The oil cooler is an old Jagg unit that I had in my junk bin.  I used to run it on my Harley Softail.  This thing is intended to be installed in the return line from the scavenge pump back to the oil tank.  I don’t think it was intended to be used in a pressurized system, so I must be careful with it.  With a flow control jet upstream, and an open-ended spray tube downstream, I think the cooler will be OK.

The cooler and associated hoses hold a significant amount of oil.  That oil drains back to the sump when you shut the engine down.  So, when the engine is running, the oil level in the sump will be below the desired range.  To compensate, you must fill the engine to the normal level, and then add an additional amount of oil. That additional amount should be whatever the cooler holds when the engine is running.  In my case, the Jagg cooler holds 8 ounces of oil.

To set up the additional bleed, I drilled & tapped the existing 6mm threaded hole for the crankshaft seal.  That hole goes directly through the clutch cover and penetrates the filter cavity.  I tapped the hole for a 5/16-24 UNF screw, then made a special fastener to hold the seal retainer in place.  

The gear-spray was the hardest part of the job.  It required a special penetration block for the rear of the engine case.   The special penetration was a set of aluminum discs with a 90° hose fitting on the inlet side and 1/8” copper tubing on the spray side.  The tubing runs over the top of the transmission gears and is fastened to the case with small aluminum clips.  I drilled holes through the case to permit the use of small screws to secure the clips to the case.

The spray tubing is aligned so that oil is discharged directly into the gear mesh.  Since the input gear is rotating counterclockwise, and the output gear is rotating clockwise, the cool oil is pulled right through the mesh.  I can’t get much better than that.

This is the case with the special piece epoxied in place.  It requires an o-ring that is the same OD as stock, but the cross section is thinner.

So, how did all this work?

With a #120 flow control jet to the cooler, the oil pressure is now about 5 psi at idle, and 10 to 11 psi at 4000 rpm.  So, about double.
 
No problems with the pump drive gears.  No unusual noise or vibration.  No fluctuating oil pressure at high rpm.  You can run it up to 7K and the gage shows no signs of cavitation or loss of suction.
 
Oil temperature remained at 200°F.   I know the gear spray has adequate flow because the cooler gets hot.  If there was no flow, or low flow, the cooler would not get hot.  It clearly has a lot of oil flowing through the cooler, but not so much that the sump temperature drops below what it was before.  So, flow through the cooler seems pretty close with the #120 jet.
 
I did not have to use the special oil bleed in the filter housing.  It is plugged with a set screw.  But I haven’t done any tests to see if the filter bypass is lifting.  The filter shows no signs of distress, no evidence of tearing, deformation, or collapse.  I need to get a gage in between the #120 jet and the pump.  It’s on my to-do list.

The transmission supply passage is dry at the case joint.  No leaks.

The transmission output shaft is dry.  No leaks.

The special fitting I installed on the rear of the case is dry.  No leaks.

The clutch works perfectly.  Repeated inspections show no evidence of bronze deposits on the sleeve.  No slipping, no grabbing, no squealing.  I suspect most of this improvement is due to the wave washer installation, but I’m sure the extra oil is helping too.