Lifter - Single

Replace a single hydraulic valve lifter on the AMC 390ci V8 engine, requiring removal of intake manifold, valve cover, rocker assembly, and pushrod to access the lifter.

Warnings

Tools required

Parts

• Hydraulic valve lifter × 1 — Use OEM specification or equivalent for AMC 390
• Intake manifold gasket set × 1 — AMC 390 V8 intake gasket set
• Valve cover gasket × 1 — AMC 390 V8 valve cover gasket
• Pushrod (if damaged) × 1 — AMC 390 V8 pushrod
• Engine assembly lubricant × 1 — Moly-based cam/lifter assembly lube
• RTV silicone sealant × 1 — High-temp RTV

Fluids

• Engine oil SAE 10W-30 or 10W-40 — 1 qt

Preparation

1. Disconnect negative battery cable and secure away from battery post
2. Allow engine to cool completely for minimum 2 hours if recently operated
3. Drain coolant from radiator if intake manifold removal interferes with coolant passages on your specific configuration
4. Remove air cleaner assembly and label all vacuum hoses for reinstallation
5. Photograph or diagram carburetor linkage, vacuum lines, and wire routing for reference
6. Place drain pan under engine to catch oil drips
7. Identify which lifter is being replaced and determine which cylinder/valve it operates
8. Gather all parts, fluids, and tools before beginning

Procedure

1. 1

   Remove carburetor and intake manifold
   Disconnect fuel line at fuel pump or carburetor, plugging open lines. Disconnect throttle linkage, vacuum advance line, PCV hose, and all vacuum lines from carburetor and intake manifold. Remove distributor cap and mark distributor position relative to block. Remove carburetor mounting nuts and lift carburetor clear. Remove intake manifold bolts in reverse order from center outward (start at ends, work toward center). Break manifold seal with gentle prying at casting ears only, never between gasket surfaces. Lift intake manifold straight up and off engine.
   ⚠Gasoline spillage is a fire hazard. Have fire extinguisher accessible and work in well-ventilated area.
   ⚠Do not pry between gasket surfaces as this will damage sealing surfaces and cause future leaks.
2. 2

   Remove valve cover on affected cylinder bank
   Disconnect any breather hoses, PCV connections, or wiring attached to valve cover. Remove valve cover bolts or wing nuts. Gently tap cover with rubber mallet to break gasket seal if stuck. Lift valve cover straight up. Clean any oil residue from exposed valve train and inspect for obvious damage or wear patterns.
   ℹ️AMC 390 uses cork or rubber valve cover gaskets. Cork gaskets are fragile and almost always require replacement.
3. 3

   Rotate engine to safe position
   Using breaker bar on harmonic balancer bolt, rotate engine clockwise (viewed from front) until the lifter being replaced is on the base circle of the camshaft lobe. The pushrod for this valve should have slight wiggle room and not be under load. This is typically when the opposite cylinder is at TDC compression stroke. Verify pushrod is loose before proceeding.
   ⚠Attempting to remove rocker arm while lifter is on cam lobe can damage rocker arm, pushrod, or valve stem.
4. 4

   Remove rocker arm and pushrod
   Loosen rocker arm adjusting nut or bolt (AMC 390 typically uses individual rocker arm studs with adjusting nuts). Back off nut until rocker arm pivots freely. Rotate rocker arm to side to clear pushrod. Lift pushrod straight up out of lifter. Mark pushrod location and inspect for wear, scoring, or bending. Clean pushrod thoroughly and check for straightness by rolling on flat surface. Set aside in organized holder labeled by cylinder position.
   ℹ️Pushrods must be straight. Any bend exceeding 0.015 inches requires replacement.
5. 5

   Extract hydraulic lifter
   Using magnetic lifter removal tool, insert into lifter bore alongside the lifter. Position magnet against lifter body and extract lifter straight up with steady pulling force. If lifter is stuck due to varnish buildup, apply penetrating oil around lifter body and wait 15 minutes. Do not pry or use excessive force. Clean lifter bore thoroughly with parts cleaning solvent and lint-free cloth. Inspect bore for scoring, galling, or excessive wear.
   ⚠Lifter bores are precision-machined. Any scoring or damage to bore requires professional machine shop evaluation.
   ℹ️If lifter cannot be removed with magnetic tool, specialized hydraulic lifter puller may be required.
6. 6

   Inspect camshaft lobe and lifter contact surface
   Using flashlight and inspection mirror, examine the camshaft lobe corresponding to removed lifter. Look for scoring, pitting, uneven wear, or flat spots on lobe. Examine removed lifter foot (bottom contact surface) for concave wear pattern, which is normal, or convex/flat wear indicating cam lobe failure. If cam lobe shows damage, complete camshaft replacement is required and this repair should not proceed.
   ⚠️Installing new lifter on damaged cam lobe will result in immediate lifter failure and metal contamination throughout engine. If cam lobe is damaged, stop and consult professional machinist.
7. 7

   Prepare and install new lifter
   Remove new lifter from packaging and verify it matches original lifter design (flat tappet vs roller, height, diameter). Prime hydraulic lifter by submerging in clean engine oil and manually working plunger until no air bubbles emerge. Coat lifter body and foot liberally with engine assembly lubricant (moly-based). Coat lifter bore with assembly lube. Insert lifter into bore with gentle twisting motion, ensuring it slides freely. Lifter must drop to bottom of bore under its own weight.
   ⚠Dry installation of lifter will cause immediate wear and potential failure. Assembly lubricant is mandatory.
   ℹ️If installing used lifter from same engine, it MUST go back in exact same bore. Used lifters wear to match specific cam lobes.
8. 8

   Reinstall pushrod and rocker arm
   Apply engine assembly lubricant to both ends of pushrod and along length. Insert pushrod into lifter cup, ensuring it seats properly in lifter pocket. Guide upper end into rocker arm cup. Rotate rocker arm into position over pushrod and valve stem tip. Thread rocker arm adjusting nut finger-tight. Verify pushrod is properly seated at both ends before tightening.
   ⚠Pushrod must seat completely in lifter cup. Partial seating will cause immediate pushrod or rocker arm failure.
9. 9

   Adjust valve lash
   For AMC 390 hydraulic lifters, tighten rocker arm adjusting nut while rotating pushrod with fingers. Continue tightening just until all free play is eliminated and pushrod cannot be rotated easily. This is zero lash. From zero lash position, tighten adjusting nut an additional 1/2 to 3/4 turn to center the hydraulic lifter plunger. Hold adjusting nut and tighten locknut if equipped. Verify pushrod has slight resistance but is not completely locked.
   ⚠Over-tightening adjustment can collapse hydraulic lifter and cause valve to stay open, resulting in engine damage. Under-tightening causes valve train noise and wear.
10. 10

    Reinstall valve cover
    Clean valve cover gasket surface on cylinder head with gasket scraper and solvent. Remove all old gasket material and RTV residue. Install new valve cover gasket, using small dabs of RTV at corners if gasket design requires. Position valve cover over studs or bolt holes and install fasteners. Tighten valve cover bolts in cross pattern from center outward to 4-6 ft-lb. Do not overtighten.
    ⚠Valve covers are typically thin stamped steel. Over-tightening will warp cover and cause oil leaks.
11. 11

    Reinstall intake manifold
    Clean all gasket surfaces on cylinder heads and block end rails with gasket scraper. Ensure surfaces are completely clean and dry. Install new intake manifold end seals at block. Position new intake manifold gaskets on cylinder heads, using alignment pins or small dabs of RTV to hold in position. Apply thin bead of RTV at corners where end seals meet head gaskets. Carefully lower intake manifold into position. Install all manifold bolts finger-tight. Torque manifold bolts in sequence from center outward in three stages: first to 10 ft-lb, then 20 ft-lb, finally 35-40 ft-lb.
    ⚠Improper intake manifold bolt sequence or torque will cause vacuum leaks and coolant leaks. Follow torque sequence carefully.
12. 12

    Reinstall carburetor and reconnect systems
    Install new carburetor base gasket. Position carburetor on intake manifold and install mounting nuts, torquing to 12-15 ft-lb in cross pattern. Reconnect throttle linkage, vacuum lines, PCV hose, and fuel line using photos/diagrams from preparation. Verify distributor rotor position has not changed. Reinstall distributor cap. Reconnect all vacuum hoses and wiring to original positions.
    ℹ️Verify throttle linkage operates smoothly and returns to idle position when released before starting engine.
13. 13

    Refill fluids and initial startup
    Refill cooling system to proper level if coolant was drained. Reconnect negative battery cable. Check engine oil level and add if needed. Before starting, remove spark plugs and crank engine with starter for 10-15 seconds to circulate oil through new lifter. Reinstall spark plugs. Start engine and immediately check for oil leaks at valve cover and coolant/vacuum leaks at intake manifold. Allow engine to idle and listen for valve train noise.
    ⚠Some valve train noise is normal for first 5-10 minutes while new lifter pumps up. Excessive or prolonged noise indicates adjustment or installation problem.

Reassembly

1. Torque all fasteners in proper sequence: intake manifold from center outward, valve cover in cross pattern
2. Verify all vacuum lines, fuel lines, and electrical connections are restored to original positions
3. Check that throttle linkage operates freely through full range and returns to idle
4. Double-check valve adjustment on replaced lifter after engine reaches operating temperature
5. Monitor for oil leaks at valve cover and intake manifold gaskets during first test drive

Verification

• Engine should idle smoothly with no misfires or rough running
• No valve train clicking or tapping noise should be present after 10-minute warm-up period
• No oil leaks visible at valve cover gasket
• No vacuum leaks audible at intake manifold (hissing sounds)
• Engine should produce normal power and acceleration with no flat spots
• Oil pressure should remain normal and stable at idle and operating RPM
• After 50-100 miles, recheck valve cover and intake manifold bolt torque and retighten if necessary
• Change engine oil and filter after 500 miles to remove any assembly lubricant and break-in debris

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