Leakage Points; Compression Test; Compression Gauge Check; Test Results - Ford LRG-423 Service Manual

01-7
Engine Service 01-7
SERVICE PROCEDURES (Continued)
Leakage Points
Examine the following areas for oil leakage.
l
Rocker cover sealant or gaskets
l
Intake manifold gaskets/end seals
l
Cylinder head gaskets
l
Oil bypass filter (6714)
l
Oil level indicator (dipstick) tube connection
l
Oil pressure sensor (9278)
l
Cup plugs and/or pipe plugs at end of oil
passages
l
Oil pan gasket (6710)
l
Oil pan front and rear end seals
l
Crankshaft front seal (6700)
l
Crankshaft rear oil seal (6701)
l
Oil pump
l
Crankshaft rear oil seal (6701)
Air leakage in area around a crankshaft rear oil seal
(6701) does not necessarily indicate a rear seal leak.
However, if no other cause can be found for oil
leakage, it can be assumed that rear seal is the cause
of the oil leakage.
l
Rear main bearing cap parting line.
l
Rear main bearing cap and seals.
l
Flywheel mounting bolt holes.
l
Rear cup plugs and/or pipe plugs at the end of oil
passages.
Oil leaks at crimped seams in sheet metal parts and
cracks in cast or stamped parts can be detected when
pressurizing the crankcase.
Compression Pressure Limit Chart
Light foaming equally around rocker arm cover bolts
and crankshaft seals is not detrimental and no
corrections are required in such cases.
Compression Test
Compression Gauge Check
1.
5.
Make sure oil in crankcase is of the correct
viscosity and at proper level, and battery (10655)
is properly charged. Operate the engine until it is
at normal operating temperature. Turn off ignition
switch (11572), then remove all spark plugs
(12405).
Set throttle plates in wide-open position.
Install a compression gauge such as Rotunda
Compression Tester 059-R0009, or equivalent, in
No. 1 cylinder.
Install an auxiliary starter switch in starting circuit.
With ignition switch (11572) in the OFF position,
and using auxiliary starter switch, crank engine at
least five compression strokes and record highest
reading. Note the approximate number of
compression strokes required to obtain the
highest reading.
Repeat test on each cylinder, cranking the engine
approximately the same number of compression
strokes.
Test Results
The indicated compression pressures are considered
within specification if the lowest reading cylinder is
within 75 percent of the highest. Refer to the chart
below.
Maximum Minimum
Maximum Minimum Maximum Minimum Maximum Minimum
psi psi psi psi psi
psi psi psi
734 707 764 723 794 745 224 768
136 102 766 724 796 147 226 169
738 704 768 726 798 748 228 171
I
140 105 170 127 200 750 230 772
742 707 772 129 202 157 232 774
744 708 174 131 204 753 234 775
746 170 776 132 206 754 236 777
748 771 178 133 208 156 238 778
750 173 180 135 270 757 240 180
752 774 782 736 212 758 242 787
,
754 775 184 138 214 160 244 783
156 777 186 140 216 762 246 184
758 718 188 141 218 163 248 186
160 120 190 742 220 165 250 187
762 121 192 144 222 166