Modern Engine Blueprinting Techniques. Mike Mavrigian

it uses a remote reservoir. It’s typically mounted in a variety of locations under the hood of a street vehicle or in the cockpit of a race car. In very basic terms, the external pump draws oil from the remote reservoir and forces the oil through the plumbing. In this manner, oil can be directly sent to the main bearings through a block port and delivered directly to the valvetrain with one or two plumbed hoses, then directly delivered to a turbocharger, for example.

      Dry sump pumps are offered in several configurations, depending on how many direct-delivery and return routes are required. This provides direct oil delivery to specific areas, and elimination of oil starvation caused by angle and centrifugal forces placed on the car. Thus, the oil pump never sucks in air, and the potential for oil aeration is eliminated. The scavenge section(s) of the dry sump pump draws oil from the dry sump pan. Vacuum is created and that draws excess oil from the surfaces of the crank and rods, and this mitigates parasitic drag. As a result, the engine operates more efficiently.

      When plumbing a dry sump system, size requirements may vary, but a general rule is to use –10, –12 and –16 hose, fitting, and hose end sizes. For some turbo applications, a –6 hose size may be recommended to feed the turbo. Generally, a larger size is required for the return hose that runs from the pump to the remote oil reservoir. For instance, if –12 hoses are used for all feeds, a –16 hose is used for oil return to the reservoir.

       Dry sump oil systems use an externally mounted oil pump, a special pan design, and a remote oil reservoir from which the pump draws oil. External plumbing allows direct oil delivery to specific areas of the engine. Oil returning to the shallow pan is then pulled, or scavenged, back to the pump, which returns the oil to the remote reservoir. Dry sump systems allow you to deliver oil directly to specific areas of the engine instead of relying on one central pumping source to send oil throughout the engine. Since a dry sump system stores the oil in a remote reservoir, the pan is used simply as a seal to the bottom end, resulting in a shallower pan for improved ground clearance.

       Typical belt-drive dry sump setup (three-stage shown here). Oil is drawn from the remote reservoir to the pump, which feeds oil to the engine. Scavenge plumbing pulls drained oil from the pan and sends it back to the remote reservoir. (Illustration Courtesy Aviaid Competition Oil Systems)

       Another example of a three-stage system, but here the pump is driven by the camshaft instead of using a belt drive. (Illustration Courtesy Aviaid Competition Oil Systems)

      Threaded bungs are installed on a dry sump oil pan for suction line fittings in which the pump draws drainback oil. Tapping and fitting special adapters may be required for plumbing to the block or other areas. The aftermarket typically offers a variety of adapters for all popular blocks to supply oil to the block’s main galley at the stock oil filter location. By the way, if you’re using the OEM filter location for oil feed, you remotely locate an oil filter.

      A pulley on the crankshaft snout directly drives a notched belt that connects to an externally mounted dry sump oil pump with most setups. Dry sump pumps, via the proper pulley diameters, are generally driven at about half the crankshaft speed. Dry sump pumps are also available that are driven by the nose of the camshaft, with the pump mounted on the face of a special timing cover. A dry sump system has many advantages: It has consistent oil pressure; the oil pickup does not become uncovered and starve the engine for oil in severe turns, acceleration or braking; oil pressure is adjustable; capacity is increased; the short-depth pan allows lower mounting of the engine in the chassis; and positive oil delivery to vital engine components. The engine also enjoys a cooler oil supply because the oil is quickly returned to the remote reservoir instead of being stored in the hot oil pan.

       Dry Sump Stage and Section Designs

Type	Pressure Sections	Scavenge Sections
2-stage	1	1
3-stage	1	2
4-stage	1	3
5-stage	2	3
6-stage	2	4

       Dry Sump Oil System Components

      • Dry sump pump

      • Dry sump pump pulley

      • Toothed pump drive belt

      • Pump fittings (male –AN 37-degree flare to accept female –AN hose ends)

      • Pump mounting bracket

      • In-line screened oil filter(s)

      • Remote in-line oil filter and filter mount

      • Remote-mounted oil tank

      • Breather (separate or on-tank)

      • Oil filter block-off plate for engine block

      • –AN hose assemblies as required

      Sections and Stages

      A dry sump pump has two sections. The pressure section delivers oil to the engine. The scavenge section pulls “leftover” oil from the dry sump pan and sends it back to the remote oil reservoir.

      Dry sump pumps are built in stages, with one pressure section and one or more scavenge sections. The additional scavenge sections (as few as one, as many as six) allow oil to be scavenged more quickly and efficiently from specific areas of the engine, instead of waiting for the oil to be drawn into the pan for scavenge pickup.

       Whenever dealing with aluminum (–AN) fittings and hose ends, always use a dedicated aluminum wrench to avoid damaging the hose ends and fittings.

       Dry sump pumps have a series of individual pumps stacked together. These individual pumps are referred to as stages. Pumps are available in two-, three-, four-stage, etc., depending on how many individual oil feed and scavenge lines are required for a particular engine.