Tappets And Pushrods Examination; Camshaft And Bearings - Examination And Renovation; Cylinder Heads - Overhaul - Ford Scorpio Owner's Manual

20.2 Rocker shaft and associated
components
3 Examine the rocker shaft and rocker arms for
wear. If the rocker arm surface that contacts the
valve stem is considerably worn, renew the
rocker arm. If it is worn slightly step-shaped it
may be cleaned up with a fine oil stone.
4 Oil the parts and reassemble them on their
shafts in the original order. With both rocker
shafts fitted the oil holes must face
downwards to the cylinder heads. This
position is indicated by a notch on one end
face of the rocker shaft (see illustration).
21 Tappets and pushrods -
examination
Inspect the tappets for scuffing, surface wear
or other damage. Renew them if necessary. It is
good practice to renew the tappets if a new
camshaft is being fitted.
23.2a Compressing a valve spring to
expose the collets
23.2b Removing the spring retainer and
spring
20.4 Notch (arrowed) shows position of oil
holes
Check the pushrods for bending by rolling
them on a flat surface. Straighten or renew as
necessary. Also check the pushrod ends for
wear or damage.
22 Camshaft and bearings -
examination and renovation
1 If there is excessive wear in the camshaft
bearings they will have to be renewed. As the
fitting of new bearings requires special tools
this should be left to your local Ford dealer.
2 The camshaft may show signs of wear on
the bearing journals or cam lobes. The main
decision to take is what degree of wear
necessitates renewing the camshaft, which is
expensive. Scoring or damage to the bearing
journals cannot be removed by regrinding;
renewal of the camshaft is the only solution.
3 The cam lobes may show signs of ridging or
pitting on the high points. If ridging is slight
then it may be possible to remove it with a fine
oil stone or emery cloth. The cam lobes,
however, are surface hardened and once the
hard skin is penetrated wear will be very rapid.
4 Excessive endfloat of the camshaft may be
remedied by fitting a thicker spacer and/or
thrust plate - see Specifications.
5 Excessive backlash in the camshaft drive
gears (timing gears), which will have been
noticed before dismantling by virtue of the
characteristic growling noise, can only be
remedied by renewing the gears.
23.2c Removing an inlet valve
V6 engines 2C•13

23 Cylinder heads - overhaul

1 Clean the dirt and oil off the cylinder heads.
Remove the carbon deposits from the
combustion chambers and valve heads with a
scraper or rotary wire brush.
2 Remove the valves by compressing the
valve springs with a suitable valve spring
compressor and lifting out the collets. Release
the valve spring compressor and remove the
valve spring retainer, spring and valve (see
illustrations). Note: When removing and
refitting the valve spring take care not to
damage the valve stem when pressing down
the valve spring retainer to remove or refit the
collets. If the stem gets damaged the sealing
will be ineffective and result in excessive oil
consumption and wear of the valve guides.
Mark each valve so that they
can be fitted in the same
location.
3 Remove the valve stem oil seals from the
valve guides and discard them.
4 With the valves removed clean out the
carbon from the ports.
5 Examine the heads of the valves and the
valve seats for pitting and burning. If the
pitting on valve and seat is slight it can be
removed by grinding the valves and seats
together with coarse, and then fine, valve
grinding paste.
6 Severe pitting or burning of the valves
probably means that they must be renewed.
Badly burnt valve seats can be recut, or
inserts can be fitted, by a Ford dealer or other
specialist.
7 Check the valve guides for wear by inserting
the valve into its guide until the valve stem is
flush with the end of the guide, then checking
the play at the valve head (see illustration).
Movement in excess of 0.6 mm (0.024 in)
means that the clearance between guide and
stem is excessive.
8 Valve guide wear is dealt with by reaming
the guides to a known oversize and fitting new
valves with oversize stems. Again, this is a
dealer or specialist task.
23.7 Checking valve guide wear using a
valve and a dial test indicator
2C