5-20. CYLINDER BLOCK-MAINTENANCE INSTRUCTIONS (Continued).
The tapped holes in the cylinder blocks may be
tapped with a 5/8 inch-11 UNC3B thread tap. The
stud holes and unplugged bolt holes must have the
thread extending 1.85 inch below the block surface.
If the bolt hole in the block is plugged, the plug
must be a minimum of 1.92 inch below the surface
of the block and threaded the full distance. When
replacing a bolt hole plug in the current water-
m. Check the remaining cylinder block surfaces and
threaded holes. Check all of the mating surfaces,
or mounting pads, for flatness, nicks and burrs.
Clean-up damaged threads in tapped holes with a
tap or install helical thread inserts, if necessary.
n. After inspection, if the cylinder block is not to
be used immediately, spray the machined surfaces
with engine oil. If the block is to be stored for
an extended period of time, spray or dip it in a
polar type rust preventive such as Valvoline Oil
Company's "Tectyl 502-C", or equivalent. Castings
free of grease or oil will rust when exposed to
Wear protective goggles when using compressed air.
Before a reconditioned or new service replacement cylinder block is used, steam
clean it to remove the rust preventive and blow out the oil galleries with