spring I replaced the Gulliverian rear main seal assembly (during trans rebuild); in '16 I replaced the insufferable F'ing OEM SINGLE-lip front main seal with a hard-searched twin-lip substitute (during HG/TBelt/ Rockers, etc). However, even before I performed those major surgeries on my beast I never had leaks at either front/rear seal. So, whatever case-pressure prevailed it violated neither the main seals nor the old turbo's journal bearing seal.

If you haven't noticed that your time is finite, pay attention.
I would rather be doing almost anything than working on a jeep that should be reliably delivering me to worthy coves and caves, bluffs and beaches. Too old for this. Grrr.

That does not, however, mean that I am not immensely grateful for the knowledgeable insight and advice of the LJ Brain-Trust. To the contrary.
Thanks!