mileage FORD SIERRA 1983 1.G SOHC Engines Workshop Manual

Note: A valve spring compressor will be
required during this procedure. New valve
stem oil seals should be used on reassembly.
Dismantling
1With the cylinder head removed, remove
the camshaft.
2Using a valve spring compressor, compress
one of the valve springs until the split collets
can be removed from the groove in the valve
stem. Release the compressor and remove
the cap and spring, identifying them for
location. If the cap is difficult to release, do
not continue to tighten the compressor, but
gently tap the top of the tool with a hammer.
Always make sure that the compressor is
firmly located on the valve head and the cap.
Withdraw the valve (see illustrations).
3Repeat the procedure given in paragraph 2
for the remaining valves, keeping all
components identified for location so that
they can be refitted in their original positions.
4Prise the valve stem oil seals from the tops
of the valve guides (see illustration).
5Unscrew the cam follower ball-pins from
the cylinder head, keeping them identified for
location.
Reassembly
6Commence reassembly by refitting the cam
follower ball-pins to their original locations,
where applicable.
7Lubricate the valve stems and guides with
SAE 80/90 hypoid oil, then insert the valves
into their original guides.
8Wrap a thin layer of adhesive tape over the
collet groove of each valve, then smear the
new oil seals with a little SAE 80/90 hypoid oil
and slide them down the valve stems onto the
guides. If necessary use a suitable metal tube
to press the oil seals into the guides. Remove
the adhesive tape.
9Working on each valve in turn, fit the valve
spring and cap, then compress the spring
using the valve spring compressor and fit the
split collets to the groove in the valve stem.
Release the compressor and tap the end of
the valve stem with a soft-faced mallet tosettle the components. If the original
components are being refitted, ensure that
they are refitted in their original locations.
10Refit the camshaft.
Note: On engines fitted with hardened valve
seats for use with unleaded petrol, valve and
valve seat grinding and recutting cannot be
carried out without the use of specialist
equipment. Consult a Ford dealer for further
advice.
1This operation will normally only be
required at comparatively high mileages.
However, if persistent pre-ignition (ÒpinkingÓ)
occurs and performance has deteriorated
even though the engine adjustments are
correct, de-carbonizing and valve grinding
may be required.
2With the cylinder head removed, use a
scraper to remove the carbon from the
combustion chambers and ports. Remove all
traces of gasket from the cylinder head
surface, then wash it thoroughly with paraffin.
3Use a straight edge and feeler blade to
check that the cylinder head surface is not
distorted. If it is, it must be resurfaced by a
suitably equipped engineering works.
4If the engine is still in the vehicle, clean the
piston crowns and cylinder bore upper edges,
but make sure that no carbon drops between
the pistons and bores. To do this, locate two
of the pistons at the top of their bores and
seal off the remaining bores with paper andmasking tape. Press a little grease between
the two pistons and their bores to collect any
carbon dust; this can be wiped away when
the piston is lowered. To prevent carbon
build-up, polish the piston crown with metal
polish, but remove all traces of the polish
afterwards.
5Examine the heads of the valves for pitting
and burning, especially the exhaust valve
heads. Renew any valve which is badly burnt.
Examine the valve seats at the same time. If
the pitting is very slight, it can be removed by
grinding the valve heads and seats together
with coarse, then fine, grinding paste.
6Where excessive pitting has occurred, the
valve seats must be recut or renewed by a
suitably equipped engineering works.
7Valve grinding is carried out as follows.
Place the cylinder head upside down on a
bench on blocks of wood.
8Smear a trace of coarse carborundum
paste on the valve seat face and press a
suction grinding tool onto the valve head.
With a semi-rotary action, grind the valve
head to its seat, lifting the valve occasionally
to redistribute the grinding paste. When a dull
matt even surface is produced on the mating
surface of both the valve seat and the valve,
wipe off the paste and repeat the process with
fine carborundum paste as before. A light
spring placed under the valve head will greatly
ease this operation. When a smooth unbroken
ring of light grey matt finish is produced on
the mating surface of both the valve and seat,
the grinding operation is complete.
9Scrape away all carbon from the valve head
and stem, and clean away all traces of
grinding compound. Clean the valves and
seats with a paraffin soaked rag, then wipe
with a clean rag.
10If the guides are worn they will need
reboring for oversize valves or for fitting guide
inserts. The valve seats will also need
recutting to ensure that they are concentric
with the stems. This work should be entrusted
to a Ford dealer or local engineering works.
11Check that the free length of the valve
springs is as specified, and renew if
necessary. Do not renew individual springs; if
any springs are excessively worn, renew all
the springs as a set.
23Cylinder head - inspection
and renovation
22Cylinder head - dismantling
and reassembly
2A¥16SOHC engines
22.2a Compressing a valve spring22.2c Removing a valve
22.4 Removing a valve stem oil seal
22.2b Removing a valve spring and cap

components, but there must be no tight spots
or binding.
28Check that the crankshaft endfloat is
within the specified limits by inserting a feeler
blade between the centre crankshaft web and
the thrustwashers.
29Make sure that the rear oil seal is fully
located onto its seating. Coat the rear main
bearing cap sealing wedges with sealing
compound, then press them into position
using a blunt screwdriver with the rounded
red face towards the cap (see illustration).
30Refit the oil pump and pick-up tube.
31Refit the crankshaft front oil seal housing
and the auxiliary shaft front cover using a new
gasket, and tighten the securing bolts. Smear
the lip of the oil seal with clean engine oil
before fitting; and using a straight edge, ensure
that the bottom face of the oil seal housing is
aligned with the bottom face of the cylinder
block before finally tightening the bolts.
32Refit the pistons and connecting rods.
33Refit the flywheel/driveplate and the
auxiliary shaft sprocket, crankshaft sprocket,
and timing belt.
1Examine the bearing surfaces of the
crankshaft for scratches or scoring and, using
a micrometer, check each journal and
crankpin for ovality. Where this is found to be
in excess of 0.0254 mm (0.001 in) the
crankshaft will have to be reground and
undersize bearings fitted.
2Crankshaft regrinding should be carried out
by a suitable engineering works, who will
normally supply the matching undersize main
and big-end shell bearings.
3Note that undersize bearings may already
have been fitted, either in production or by a
previous repairer. Check the markings on the
backs of the old bearing shells, and if in doubt
take them along when buying new ones.
Production undersizes are also indicated by
paint marks as follows:
White line on main bearing cap - parent bore
0.40 mm oversize
Green line on crankshaft front counterweight
- main bearing journals 0.25 mm
undersize
Green spot on counterweight - big-end
bearing journals 0.25 mm undersize4If the crankshaft endfloat is more than the
maximum specified amount, new
thrustwashers should be fitted to the centre
main bearings. These are usually supplied
together with the main and big-end bearings
on a reground crankshaft.
5An accurate method of determining bearing
wear is by the use of Plastigage. The
crankshaft is located in the main bearings
(and big-end bearings if necessary) and the
Plastigage filament located across the journal
which must be dry. The cap is then fitted and
the bolts/nuts tightened to the specified
torque. On removal of the cap the width of the
filaments is checked against a scale which
shows the bearing running clearance. This
clearance is then compared with that given in
the Specifications (see illustration).
6If the spigot bearing in the rear of the
crankshaft requires renewal, extract it with a
suitable puller. Alternatively fill it with heavy
grease and use a close fitting metal dowel
driven into the centre of the bearing. Drive the
new bearing into the crankshaft with a soft
metal drift.
1The cylinder bores must be examined for
taper, ovality, scoring and scratches. Start by
examining the top of the bores; if these are
worn, a slight ridge will be found which marks
the top of the piston ring travel. If the wear is
excessive, the engine will have had a high oil
consumption rate accompanied by blue
smoke from the exhaust.
2If available, use an inside dial gauge to
measure the bore diameter just below the
ridge and compare it with the diameter at the
bottom of the bore, which is not subject to
wear. If the difference is more than 0.152 mm
(0.006 in), the cylinders will normally require
reboring with new oversize pistons fitted.
3Proprietary oil control rings can be obtained
for fitting to the existing pistons if it is felt that
the degree of wear does not justify a rebore.
However, any improvement brought about by
such rings may be short-lived.
4If new pistons or piston rings are to be fitted
to old bores, deglaze the bores with abrasive
paper or a Òglaze busterÓ tool. The object is to
produce a light cross-hatch pattern to assistthe new rings to bed in.
5If there is a ridge at the top of the bore and
new piston rings are being fitted, either the
top piston ring must be stepped (Òridge
dodgerÓ pattern) or the ridge must be
removed with a ridge reamer. If the ridge is
left, the piston ring may hit it and break.
6Thoroughly examine the crankcase and
cylinder block for cracks and damage and use
a piece of wire to probe all oilways and
waterways to ensurethatthey are
unobstructed.
1Make a final check to ensure that
everything has been reconnected to the
engine and that no rags or tools have been left
in the engine bay.
2Check that oil and coolant levels are
correct.
3Start the engine. This may take a little
longer than usual as fuel is pumped up to the
engine.
4Check that the oil pressure light goes out
when the engine starts.
5Run the engine at a fast tickover and check
for leaks of oil, fuel or coolant. Also check
power steering and transmission fluid cooler
unions, where applicable. Some smoke and
odd smells may be experienced as assembly
lubricant burns off the exhaust manifold and
other components.
6Bring the engine to normal operating
temperature, then check the ignition timing
and the idle speed (where applicable) and
mixture.
7If splined type cylinder head bolts have
been used, stop the engine after it has been
running for 15 minutes, then remove the
crankshaft cover and tighten the cylinder
head bolts to the fourth stage given in the
Specifications, in the correct order.
8When the engine has completely cooled,
re-check the oil and coolant levels, and
check, and if necessary adjust, the valve
clearances.
9If new bearings, pistons etc have been
fitted, the engine should be run-in at reduced
speeds and loads for the first 500 miles (800
km) or so. It is beneficial to change the engine
oil and filter after this mileage.
37Initial start-up after overhaul or
major repair
36Cylinder block and bores -
examination and renovation35Crankshaft and bearings -
examination and renovation
2A¥24SOHC engines
34.24 Fitting a thrustwasher to the centre
main bearing cap35.5 Checking the width of the filament
against the scale of the packet34.29 Fitting a sealing wedge to the rear
main bearing cap