When it comes to dry sump oiling systems, precision is the name of the game. An aftermarket dry sump pump operates in a totally different environment than a factory, or factory-replacement pump. As such, the manufacturing tolerances are much tighter.
Watching this video from Peterson Fluid Systems makes the process of assembling one of these precision pieces of machinery look easy, but that is only because of the experienced hands performing the assembly process, and the precision machined components which fit together perfectly.
72 pieces make up the puzzle for a single stage R4 pump, while that number more than doubles for a five-stage pump. Similarly, the hour-long assembly and testing process for the single-stage pump doubles for the five-stage R4 variant. A process which has been condensed in the above video.
While they may look almost identical from the exterior, the pressure and scavenge sections of the multi-stage pumps are, in fact, different. “The pressure section body internal contouring is a little different from the scavenge sides,” confirms Peterson’s Pat Haberkorn. “But outside of that it’s essentially the same part with the same tolerances as all the other bodies, in terms of rotor-to-wall tolerance and rotor-to-rotor tolerance.”
Available in two rotor sizes, both are 60-degree-helix, 4-lobe rotor designs much like you’ll find in a roots supercharger setup. On the pressure side, a 1.2-inch rotor will flow 16 gpm through a -12 hose and 28.5 gpm through a -20 hose. The larger 1.4-inch rotor will flow 19 gpm through a -12 hose and a stout 31 gpm through a -20 hose.
For the slightly different scavenge side pumps, the standard is being able to draw 22 inches of mercury on the test stand, after the oil supply is shut off. “On the scavenge side during testing the amount of vacuum drawn in the body is measured in each section, confirming performance of the scavenge side of the oil pump,” says Haberkorn.
“Every single pump is tested individually to ensure a high level of performance right out of the box. Customer’s engines deserve the best, highest quality part we can provide and the only way we can ensure that is by thoroughly testing every single pump that goes out of our doors.”