Vanden Plas L6-4.0L (1990)
spark plug gap as described below.
In addition, on engines with numbers below 9L103934 (XJS Range) or 9J103935 (Sedan Range), modify the bolts retaining the upper chain damper to
the upper damper saddle as described at the appropriate point in the procedure.
1.
Disconnect the battery negative cable.
2.
Remove the coil cover and the on-plug coils. Discard the seal and gaskets.
3.
Remove the camshaft cover and discard the seal. Remove all six spark plugs.
4.
Check the tappet clearances with the engine at room temperature. If necessary, adjust any that are not within the specifications of 0.012 - 0.014
inch (0.30 - 0.36 mm). Refer to section 12.29.48 of the AJ16 Engine Service Manual.
5.
Turn the crankshaft until the No. 1 cylinder is at Top Dead Center (TDC) on the compression stroke, i.e. with the cam lobes on the No. 1 cylinder
pointing upwards as in Illustration 1. This position can be checked by temporarily inserting the camshaft setting tool 18G-1433/A into the slot on
each camshaft.
6.
On engines with numbers below 9L103934 (XJS Range) or 9J103935 (Sedan Range) only, remove the upper chain damper and saddle assembly
and set aside for modification.
7.
On all engines, attach an engine lifting eye to the intake camshaft cap as shown in Illustration 1.
8.
Position the magnetic base of a dial indicator gauge on the lifting eye.
9.
Install the dial indicator gauge with an extension pointing downward, into the spark plug bore, contacting the top of the piston.
10.
Bend back the locking tabs that lock the bolts holding the camshaft sprocket vernier couplings to the camshafts. Loosen the bolts slightly, but do
not remove them.
11.
Remove the camshaft setting tool. Rotate the crankshaft back and forth slightly across the TDC position to determine the true TDC point for the
no. 1 piston and then zero the gauge.
