Replace valve stem seals on the 327ci V8 to stop oil consumption and smoking without removing the cylinder heads, using compressed air or rope to hold valves in place.

Warnings

Tools required

Parts

• Valve stem seal set (16 piece - intake and exhaust) × 1 — Use OEM specification
• Valve cover gaskets × 2 — Use OEM specification
• Valve cover grommets × 8 — Use OEM specification
• Intake manifold gasket set × 1 — Use OEM specification
• Spark plug wire retainer clips × 8 — Use OEM specification

Fluids

• 5W-30 Conventional Engine Oil — 5 qt

Preparation

1. Park vehicle on level surface and engage parking brake
2. Disconnect negative battery cable
3. Allow engine to cool completely (minimum 2 hours after running)
4. Remove air cleaner assembly and label all vacuum hoses for reinstallation
5. Drain engine oil completely into appropriate container
6. Remove distributor cap and set aside without disconnecting wires
7. Label all spark plug wires with cylinder numbers before removal
8. Prepare clean workspace and parts organizer trays labeled 1-8 for each cylinder's components

Procedure

1. 1

   Remove valve covers and intake manifold
   Remove 8 valve cover bolts from each valve cover using appropriate socket. Carefully pry valve covers off and set aside. Disconnect all intake manifold vacuum lines, throttle linkage, and fuel line. Remove the 12 intake manifold bolts in reverse order from outside to inside. Lift intake manifold straight up to avoid damaging gasket surfaces. Stuff clean rags into intake ports to prevent debris entry.
2. 2

   Remove spark plugs
   Remove all 8 spark plugs using deep well spark plug socket. Inspect plugs for oil fouling to identify which cylinders have failing seals. Keep spark plugs organized and store in numbered tray.
3. 3

   Position cylinder 1 at TDC compression stroke
   Rotate engine clockwise using breaker bar on harmonic balancer bolt until cylinder 1 is at top dead center on compression stroke (both valves closed, rotor pointing to cylinder 1 terminal). Verify timing mark aligns with zero on timing tab. This ensures piston is at highest position to support the valves.
4. 4

   Remove rocker arms for cylinder 1
   Loosen rocker arm stud nuts on cylinder 1 (front left cylinder) while noting their adjustment position. Remove both rocker arm nuts, rocker arm balls, and rocker arms. Remove pushrods and store vertically in order. Place all components in cylinder 1 tray.
5. 5

   Install air adapter and pressurize cylinder 1
   Thread air hose adapter into cylinder 1 spark plug hole. Connect air compressor and pressurize cylinder to 90-100 PSI. Air pressure will hold both valves seated against their seats. Listen for air leaking from oil filler, PCV, or exhaust - minor leakage is normal but excessive leakage indicates ring problems and this method may not work.
6. 6

   Compress valve springs and remove keepers for cylinder 1
   Position valve spring compressor on intake valve spring retainer for cylinder 1. Compress spring carefully while maintaining air pressure. Use magnetic pick-up tool to remove both valve keepers from valve stem groove. Slowly release spring compressor and remove spring retainer and spring. Repeat process for exhaust valve. Keep intake and exhaust springs separate in cylinder 1 tray.
7. 7

   Replace valve seals on cylinder 1
   Use pliers or seal removal tool to carefully pull old valve seal off valve guide. Inspect valve guide for wear or damage. Lubricate new seal with clean engine oil. Install new positive seal over valve guide by hand, ensuring it seats fully on guide boss. Use appropriate seal installation tool or deep socket to gently tap seal into place - do not damage seal lips. Install new seal on both intake and exhaust valves for cylinder 1.
8. 8

   Reassemble cylinder 1 valve train
   Install valve spring and retainer over valve stem. Compress spring with valve spring compressor while maintaining air pressure. Carefully install both valve keepers into valve stem groove using magnetic tool - ensure keepers are fully seated in groove. Slowly release compressor and verify keepers are locked in place. Repeat for second valve. Remove air adapter. Install pushrods in original locations, then install rocker arms, balls, and nuts finger tight.
9. 9

   Complete remaining cylinders in firing order sequence
   Rotate engine to bring next cylinder in firing order (1-8-4-3-6-5-7-2) to TDC compression stroke. Repeat steps 4 through 8 for each cylinder: remove rocker arms, pressurize cylinder, remove keepers and springs, replace seals, reassemble valve train. Work methodically through all 8 cylinders, maintaining organization of parts by cylinder number. Verify each cylinder's keepers are properly seated before moving to next cylinder.
10. 10

    Adjust valve lash on all cylinders
    With engine at TDC compression stroke for cylinder 1 (both valves closed), adjust intake rocker arm: loosen nut until lash exists, then tighten nut until all lash is removed (pushrod cannot be rotated), then tighten nut an additional one full turn. Repeat for exhaust valve. Rotate engine 90 degrees (1/4 turn) and adjust next cylinder in firing order. Continue until all 16 valves are adjusted. This provides approximately 0.5 turn preload on hydraulic lifters.
11. 11

    Clean and prepare mating surfaces
    Remove rags from intake ports. Thoroughly clean all gasket surfaces on valve covers, cylinder heads, and intake manifold using gasket scraper. Ensure no gasket material or debris remains. Clean surfaces with brake cleaner and wipe dry. Inspect surfaces for warping or damage.
12. 12

    Install intake manifold
    Position new intake manifold gaskets on cylinder heads with all port openings aligned. Apply small dab of RTV silicone to front and rear valley pan corners. Carefully lower intake manifold into position, ensuring gaskets stay aligned. Install all 12 manifold bolts finger tight, then torque in sequence from center outward in three stages. Reconnect all vacuum lines, throttle linkage, and fuel line according to labels.
13. 13

    Install valve covers
    Install new valve cover grommets in valve cover bolt holes. Position new valve cover gaskets on valve covers. Place valve covers on cylinder heads and install 8 bolts per side. Tighten bolts evenly in crisscross pattern to snug specification - do not overtighten as this will distort covers and cause leaks.
14. 14

    Reinstall ignition components
    Install spark plugs and torque to specification. Reconnect spark plug wires according to firing order and cylinder labels. Install distributor cap. Reconnect all vacuum lines and install air cleaner assembly.
15. 15

    Refill engine oil and perform initial start
    Reconnect negative battery cable. Fill engine with 5 quarts of 5W-30 conventional engine oil. Start engine and check immediately for oil pressure. Allow engine to idle and inspect for oil leaks around valve covers and intake manifold. Listen for any abnormal valve train noise indicating improper adjustment or dropped keeper. Check for vacuum leaks.

Reassembly

1. Ensure all rocker arm adjustments are completed before extended running
2. Retorque intake manifold bolts after first heat cycle (50-100 miles)
3. Retighten valve cover bolts after first heat cycle if minor seepage occurs
4. Replace oil and filter after 500 miles to remove any debris from seal replacement

Verification

• Engine should idle smoothly with no valve train noise or ticking
• No oil leaks visible from valve covers or intake manifold after 10 minutes of running
• Blue smoke on deceleration or startup should be eliminated or significantly reduced after 100 miles of operation
• Oil consumption should drop to normal levels (less than 1 quart per 1000 miles) after break-in period
• Compression test all cylinders - readings should be within 10% of each other and meet specification
• No air leaks audible from PCV system or valve covers during operation

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