Oil Pumps, Pickups & Parts

How Does an Engine Oil Pump Work?

An engine oil pump pulls oil from the pan through the pickup and screen, then pressurizes it and sends it through the filter and galleries. From there, oil reaches the crank and rod bearings, the cam and the valvetrain. Most wet-sump pumps are driven by the camshaft or crankshaft, so output climbs with engine rpm.

A spring-loaded relief valve inside the pump caps maximum pressure by routing excess oil back to the inlet side. That's why relief spring rate matters as much as pump size when you're setting up a build. The screen keeps debris out of the gears or rotors, and an air leak at the pickup can drop pressure fast.

If you're new to the full circuit, our guide on how engine oil systems work covers pans, pumps, filters and galleries. You can also browse all oil system components to plan the rest of your setup.

Do You Need a High-Volume or High-Pressure Oil Pump?

Most street engines with factory clearances run well on a standard-volume pump, while high-volume and high-pressure pumps suit engines with looser clearances or higher rpm. Here's how the three types compare:

• Standard-volume pumps match factory output for stock or mildly modified engines.
• High-volume pumps use taller gears or a larger housing to move more oil per revolution.
• High-pressure pumps use a stiffer relief spring to raise maximum oil pressure.

Some pumps combine both traits, such as a high-volume, high-pressure big-block Chevy pump sold with a matching pickup. Whether you're shopping for an SBC oil pump or a big-block unit, match output to your bearing clearances, rpm range and pan capacity. Extra volume takes more power to drive, and it can pull a small pan low at high rpm.

Higher flow also sends more oil through the filter, so pair your pump with performance oil filters that suit your engine.

How Do You Choose the Right Oil Pump Pickup Tube?

Choose an oil pump pickup tube that matches your pan depth, sump location, pump model and engine family. The screen needs consistent clearance from the pan floor. A pickup set too high can suck air, and one set too low can starve the pump. Pickups built for a specific pan take out the guesswork, so shop oil pans and components alongside your pickup.

Next, check the mounting style. Bolt-on pickups use a flange and gasket, while press-fit tubes are pressed into the pump body and often need a support bracket. On LS engines, a pickup hold-down girdle helps keep the tube from shifting under load.

Racers should look at application-specific designs for drag race or road race oiling demands. Moroso offers oil pickup tubes for SBC, BBC, Ford FE and Coyote engines. Milodon pickups cover BBC drag race, Ford 289-302 and Chrysler 340-360 applications.

When Do You Need a Dry-Sump Oil Pump?

A dry-sump oil pump makes sense when you need consistent oil control at high rpm, under hard cornering or with a low-mounted engine. A wet-sump system stores oil in the pan and uses one internal pump. A dry-sump system uses an external multi-stage pump. Its scavenge sections pull oil from a shallow pan, and a pressure section feeds the engine from a remote tank.

Pulling oil out of the crankcase also keeps the pickup from uncovering under load. Peterson Fluid Systems R4 dry-sump pumps, for example, are multi-stage units with 1.400-inch scavenge rotors.

Because a dry-sump setup adds a tank, lines and a dedicated pan, plan the system as a package with our dry sump components. If you're still weighing your options, read our comparison of wet sump vs dry sump oil systems before you buy.

Which Oil Pump Repair Kits, Screens and Drive Parts Do You Need?

An oil pump repair kit restores a worn stock pump with new internal parts, which works well when the housing is still in good shape. Melling offers stock-replacement repair kits such as K334, K417-OS, K-93AG and K534 for Honda/Acura engines. Melling also offers gear-and-shaft sets like G-39B for replacing worn pump gears.

Check the oil pump screen whenever the pan is off. A torn or clogged screen lets debris reach the pump or restricts flow, so replace it during any rebuild.

On the drive side, the pump shaft links the distributor or cam drive to the pump. An upgraded shaft helps resist twisting when you run a high-volume or high-pressure pump. A primer tool lets you spin the pump and fill the system before first startup. Find both in our oil pump shafts and primers.