This procedure covers the removal and replacement of the fan belt (V-belt) on a 1966 Chevrolet Corvette with the 327ci V8 engine, including inspection of pulleys and proper belt tension adjustment.

Warnings

Tools required

Parts

• Fan belt (V-belt) × 1 — Gates 9420 or equivalent 42" V-belt

Preparation

1. Park vehicle on level surface and engage parking brake
2. Allow engine to cool completely (minimum 30 minutes after last operation)
3. Open hood and secure with prop rod
4. Visually inspect fan belt routing and condition to aid in correct reinstallation
5. Take photo of belt routing path for reference if desired

Procedure

1. 1

   Document and inspect belt routing
   The 1966 Corvette 327 V8 base configuration uses a V-belt that routes around the crankshaft pulley, water pump pulley, and alternator pulley. Note that cars equipped with power steering or air conditioning will have additional belts/pulleys; document the exact routing for your specific configuration. Note the exact routing path. Inspect the belt for cracks, glazing, fraying, or oil contamination. Check all pulley faces for damage, scoring, or misalignment. Verified detail (OEM/aftermarket part numbers require direct manufacturer-doc verification. The Gates 9420 number and the 42" length are not confirmed for this specific application and belt length varies significantly with accessory configuration.): Correct V-belt for your specific accessory configuration — verify exact length against the old belt or a parts lookup (e.g., Gates/Dayco catalog) before purchase
2. 2

   Release belt tension at alternator
   The alternator acts as the tensioner on this system. Locate the alternator adjustment bolt (long bolt running horizontally through the alternator mounting bracket) and the alternator pivot bolt at the lower mounting point. Loosen the adjustment bolt completely by turning counterclockwise, but do not remove it. This bolt typically requires a 9/16" socket.
3. 3

   Pivot alternator to release belt
   Using a pry bar or by hand, push the alternator toward the engine block to create maximum slack in the belt. The alternator will pivot on its lower mounting bolt. Push until sufficient slack is achieved to slip the belt off the pulleys.
4. 4

   Remove old fan belt
   With tension fully released, slip the belt off the crankshaft pulley first, then the water pump pulley, and finally off the alternator pulley. Remove the belt from the engine compartment. Inspect the belt one final time to identify failure mode (cracking, stretching, glazing) to prevent repeat failure.
5. 5

   Inspect pulleys and clean surfaces
   With the belt removed, rotate each pulley by hand to check for bearing roughness or noise. The water pump pulley should spin smoothly without lateral play. The alternator pulley should turn freely. Clean any oil, dirt, or belt residue from all pulley grooves using a wire brush or shop towel. Check pulley alignment with a straight edge across the pulley faces.
6. 6

   Route new belt onto pulleys
   Begin installation by routing the new belt around the crankshaft pulley first, ensuring it seats fully in the pulley groove. Route over the water pump pulley next, again ensuring full seating. Finally, loop the belt over the alternator pulley. The alternator should still be pushed toward the engine block for slack. Verify the belt is seated in all pulley grooves and not riding on pulley edges.
7. 7

   Apply initial belt tension
   Using a pry bar positioned between the alternator body and the engine block, carefully pry the alternator away from the engine to apply tension to the belt. Pry at the alternator mounting ears or a reinforced section, never at the alternator housing itself. Apply moderate tension, then hand-tighten the adjustment bolt to hold position temporarily.
8. 8

   Set proper belt tension
   Proper tension for a new V-belt on this application is 1/2 inch deflection at the longest belt span (typically between crankshaft and water pump pulleys) when pressed with thumb pressure (approximately 10 pounds force). Use a straight edge and ruler to measure deflection, or use a belt tension gauge set to the value specified in the factory service manual for this application (typically in the 70-100 lb range for a new belt). Adjust alternator position as needed using the pry bar and adjustment bolt until correct tension is achieved.
9. 9

   Tighten alternator adjustment bolt
   While maintaining belt tension with the pry bar, tighten the alternator adjustment bolt securely. Tighten the adjustment bolt firmly to hold the alternator securely (this is not a critical precision torque; consult the factory service manual if a specific value is desired). Ensure the alternator does not shift position during final tightening.
10. 10

    Verify belt tension after tightening
    After securing the adjustment bolt, recheck belt tension using the deflection method or tension gauge. The belt should have 1/2 inch deflection at the longest span. If tension has changed, loosen the adjustment bolt and repeat the tensioning process.
11. 11

    Perform initial run-in and recheck tension
    Start the engine and allow it to run for 2-3 minutes at idle. Listen for belt squeal or unusual noises. Shut off the engine and allow it to cool for 5 minutes. Recheck belt tension, as new belts typically seat into the pulley grooves and may lose initial tension. Readjust if deflection exceeds 1/2 inch. This initial stretch is normal.

Reassembly

1. No disassembly of other components required for this procedure
2. Ensure all tools and parts are removed from engine compartment before closing hood

Verification

• Start engine and verify no belt squeal or slippage occurs
• Observe belt operation at idle and verify proper tracking in all pulley grooves
• Check alternator charging system by verifying voltmeter reads 13.5-14.5 volts at idle with lights on
• After first 100 miles of operation, recheck belt tension and adjust if necessary as belt seats fully

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