Valve Timing Verification
STANDARD PROCEDURE - ENGINE TIMING VERIFICATIONCAUTION: The 4.7L is a non free-wheeling design engine. Therefore, correct engine timing is critical.
NOTE: Components referred to as left hand or right hand are as viewed from the drivers position inside the vehicle.
NOTE: The blue link plates on the chains and the dots on the camshaft drive sprockets may not line up during the timing verification procedure. The blue link plates are lined up with the sprocket dots only when re-timing the complete timing drive. Once the timing drive is rotated blue link-to-dot alignment is no longer valid.
Engine base timing can be verified by the following procedure:
1. Remove the cylinder head covers.
2. Using a mirror, locate the TDC arrow on the front cover (Fig. 124). Rotate the crankshaft until the mark on the crankshaft damper is aligned with the TDC arrow on the front cover. The engine is now at TDC.
3. Note the location of the V8 mark stamped into the camshaft drive gears (Fig. 125). If the V8 mark on each camshaft drive gear is at the twelve o'clock position, the engine is at TDC (cylinder # 1) on the exhaust stroke. If the V8 mark on each gear is at the six o'clock position, the engine is at TDC (cylinder # 1) on the compression stroke.
4. If both of the camshaft drive gears are off in the same or opposite directions, the primary chain or both secondary chains are at fault.
5. If only one of the camshaft drive gears is off and the other is correct, the problem is confined to one secondary chain.
6. If both camshaft drive gear V8 marks are at the twelve o'clock or the six O' clock position the engine base timing is correct. Reinstall the cylinder head covers.