Honda Acura NSX 1991 Service Manual page 121

Valve Installation
When installing valves in cylinder head, coat valve
l
stems with oil before inserting into valve guides, and
make sure valves move up and down smoothly.
l When valves and springs are in place, lightly tap the
end of each valve stem two or three times to ensure
proper seating of valve and valve keepers (use ham-
mer handle bottom).
Cylinder Heads
HAMMER HANDLE
BOTTOM
Install the cylinder heads in the reverse order of removal:
Always use new head gaskets.
l
Cylinder heads and engine block surface must be
l
clean.
Turn the crankshaft so that No. 1 piston is at TDC
l
(page 6-26).
Install the front and rear exhaust manifolds to each
cylinder head, then tighten the self-locking nuts in
a criss-cross pattern in two or three steps, beginning
with the inner nut.
Always use new exhaust manifold gaskets.
l
CAUTION:
l Install the oxygen sensors after installing the ex-
haust manifolds.
locking nuts if the oxygen sensors are not to be
removed.
2. install the exhaust manifold covers.
Front:
OXYGEN SENSOR
45
N-m (4.5 kg-m, 33 lb-ft)
Be careful not to damage.
S E L F - L O C K I N G
34
25 lb-ft)
Replace.
\
22
16 lb-ft)