Hi OM,
thank you for the very interesting scans you added on the recovery system.
It seems Twin Disc allowed for the leakage collection in sensitive environment applications--gen set, marine, etc.
Thanks too for the Charge pressure values.

I think with the 3 stage units Cat would have worked with Twin Disc to have adequate charge pressure--I cannot find any Charge pressure values in my limited literature for the fuel charge supply to the T/C as the only fluid system diagram shows what I believe to be the engine transfer pump only.
Operation Instructions in the OMI say that the T/C charge pressure should be in the White Range of the dash mounted T/C pressure gauge--good now to have an expected pressure range for these units.

To clarify the T/C cavitation I encountered was on in a Single Stage oil charged unit in, I believe a D8K, with a grossly excessive rack setting that I believe overpowered the single stage unit.
The Trans. pressure tests and the T/C-engine Stall Speed tests were just under specs as long as the rack only reached the sticky point--slightly less than full rack spec-- and did not beyond that--if it went past the sticky point to an excessive rack condition then the cavitation noises occurred and the engine RPM's increased and power to drive the tractor decreased.
Low push power was the complaint I was checking for after several others had been to it.

Cheers,
Eddie B.

Hi Team,
hunted and found my 2 Allis books. One is a HD19H Operators Manual, the other is "Torque Converter Repair Information" (Export Only)
It contains engineering drawings and data to replace the Vanes in the turbine wheel, and clearance ranges for the labyrinth seal area diameters used between the different stage members--ie. turbine, stator and impeller.

From the Repair book the labyrinth clearance maximums are as follows :-

First Stage Labyrinth = 0.020" max. clearance.

Second Stage Labyrinth = 0.016" max. clearance.

Turbine hub seal lip wear groove = 0.015" deep.


Alas, the HD19H does not use a recovery system it also runs the seal leakage drain fuel to ground as does Cat but does not specify a maximum leakage rate.

The T/C seal drains are connected to the GM diesel engine air box drain line.
See scan below for explanation of suction applied to the seal drain by air coming from the air box drain (Venturi effect ?) along with a small air filter located at the top of the T/C housing--likely to keep air flow thru the T/C seal drain lines.
It is mentioned also that it is very important that the end of the air box drain tube is kept clear at all times.
I could picture a backup of 30 to 55 PSI fuel leakage from T/C seals during operation and gravity pressure fuel when stationary flowing back into the air box--stand back boys, a runaway engine no doubt would result.

Thus we are no closer to a definitive explanation or layout for the recovery set up, thus we only have OM's description and side view picture from his book. I guess that by using some ingenuity one should be able to be built using components as OM has described.

Cheers,
Eddie B.

Thanks for the follow up Eddie.
Seems a very poor solution to disposing of seal leakage. Plug that air box drain line and away the engine goes. Better off dumping to ground but if those drain lines get plugged away goes the bearings.