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Valves and Valve Stem Seals – Inspection
Valve to Valve Guide Clearance
If the valve guides are worn beyond the service limit given below, the cylinder head must
be replaced.
Valve Stem to Guide Clearance
0.010 -0.037 mm (standard)
0.020 -0.042 mm (standard)
Valve Face Inspection
1. Remove any carbon build-up from the valve head area. Examine the valve seat face,
checking in particular for signs of cracking or pitting.
Valves and Valve Stem Seals – Installation
1. Apply a thin coat of engine oil to the valve stem.
2. Install the valve into the valve guide and refit the spring platform to the valve spring
recess in the head.
3. Fit the valve stem seal over the valve stem and, using a suitable tool, press down fully
until the seal is correctly seated over the valve guide.
Firstly, press the seal down the valve stem until the lower side of the seal comes into
contact with the valve guide. Further gentle pressure is then required to locate the seal
over the top end of the valve guide.
Once correctly positioned, the seal cannot be pushed down any further.
Incorrect fitment of the valve stem oil seals could lead to high oil consumption and
blue smoke emissions from the exhaust system. Do not use excessive force in fitting
the seal as this may break the seal ring.
4. Install the valve spring over the valve stem.
5. Compress the valve spring ensuring that the spring is compressed squarely to
prevent damage to the valve stem and cylinder head.
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