Lifters/Tappets - All

Complete replacement of all hydraulic valve lifters on the 390ci V8 engine, requiring removal of intake manifold, valve covers, rocker arms, and pushrods to access lifter gallery.

Warnings

Tools required

Parts

• Hydraulic valve lifters × 16 — AMC 390 V8 hydraulic lifters
• Intake manifold gasket set × 1 — AMC 390 V8 intake gasket kit
• Valve cover gaskets × 2 — AMC 390 V8 valve cover gaskets
• Valve cover grommets × 8 — Use OEM specification
• Pushrod guide plates (if equipped) × 16 — Use OEM specification
• Engine assembly lube × 1 — Moly-based cam assembly lube
• RTV silicone gasket maker × 1 — High-temp silicone sealant
• Intake manifold end seals × 2 — AMC 390 V8 intake end seals

Fluids

• SAE 10W-30 motor oil — 5 qt
• Engine coolant (ethylene glycol) — 2 qt

Preparation

1. Ensure engine is completely cold to the touch
2. Disconnect negative battery cable
3. Remove air cleaner assembly and note carburetor linkage configuration with photos
4. Drain coolant from radiator into appropriate container
5. Label and disconnect all vacuum lines from intake manifold and carburetor
6. Disconnect fuel line from carburetor and plug to prevent spillage
7. Disconnect throttle linkage, kickdown linkage (automatic transmission), and choke cable
8. Remove distributor cap and mark distributor position relative to block for reinstallation
9. Remove spark plug wires and label cylinder positions
10. Place transmission in Park (automatic) or gear (manual) and set parking brake
11. Cover carburetor opening with clean rag to prevent debris entry

Procedure

1. 1

   Remove valve covers
   Remove the valve cover retaining bolts from both valve covers. Note the AMC 390 typically uses 4 bolts per cover. Carefully lift valve covers straight up to avoid bending. Inspect rocker arm assembly for wear patterns or damage before proceeding.
2. 2

   Remove intake manifold
   Remove all intake manifold bolts in reverse of tightening sequence (work from ends toward center). Disconnect any remaining hoses including heater hoses and bypass hose. Carefully lift intake manifold straight up - it will be heavy and may require wiggling to break gasket seal. Place on padded surface. Remove and discard all old gaskets and end seals.
3. 3

   Document rocker arm configuration
   Before removing any rocker arms, note that AMC 390 uses individually mounted rocker arms on ball pivots. Take photos of rocker arm orientation and positions. Mark pushrods for cylinder position using tape or numbered container if reusing.
4. 4

   Remove rocker arms and pushrods
   Loosen each rocker arm retaining nut and rotate rocker arm off pushrod. Remove ball pivot if necessary. Remove each pushrod and place in numbered order. Inspect pushrods by rolling on flat surface - any bent pushrod must be replaced. Measure pushrod length if different length pushrods are suspected.
   ⚠Pushrods must be reinstalled in their original positions unless all new lifters are being installed. Mixing positions can affect break-in and cause premature wear.
5. 5

   Remove lifters from bores
   Using lifter removal tool or strong magnet, carefully extract each lifter from its bore. AMC 390 lifters may be tight in bores. Avoid scratching lifter bores. Place each lifter in numbered container matching cylinder and intake/exhaust position. If lifter is stuck, use penetrating oil and gentle rotation - never pry with screwdriver as this damages bore.
   ⚠Lifter bores connect directly to camshaft valley. Do not drop anything into engine. Keep work area clean and use magnetic tray for small parts.
6. 6

   Inspect lifter bores and camshaft
   Clean each lifter bore with brake cleaner and lint-free cloth. Inspect for scoring, scratches, or excessive wear. Rotate engine by hand using breaker bar on crankshaft bolt and inspect each camshaft lobe through lifter bores for pitting, scoring, or unusual wear patterns. If camshaft shows damage, it must be replaced before installing new lifters.
   ℹ️Damaged camshaft lobes will destroy new lifters within hours of operation. Do not proceed if cam lobes show wear.
7. 7

   Prepare new lifters
   Remove new lifters from packaging. Inspect each for damage or defects. Submerge each lifter in clean engine oil and work plunger up and down to prime internal check valve. This removes air from lifter and ensures proper initial operation. Coat entire lifter body with engine assembly lube, paying special attention to foot that contacts camshaft.
8. 8

   Install new lifters
   Install each new lifter into its corresponding bore, rotating slightly as you insert to distribute assembly lube. Lifters should slide in with moderate finger pressure - if bore is tight, coat bore lightly with oil. Ensure each lifter is fully seated in its bore. AMC lifters are not directional but must sit flat on cam lobe.
   ⚠Do not force lifters. Forced installation can damage lifter body or bore, causing oil pressure loss and engine damage.
9. 9

   Install pushrods
   Coat pushrod ends with assembly lube. Install each pushrod into its original position (or all new if using new lifters), ensuring lower end seats properly in lifter cup. Rotate pushrod while inserting to confirm it is seated. Pushrods should stand vertically without binding when properly seated.
10. 10

    Install rocker arms
    Coat rocker arm ball pivots and valve stem tips with assembly lube. Install ball pivots into block (if removed). Position each rocker arm over its corresponding ball and pushrod. Thread rocker arm nut finger-tight only at this stage. Ensure pushrod is properly seated in both lifter cup and rocker arm cup.
    ⚠Do not tighten rocker arms until lifters have bled down. Tightening with lifters pumped up can bend pushrods or damage valves.
11. 11

    Adjust rocker arms
    Rotate engine to position each cylinder at TDC compression stroke (both valves closed, rocker arms loose). For each cylinder at TDC, tighten rocker arm nut while rotating pushrod with fingers until you feel resistance (zero lash). Then tighten additional 1/2 to 3/4 turn for AMC hydraulic lifters. Repeat for all 16 rocker arms by rotating engine through full cycle.
    ℹ️Proper preload is critical. Too little preload causes valve train noise; too much preload keeps valves open and prevents lifter operation.
12. 12

    Prepare and install intake manifold
    Thoroughly clean all gasket surfaces on block and intake manifold using gasket scraper and brake cleaner. Ensure no old gasket material remains. Apply thin bead of RTV to block at front and rear where end seals meet block. Install new end seals. Position intake gaskets on block, aligning all ports carefully. Some gaskets require RTV at coolant passage areas - follow gasket manufacturer instructions. Carefully lower intake manifold into position, ensuring gaskets do not shift.
    ⚠Misaligned intake gaskets cause vacuum leaks, coolant leaks, and poor engine performance. Double-check port alignment before tightening.
13. 13

    Install intake manifold bolts
    Install all intake manifold bolts finger-tight. Tighten in three stages using proper sequence (center bolts first, working outward in circular pattern). Without factory torque specifications, use conservative 25-30 ft-lbs for AMC 390 intake manifold bolts, tightening in 10 ft-lb increments. Do not overtighten as this can crack manifold or distort gasket sealing surface.
    ℹ️Without verified torque specifications, conservative torque values are recommended. Overtightening causes more problems than slight undertightening.
14. 14

    Install valve covers
    Install new valve cover gaskets and grommets. Position valve covers carefully to avoid pinching gaskets. Install valve cover bolts with flat washers. Tighten evenly in cross pattern to approximately 5-7 ft-lbs - just enough to compress gasket without deforming cover. Overtightening thin stamped valve covers causes oil leaks.
15. 15

    Reconnect all components
    Reinstall distributor in marked position. Reconnect all vacuum lines per labels and photos. Reconnect fuel line, throttle linkage, kickdown linkage, and choke cable. Install spark plug wires per labels. Install air cleaner assembly. Reconnect battery cable. Refill cooling system with appropriate coolant mixture.

Reassembly

1. Before starting engine, remove spark plugs and crank engine for 10-15 seconds to prime oil system and bleed down lifters
2. Reinstall spark plugs and check that oil pressure registers immediately upon startup
3. Verify all fasteners are tight and no tools remain in engine compartment
4. Double-check all fluid levels including oil and coolant

Verification

• Start engine and listen for abnormal valve train noise - new lifters may tick for 30-60 seconds while purging air
• Check for oil leaks around valve covers and intake manifold while engine idles
• Check for coolant leaks at intake manifold end seals and gaskets
• Check for vacuum leaks causing rough idle or hissing sounds
• Verify proper oil pressure on gauge (30+ PSI at idle when warm for AMC 390)
• Road test vehicle gently, avoiding sustained high RPM for first 500 miles to properly break in new lifters
• After 100 miles, recheck rocker arm adjustment as new lifters may settle slightly
• Monitor for valve train noise during break-in period - persistent ticking after warm-up indicates adjustment or installation problem

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