check engine LEXUS SC400 1991 Service Repair Manual

DISASSEMBLY OF CYLINDER BLOCK
(See Components on page EM±75)
1. REMOVE REAR OIL SEAL RETAINER (a) Remove the six bolts.
(b) Remove the oil seal retainer by prying the area between
the oil seal retainer and main bearing cap with a
screwdriver.
2. CHECK CONNECTING ROD THRUST CLEARANCE Using a dial indicator, measure the thrust clearance while
moving the two connecting rods back and forth.
Standard thrust clearance: 0.250±0.402 mm
(0.0098±0.0158 in.)
Maximum thrust clearance: 0.50 mm (0.0197 in.)
If the thrust clearance is greater than maximum, replace the
connecting rod assembly(s). If necessary, replace the crank-
shaft.
Connecting rod thickness: 25.898±25.950 mm (1.0196±1.0217 in.)
3. REMOVE CONNECTING ROD CAPS AND CHECK OILCLEARANCE
(a) Check the matchmarks on the connecting rod and cap.
(b) Remove the connecting rod cap bolts.
(c) Using the two removed connecting rod bolts, removethe connecting rod cap and lower bearing by wiggling
the connecting rod cap right and left.
HINT: Keep the lower bearing inserted with the connecting
rod cap.
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ENGINE MECHANICAL Cylinder BlockEM±77
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HINT:
wKeep the bearings, connecting rod and cap together.
w Arrange the piston and connecting rod assemblies in
correct order.
5. CHECK CRANKSHAFT THRUST CLEARANCE Using a dial indi cator, measure the thrust clearance while pry-
ing the crankshaft back and forth with a screwdriver.
Standard thrust clearance: 0.020±0.220 mm
(0.0008±0.0087 in.)
Maximum thrust clearance: 0.30 mm (0.0118 in.)
If the thrust clearance is greater than maximum, replace the
thrust washers as a set.
Thrust washer thickness:
1.940±1.990 mm (0.0764±0.0783 in.)
6. REMOVE MAIN BEARING CAPS AND CHECK OILCLEARANCE
(a) Remove the main bearing cap bolts.
(b) Using the removed main bearing cap bolts, pry the main
bearing cap back and forth, and remove the main
bearing caps, lower bearings and lower thrust washers
(No. 4 main bearing cap only).
HINT:
w Keep the lower bearing and main bearing cap together.
w Arrange the main bearing caps and lower thrust
washers in correct order.
(c) Lift out the crankshaft.
HINT: Keep the upper bearing and upper thrust washer to-
gether with the cylinder block.
EM±80
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(d) Clean each main journal and bearing.
(e) Check each main journal and bearing for pitting andscratches.
If the journal or bearing is damaged, replace the bearings.
If necessary, grind or replace the crankshaft.
(f) Place the crankshaft on the cylinder block.
(g) Lay a strip of Plastigage across each journal.
(h) Install the main bearing caps.
(See step 4 on pages EM±97 and 98)
Torque: 1st 44 N Vm (450 kgf Vcm, 33 ft Vlbf)
2nd turn 90 5
HINT: Do not turn the crankshaft.
(i) Remove the main bearing caps.
(See procedures (a) and (b) above)
(j) Measure the Plastigage at its widest point.
Standard clearance:
STD size 0.026±0.040 mm (0.0010±0.0016 in.)
U/S 0.25 0.025±0.061 mm (0.0010±0.0024 in.)
Maximum clearance: STD size 0.06 mm (0.0024 in.)
U/S 0.25 0.08 mm (0.0031 in.)
If the oil clearance is greater than maximum, replace the bearings.
If necessary, replace the crankshaft.
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INSPECTION AND REPAIR OF
CYLINDER BLOCK
1. CLEAN CYLINDER BLOCK
A. Remove gasket materialUsing a gasket scraper, remove all the gasket material from
the cylinder block surface.
B. Clean cylinder block Using a soft brush and solvent, thoroughly clean the cylinder
block.
2. INSPECT CYLINDER BLOCK SURFACE FOR FLATNESS Using precision straight edge and feeler gauge, measure the
top surfaces of the cylinder block for warpage.
Maximum warpage: 0.07 mm (0.0028 in.)
If warpage is greater than maximum, replace the cylinder
block.
3. INSPECT CYLINDER FOR VERTICAL SCRATCHES Visually check the cylinder for vertical scratches.
If deep scratches are present, replace the cylinder block.
4. INSPECT CYLINDER BORE DIAMETER (a) Using a cylinder gauge, measure the cylinder borediameter at positions A, B and C in the thrust and axial
directions.
Standard diameter: 86.000±86.013 mm
(3.3858±3.3863 in.)
Maximum diameter: 86.02 mm (3.3866 in.)
If the diameter is greater than maximum, replace the cylinder
block.
(b) Difference between measurements A, B and C is greater than taper limit.
Taper limit: 0.01 mm (0.0004 in.)
(c) Difference between the thrust and axial measurementsis greater than out±of±round limit.
Out±of±round limit: 0.02 mm (0.0008 in.)
EM±84±
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5. REMOVE CYLINDER RIDGEIf the wear is less than 0.2 mm (0.008 in.), using a ridge ream-
er, grind the top of the cylinder.
6. INSPECT MAIN BEARING CAP BOLTS Using vernier calipers, measure the minimum diameter of the
compressed thread at the measuring point.
Standard diameter: 9.96±9.97 mm
(0.3921±0.3925 in.)
Minimum diameter: 9.7 mm (0.3819 in.)
If the diameter is less than minimum, replace the bolt.
DISASSEMBLY OF PISTON AND
CONNECTING ROD ASSEMBLIES
1. CHECK FIT BETWEEN PISTON AND PISTON PIN Try to move the piston back and forth on the piston pin.
If any movement is felt, replace the piston and pin as a set.
2. REMOVE PISTON RINGS
(a) Using a piston ring expander, remove the two compression rings.
(b) Remove the two side rails and oil ring expander by hand. HINT: Arrange the piston rings in correct order only.
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3. INSPECT CONNECTING ROD
A. Inspect connecting rod alignmentUsing a feeler gauge and rod aligner, check the connecting
rod alignment.w Check for bend.
Maximum bend:
0.05 mm (0.0020 in.) per 100 mm (3.94 in.)
If bend is greater than maximum, replace the connecting rod
assembly.
w Check for twist.
Maximum twist:
0.15 mm (0.0059 in.) per 100 mm (3.94 in.)
If twist is greater than maximum, replace the connecting rod
assembly.
B. Inspect piston pin oil clearance (a) Using a caliper gauge, measure the inside diameter ofthe connecting rod bushing.
Bushing inside diameter: 22.005±22.014 mm
(0.8663±0.8667 in.)
(b) Using a micrometer, measure the piston pin diameter.
Piston pin diameter: 21.997±22.006 mm(0.8660±0.8664 in.)
(c) Subtract the piston pin diameter measurement from thebushing inside diameter measurement.
Standard oil clearance: 0.005±0.011 mm
(0.0002±0.0004 in.)
Maximum oil clearance: 0.05 mm (0.0020 in.)
If the oil clearance is greater than maximum, replace the
bushing. If necessary, replace the piston and piston pin as a
set.
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C. If necessary, replace connecting rod bushing(a) Using SST and a press, press out the bushing.
SST 09222±30010
(b) Align the oil holes of a new bushing and the connectingrod.
(c) Using SST and a press, press in the bushing.
SST 09222±30010
(d) Using a pin hole grinder, bore the bushing to obtain the
standard specified clearance (see step B above)
between the bushing and piston pin.
(e) Check the piston pin fit at room temperature.
Coat the piston pin with engine oil, and push it into the con-
necting rod with your thumb.
D. Inspect connecting rod bolts Using vernier calipers, measure the minimum diameter of the
compressed bolt at the measuring point.
Standard diameter: 8.2±8.3 mm
(0.325±0.327 in.)
Minimum diameter: 8.0 mm (0.315 in.)
If the diameter is less than minimum, replace the connecting
rod bolt.
EM±90
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INSPECTION OF CRANKSHAFT
1. INSPECT CRANKSHAFT FOR RUNOUT(a) Place the crankshaft on V±blocks.
(b) Using a dial indicator, measure the circle runout at thecenter journal.
Maximum circle runout: 0.06 mm (0.0024 in.)
If the circle runout is greater than maximum, replace the
crankshaft.
2. INSPECT MAIN JOURNALS AND CRANK PINS (a) Using a micr ometer, measure the diameter of each main
journal and crank pin.
Main journal diameter: 61.984±62.000 mm
(2.4403±2.4409 in.)
Crank pin diameter: 51.982±52.000 mm (2.0465±2.0472 in.)
If the diameter is not as specified, check the oil clearance
(See page EM±77 or EM±80).
(b) Check each main journal and crank pin for taper andout±of±round as shown.
Maximum taper and out±of round: 0.02 mm
(0.0008 in.)
If the taper or out±of±round is greater than maximum, re-
place the crankshaft.
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(c) Mark the front of the main bearing cap bolt head withpaint.
(d) Second, retighten the main bearing cap bolts 90
in the
numerical order shown above.
(e) Check that the painted mark is now at a 90
angle to the
front.
(f) Check that the crankshaft turns smoothly.
(g) Check the crankshaft thrust clearance. (See step 5 on page EM±80)
5. INSTALL PISTON AND CONNECTING ROD ASSEMBLIES Using a piston ring compressor, push the correctly numbered
piston and connecting rod assemblies into each cylinder with
the front mark of the piston facing forward.
6. INSTALL CONNECTING ROD CAPS
A. Place connecting rod cap on connecting rod (a) Match the numbered c onnecting rod cap with the
connecting rod.
(b) Install the connecting rod cap by aligning the dowel pin to the corrosponding hole.
B. Install connecting rod cap bolts HINT:
wThe connecting rod cap bolts are tightened in two
progressive steps (steps (b) and (d)).
w If any of the connecting rod bolts break or deform,
replace them.
EM±98
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(a) Apply a light coat of engine oil on the threads and under
the heads of the connecting rod cap bolts.
(b) At first, install and alternately tighten the bolts of the connecting rod cap in several passes.
Torque: 29 N Vm (300 kgf Vcm, 22 ft Vlbf)
If any one of the connecting rod cap bolts does not meet the
torque specification, replace the cap bolt.
(c) Mark the front of the connecting rod cap bolt with paint.
(d) Retighten the connecting rod cap bolts 905 in the
numerical order shown.
(e) Check that the painted mark is now at a 905 angle to the
front.
(f) Check that the crankshaft turns smoothly.
(g) Check the connecting rod thrust clearance. (See step 2 on page EM±77)
7. INSTALL REAR OIL SEAL RETAINER (a) Remove any old packing (FIPG) material and be carefulnot to drop any oil on the contact surfaces of the retainer
and cylinder block.
w Using a razor blade and gasket scraper, remove all the
old packing (FIPG) material from the gasket surfaces
and sealing groove.
w Thoroughly clean all components to remove all debris.
w Using a non±residue solvent, clean both sealing
surfaces.
(b) Apply seal packing to the retainer as shown in the illustration.
Seal packing: Part No. 08826±00080 or equivalent
w Install a nozzle that has been cut to a 2±3 mm
(0.08±0.12 in.) opening.
w Parts must be assembled within 3 minutes of
application. Otherwise the material must be removed
and reapplied.
w Immediately remove nozzle from the tube and reinstall
cap.
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