Valve Job - Complete

Complete valve job including cylinder head removal, valve grinding, seat machining, guide inspection/replacement, and valve train reassembly for the 1966 Chevrolet Corvette 327ci V8.

Warnings

Tools required

Parts

• Cylinder head gasket set (both heads) × 1 — Use OEM specification
• Intake manifold gasket set × 1 — Use OEM specification
• Exhaust manifold gaskets × 2 — Use OEM specification
• Valve cover gaskets × 2 — Use OEM specification
• Intake valves (if replacement needed) × 8 — Use OEM specification
• Exhaust valves (if replacement needed) × 8 — Use OEM specification
• Valve stem seals (umbrella or positive seal type) × 16 — Use OEM specification
• Valve guides (if replacement needed) × 16 — Use OEM specification
• Valve springs (if out of spec) × 16 — Use OEM specification
• Valve spring retainers × 16 — Use OEM specification
• Valve keepers (locks) × 32 — Use OEM specification
• Pushrod guide plates (if equipped) × 2 — Use OEM specification
• Rocker arm pivot balls × 16 — Use OEM specification
• Rocker arm nuts × 16 — Use OEM specification
• Water pump gasket × 1 — Use OEM specification
• Thermostat housing gasket × 1 — Use OEM specification
• Head bolt sealer (ARP or equivalent) × 1 — Use OEM specification
• RTV silicone sealant (intake manifold end seals) × 1 — Use OEM specification

Fluids

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

Preparation

1. Disconnect negative battery cable
2. Drain engine coolant completely from radiator and engine block drain plugs
3. Remove air cleaner assembly and carburetor
4. Label and disconnect all vacuum lines, electrical connectors, and coolant hoses from cylinder heads
5. Remove distributor and mark position for reinstallation
6. Remove valve covers
7. Remove intake manifold (both halves if applicable)
8. Remove exhaust manifolds from both cylinder heads
9. Position drain pans under vehicle to catch residual fluids
10. Organize workspace with labeled containers for bolts, pushrods, and rocker arms by cylinder position

Procedure

1. 1

   Remove rocker arms and pushrods
   Loosen each rocker arm adjusting nut and remove the rocker arm assembly from each stud. Remove all 16 pushrods, keeping them in order (use a numbered rack or label them 1-16). Inspect pushrod ends for wear, scoring, or mushrooming. Inspect rocker arm pivot balls and roller tips for wear patterns.
2. 2

   Remove cylinder heads
   Remove the 17 cylinder head bolts from each head in reverse of the tightening sequence (start from outer bolts, work toward center). Carefully lift cylinder heads off engine block. If heads are stuck, gently tap with rubber mallet near casting—never pry between head and block surfaces. Place heads on padded workbench or cylinder head stands.
3. 3

   Disassemble valve train components
   Using a valve spring compressor, compress each valve spring and remove the two valve keepers (locks) from the valve stem groove. Slowly release spring tension and remove spring retainer, valve spring, and valve stem seal. Remove valve from combustion chamber side. Keep all components organized by cylinder and valve position (intake vs exhaust). Repeat for all 16 valves on both heads.
4. 4

   Clean cylinder heads thoroughly
   Remove all carbon deposits from combustion chambers, valve seats, and ports using a gasket scraper and wire brush. Clean valve guide bores and spring pockets. Use brake cleaner to remove all oil and debris. Inspect heads for cracks, especially between valve seats and in exhaust ports. Check head deck surface for warpage using a precision straightedge and feeler gauge—maximum allowable warpage is 0.003 inches over the full length.
5. 5

   Measure valve guides for wear
   Insert a new or known-good valve into each guide and measure side-to-side play. Alternatively, use a telescoping gauge to measure guide inside diameter and compare to valve stem outside diameter with a micrometer. Intake valve guide clearance should be 0.001-0.003 inches; exhaust guide clearance should be 0.0015-0.0035 inches. Mark any guides exceeding 0.005 inches clearance for replacement.
6. 6

   Replace worn valve guides (if necessary)
   Heat cylinder head to 400-500°F in an oven or with a torch (heated evenly). Using a valve guide driver, drive out worn guides from the combustion chamber side toward the spring side. Chill new guides in freezer for 30 minutes. Drive new guides into head from spring side until they seat at the proper depth (guides should protrude approximately 0.500 inches above spring pocket). After installation, ream guides to proper diameter (0.3425-0.3435 inches for standard valves) to achieve correct clearance.
7. 7

   Inspect and resurface valve seats
   Examine all valve seats for pitting, burning, or wear grooves. Using a valve seat cutter set, cut seats with 45° stone or cutter to remove damage and establish fresh seating surface. Use 30° top cut and 60° throat cut to establish proper seat width of 0.060-0.080 inches for intake, 0.070-0.090 inches for exhaust. Seat should contact valve face at approximately center of valve face width. Ensure concentricity within 0.002 inches total indicator runout.
8. 8

   Inspect and grind valves
   Inspect each valve for burned faces, excessive stem wear, bent stems, or cracked heads. Measure valve stem diameter—standard diameter is 0.3410-0.3417 inches. Check valve face runout and margin thickness (minimum 0.030 inches). Grind valve faces to 45° angle on valve grinding machine to remove pitting and restore sealing surface. Do not remove excessive material—if margin becomes too thin, replace valve.
9. 9

   Lap valves to seats
   Apply a thin layer of fine valve lapping compound to valve face. Insert valve into guide and rotate back and forth with lapping tool while applying light downward pressure. Lap until a consistent, even gray matte finish appears on both valve face and seat (typically 360° contact pattern). Clean all lapping compound thoroughly with brake cleaner—any residual compound will damage engine. Verify seal by marking valve face with Prussian blue and checking contact pattern.
10. 10

    Test valve sealing
    With valves installed in guides, pour solvent or light oil into intake and exhaust ports. Let sit for 5 minutes and check for leakage past valve seats into combustion chamber. Any significant seepage indicates poor valve-to-seat contact and requires additional lapping or seat correction. Alternatively, perform vacuum test on each valve.
11. 11

    Measure valve spring specifications
    Measure valve spring free height, installed height, and pressure using a spring tester. Free height should be approximately 2.03 inches. Installed height (spring seat to retainer) should be 1.70 inches. Spring pressure at installed height should be 78-82 lbs. Replace any springs that are out of specification or show signs of corrosion, pitting, or uneven wear.
12. 12

    Reassemble valves into cylinder heads
    Lubricate valve stems with assembly lube or clean engine oil. Install each valve into its corresponding guide from combustion chamber side. Slide new valve stem seal over valve stem and seat firmly onto guide (umbrella seals sit on valve stem; positive seals press onto guide). Install valve spring (with closer-wound coils toward head), spring retainer, then compress spring and install two valve keepers into stem groove. Slowly release compressor and verify keepers are fully seated by tapping retainer with plastic mallet.
13. 13

    Prepare engine block deck surface
    Clean cylinder head mating surfaces on engine block thoroughly with gasket scraper and brake cleaner. Remove all old gasket material, carbon, and sealant. Inspect for damage or corrosion. Check deck surface for flatness. Ensure all head bolt holes are clean and dry—run a thread chaser through each hole and blow out with compressed air. Oil residue in blind holes can cause hydraulic lock and inaccurate torque readings.
14. 14

    Install cylinder heads
    Position new head gaskets on block with markings facing up (if applicable). Apply thin coat of head bolt sealer to bolt threads and under bolt heads. Carefully lower cylinder heads onto block, aligning over dowel pins. Install all 17 head bolts per head finger-tight. Torque head bolts in three stages following proper sequence (center bolts first, spiral outward): Stage 1 to 30 ft-lbs, Stage 2 to 60 ft-lbs, Stage 3 to 65 ft-lbs final torque. Allow engine to sit 30 minutes, then verify final torque on all bolts.
15. 15

    Install pushrods and rocker arms
    Apply assembly lube or engine oil to both ends of each pushrod. Install pushrods into their original positions, ensuring lower end seats fully in lifter cup. Install rocker arm pivot balls onto cylinder head studs. Position rocker arms over studs and pushrods, then thread rocker arm nuts onto studs finger-tight. Verify each pushrod spins freely by hand.
16. 16

    Adjust valve lash
    Rotate crankshaft to TDC compression stroke for cylinder 1 (both valves closed, timing mark at zero). Adjust intake and exhaust valves for cylinder 1 by tightening rocker nut until all lash is removed (pushrod cannot be spun easily), then tighten an additional 1 full turn to center hydraulic lifter plunger. Follow firing order (1-8-4-3-6-5-7-2) and repeat adjustment procedure for each cylinder at its TDC compression stroke. Alternatively, use EO/IC method: when exhaust valve opens, adjust intake on paired cylinder; when intake closes, adjust exhaust.
17. 17

    Reinstall intake and exhaust manifolds
    Install new exhaust manifold gaskets and bolt exhaust manifolds to cylinder heads. Install new intake manifold gaskets, apply small bead of RTV silicone to front and rear block-to-manifold joints (China walls), and carefully lower intake manifold into position. Install intake manifold bolts and torque in sequence from center outward to 30 ft-lbs. Reinstall distributor in original position.
18. 18

    Reinstall valve covers and accessories
    Clean valve cover mating surfaces thoroughly. Install new valve cover gaskets (use rubber gaskets with small bead of RTV at corners, or cork gaskets with contact adhesive). Install valve covers and torque bolts evenly to 45-55 inch-lbs (do not overtighten—covers will distort). Reconnect all vacuum lines, coolant hoses, and electrical connectors according to labels. Reinstall carburetor and air cleaner.
19. 19

    Refill fluids and initial start
    Refill cooling system with 10 quarts of DEX-COOL Extended Life coolant mixed 50/50 with distilled water. Remove oil drain plug, install new oil filter, and refill crankcase with 5 quarts of 5W-30 conventional engine oil. Reconnect battery. Prime oil system by disabling ignition and cranking engine for 10 seconds (watch for oil pressure gauge movement). Start engine and check immediately for oil pressure, unusual noises, and leaks. Allow engine to reach operating temperature while monitoring for leaks and verifying all systems function properly.

Reassembly

1. Retorque cylinder head bolts after first heat cycle (20-30 minutes of operation) if using standard bolts
2. Recheck valve lash adjustment after 500 miles of operation
3. Monitor oil consumption and check for valve cover leaks during first 100 miles
4. Verify ignition timing and carburetor adjustment after valve job is complete

Verification

• Perform compression test on all cylinders—readings should be within 10% of each other and between 150-170 psi
• Perform cylinder leakage test if available—leakage should be less than 10% per cylinder
• Check for oil leaks around valve covers, intake manifold, and head gaskets
• Listen for unusual valve train noise (clicking, tapping, or rattling) at idle and under load
• Verify oil pressure is within normal range (30-40 psi at idle warm, 50-60 psi at 2000 RPM)
• Monitor coolant level and check for combustion gases in cooling system (bubbles in radiator)
• Test drive vehicle and verify smooth acceleration, no misfires, and proper engine temperature

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