XL-7 4WD V6-2.7L (2003)
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Don't turn camshafts or start engine (i.e., valves should not be operated) for about half an hour aver reinstalling hydraulic valve lash adjusters
and camshafts. As it takes time for valves to settle in place, operating engine within half an hour aver their installation may cause interference
to occur between valves themselves or valves and piston.
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If air is trapped in valve lash adjuster, valve may make tapping sound when engine is operated aver valve lash adjuster is installed. In such a
case, run engine for about half an hour at about 2000 to 3000 rpm, and then air will be purged and tapping sound will cease. Should tapping
sound not cease, it is possible that valve lash adjuster is defective. Replace it if defective. If defective adjuster can't be located by hearing
among 24 of them, check as follows.
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Stop engine and remove cylinder head cover.
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Push adjuster downward by hand (with less than 20 kg or 44 lbs. force) when can crest is not on adjuster to be checked and check if
clearance exists between cam and adjuster. If it does, adjuster is defective and needs replacement.
Inspection
Cam Wear
Using a micrometer, measure cam height "a". If measured height is below its limit, replace camshaft.
Intake cam height
Standard: 40.402 - 40.562 mm (1.5906 - 1.5969 inch)
Limit: 40.300 mm (1.3581 inch)
Exhaust cam height
Standard: 39.428 - 39.588 mm (1.5523 - 1.586 inch)
Limit: 39.400 mm (1.5512 inch)
Camshaft Runout
Set camshaft between two"V" blocks, and measure its runout by using a dial gauge.
If measured runout exceeds specified limit, replace camshaft.
Camshaft runout Limit: 0.04 mm (0.002 inch)
Camshaft Journal Wear
Check camshaft journals and camshaft housings for pitting, scratches, wear or damage.
If any malcondition is found, replace camshaft or cylinder head with housing. Never replace cylinder head without replacing housings.
Check clearance by using gauging plastic. The procedure is as follows.
1. Clean housings and camshaft journals.
2. Make sure that all valve lash adjusters are removed and install camshaft to cylinder head.
3. Place a piece of gauging plastic the full width of journal of camshaft (parallel to camshaft).
4. Install camshaft housing.
