Refit Camshaft and Tappets in Engine Overhaul Procedure
ENGINE
OVERHAUL
31
Camshaft and tappets - inspection
1. Thoroughly clean all components.
2. Inspect camshaft bearing journals and lobes
for signs of wear, pitting, scoring and
overheating.
3. Support camshaft front and rear bearings on
vee blocks, and using a DTI, measure
camshaft run-out on centre bearing:
Maximum permitted run-out = 0.05 mm (0.002
in)
4. Inspect thrust plate for wear, replace plate if
wear is evident.
5. Clean and inspect tappets. Check for an even,
circular wear pattern on the camshaft contact
area. If contact area is pitted or a square wear
pattern has developed, tappet must be
renewed.
6. Inspect tappet body for excessive wear or
scoring. Replace tappet if scoring or deep wear
patterns extend up to oil feed area. Clean and
inspect tappet bores in cylinder block.
7. Ensure that tappets rotate freely in their
respective bores.
8. Inspect pushrod contact area of tappet, replace
tappet if surface is rough or pitted.
Camshaft and tappets - refit
NOTE: If a replacement camshaft is to be
fitted, ensure colour coding is correct.
Camshafts fitted to 4.0 litre engines are
colour coded ORANGE whilst those fitted to 4.6
litre engines are colour coded RED.
1. Lubricate camshaft journals with engine oil and
carefully insert camshaft into cylinder block.
2. Fit camshaft thrust plate, fit bolts and tighten to
25 Nm (18 lbf.ft).
NOTE: If camshaft or thrust plate has been
replaced, it will be necessary to re-check
camshaft end-float.
3. Immerse tappets in engine oil. Before fitting,
pump the inner sleeve of tappet several times
using a pushrod to prime tappet; this will
reduce tappet noise when engine is first
started.
4. Lubricate tappet bores with engine oil and fit
tappets in removed order.
NOTE: Some tappet noise may still be
evident on initial start-up. If necessary, run
the engine at 2500 rev/min for a few
minutes until noise ceases.
5. Fit timing chain and gears.
6. Fit rocker shaft assemblies.