Lotus Elise Service Notes page 188

A
NOTE: Two types of exhaust valve may be
fitted, standard valves, A in illustration or
carbon break valves, B in illustration.
Carbon break valves may be identified by the
machined profile C on the valve stem. To prevent
exhaust valves from sticking, standard valves
should be replaced with carbon break valves
during engine overhaul.
3. Check existing valve stem diameters A,
replace any valve if stem diameter is less than
specified.
4. Check inlet and exhaust valve to guide
clearances C using the following procedures:
5. Insert valve into its respective guide.
6. Extend valve head 10 mm out of valve guide
and position suitable DTI gauge to rear of valve
head.
7. Move valve towards front of cylinder head,
pre-load gauge to valve head then zero gauge.
8. Move valve towards rear of cylinder head,
record reading obtained to give valve stem to
guide clearance B.
9. Repeat above procedures for each valve in
turn.
1. Remove carbon deposits from exhaust valve
guides using tool:
K8-18G1772
K16-18G1771
» CAUTION: Tool must be inserted into
} \ valve guide from combustion face side of
cylinder head.
2. Remove carbon from inlet valve guides, inlet
and exhaust valves and valve seat inserts.
Remove all loose particles of carbon on
completion.
OVERHAUL 5 1