Measuring Timing Chain Stretch

Fig. 11 Measuring timing chain wear. V8 engine:

1. Disconnect battery ground cable.
2. Remove timing case cover.
3. Rotate camshaft or crankshaft sprocket until right side of timing chain is taut.
4. Determine a reference point for timing chain deflection measurement as follows:
a. Measure 3/4 of an inch up from dowel pin located on right side of engine and mark location, Fig. 11.
b. Position a suitable straightedge across timing chain from point at lowest root of camshaft sprocket to point obtained (marked) in step 4a, Fig. 11.
c. Grasp timing chain at point where straightedge dissects (cuts across) timing chain and use this point as a reference.
d. Move timing chain inward toward center line of engine and mark engine block at point of maximum inward chain deflection, Fig. 11.
e. Move timing chain outward from center line of engine and mark engine block at point of maximum outward chain deflection.
f. Measure distance between inward and outward chain deflection marks placed on engine block.
g. Replace timing chain assembly if deflection (wear) exceeds 7/8 inch.
5. Install timing case cover and connect battery ground cable.