Onan MJA Series Service Manual page 79

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C Y LIN DE R H EAn&. AND V A L VE S
7'
2. Oil the stem of each valve lightly and insert each in it's own guide.
Check each valve for a tight seat with an air pressure type tester.
If
a tester isn't available, make pencil marks at intervals on the
valve face and observe if the marks rub off uniformly when the
valve is rotated part of a turn in the seat.
If
the seat isn't tight,
regrind the valves.
4. Using a valve spring compressor, compress each valve spring
with its spring retainer in place and insert the retainer locks.
5. Coat both sides of head gasket with Permatex No.3 (pliable sealer)
Install the head assembly and gasket to the cylinder block. Tighten
the head bolts to 44 to 46 lb. ft. following the sequence in Fig 3.7.]
NOTE: Four-cylinder models; observe this special procedure to
align the two heads and prevent air leaks.
A. Assemble the heads and
gaskets to the block and
install the cap screws,
but don't tighten.
B. Install the intake manifold
to the heads and tighten
the nuts to 13-15 lb. ft.
C. Tighten the cylinder head
capscrews to 44 to 46 lb.
ft. following the sequence
in Fig 3. 7 . E .
6. Install the manifold, oil lines,
water lines, spark plugs, and
carburetor.
7. Install the valve stem caps.
8.' Install the pushrods, rocker arms; and rocker arm n'Ut$ ...
9. . Set the valve clearance, Fig 3. 7. B .
NOTE: After the first 50. hours of operation, retighten the cylinder
head bolts and check valve clearance.
10.. Reinstall the rocker box cover.
11. Reinstall the thermostat assembly and refill the cooling system.
FIG. 3.7.E - CYLINDER HEAD
BOLT TIGHTENING
SEQUENCE MJB, 11JC