bolt pattern FORD MONDEO 1993 Service Repair Manual

15Measure the piston diameter at right-
angles to the gudgeon pin axis, just above the
bottom of the skirt; again, note the results
(see illustration).
16If it is wished to obtain the piston-to-bore
clearance, measure the bore and piston skirt
as described above, and subtract the skirt
diameter from the bore measurement. If the
precision measuring tools shown are not
available, the condition of the pistons and
bores can be assessed, though not quite as
accurately, by using feeler gauges as follows.
Select a feeler gauge of thickness equal to the
specified piston-to-bore clearance, and slip it
into the cylinder along with the matching
piston. The piston must be positioned exactly
as it normally would be. The feeler gauge
must be between the piston and cylinder on
one of the thrust faces (at right-angles to the
gudgeon pin bore). The piston should slip
through the cylinder (with the feeler gauge in
place) with moderate pressure; if it falls
through or slides through easily, the clearance
is excessive, and a new piston will be
required. If the piston binds at the lower end
of the cylinder, and is loose toward the top,
the cylinder is tapered. If tight spots are
encountered as the piston/feeler gauge is
rotated in the cylinder, the cylinder is out-of-
round (oval).
17Repeat these procedures for the
remaining pistons and cylinder bores.
18Compare the results with the
Specifications at the beginning of this
Chapter; if any measurement is beyond the
dimensions specified for that class (check the
piston crown marking to establish the class of
piston fitted), or if any bore measurement is
significantly different from the others
(indicating that the bore is tapered or oval),
the piston or bore is excessively-worn.
19Worn pistons must be renewed; at the
time of writing, pistons are available as Ford
replacement parts only as part of the
complete piston/connecting rod assembly.
See a Ford dealer or engine reconditioning
specialist for advice.
20If any of the cylinder bores are badlyscuffed or scored, or if they are excessively-
worn, out-of-round or tapered, the usual
course of action would be to have the cylinder
block/crankcase rebored, and to fit new,
oversized, pistons on reassembly. See a Ford
dealer or engine reconditioning specialist for
advice.
21If the bores are in reasonably good
condition and not excessively-worn, then it
may only be necessary to renew the piston
rings.
22If this is the case (and if new rings can be
found), the bores should be honed, to allow
the new rings to bed in correctly and provide
the best possible seal; before honing the
bores, refit the main bearing caps (without the
bearing shells), and tighten the bolts to the
specified torque wrench setting. Note:If you
don’t have the tools, or don’t want to tackle
the honing operation, most engine
reconditioning specialists will do it for a
reasonable fee.
23Two types of cylinder hones are
commonly available - the flex hone or “bottle-
brush” type, and the more traditional
surfacing hone with spring-loaded stones.
Both will do the job and are used with a
power drill, but for the less-experienced
mechanic, the “bottle-brush” hone will
probably be easier to use. You will also need
some paraffin or honing oil, and rags.
Proceed as follows:
(a) Mount the hone in the drill, compress the
stones, and slip it into the first bore (see
illustration). Be sure to wear safety
goggles or a face shield!
(b) Lubricate the bore with plenty of honing
oil, switch on the drill, and move the hone
up and down the bore, at a pace that will
produce a fine cross-hatch pattern on the
cylinder walls. Ideally, the cross-hatch
lines should intersect at approximately a
60° angle (see illustration). Be sure to
use plenty of lubricant, and don’t take off
any more material than is absolutely
necessary to produce the desired finish.
Note:Piston ring manufacturers may
specify a different crosshatch angle - readand follow any instructions included with
the new rings.
(c) Don’t withdraw the hone from the bore
while it’s running. Instead, switch off the
drill, and continue moving the hone up
and down the bore until it comes to a
complete stop, then compress the stones
and withdraw the hone. If you’re using a
“bottle-brush” hone, switch off the drill,
then turn the chuck in the normal
direction of rotation while withdrawing the
hone from the bore.
(d) Wipe the oil out of the bore, and repeat
the procedure for the remaining cylinders.
(e) When all the cylinder bores are honed,
chamfer the top edges of the bores with a
small file, so the rings won’t catch when
the pistons are installed. Be very careful
not to nick the cylinder walls with the end
of the file.
(f) The entire cylinder block/crankcase must
be washed very thoroughly with warm,
soapy water, to remove all traces of the
abrasive grit produced during the honing
operation. Note:The bores can be
considered clean when a lint-free white
cloth - dampened with clean engine oil -
used to wipe them out doesn’t pick up
any more honing residue, which will show
up as grey areas on the cloth. Be sure to
run a brush through all oil holes and
galleries, and flush them with running
water.
(g) When the cylinder block/crankcase is
completely clean, rinse it thoroughly and
dry it, then lightly oil all exposed
machined surfaces, to prevent rusting.
24The cylinder block/crankcase should now
be completely clean and dry, with all
components checked for wear or damage,
and repaired or overhauled as necessary.
Refit as many ancillary components as
possible, for safekeeping (see paragraphs 9
and 10 above). If reassembly is not to start
immediately, cover the block with a large
plastic bag to keep it clean, and protect the
machined surfaces as described above to
prevent rusting.
2B•16 Engine removal and general engine overhaul procedures
11.15 Measure the piston skirt diameter at
right-angles to the gudgeon pin axis, just
above the base of the skirt11.23A A “bottle-brush” hone will produce
better results if you have never honed
cylinders before11.23B The cylinder hone should leave a
smooth, cross-hatch pattern with the lines
intersecting at approximately a 60º angle
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