External Components

Fig. 10 Rocker arm inspection:

CAMSHAFT ROCKER ARMS & SHAFT

1. Check rocker arm in the positions indicated in Fig. 10.
2. Check to ensure that oil holes are clear.
3. Check rocker arm shaft at rocker arm mounting positions for wear.
4. Check rocker arm shaft oil holes to ensure holes are clear.
5. Check camshaft for wear or damage and replace as necessary.

CYLINDER HEAD

Check cylinder head gasket surface for squareness, using a suitable straightedge and feeler gauge. Place a straightedge across cylinder head, then check for warpage with feeler gauge. If clearance exceeds .004 inch in any direction, replace or lightly machine cylinder head. If machining, do not remove more than .008 inch from gasket surface.

VALVES & SPRINGS

1. Check each valve for wear and damage or defects in valve head and stem. Replace valve if unable to repair.
2. If stem tip has been pitted, grind stem tip slightly. Also grind valve face slightly.
3. Check stem to guide clearance. If clearance is not within specification, replace valve and/or valve guide as necessary.

Fig. 11 Checking valve face margin:

4. Replace valve if margin of face has decreased to less than .02 inch, Fig. 11.
5. If improper contact with valve seat is evident, reseat valve.
6. Check valve seat for evidence of overheating and improper contact with valve face, and replace as necessary.
7. Check free height of each valve spring, spring should measure 1.9 inches. If spring does not meet specification, replace as necessary.
8. Test spring for squareness; if it exceeds 1.5°, replace spring.

SILENT SHAFT, OIL PUMP & FRONT CASE

1. Check gear contacting surface of front case and oil pump cover for step wear. If wear is evident, replace front case.
2. Check silent shaft journals for wear and damage. If excessive damage or wear is evident, check bearing. If necessary, replace silent shaft and/or bearing.

CRANKSHAFT, MAIN & ROD BEARINGS

1. Measure main bearing clearance. If clearance is not within specification, replace bearing.
2. Check crankshaft journals for damage or wear. If necessary, replace crankshaft or machine journal.

Fig. 12 Piston assembly identification marks:

PISTON & ROD ASSEMBLY

The piston and rod is assembled with the indented arrow on the piston and the embossed numeral on the rod facing toward front of engine, Fig. 12.

PISTON, PINS & RINGS

Pistons and rings are available in standard sizes and oversizes of .010, .020, .030 and .039 inch. Oversize pins are not available.