Oil Pump & Priming Components

The oil pump feeds every bearing in the engine, so a loose pump or a broken drive shaft starves them quickly. ARP’s kits here cover pump bolts and studs, drive shafts, primer kits, a pump-to-pickup stud kit and oil pan bolts, each listed by engine in the title.

On many V8 engines with a distributor, a slim intermediate shaft drives the pump from the distributor gear. That shaft carries all the torque needed to turn the pump, which peaks with cold, thick oil and with high-volume pumps or stiff relief springs. If it twists or snaps, oil pressure falls to zero at once.

The pump itself must be held square and tight. If it shifts, the drive can bind, and an air leak at the pickup joint lets the pump draw air instead of oil, which shows as falling or unsteady pressure.

The listings cover these parts:

• Drive shafts: length matters. Blocks with a raised cam need a taller shaft, such as the +.400 in version, so confirm the block before choosing.
• Pump studs and bolts: hex or 12-point. Stud kits are listed separately for standard and high-volume pumps, whose taller bodies usually need longer studs.
• Pickup studs: a stud kit fixes the pickup to the pump.
• Oil pan bolts: hex or 12-point, in stainless steel or black oxide, including kits for pans with side rails.
• Primer kits: standard and deluxe kits drive the pump from an electric drill, in place of the distributor.

Prime a new or rebuilt engine before its first start. Run the pump with the primer until pressure shows on the gauge and oil reaches the top end, turning the crank by hand now and then. Once the distributor is in, check that the drive shaft has a little end play, so it is not squeezed between pump and gear.

Inside the sump, a loose fastener can end up in the pump, so secure pump fasteners with thread-locking compound or lock wire as the kit instructs. Check the pickup’s height above the sump floor before the pan goes on. Tighten oil pan bolts evenly from the middle outwards, as overtightening can dent the pan flange and cause leaks.