Valve Springs - All

Complete replacement of all valve springs on the 390ci V8 engine, requiring cylinder head removal to access and replace worn or damaged valve springs and related components.

Warnings

Tools required

Parts

• Valve springs (intake) × 8 — Use OEM specification or high-performance equivalent
• Valve springs (exhaust) × 8 — Use OEM specification or high-performance equivalent
• Valve spring retainers × 16 — Use OEM specification
• Valve stem seals × 16 — Use OEM specification or Viton seals
• Cylinder head gaskets × 2 — Use OEM specification or performance gasket set
• Intake manifold gasket set × 1 — Use OEM specification
• Exhaust manifold gaskets × 2 — Use OEM specification
• Valve cover gaskets × 2 — Use OEM specification
• Head bolt sealer (if applicable) × 1 — Use thread sealer per AMC specification
• Valve keepers (split keepers) × 32 — Use OEM specification

Fluids

• Engine oil (SAE 10W-40 or equivalent) — 5 qt
• Engine coolant (ethylene glycol) — 4 qt

Preparation

1. Disconnect negative battery cable and remove battery for clearance
2. Drain engine coolant completely into appropriate container
3. Drain engine oil and remove oil filter
4. Remove air cleaner assembly and carburetor for access
5. Remove intake manifold with all attached components (fuel lines, vacuum lines, throttle linkage)
6. Disconnect exhaust manifolds at cylinder heads
7. Remove valve covers from both cylinder heads
8. Remove rocker arm assemblies and pushrods, keeping them organized by cylinder number and position
9. Label and disconnect all wiring, hoses, and brackets attached to cylinder heads
10. Clean work area and prepare clean surface for disassembled components

Procedure

1. 1

   Remove cylinder heads
   Remove cylinder head bolts in reverse of tightening sequence (outside bolts first, working inward). Carefully lift cylinder heads off engine block. If heads are stuck, gently tap with rubber mallet on casting - never pry between gasket surfaces. Place heads on clean wooden blocks with combustion chambers facing up.
2. 2

   Remove valves from cylinder head #1
   Working on the right (passenger side) cylinder head first, position valve spring compressor over first valve. Compress spring until keepers are accessible. Use magnetic pickup tool to remove both split keepers from valve stem groove. Slowly release spring compressor tension and remove compressor. Remove valve spring retainer, valve spring, valve spring seat (if equipped), and valve stem seal. Withdraw valve from combustion chamber side of head. Place all components in organized container labeled for cylinder #1.
3. 3

   Remove valves from remaining cylinders on head #1
   Repeat valve removal process for all remaining valves on right cylinder head (cylinders 2, 4, 6, 8). Keep each cylinder's components completely separate and labeled. Inspect each valve stem, face, and margin for wear or damage. Inspect valve guides for excessive wear.
4. 4

   Remove valves from cylinder head #2
   Move to left (driver side) cylinder head and repeat valve removal process for all valves on cylinders 1, 3, 5, and 7. Maintain strict organization of all components by cylinder number and valve position (intake vs exhaust).
5. 5

   Clean valve components
   Clean all valve stems with solvent and lint-free cloth. Remove carbon deposits from valve faces and seats using appropriate valve cleaning tools. Clean valve spring seats on cylinder heads. Inspect all valve springs for cracks, corrosion, or uneven coils - replace any suspect springs even if not part of original plan.
6. 6

   Install new valve stem seals on head #1
   Working on right cylinder head, install new valve stem seals on each valve guide. Use appropriate seal installation tool or deep socket to press seals squarely onto guides - do not hammer directly on seals. Ensure seals are fully seated. Apply small amount of engine oil to inside of each seal.
7. 7

   Install valves and new springs on head #1
   For each valve on right cylinder head: coat valve stem with engine oil, insert valve through guide from combustion chamber side, install valve spring seat (if applicable), install new valve spring with tighter coils toward cylinder head, and install valve spring retainer. Position valve spring compressor and compress spring enough to expose keeper grooves on valve stem. Install both split keepers into stem groove using magnetic tool - ensure keepers are fully seated in groove. Carefully release spring compressor and verify keepers are locked in place. Tap retainer lightly with plastic mallet to ensure positive keeper engagement.
8. 8

   Install new valve stem seals on head #2
   Move to left cylinder head and install new valve stem seals on each valve guide using same procedure as right head. Ensure all seals are properly seated and lubricated.
9. 9

   Install valves and new springs on head #2
   Install all valves with new springs on left cylinder head using identical procedure as right head. Double-check that each valve moves freely after spring installation and that all keepers are properly engaged.
10. 10

    Verify valve spring installation
    On both cylinder heads, verify that all valve springs are installed with correct orientation (tighter coils toward head). Check each valve for smooth operation by pressing down on valve stem - each should return freely. Measure installed valve spring height with calipers if specifications are available. Verify no keepers are missing or improperly seated.
11. 11

    Prepare for cylinder head installation
    Thoroughly clean cylinder head gasket surfaces on engine block using gasket scraper - remove all old gasket material without gouging surfaces. Clean head bolt holes in block and ensure they are free of oil or coolant. Clean mating surfaces on cylinder heads. Place new head gaskets on engine block with proper orientation (UP marking visible, alignment dowels engaged). Do not use gasket sealer unless specifically required by gasket manufacturer.
12. 12

    Install cylinder heads
    Carefully position cylinder heads onto engine block, aligning with dowel pins. Install all head bolts finger-tight. Note: Some AMC 390 head bolts may require thread sealer - verify with service manual. Torque head bolts to specification in three stages using proper sequence (start at center, work outward in crisscross pattern). Without factory torque specifications, follow conservative tightening pattern and consult AMC service documentation. Allow engine to sit for 30 minutes, then re-torque head bolts to final specification.
13. 13

    Install valve train components
    Install pushrods in their original positions with proper orientation (tapered end typically toward rocker arm). Install rocker arm assemblies and adjust valve lash to specification. For hydraulic lifters, typical procedure is zero lash plus 1/2 to 1 turn. Rotate engine by hand two complete revolutions and recheck all valve adjustments.

Reassembly

1. Install valve covers with new gaskets, ensuring proper torque on cover bolts to prevent leaks
2. Install exhaust manifolds with new gaskets and torque fasteners to specification
3. Install intake manifold with new gaskets, following proper torque sequence
4. Reconnect all vacuum lines, fuel lines, throttle linkage, and electrical connections per original configuration
5. Install carburetor and air cleaner assembly
6. Reinstall battery and connect cables
7. Fill cooling system with fresh coolant mixture (50/50 ratio)
8. Install new oil filter and fill engine with fresh oil to proper level

Verification

• Before starting engine, remove spark plugs and crank engine to verify oil pressure builds on gauge
• Reinstall spark plugs and start engine, listening for unusual valve train noise
• Check for oil leaks at valve covers and coolant leaks at head gaskets immediately after start
• Allow engine to reach normal operating temperature and verify no overheating occurs
• Check for exhaust leaks at manifold gaskets
• After initial warm-up and cool-down cycle, re-check valve adjustment and head bolt torque
• Road test vehicle under light load, gradually increasing to normal operating conditions
• After 500 miles, change oil and filter, and perform final valve adjustment check

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