Tools Required
• | J 7872 Magnetic
Base Dial Indicator Set |
• | J 8520 Camshaft
Lobe Lift Indicator |
- Clean the components in
solvent.
Caution: Refer to Safety Glasses Caution in the Preface section.
- Dry the components with compressed air.
- Inspect the camshaft bearing journals (1) for scoring or
excessive wear.
- Inspect the camshaft valve lifter lobes (2) for scoring
or excessive wear.
- Inspect the threaded bolt holes (3) in the front of the
camshaft for damaged threads or debris.
- Inspect the camshaft sprocket pin (204) for damage.
- Inspect the camshaft position reluctor ring for nicks or damage.
- Inspect the camshaft retainer
plate for wear or a damaged sealing gasket.
If the camshaft retainer
plate sealing gasket is not cut or damaged, it may be used again.
- Inspect the camshaft bearings for proper fit in the engine block. The
camshaft bearings have an interference fit to the engine block and should
not be loose in their engine block bearing bores.
- Inspect the camshaft bearings for excessive wear or scoring.
Bearings with excessive scoring or wear must be replaced.
- Measure the camshaft journals
for wear and out-of-round with a micrometer.
• | A camshaft with bearing journals that measure more than 0.025 mm
(0.001 in) out-of-round, must be replaced. |
• | A camshaft with bearing journal diameters that measure less that
54.99 mm (2.164 in), must be replaced. |
- Measure the camshaft lobes
for wear with a micrometer.
• | A camshaft with an intake lobe that measures 46.67 mm (1.8376 in)
or less, must be replaced. |
• | A camshaft with an exhaust lobe that measures 46.67 mm
(1.8376 in) or less, must be replaced. |
- Measure the camshaft runout.
13.1. | Mount the camshaft in wooden V-blocks or between centers
on a fixture. |
13.2. | Check the runout of the intermediate camshaft bearing journals
using the J 7872
. |
13.3. | If camshaft runout exceeds 0.05 mm (0.002 in), the
camshaft is bent and should be replaced. |
Measuring Camshaft Lobe Lift
Important: Measuring camshaft lobe lift is a procedure used to determine if the
camshaft lobes have worn. This test is to be performed prior to engine disassembly
and with the camshaft and valve train components installed in the engine.
- Measure camshaft lobe lift using J 8520
.
1.1. | Remove the valve rocker arms and bolts |
1.2. | Install the dial indicator mounting stud into the valve rocker
arm bolt hole. |
1.3. | Assemble the components of the J 8520
and position onto the stud. |
1.4. | Position the shaft of the dial indicator onto the end of the pushrod. |
1.5. | Rotate the face of the dial indicator to zero. |
1.6. | Slowly rotate the crankshaft clockwise until the dial indicator
obtains its highest and lowest readings. |
1.7. | Compare the total lift shown to specifications. |
• | The proper lobe lift for the intake lobes is 7.43 mm (0.292 in). |
• | The proper lobe lift for the exhaust lobes is 7.43 mm (0.292 in). |
- Compare measurements to specifications.
If the readings
are not within specifications, remove the camshaft. Inspect and/or replace
components as required.