Engine Mechanical – V6
Page 6A1–169
Valve Guide Measurement
1
Measure the valve stem (1) to-guide (2) clearance.
Excessive valve stem-to-guide clearance may cause
excessive oil consumption and may also cause a
valve to break. Insufficient clearance will result in
noisy and sticky functioning of the valve and will
disturb the engine assembly smoothness.
2
Clamp a dial indicator to the cylinder head at the
camshaft cover rail.
3
Locate the dial indicator so the movement of the valve
stem from side to side, crossways to the cylinder
head, will cause a direct movement of the indicator
stem. The dial indicator stem must contact the side of
the valve stem just above the valve guide.
4
Drop the valve head about 0.064 mm off the valve
seat.
5
Use light pressure when moving the valve stem from
side to side to obtain a clearance reading, refer to 5
Specifications.
•
If the clearance for the valve is greater than
specified and a new standard diameter valve
stem will not bring the clearance within
specifications, the valve guide may be oversized
by 0.075 mm using the valve guide reamer, Tool
No. J 42096 or by 0.375 mm using the valve
guide reamer, Tool No. EN-46120. Two sizes of
oversized valve stems are available for service.
•
Valve guide wear at the bottom 10 mm of the
valve guide is not significant enough to affect
normal operation.
•
If over sizing the guide does not bring the
clearance within specifications, replace the
cylinder head.
Figure 6A1 – 289
Valve Spring Inspection and Measurement
Inspection Procedure
1
Clean the valve springs in solvent.
Safety glasses must be worn when using
compressed air
2
Dry the valve springs with compressed air.
3
Inspect the valve springs for broken coils or coil ends.