Lexus NX: Inspection

INSPECTION

PROCEDURE

1. INSPECT CYLINDER BLOCK FOR WARPAGE

(a) Using a precision straightedge and feeler gauge, measure the warpage of the surface that contacts the cylinder head gasket. Maximum warpage: 0.05 mm (0.00197 in.) If the warpage is more than the maximum, replace the cylinder block.

2. INSPECT CYLINDER BORE

(a) Using a cylinder gauge, measure the cylinder bore diameter at positions A and B in the thrust and axial directions.

*a	Thrust Direction
*b	Axial Direction
*c	10 mm (0.394 in.)
	Front

Reference value (new parts):

90.000 to 90.013 mm (3.543 to 3.544 in.)

Maximum diameter:

90.13 mm (3.55 in.)

If the average diameter of the 4 positions is more than the maximum, replace the cylinder block.

3. INSPECT PISTON

(a) Using a gasket scraper, remove the carbon from the piston top.

(b) Using a groove cleaning tool or a broken ring, clean the piston ring grooves.

(c) Using a brush and solvent, thoroughly clean the piston.

NOTICE:

Do not use a wire brush.

(d) Using a micrometer, measure the piston diameter at a position that is 10.5 mm (0.413 in.) from the bottom of the piston (refer to the illustration). Reference value (new parts): 89.986 to 89.996 mm (3.5427 to 3.5431 in.)

*a 10.5 mm (0.413 in.)

4. INSPECT PISTON OIL CLEARANCE

(a) Subtract the piston diameter measurement from the cylinder bore diameter measurement.

Reference value (new parts):

0.004 to 0.042 mm (0.000157 to 0.00165 in.)

Maximum oil clearance:

0.10 mm (0.00394 in.)

If the oil clearance is more than the maximum, replace all the pistons. If necessary, replace the cylinder block.

5. INSPECT RING GROOVE CLEARANCE

(a) Using a feeler gauge, measure the clearance between a new piston ring and the wall of the ring groove.

Standard Ring Groove Clearance:

If the groove clearance is not as specified, replace the piston with pin.

6. INSPECT PISTON RING END GAP

(a) Insert the piston ring into the cylinder bore.

(b) Using a piston, push the piston ring a little beyond the bottom of the ring travel, 120 mm (4.72 in.) from the top of the cylinder block.

(c) Using a feeler gauge, measure the end gap.

Standard End Gap:

Maximum End Gap:

If the end gap is more than the maximum, replace the piston ring. If the end gap is more than the maximum even with a new piston ring, replace the cylinder block.

7. INSPECT PISTON PIN OIL CLEARANCE

(a) Check each mark on the piston, piston pin and connecting rod.

HINT:

The front mark is "2H" printed in raised letters.

(b) Using a caliper gauge, measure the inside diameter of the piston pin hole. Standard Piston Pin Hole Inside Diameter: Item Specified Condition Mark A 22.001 to 22.004 mm (0.86618 to 0.86630 in.) Mark B 22.005 to 22.007 mm (0.86634 to 0.86642 in.) Mark C 22.008 to 22.010 mm (0.86645 to 0.86653 in.)

(c) Using a micrometer, measure the piston pin diameter. Standard Piston Pin Diameter: Item Specified Condition Mark A 21.997 to 22.000 mm (0.86602 to 0.86614 in.) Mark B 22.001 to 22.003 mm (0.86618 to 0.86626 in.) Mark C 22.004 to 22.006 mm (0.86630 to 0.86638 in.) If the diameter is not as specified, replace the piston pin.

*a 5 mm (0.197 in.) *b 28 mm (1.10 in.)

(d) Using a caliper gauge, measure the connecting rod small end bush inside diameter.

Standard Connecting Rod Small End Bush Inside Diameter:

If the diameter is not as specified, replace the connecting rod.

(e) Subtract the piston pin diameter measurement from the piston pin hole inside diameter measurement.

Standard oil clearance:

0.001 to 0.007 mm (0.0000394 to 0.000276 in.)

Maximum oil clearance:

0.013 mm (0.000512 in.)

If the oil clearance is more than the maximum, replace the piston and piston pin as a set.

(f) Subtract the piston pin diameter measurement from the connecting rod small end bush inside diameter measurement.

Standard oil clearance:

0.005 to 0.011 mm (0.000197 to 0.000433 in.)

Maximum oil clearance:

0.017 mm (0.000669 in.)

If the oil clearance is more than the maximum, replace the connecting rod. If necessary, replace the connecting rod and piston pin as a set.

8. INSPECT CONNECTING ROD

(a) Using a connecting rod aligner and feeler gauge, check the connecting rod alignment.

(1) Check for bend.

Maximum bend:

0.05 mm (0.00197 in.) per 100 mm (3.94 in.)

If the bend is more than the maximum, replace the connecting rod.

(2) Check for twist. Maximum twist: 0.15 mm (0.00591 in.) per 100 mm (3.94 in.) If the twist is more than the maximum, replace the connecting rod.

9. INSPECT CRANKSHAFT

(a) Inspect for circle runout.

(1) Using a dial indicator and V-blocks, measure the circle runout.

Maximum circle runout:

0.03 mm (0.00118 in.)

If the circle runout is more than the maximum, replace the crankshaft.

(b) Inspect the main journals. (1) Using a micrometer, measure the diameter of each main journal. Standard main journal diameter: 54.988 to 55.000 mm (2.1649 to 2.1654 in.) If the diameter is not as specified, check the crankshaft oil clearance. If necessary, replace the crankshaft. (2) Check each main journal for taper and out-of-round as shown in the illustration. Maximum taper and out-of-round: 0.003 mm (0.000118 in.) If the taper and out-of-round are more than the maximum, replace the crankshaft.

(c) Inspect the crank pin. (1) Using a micrometer, measure the diameter of each crank pin. Standard crank pin diameter: 51.492 to 51.500 mm (2.0272 to 2.0276 in.) If the diameter is not as specified, check the connecting rod oil clearance. If necessary, replace the crankshaft. (2) Inspect each crank pin for taper and out-of-round as shown in the illustration. Maximum taper and out-of-round: 0.003 mm (0.000118 in.) If the taper and out-of-round are more than the maximum, replace the crankshaft.

10. INSPECT CRANKSHAFT OIL CLEARANCE

(a) Install the crankshaft bearings.

Click here

(b) Install the crankshaft thrust washers.

Click here

(c) Clean each main journal and bearing.

*a Plastigage

(d) Place the crankshaft onto the cylinder block.

(e) Lay a strip of Plastigage across each journal.

(f) Install the crankshaft bearing caps.

Click here

NOTICE:

Do not turn the crankshaft.

(g) Remove the crankshaft bearing caps.

Click here

(h) Measure the Plastigage at its widest point.

Standard oil clearance:

0.017 to 0.040 mm (0.000669 to 0.00158 in.)

Maximum oil clearance:

0.05 mm (0.00197 in.)

NOTICE:

Remove the Plastigage completely after the measurement.

If the oil clearance is more than the maximum, replace the crankshaft bearing. If necessary, replace the crankshaft.

HINT:

If replacing a bearing, select a new one with the same number. If the number of the bearing cannot be determined, calculate the correct bearing number by adding together the numbers imprinted on the cylinder block and crankshaft. Then select a new bearing with the calculated number. There are 4 sizes of standard bearings, marked "1", "2", "3" and "4" accordingly.

(i) Perform the inspection above for each journal.

11. INSPECT CRANKSHAFT BEARING CAP BOLT

(a) Using a vernier caliper, measure the diameter of the tension portion of the crankshaft bearing cap bolts. Measuring point: 58.5 mm (2.30 in.) Standard diameter: 9.77 to 9.96 mm (0.385 to 0.392 in.) Minimum diameter: 9.1 mm (0.358 in.) If the diameter is less than the minimum, replace the crankshaft bearing cap bolt.

*a Measuring Point

12. INSPECT CONNECTING ROD BOLT

(a) Using a vernier caliper, measure the diameter of the tension portion of the connecting rod bolt. Standard diameter: 8.5 to 8.6 mm (0.335 to 0.339 in.) Minimum diameter: 8.3 mm (0.327 in.) HINT: Diameter measurements should be done at several points. If the diameter is less than the minimum, replace the connecting rod bolt.

*a Tension Portion

13. INSPECT NO. 1 OIL NOZZLE SUB-ASSEMBLY

(a) Push the check valve with a pin to check if it is stuck. If stuck, replace the No. 1 oil nozzle sub-assembly.

(b) Push the check valve with a pin to check if it moves smoothly.

If the valve does not move smoothly, clean or replace the No. 1 oil nozzle sub-assembly.

(c) Apply air into A. Check that air does not leak through B. If air leaks, clean or replace the No. 1 oil nozzle sub-assembly.

(d) Push the check valve while applying air into A. Check that air passes through B. If air does not pass through B, clean or replace the No. 1 oil nozzle sub-assembly.

14. INSPECT NO. 2 OIL NOZZLE SUB-ASSEMBLY

(a) Push the check valve with a pin to check if it is stuck. If stuck, replace the No. 2 oil nozzle sub-assembly.

(b) Push the check valve with a pin to check if it moves smoothly.

If the valve does not move smoothly, clean or replace the No. 2 oil nozzle sub-assembly.

(c) While covering A, apply air into B. Check that air does not leak through C. Perform the check again while covering B and applying air into A. If air leaks, clean or replace the No. 2 oil nozzle sub-assembly.

(d) Push the check valve while covering A, and apply air into B. Check that air passes through C. Perform the check again while covering B, pushing the check valve and applying air into A. If air does not pass through C, clean or replace the No. 2 oil nozzle sub-assembly.

READ NEXT: