Camshaft R&R

Complete removal and replacement of the camshaft in a 1966 Chevrolet Corvette 327 V8, requiring engine disassembly of front accessories, timing cover, timing chain, valve train components, and camshaft extraction.

Warnings

Tools required

Parts

• Camshaft (specify desired grind/specification) × 1 — Use OEM specification or performance replacement
• Timing chain set (chain, gears, and hardware) × 1 — Use OEM specification
• Camshaft bearings (if replacing) × 1 — Use OEM specification
• Lifter set (hydraulic or mechanical as per camshaft) × 1 — Use OEM specification or match camshaft
• Timing cover gasket × 1 — Use OEM specification
• Timing cover seal × 1 — Use OEM specification
• Oil pan gasket × 1 — Use OEM specification
• Intake manifold gasket set × 1 — Use OEM specification
• Valve cover gaskets × 2 — Use OEM specification
• Pushrod set (if replacing) × 1 — Use OEM specification or match camshaft
• Engine assembly lube (camshaft installation) × 1 — Use high-pressure assembly lube
• RTV silicone sealant (for timing cover) × 1 — Use OEM specification
• Harmonic balancer bolt × 1 — Use OEM specification

Fluids

• 5W-30 Conventional Engine Oil — 5 qt
• DEX-COOL Extended Life Coolant (Orange) — 10 qt

Preparation

1. Park vehicle on level surface and engage parking brake.
2. Disconnect negative battery cable and secure away from battery terminal.
3. Allow engine to cool completely if recently operated.
4. Drain engine coolant into appropriate container by opening radiator petcock and removing radiator cap.
5. Drain engine oil into appropriate container by removing drain plug from oil pan.
6. Remove air cleaner assembly and set aside.
7. Label and disconnect all vacuum lines from carburetor and intake manifold.
8. Label and photograph all wiring connections on distributor, temperature sender, and other components that will be removed.
9. Have clean workspace prepared for storing removed components in organized manner.

Procedure

1. 1

   Remove upper engine accessories
   Remove both valve covers by removing the 4 bolts per cover. Remove the distributor by marking rotor position relative to distributor body and distributor body position relative to intake manifold, then removing the distributor hold-down clamp bolt and pulling distributor straight up and out. Remove the intake manifold by disconnecting fuel line, throttle linkage, and all vacuum lines, then removing the 12 intake manifold bolts and lifting manifold off engine. Remove carburetor from manifold if desired for separate storage.
2. 2

   Remove valve train components
   Remove the rocker arm assemblies by removing the rocker arm stud nuts from each rocker arm. Keep rocker arms organized in order for reinstallation. Remove all 16 pushrods and store them in order, marking intake versus exhaust position. Using valve spring compressor, compress each valve spring and remove the valve spring retainers and keepers. Remove valve springs and set aside. Carefully remove all 16 hydraulic lifters from their bores using a lifter removal tool or magnet. Store lifters in order if reusing (though new lifters are required with new camshaft). Clean lifter bores thoroughly.
3. 3

   Remove front accessories and water pump
   Remove fan shroud if equipped by removing mounting bolts. Remove fan blade assembly by removing 4 fan-to-water pump pulley bolts. Remove drive belts by loosening adjustments on alternator and power steering pump. Remove water pump pulley by removing 4 pulley bolts. Remove power steering pump and alternator with brackets, supporting them out of the way without disconnecting hydraulic or electrical lines. Remove water pump by removing 4 mounting bolts and pulling pump away from timing cover. Remove thermostat housing if it interferes with timing cover access.
4. 4

   Remove harmonic balancer
   Remove the single center bolt from the harmonic balancer. This bolt is torqued to approximately 60 ft-lb and may require significant force to break loose. Install harmonic balancer puller onto the balancer, ensuring puller jaws grip the outer portion of balancer and center screw contacts the crankshaft snout (not the bolt threads). Tighten puller to extract harmonic balancer from crankshaft. Do not use a jaw-type puller that grips the outer rubber ring as this will damage the balancer. Once removed, inspect balancer for wobble or separation between inner hub and outer ring.
5. 5

   Remove timing cover
   Remove the timing tab/pointer attached to timing cover. Remove all timing cover bolts; there are 10 bolts securing the timing cover to the block and front of the oil pan. Note that the two lower bolts pass through the oil pan flange. Carefully pry timing cover away from block using a flat blade screwdriver or gasket scraper, working around the perimeter. The cover seal will be tight against the crankshaft. Once loose, pull timing cover straight off crankshaft and remove. Remove and discard old timing cover gasket and front seal.
6. 6

   Remove timing chain and gears
   Rotate crankshaft until timing marks on camshaft gear and crankshaft gear are aligned and facing each other (this is TDC on cylinder 1 compression stroke). Verify mark alignment before proceeding. Remove the 3 camshaft gear retaining bolts from the front of the camshaft gear. The camshaft gear and timing chain should now slide forward off the camshaft and crankshaft. If gear is tight on camshaft, gently pry behind gear using two pry bars positioned 180 degrees apart. Remove timing chain and both gears as an assembly. Inspect chain for wear, stretching, or damaged links. Inspect gear teeth for wear or damage.
7. 7

   Remove camshaft thrust plate
   With timing gear removed, the camshaft thrust plate is now visible behind where the cam gear was located. Remove the 2 bolts securing the thrust plate to the engine block. Remove thrust plate and set aside. Inspect thrust plate for wear or scoring. Measure thrust plate thickness if camshaft endplay is a concern.
8. 8

   Extract camshaft from engine
   Thread a long 3/8"-16 bolt into the front of the camshaft snout, or use a dedicated camshaft removal handle. This will provide a handle to pull the camshaft. Carefully and slowly pull the camshaft straight forward out of the block, rotating it slightly as you pull to help clear the cam lobes past the lifter bores. Support the camshaft as it emerges to prevent the lobes from contacting or damaging the camshaft bearings. The camshaft is approximately 20 inches long and must clear the radiator opening. Work carefully and patiently. Once the rear journal clears the block, remove camshaft completely. On some installations with limited clearance, the radiator may need to be unbolted and leaned forward to provide adequate clearance.
9. 9

   Inspect camshaft bearings and block
   With camshaft removed, inspect all camshaft bearing surfaces inside the block using a flashlight. Look for scoring, wear, or discoloration indicating inadequate lubrication. If bearings show wear, they must be replaced using a camshaft bearing installation tool (this requires specialized equipment and is often performed by a machine shop). Clean all camshaft bearing surfaces thoroughly. Inspect cam bore alignment by inserting a straightedge or rod through all bearing bores. Check for debris or obstructions in oil passages feeding camshaft bearings. Clean block deck surface where timing cover mounts.
10. 10

    Prepare and install new camshaft
    Thoroughly clean new camshaft with solvent to remove protective coating. Liberally coat all camshaft lobes and journals with camshaft assembly lube or high-pressure engine assembly lube. Ensure complete coverage of all bearing surfaces and lobe faces. Coat all cam bearings inside the block with assembly lube. Install new camshaft bearings if old bearings were removed (requires cam bearing installation tool). Carefully insert new camshaft into engine block using the same slow, rotating technique used for removal. Thread installation handle bolt into cam snout to guide installation. Support camshaft weight to avoid dragging lobes across bearings. Work camshaft slowly and patiently through all bearing journals until fully seated. Do not force or rush this step.
11. 11

    Install camshaft thrust plate and verify endplay
    Install camshaft thrust plate with the 2 bolts. Position thrust plate with oil clearance grooves facing toward the camshaft gear. Tighten bolts to snug specification. Using a dial indicator or feeler gauge, measure camshaft endplay by pushing camshaft fully rearward, zeroing indicator, then pulling camshaft fully forward. Endplay should be between 0.004" and 0.012". If endplay is excessive, verify correct thrust plate and inspect for wear. If endplay is insufficient, verify thrust plate is not bottoming against block.
12. 12

    Install timing chain and gears
    Install crankshaft gear onto crankshaft with timing mark facing outward. Gear should press onto crank snout with light tapping using soft mallet if necessary. Install camshaft gear onto camshaft temporarily without chain to verify gear alignment and fit. Remove camshaft gear. Drape new timing chain over camshaft gear with timing mark positioned correctly. Install chain and camshaft gear assembly onto camshaft, aligning cam gear keyway with camshaft key. Rotate assembly as needed to engage chain with crankshaft gear while maintaining timing mark alignment. When properly installed, timing marks on both gears should be closest together and facing each other on a centerline between the two shaft centers. Install the 3 camshaft gear bolts with washers and tighten in a crisscross pattern.
13. 13

    Install timing cover and harmonic balancer
    Install new front seal into timing cover by carefully tapping seal into bore until flush with cover face, lip facing inward toward engine. Apply thin bead of RTV sealant to block surface and oil pan flange where timing cover mounts. Install new timing cover gasket onto block, aligning all bolt holes. Install timing cover onto block, carefully sliding cover over crankshaft snout without damaging seal lip. Install all 10 timing cover bolts and tighten in a crisscross pattern. Install timing tab/pointer onto cover. Lubricate inside of harmonic balancer seal surface with light oil. Install harmonic balancer onto crankshaft by aligning keyway and pressing balancer onto snout. Balancer should slide on with hand pressure; if excessive force is required, verify key alignment. Install harmonic balancer center bolt and tighten.
14. 14

    Install lifters and valve train
    If reusing lifters (not recommended with new camshaft), install each lifter into its original bore. If installing new lifters (required practice), prime each new lifter with engine oil by submerging in oil and working plunger until air bubbles cease. Coat each lifter body with assembly lube and install into lifter bores. Install valve springs, retainers, and keepers onto each valve using valve spring compressor. Ensure keepers are fully seated in retainer grooves. Coat all pushrod ends with assembly lube and install pushrods into their original positions (or new pushrods if equipped), ensuring lower end is seated in lifter cup. Install rocker arms onto studs with pushrods seated in rocker arm cups. Install rocker arm nuts and tighten to zero lash (rocker arm just contacts valve stem with pushrod seated on lifter), then tighten an additional 1/2 to 3/4 turn to achieve proper preload on hydraulic lifters. Final adjustment should be performed with engine at operating temperature.
15. 15

    Reinstall upper engine components
    Install new intake manifold gaskets onto cylinder heads, ensuring port alignment and coolant passage alignment. Apply thin bead of RTV sealant to front and rear china wall areas of block where intake manifold seals against block. Install intake manifold onto engine, carefully lowering into position to avoid disturbing gaskets. Install all 12 intake manifold bolts and tighten in proper sequence from center outward in a crisscross pattern. Reconnect all vacuum lines, fuel line, and throttle linkage to carburetor and intake manifold per photos and labels from disassembly. Install distributor by aligning rotor with marked position and inserting distributor into block with gear teeth engaging cam gear. Distributor housing should drop into place when gear teeth mesh; rotate rotor slightly if needed. Install distributor hold-down clamp and bolt, tightening just enough to hold distributor but allow rotation for timing adjustment. Install valve covers with new gaskets and tighten bolts evenly. Reconnect all wiring to distributor, temperature sender, and other components per labels.
16. 16

    Reinstall front accessories and finalize
    Install water pump with new gasket and tighten 4 mounting bolts evenly to approximately 30 ft-lb. Install thermostat housing if removed. Reinstall power steering pump, alternator with brackets, and mounting hardware. Install water pump pulley with 4 bolts. Install and tension all drive belts to proper specification using belt tension gauge or deflection method. Install fan blade assembly to water pump pulley with 4 bolts. Install fan shroud if equipped. Reinstall air cleaner assembly. Install oil pan drain plug with new washer and tighten. Refill cooling system with conventional ethylene glycol (green) coolant mixed 50/50 with water, approximately 16-18 quarts total capacity for the 327 V8. Refill engine with 5 quarts of high-zinc (ZDDP) break-in oil, such as a 10W-30 or 20W-50 formulated for flat-tappet camshafts. Reconnect negative battery cable.

Reassembly

1. Double-check all fasteners are tightened to proper specifications, paying particular attention to intake manifold bolts and rocker arm adjustment.
2. Verify all vacuum lines, fuel lines, and electrical connections are properly reconnected per labels and photographs taken during disassembly.
3. Ensure all drive belts are properly tensioned before starting engine.
4. Before initial startup, remove spark plugs and crank engine with starter motor to prime oil system and verify oil pressure builds on gauge.
5. New camshafts require special break-in procedure: start engine and immediately bring to 2000-2500 RPM for 20-30 minutes to properly break in cam lobes and lifter faces. Do not allow engine to idle during break-in period. Monitor oil pressure and engine temperature closely.
6. After break-in, allow engine to cool and retorque intake manifold bolts and valve cover bolts. Recheck rocker arm adjustment at operating temperature.
7. Change engine oil and filter after first 500 miles when installing new camshaft to remove break-in debris.

Verification

• Start engine and verify oil pressure immediately rises to normal operating range (40-60 PSI at 2000 RPM when warm).
• Listen for any unusual valve train noise such as ticking, tapping, or rattling that would indicate improper lifter preload, collapsed lifter, or inadequate lubrication.
• Verify engine idles smoothly after initial break-in period and throttle response is normal.
• Check for coolant, oil, or fuel leaks around all disturbed gaskets and seals, particularly timing cover, intake manifold, valve covers, and water pump.
• Verify ignition timing is set correctly using timing light; initial timing should be per camshaft manufacturer specification or factory specification if using stock camshaft.
• After test drive, recheck all fluid levels and inspect for any leaks or abnormal sounds.
• Monitor engine closely for first 500 miles for any abnormal operation, excessive oil consumption, or unusual noises.

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