Valve Train Analysis

Valve Train Analysis-Engine Off-Valve Cover Removed
Check for damaged or severely worn parts and correct assembly. Make sure correct parts are used with the static engine analysis as follows.

Valve Train Analysis-Engine Off
^ Check for loose mounting bolts on camshaft caps.
^ Check valve shim to camshaft gap.

Valve Train Analysis-Engine Off, Camshaft-Engines
^ Check for broken or damaged parts.

Valve Train Analysis-Valve Springs
^ Check for broken or damaged parts.

Valve Train Analysis-Engine Off, Valve Spring Retainer and Valve Spring Retainer Keys
^ Check for correct seating of the valve spring retainer key on the valve stem and in valve spring retainer.
^ Check for correct seating on the valve stem.

Valve Train Analysis-Engine Off, Valves and Cylinder Head
^ Check for plugged oil drain back holes.
^ Check for worn or damaged valve tips.
^ Check for missing or damaged valve stem seals or guide-mounted valve stem seal.
^ Check valve tappet shim gap.
^ Check for missing or worn valve spring seats.
^ Check for plugged oil metering orifice in cylinder head oil reservoir (if equipped).
Static checks (engine off) are to be made on the engine prior to the dynamic procedure.

Valve Train Analysis-Engine Off, Camshaft Lobe Lift-OHC Engines
Check the lift of each camshaft lobe in consecutive order and make a note of the readings.
1. Remove the valve covers.
2. Remove the spark plugs.
3. Install the special toot so the rounded tip of indicator is on top of the camshaft lobe and on the same plane as the valve tappet.





4. Rotate the crankshaft using a breaker bar and socket attached to the crankshaft pulley retainer bolt. Rotate the crankshaft until the base circle of the camshaft lobe is reached.
5. Zero the dial indicator. Continue to rotate the crankshaft until the high-lift point of the camshaft lobe is in the fully-raised position (highest indicator reading).
6. To check the accuracy of the original indicator reading, continue to rotate crankshaft until the base circle is reached. The indicator reading should be zero. If zero reading is not obtained, repeat Steps 1 through 6.
7. Install the spark plugs.
8. Install the valve covers.

Valve Train Analysis-Engine Off, Valve Tappet
Valve tappet noise can be caused by any of the following:
^ excessive valve tappet shim gap
^ excessive valve guide wear

Excessive collapsed valve tappet shim gap can be caused by loose rocker arm seat bolts/nuts, incorrect initial adjustment or wear of valve tappet shim face.