LEXUS LS430 2003 Factory Repair Manual

Fig. 434: Measuring Surfaces Contacting Cylinder Head
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
d. Visuall
y check the cylinder for vertical scratches.

If deep scratches are present, replace the cylinder block sub-assy.
Fig. 435: Identifying Cylinder Block Sub
-Assy
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
e. Inspect the cylinder bore diameter.
HINT:
There are 3 sizes of the standard cylinder bore diameter, marked "1", "2" and "3" accordingly. The
mark is stamped on the top of the cylinder block.
If deep scratches are present, replace the c
ylinder block sub-assy.

Fig. 436: Identifying Cylinder Bore Diameter
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
1. Using a cylinder gauge, measure the cylinder bore diameter at positions A and B in the thrust
and axial directions.
STANDARD DIAMETER:
CYLINDER BORE DIAMETER
Maximum diameter: 91.149 mm (3.5885 in.)
If the avera
ge of the diameter is greater than the maximum, replace the cylinder block.
Mark 191.000 to 91.008 mm (3.5827 to 3.5830 in.)
Mark 291.008 to 91.021 mm (3.5830 to 3.5835 in.)
Mark 391.021 to 91.029 mm (3.5835 to 3.5838 in.)

Fig. 437: Measuring Cylinder Bore Diameter Positions (A) And (B) Using Cylinder Gauge
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
f. Remove the cylinder ridge.
If the wear is less than 0.2 mm (0.008 in.), using a ridge reamer, grind the top of the cylinder.
Fig. 438: Removing Cylinder Ridge

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9.INSPECT W/PIN PISTON SUB-ASSY
a. Clean the piston.
1. Usin
g a gasket scraper, remove the carbon from the piston top.

Fig. 439: Removing Carbon From Piston Top
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
2. Usin
g a groove cleaning tool or broken ring, clean the piston ring grooves.

Fig. 440: Cleaning Piston Ring Grooves
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3. Using solvent and a brush, thoroughly clean the piston.

Fig. 441: Cleaning Piston Using Solvent And Brush
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b. Inspect the piston oil clearance.
HINT:
There are 3 standard piston diameter size, marked "1", "2" and "3". The mark is stamped on the
piston top.
1. Using a micrometer, measure the piston diameter at right angles to the piston pin center line,
28.1 mm (1.106 in.) from the piston head.
PISTON DIAMETER:
PISTON DIAMETER SPECIFICATIONS
2. Measure the c
ylinder bore diameter in the thrust directions (see step 8 above).
Mark 190.910 to 90.940 mm (3.5791 to 3.5803 in.)
Mark 290.920 to 90.948 mm (3.5795 to 3.5806 in.)
Mark 390.928 to 90.958 mm (3.5798 to 3.5810 in.)

3. Subtract the piston diameter measurement from the cylinder bore diameter measurement.
Standard oil clearance:
0.060 to 0.104 mm (0.0023 to 0.0041 in.)
Maximum oil clearance: 0.124 mm (0.0049 in.)
If the oil clearance is greater than the maximum, replace all the 8 pistons. If necessary, replace the
c
ylinder block sub-assy.

Fig. 442: Measuring Piston Diameter At Right Angles Using Micrometer
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.