1991 LEXUS SC400 engine

3. DISCONNECT ENGINE WIRE FROM TRANSMISSION(a) Disconnect the following connectors:(1) O/D direct clutch speed sensor connector
(2) No.1 speed sensor connector
(3) No.2 speed sensor connector
(4) Neutral start switch connector
(b) Disconnect the five wire clamps from the brackets on the
transmission.
4. SEPARATE ENGINE AND TRANSMISSION (See AT section)
EM±130
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ENGINE MECHANICAL Cylinder Block
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COMPONENTS FOR DISASSEMBLY AND ASSEMBLY OF CYLINDER BLOCK
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ENGINE MECHANICAL Cylinder BlockEM±131
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PREPARATION FOR DISASSEMBLY
(See Components on page EM±131)
1. REMOVE DRIVE PLATE Remove the eight bolts, two spacers and drive plate.
2. INSTALL ENGINE TO ENGINE STAND FOR DISASSEMBLY
3. REMOVE TIMING BELT AND PULLEYS (See pages EM±36 to 44)
4. REMOVE Cylinder Block (See pages EM±61 to 75)
5. REMOVE RH ENGINE MOUNTING BRACKET Remove the four bolts and mounting bracket.
6. REMOVE LH ENGINE MOUNTING BRACKET (a) Remove the clamp bolt, and disconnect the engine wirefrom the engine mounting bracket.
(b) Remove the four bolts and mounting bracket.
7. REMOVE STARTER (a) Remove the two bolts, and disconnect the starter fromthe cylinder block.
EM±132
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ENGINE MECHANICAL Cylinder Block
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(b) Disconnect the wire clamp from the bracket on thestarter.
(c) Remove the nut, and disconnect the wire.
(d) Disconnect the connector, and remove the starter.
8. REMOVE KNOCK SENSORS (a) Disconnect the two knock sensor connectors.
(b) Using SST, remove the two knock sensors.
SST 09816±30010
9. REMOVE WATER BY±PASS PIPE (a) Remove the two bolts.
(b) Pull out the by±pass pipe from the water pump.
(c) Remove the O±ring from the by±pass pipe.
10. REMOVE ENGINE WIRE (a) Disconnect the following connectors:(1) Oil level sensor connector
(2) Oil pressure switch connector
(b) Remove the three bolts and wire cover from the LH side
of the cylinder block.
(c) Remove the two bolts and engine wire.
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ENGINE MECHANICAL Cylinder BlockEM±133
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11. REMOVE WATER PUMP(a) Remove the five mounting bolt, two mounting stud boltsand mounting nut.
(b) Remove the water pump by prying the portions between
the water pump and cylinder block with a screwdriver.
12. REMOVE NO.2 AND NO.1 OIL PANS (See steps 7 to 12 on pages LU±9 to 11)
13. REMOVE OIL PUMP (a) Remove the eight mounting bolts.
(b) Remove the oil pump by prying the portions between the
oil pump and cylinder block with a screwdriver.
(c) Remove the O±ring from the cylinder block.
14. REMOVE ALTERNATOR BRACKET Remove the bolt and bracket.
15. REMOVE WATER SEAL PLATE
Remove the two nuts and seal plate.
EM±134
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DISASSEMBLY OF CYLINDER BLOCK
(See Components on page EM±131)
1. REMOVE REAR OIL SEAL RETAINER (a) Remove the seven bolts.
(b) Remove the oil seal retainer by prying the portions
between the oil seal retainer and main bearing cap with
a screwdriver.
(c) Remove the O±ring.
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: 0.160±0.290 mm
(0.0063±0.0114 in.)
Maximum thrust clearance: 0.35 mm (0.0138 in.)
If the thrust clearance is greater than maximum, replace the
connecting rod assembly(s). If necessary, replace the crank-
shaft.
Connecting rod thickness: 22.880±22.920 mm (0.9008±0.9024 in.)
3. REMOVE CONNECTING ROD CAPS AND CHECK OILCLEARANCE
(a) Using a punch or numbering stamp, place thematchmarks on the connecting rod and cap to ensure
correct reassembly.
(b) Using SST, remove the two connecting rod bolts.
SST 09011±38121
(c) Using the two removed connecting rod bolts, remove the 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±135
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(d) Clean the crank pin and bearings.
(e) C h e c k t h e c r a n k p i n a n d b e a r i n g f o r p i t t i n g a n dscratches.
If the crank pin or bearing are damaged, replace the bear-
ings. If necessary, replace the crankshaft.
(f) Lay a strip of Plastigage across the crank pin.
(g) Install the connecting rod cap with the two bolts.
(See step 6 on pages EM±159 and 160)
Torque: 1st 25 N Vm (250 kgf Vcm, 18 ft Vlbf)
2nd Turn 90 5
NOTICE: Do not turn the crankshaft.
(h) Remove the two bolts, connecting rod cap and lower
bearing. (See procedure (b) and (c) above)
(i) Measure the Plastigage at widest point.
Standard oil clearance: 0.027±0.053 mm (0.0011±0.0021 in.)
Maximum oil clearance: 0.065 mm (0.0026 in.)
If the oil clearance is greater than maximum, replace the
bearings. If necessary, replace the crankshaft.
EM±136
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HINT: If using a standard bearing, replace with one having
the same number. If the number of the bearing cannot be de-
termined, select the correct bearing by adding together the
numbers imprinted on the connecting rod cap and crank-
shaft, then selecting the bearing with the same number as the
total. There are six sizes of standard bearings, marked º2º,
º3º, º4º, º5º, º6º and º7º accordingly.
  Number mark 
Connecting rod cap 1 1 2 1 2 3 2 3 4 3 4 4 

Crakshaft
 

1
 

2
 

1
 

3
 

2
 

1
 

3
 

2
 

1
 

3
 

2
 

3
 Use bearing 2 3 4 5 6 7
EXAMPLE: Connecting rod cap º3º + Crankshaft º1º
= Total number 4 (Use bearing º4º)
(Reference)
Connecting rod big end inside diameter:
Mark º1º 55.000±55.006 mm (2.1654±2.1656 in.)
Mark º2º 55.006±55.012 mm (2.1656±2.1658 in.)
Mark º3º 55.012±55.018 mm (2.1658±2.1661 in.)
Mark º4º 55.018±55.024 mm (2.1661±2.1663 in.)
Crankshaft crank pin diameter: Mark º1º 51.994±52.000 mm (2.0470±2.0472 in.)
Mark º2º 51.988±51.994 mm (2.0468±2.0470 in.)
Mark º3º 51.982±51.988 mm (2.0465±2.0468 in.)
Standard sized bearing center wall thickness: Mark º2º 1.484±1.487 mm (0.0584±0.0585 in.)
Mark º3º 1.487±1.490 mm (0.0585±0.0587 in.)
Mark º4º 1.490±1.493 mm (0.0587±0.0588 in.)
Mark º5º 1.493±1.496 mm (0.0588±0.0589 in.)
Mark º6º 1.496±1.499 mm (0.0589±0.0590 in.)
Mark º7º 1.499±1.502 mm (0.0590±0.0591 in.)
(j) Completely remove the Plastigage.
4. REMOVE PISTON AND CONNECTING ROD ASSEMBLIES
(a) Using a ridge reamer, remove all the carbon from the top
of the cylinder.
(b) Push the piston, connecting rod assembly and upper bearing through the top of the cylinder block.
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ENGINE MECHANICAL Cylinder BlockEM±137
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