Oil Pump

Replace the oil pump on a 1970 AMC Rebel Machine 390ci V8 by removing the oil pan and extracting the pump assembly from the engine block.

Warnings

Tools required

Parts

• Oil pump assembly × 1 — Use OEM specification
• Oil pump gasket or seal × 1 — Use OEM specification
• Oil pan gasket × 1 — Use OEM specification
• Oil filter × 1 — Use OEM specification
• Engine oil × 5 — 10W-30 or per owner preference
• Oil pan drain plug gasket × 1 — Use OEM specification

Fluids

• Engine oil — 5 qt

Preparation

1. Park vehicle on level surface and allow engine to cool completely
2. Disconnect negative battery cable
3. Raise front of vehicle and support securely on jack stands
4. Place oil drain pan under engine
5. Remove engine oil drain plug and drain all oil from crankcase
6. Remove oil filter
7. Mark distributor rotor position with tape or marker for reference

Procedure

1. 1

   Remove distributor
   Remove distributor hold-down clamp bolt and carefully lift distributor straight out of engine block. Note the position of the rotor and the alignment of the distributor body for reinstallation. The oil pump drive shaft will come out with the distributor on this engine.
2. 2

   Remove engine mount bolts and raise engine
   Support engine weight with an engine hoist or support bar across the engine compartment. Remove both front engine mount through-bolts. Carefully raise engine approximately 2-3 inches to provide clearance for oil pan removal. Ensure no hoses, wires, or accessories are strained during lifting.
3. 3

   Remove oil pan bolts and pan
   Remove all oil pan bolts working from the outside edges toward the center. There are typically 20-24 bolts around the perimeter. Carefully break the pan seal loose using a rubber mallet or pry bar at the corners. Lower the oil pan and remove it from under the vehicle. Clean any remaining oil from the pan interior.
4. 4

   Remove oil pump mounting bolts
   Locate the oil pump mounted to the main bearing cap area at the rear of the engine block. Remove the two oil pump mounting bolts that secure the pump body to the engine block. On the AMC 390, these are typically 3/8" head bolts.
5. 5

   Extract oil pump assembly
   Carefully pull the oil pump assembly downward and forward to disengage it from the engine block. The pump pickup tube extends into the oil pan area. Maneuver the pump and pickup tube assembly out through the bottom of the engine. Note the position of any alignment dowels or gaskets.
6. 6

   Inspect and clean mounting surfaces
   Thoroughly clean the oil pump mounting surface on the engine block using a scraper and solvent. Remove all old gasket material and oil residue. Inspect the oil pump drive shaft hole in the block for any debris or damage. Check the condition of the oil pump drive gear and shaft.
7. 7

   Prepare new oil pump
   Remove new oil pump from packaging and verify it matches the original. Pack the oil pump cavity with petroleum jelly or clean engine oil to prime it before installation. Install new gasket or seal onto the pump mounting flange. Ensure the pickup tube screen is clean and free of debris.
8. 8

   Install new oil pump
   Guide the oil pump assembly up into position, carefully aligning the pump drive gear with the drive shaft opening in the block. The pump must engage properly with the drive mechanism. Install and hand-tighten the two mounting bolts, then torque to manufacturer specification (typically 18-22 ft-lbs for AMC V8s, verify with service manual).
9. 9

   Install oil pan gasket and pan
   Apply a thin bead of RTV silicone to the front and rear main bearing cap corners where they meet the block. Position new oil pan gasket onto the engine block, using gasket adhesive if necessary to hold in place. Carefully lift oil pan into position and start all bolts by hand. Torque oil pan bolts in a spiral pattern from center outward to 10-12 ft-lbs to avoid warping.
10. 10

    Lower engine and reinstall mounts
    Carefully lower the engine back onto the motor mounts using the hoist or support bar. Install and torque the engine mount through-bolts to specification. Remove the engine support equipment.
11. 11

    Reinstall distributor
    Rotate the engine by hand until the number one cylinder is at top dead center on the compression stroke. Insert the oil pump drive shaft into the block, aligning with the pump drive gear. Install the distributor with the rotor pointing to the previously marked position. Install and tighten the distributor hold-down clamp.
12. 12

    Refill with engine oil and verify
    Install new oil drain plug gasket and torque drain plug to specification. Install new oil filter. Lower vehicle from jack stands. Fill engine with appropriate quantity and grade of engine oil (typically 5 quarts for AMC 390). If available, use an oil pump priming tool through the distributor opening to pre-lubricate the engine before starting.

Reassembly

1. Reconnect negative battery cable after all work is complete
2. Double-check that all bolts are properly torqued and no tools are left in engine compartment
3. Verify oil level is correct on dipstick before starting engine
4. If distributor was removed, initial timing adjustment may be required after first start

Verification

• Start engine and immediately check for proper oil pressure on gauge (should register within 5-10 seconds)
• Check for oil leaks around oil pan gasket and pump mounting area while engine idles
• Allow engine to reach operating temperature and recheck oil level, adding if necessary
• Listen for any unusual noises from the lower engine that could indicate pump installation issues
• Verify ignition timing is correct if distributor was disturbed during procedure
• Test drive vehicle and monitor oil pressure under various operating conditions

More procedures for this vehicle