80 Carter Drive
Guilford, CT 06437-2116
Phone: (203) 453-6571
Tech Line: (203) 458-0542
Fax: (203) 453-6906

Copyright © 2002 Moroso Performance Products, Inc.
All Rights Reserved.

  Tech Info

Moroso: About Gerotor Pumps
How Gerotor Pumps Work
Although gerotors come in a variety of sizes and configurations, they share the same basic principal of operation: The inner drive element (rotor) has one less tooth than the scroll section. Both rotate within the pump’s housing. Because the inner rotor has one less tooth, it revolves at a slightly faster rate than the scroll section.

As the inner rotor revolves, vacuum causes oil to be drawn into a chamber, which continues to enlarge as the pump shaft turns.Gerotor Pump 1Gerotor Pump 2

Gerotor Pump 3 The chamber reaches maximum volume when the tips and lobes seal the chamber from both the inlet side (low pressure) and outlet side (high pressure).

Further rotation causes the chamber to become connected to the discharge port, eventually forcing all of the oil out as the chamber’s volume becomes smaller.Gerotor Pump 4Gerotor Pump 5

Why Moroso's Gerotor Pump?

  • Pumps 10% more oil per stage than gear designs
  • Inlet ports are active for more than 180° of shaft rotation, providing superior fill capacity and suction
  • Needle bearings instead of standard bronze bushings used in other pumps
  • Reduced running surfaces and friction requires less horsepower
  • O-rings between each section prevent leaks
  • Hard-coat anodizing extends pump life and improves seal between rotor scroll and housing
  • External pressure control valve is adjustable ±30 psi from factory preset level of 60 psi

Gerotor PumpGerotor Pump Graph