Checking Clearance
NOTE:
Use Chain Tensioner Releaser/Retainer (JD50), Camshaft Sprocket Retainer (JD40), and Timing Gauge (C3993) when adjusting valves on XJS.
- To relieve fuel pressure, disconnect wire from inertia switch. Inertia switch is located on passenger's side footwell on the front door pillar. Start engine and let idle until engine stalls. Crank engine an additional 5 seconds.
- Disconnect negative battery lead. Discharge A/C system. Disconnect Air Temperature Sensor (ATS) from left air filter housing. Release clips and remove both air filters and housings. Disconnect auxiliary air valve hose from left air filter backplate.
- Disconnect auxiliary air valve inlet hose. Disconnect crankcase breather hose from air filter backplate. Remove both left and right air filter backplates and gaskets from throttle housing.
- Mark and disconnect vacuum lines from intake manifolds. Disconnect fuel regulator from fuel rail. Disconnect fuel line from pressure regulator. If necessary, remove fuel injector rail assembly. Disconnect canister purge hose and crankcase vent hose from intake manifolds.
- Disconnect ignition coil connectors and remove coils. Disconnect throttle cable from throttle pedestal. Remove both throttle rods (left and right side) from bellcranks. Disconnect brake vacuum hose from rear of left intake manifold. Remove air injection rail-to-check valve hose.
- Remove intake manifold nuts and washers. Remove air rails from intake manifold. Remove intake manifolds and gaskets from cylinder head. Remove cam cover nuts, bolts and washers. Remove cam covers and gaskets. Ensure camshaft bearing caps are tight. Check valve adjustment with engine cold.
- Rotate engine, and check valve clearances between heel of cam and cam follower. Record each valve clearance reading. If valve clearance is not within specification, adjustment is necessary. See the XJS VALVE CLEARANCE SPECIFICATIONS table.
XJS VALVE CLEARANCE SPECIFICATIONS
| Application | In. (mm) |
|---|---|
| Intake & Exhaust | .010-.012 (.25-.30) |