Secondary Air Injection Pump

Removal and replacement of the secondary air injection pump (smog pump) on a 1966 Corvette 327ci V8, including drive belt and mounting hardware.

Warnings

Tools required

Parts

• Secondary air injection pump × 1 — Use OEM specification or AC Delco replacement
• Air pump drive belt × 1 — Use OEM specification for 1966 327 V8 with A.I.R. system
• Air pump mounting bracket bolts (if damaged) × 1 — Use OEM specification
• Air hose clamps (if deteriorated) × 2 — Worm gear style, size appropriate for 1" hose

Preparation

1. Verify vehicle is equipped with the A.I.R. system by locating the air pump on the passenger side of the engine
2. Ensure engine is completely cool to the touch
3. Disconnect negative battery cable to prevent accidental starter engagement
4. Position vehicle on level surface and engage parking brake
5. Gather all tools and replacement parts within easy reach

Procedure

1. 1

   Remove air pump drive belt
   Locate the air pump belt tensioning bolt on the pump mounting bracket. Loosen the belt tension by backing off the adjustment bolt on the slotted mounting bracket. Once tension is released, slip the belt off the air pump pulley, then remove from crankshaft pulley and any intermediate pulleys. Inspect belt for cracks, glazing, or damage.
2. 2

   Disconnect air outlet hose
   Locate the air outlet hose connecting the pump discharge port to the air distribution manifold. Loosen the hose clamp at the pump outlet using a screwdriver or appropriate tool. Carefully twist and pull the hose from the pump outlet fitting. Inspect hose condition and clamp for reuse.
3. 3

   Disconnect air inlet hose and filter
   Remove the air inlet hose and centrifugal filter assembly from the rear of the pump. This typically involves loosening a clamp at the pump inlet and separating the assembly. Note the orientation of the filter assembly for proper reinstallation.
4. 4

   Remove pump mounting bolts
   Remove the mounting bolts securing the air pump to the front mounting bracket (verify exact count and head size against the factory service manual for the 1966 327 A.I.R. system). Support the pump with one hand while removing the final bolt. Support the pump with one hand while removing the final bolt to prevent it from falling. Carefully maneuver the pump away from the mounting bracket and out of the engine compartment.
5. 5

   Inspect mounting bracket and hardware
   With the pump removed, inspect the mounting bracket for cracks, looseness, or damage. Check all bolt holes for stripped threads or elongation. Clean mounting surfaces with a wire brush to remove rust, dirt, and old gasket material if present. Verify the bracket is securely fastened to the engine block.
6. 6

   Prepare new air pump
   Remove the new air pump from packaging and verify it matches the original in pulley diameter, mounting hole pattern, and port locations. Check that the pump rotates smoothly by hand with no binding or rough spots. Verify all ports are clear of shipping debris.
7. 7

   Install new air pump
   Position the new pump onto the mounting bracket, aligning the 3 bolt holes. Start all 3 mounting bolts by hand to ensure proper thread engagement. Tighten the mounting bolts evenly. Torque mounting bolts to the factory specification for the 1966 327 A.I.R. pump (verify value against the factory service manual). Leave the adjustment slot loose enough to allow belt installation.
8. 8

   Reconnect air inlet filter assembly
   Reinstall the centrifugal filter/fan assembly at the pump per the original orientation noted during disassembly, then secure the inlet connection with its clamp. Secure with the inlet hose clamp, tightening firmly but not excessively to avoid damaging the pump housing or stripping the clamp.
9. 9

   Install and tension drive belt
   Route the new drive belt around the crankshaft pulley and any intermediate pulleys, then over the air pump pulley. Using a pry bar on the pump body or a belt tensioning tool, apply tension to the pump by pushing it away from the engine. Belt should have approximately 1/2 inch deflection under firm thumb pressure at the longest span. Tighten the adjustment bolt while maintaining tension.
10. 10

    Reconnect air outlet hose
    Slide the air outlet hose onto the pump discharge fitting, ensuring it seats fully onto the barbed fitting. Position the hose clamp over the hose and tighten securely. Verify the hose routes properly to the air distribution manifold without kinks or sharp bends.
11. 11

    Final inspection and belt tension check
    Double-check all mounting bolts for proper torque. Verify all hose connections are secure and clamps are tight. Manually rotate the air pump pulley to ensure smooth rotation without binding. Check belt alignment across all pulleys. Reconnect negative battery cable.

Reassembly

1. Torque all mounting bolts to specification using proper sequence
2. Ensure belt tension is correct - too tight will damage pump bearings, too loose will cause slippage and reduced pump output
3. Verify all air hoses are properly routed and secured to prevent chafing against hot or moving components

Verification

• Start engine and listen for unusual noises from the air pump area - a properly functioning pump should operate quietly
• With engine running at idle, verify air pump pulley is rotating smoothly without wobble
• Check for air leaks at hose connections by feeling for escaping air
• After 5 minutes of operation, recheck belt tension as new belts may seat and require adjustment
• Rev engine briefly and verify belt does not slip or squeal under load

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