Valve Adjustment

Adjustment of valve lash clearances on the 6.0L V12 engine by removing valve covers, measuring clearances, and adjusting shims or screws to bring intake and exhaust valves within specification.

Warnings

Tools required

Parts

• Valve cover gasket set (both banks) × 1 — Use OEM specification
• Valve cover grommet/seal set × 1 — Use OEM specification
• Engine oil × 1 — 5W-30

Fluids

• engine_oil — 10.5 qt

Preparation

1. Ensure engine is completely cold (ideally overnight cool-down)
2. Disconnect negative battery terminal
3. Remove engine cover panels to access both valve covers
4. Remove ignition coil packs and set aside with connectors protected
5. Disconnect any breather hoses, PCV connections, and wiring harnesses attached to valve covers
6. Have valve lash specifications ready: typical Aston Martin V12 specifications are 0.10-0.15mm intake and 0.25-0.30mm exhaust (verify with service manual for exact cold clearances)

Procedure

1. 1

   Remove Left Bank Valve Cover
   Remove the fasteners securing the left bank valve cover (verify exact fastener count and drive type with the Aston Martin service manual). Carefully lift the valve cover off, being mindful of any remaining harness clips or breather connections. Inspect the gasket and sealing surfaces for damage or oil residue. Note: Remove the fasteners securing the left bank valve cover (verify exact fastener count and head type against the factory service manual).
2. 2

   Remove Right Bank Valve Cover
   Remove the fasteners securing the right bank valve cover (verify exact fastener count and drive type with the Aston Martin service manual). Carefully lift the valve cover off. On the right bank, additional components may need to be loosened or moved aside for clearance; identify any interfering brackets, hoses, or harnesses specific to this engine per the factory service manual. Note: Remove the fasteners securing the right bank valve cover (verify exact fastener count and head type against the factory service manual).
3. 3

   Position Crankshaft to TDC Cylinder 1
   Rotate the crankshaft in the normal direction of engine rotation (verify direction and the approved crankshaft-turning method in the service manual) until cylinder 1 is at top dead center on the compression stroke. Both intake and exhaust valves for cylinder 1 should be fully closed (cam lobes pointing away from the valve followers). Use the timing marks on the crankshaft pulley and timing cover to verify TDC position. Mark the pulley position with a paint pen for reference.
4. 4

   Measure Valve Clearances - Cylinder 1
   With cylinder 1 at TDC compression, use feeler gauges to measure the clearance between the cam lobe base circle and the valve follower/shim for both intake and exhaust valves on cylinder 1. Insert the feeler gauge between the cam and follower with light drag. Record each measurement precisely. Measure against the factory cold valve-clearance specifications for this engine (verify exact intake and exhaust values with the Aston Martin service manual — do not rely on generic figures). Note any valves out of specification for adjustment. Note: Intake and exhaust cold valve clearance specifications must be obtained directly from the Aston Martin factory service manual for the 6.0L V12 (do not rely on generic values).
5. 5

   Measure Remaining Cylinders - Firing Order Sequence
   Rotate the crankshaft following the firing order sequence to position each cylinder at TDC compression stroke. For the Aston Martin 6.0L V12, the firing interval is 60 degrees of crankshaft rotation (720/12), but successive cylinders in the firing order are not simply the next-numbered cylinder — follow the documented firing order and verify the exact crankshaft rotation needed to bring each cylinder to TDC compression against the service manual. Rotate the crankshaft to bring each cylinder to TDC compression following the engine's documented firing order (verify the exact firing order sequence with the Aston Martin service manual before proceeding). At each position, measure both intake and exhaust valve clearances for the cylinder at TDC. Record all measurements in a systematic chart noting cylinder number, valve type (intake/exhaust), measured clearance, and whether adjustment is needed. Complete all 24 valves (12 cylinders × 2 valves per cylinder). Note: For the Aston Martin 6.0L V12 the firing interval is 60 degrees, but verify the exact firing order and the correct crankshaft rotation required to bring each successive cylinder to TDC compression against the factory service manual before proceeding. Note: For the Aston Martin 6.0L V12, advance through the engine's firing order, rotating the crankshaft 60 degrees between successive cylinders (verify the exact firing order and sequence against the factory service manual before proceeding).
6. 6

   Determine Adjustment Requirements
   Review all recorded measurements against specifications. Calculate the required shim thickness change for each out-of-spec valve. This engine uses shim-under-bucket adjustment (not screw-type adjusters). For each out-of-spec valve, note the required shim thickness change. Accessing and replacing shims requires removal of the camshafts; verify the procedure against the Aston Martin service manual. Note: This engine uses shim-under-bucket adjustment. Calculate the required replacement shim thickness for each out-of-spec valve using the measured clearance and the thickness of the shim currently fitted. Removal of the camshafts is required to access and replace the shims.
7. 7

   Adjust Valve Clearances
   This engine uses shim-type (bucket tappet) valve adjustment, not screw adjusters — verify with the factory service manual. For shim-type systems: Remove the camshafts following the proper timing-chain/cam-cap procedure, measure and record the removed shim thicknesses, calculate and install replacement shims of the correct thickness to achieve specification, reinstall camshafts with proper timing alignment and correct cam cap torque sequence, then re-measure all adjusted valves. Note: The 2009 DB9 6.0L V12 uses shim-under-bucket (shim-type) adjustment. Calculate the required shim thickness change for each out-of-spec valve; accessing the shims requires removing the camshafts following the proper procedure. Note: This engine uses shim-type (shim-under-bucket) adjustment. Remove the camshafts following the proper procedure, replace the shims with the correct thickness to achieve specification, reinstall the camshafts with proper timing alignment and correct bearing cap torque, then re-measure all adjusted valves. Note: The Aston Martin 6.0L V12 uses shim-type (bucket tappet) valve adjustment, not screw-type adjusters. Calculate the required shim thickness change for each out-of-spec valve; accessing and replacing shims requires removal of the camshafts. Verify adjustment mechanism type against the factory service manual before proceeding. Note: Camshaft Bearing Cap Bolts (torque sequence per factory service manual)
   Torque spec

   Valve Lash Adjusting Screw Lock Nut20 Nm (15 lb-ft)
8. 8

   Verify All Adjustments
   After completing adjustments, rotate the engine through two complete revolutions and re-measure all valves that were adjusted. Confirm each valve is within specification. This verification step is critical because camshaft installation and bearing cap torquing can alter clearances slightly. Make any necessary fine adjustments.
9. 9

   Clean and Inspect Valve Cover Sealing Surfaces
   Thoroughly clean all gasket mating surfaces on both valve covers and cylinder heads. Remove all old gasket material and oil residue using a plastic scraper and brake cleaner. Inspect the valve cover sealing surfaces for warping or damage. Check valve cover bolt holes and grommets for damage. Replace any damaged grommets or seals.
10. 10

    Install New Valve Cover Gaskets
    Install new valve cover gaskets into the valve cover grooves, ensuring they are properly seated throughout their entire length. Install new grommets around each bolt hole. Some gaskets may have locating tabs or adhesive backing to hold them in position. Do not use additional sealant unless specifically called for by the manufacturer.
11. 11

    Install Valve Covers and Torque Fasteners
    Carefully position each valve cover onto the cylinder head, ensuring no wiring or hoses are pinched. Hand-thread all valve cover bolts, ensuring grommets are properly seated. Torque valve cover bolts in a spiral pattern starting from the center and working outward to distribute clamping force evenly. Torque to specification in two stages (verify exact figures with the Aston Martin service manual; valve cover bolts torque value must be obtained from the Aston Martin service manual (do not assume a generic M6 value)). Note: Torque the valve cover bolts to the manufacturer's specification in the sequence specified by the service manual (verify exact torque value and any staged tightening steps in the factory documentation). Note: Torque valve cover bolts in two stages: first to an intermediate seating torque, then to the final torque value specified in the Aston Martin factory service manual (obtain the exact figures before assembly).
    Torque spec

    Valve Cover Bolts10 Nm (7 lb-ft)
12. 12

    Reconnect Components and Refill Oil
    Reconnect all breather hoses, PCV connections, and wiring harnesses to the valve covers. Reinstall ignition coil packs with connectors. If oil was drained, refill engine with the correct quantity and specification of engine oil per the factory service manual (verify exact capacity and grade — do not assume oil grade or capacity — confirm the exact figures for the 2009 DB9 6.0L V12 against the Aston Martin service manual). Reinstall engine covers. Reconnect battery negative terminal. Note: If oil was drained, refill engine with the correct quantity and specification of engine oil (verify exact capacity and grade with the Aston Martin service manual). Note: if oil was drained, refill engine with the correct quantity and specification of engine oil per the factory service manual (verify exact capacity and oil grade for the 2009 DB9 6.0L V12)

Reassembly

1. Ensure all valve cover bolts are torqued in the correct sequence from center outward
2. Verify all electrical connectors and breather hoses are properly reconnected
3. Double-check that no tools or rags are left in the engine bay
4. Confirm oil level is correct on dipstick after refilling

Verification

• Start the engine and listen for any abnormal valve train noise or ticking that would indicate incorrect adjustment
• Check for oil leaks around both valve covers while engine is running
• Allow engine to reach operating temperature and verify no oil seepage from valve cover gaskets
• Monitor engine for smooth idle and proper operation across all RPM ranges
• After initial test drive, re-check valve cover bolt torque after engine has cooled

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