Checking Valve Springs; Verify Bearings And Camshaft; Checking The Cam Tops - Nanni T4.155 Workshop Manual

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9. CHECKING VALVE SPRINGS

a. Use a metal square to measure the squareness of the valve
springs.
Squaring limit:
Replace the valve spring if the maximum squaring is exceeded.
b. Use a slide caliper to measure the length of the valve spring, not
pressed.
Length not pressed:
Replace the valve spring if the free length is not within the limits stipulated
in specifications.
c. Use a spring controller to measure the tension of the valve spring
at the installed and specified length.
Installed spring tension:
301 – 332 N (30.7 – 33.9 kgf) over a 37.0 mm length
Replace the valve spring if the tension of the installed spring is not within
the limits stipulated in specifications.

10. VERIFY BEARINGS AND CAMSHAFT

A. Verify out of roundness of the camshaft
a. Install the cam shaft on V blocks.
b. Use a dial gauge to measure the out of roundness of the
center bearing.
c.
Maximum out of roundness:
If the out of roundness is greater than specifications, replace the cam
shaft.
B. Checking the cam tops
Use a micrometer to measure the cam peaks.
Cam peak height:
Intake: 54.810 – 54.910 mm
Exhaust: 56.140 – 56.240 mm
4 CYLINDERS WORKSHOP MANUAL
2.0 mm
48.54 mm
0.06 mm
108/191