Old Cosworth 2 Stage pump question

[Offcamber1]

After multiple shop moves and family interruptions over the past few years, I finally got the Datsun 1300 motor assembled, mated to the transaxle, and back into the Lola 340 DS/R chassis. I did not disassemble this project and in fact bought the car with the motor and trans out and the motor partially apart. I also do not necessarily believe that the prior owner, nor the one before that, were entirely competent in their assembly.

I am down to plumbing the dry sump system which has on old Cosworth 2 stage external pump. Unfortunately nothing was documented, nor are the inlets/outlets marked on the pump. Looking at some pictures of the the last owner took before and during disassembly I am questioning if they did not have the scavenge and pressure circuits mixed up. The first stage toward the front of the motor is labeled ZM0108, which I believe is the larger, scavenge side. The stage to back is labeled ZM0105, which I believe is the pressure side of the system.

The pictures that were taken of the car prior to disassembly by the last owner show those two systems plumbed with the scavenge plumbed to the back side of the pump labeled ZM0105. Does anyone out there have any experience with a pump like this that can verify which side has the larger impeller, hence scavenge circuit? I have at least now figured out which is suction and which is pressure on each impeller.

The good news is that once I get all this figured out I should be able to take the tooth belt off the pump and chuck the correct allen head socket into my drill, and spin the sucker until I see oil pressure. So no dry or low oil pressure when I initially fire it up for break in.

Thanks in advance for any offered advice, beyond the obvious: "Don't ever buy a race car in boxes."

Kip

[john f]

I would say that if both sets of gears are the same diameter, the wider set will be the scavenge side and the narrower the pressure.
With that said, I am Assuming that neither stage has a pressure relief on it. As far as in vs out it depends on the direction of rotation. Just remember that the oil goes around the outside of the gear in the same direction as gear rotation. Just my $0.02.

john f

[Offcamber1]

John,

Thanks for your help. I've got it figured out now.

Kip