Cylinder Blocks; Valves And Seat Inserts - Wisconsin VH4D Repair Manual

PLACE OPEN END OF
RING ON PISTON
FIRST AS SHOWN
Fig. 30
CHROME FACED
COMPRESSION RING
SCRAPER RING
OIL RING WITH
EXPANDER
F ig. 31
over piston and into correct groove, being careful not
to distort ring. Install bottom ring first and work to-
ward the head of the piston, installing top ring last.
The word 'TOP' on compression and scraper rings
indicates direction of ring placement on piston.
Beginning with serial #5538322, three ring pistons
(chrome faced compression ring, scraper ring, oil ring
and expander), with improved oil control characteris-
tics, replaces four ring pistons furnished with two
compression rings.
CAUTION: When replacing four ring pistons with
three ring pistons, a complete set of four pistons
must be used. Do not mix three and four ring pistons
in the same engine.
The outer diameter of the compression ring is chrome
plated. Mount scraper ring with scraper edge down,
otherwise oil pumping and excessive oil consumption
will result. Refer to Fig. 31 for the correct placement
of piston rings.
CYLINDER BLOCKS
Clean all dirt and foreign deposits from between the
cylinder fins and manifold ports.
The cylinder blocks do not have to be removed unless
the cylinder bore is scored, out-of-round, or worn over-
size more than 0.005 inch. In this event, the block
will have to be removed, rebated and fitted with over-
size pistons and rings. This work should be done by
an authorized Wisconsin Service Center.
In Reassembly; tighten
the cylinder block mounting
nuts, 40 to 50 foot pounds torque.
PISTON TO CYLINDER
AT PISTON SKIRT THRUST FACE
.003 to .004"
PISTON RING GAP .010 to .020"
TOP RING .002 to .004"
PISTON RING
SIDE CLEARANCE
IN GROOVES
SCRAPER RING
OIL RING
PISTON PIN TO
CONNECTING ROD BUSHING
PISTON PIN TO PISTON
.002
to .004"
.001 to .003"
.0004 to .0012
=
.0000 to .0008"
tight
CONNECTING ROD TO
.009 to .016"
CRANK PIN- SIDE CLEARANCE
CONNECTING ROD SHELL BEARING
.0012 to .0033"
TO CRANK PIN DIA. (VERTICAL)
CONNECTING ROD BABBITT
.0007 to .0020"
BEARING TO CRANK PIN
~'~
STANDARD
~ ~'/ CRANK PIN DIMENSIONS
_
11"I;56 DIA. GRIND
Fig. 32, PISTON, RING AND ROD CLEARANCES CHART
VALVES and SEAT INSERTS (Fig. 33)
Remove valve tappet inspection plate and compress
valve springs with a standard automotive type valve
lifter as illustrated. Insert a rag in the opening at the
bottom of valve chamber so the retaining locks do not
fall into engine crankcase. Remove retaining locks,
seats, springs, valves and clean these, as well as the
ports and guides, of all carbon and gum deposits. Tag
each valve so that in reassembly they willbe mounted
in the same guide they were removed from. Replace
valves that are burned or pitted.
The inlet
and exhaust valve seat inserts can be re-
moved, when replacement becomes necessary, by
means of Wisconsin Motor DF-66-A insert puller.
Before grinding valves, inspect
valve guides for pos-
sible replacement. Refer to Falve Guide paragraph.
The valve face is ground at 45°to the vertical center
line of the valve stem and the valve seat insert should
also
be ground at a 45 ° angle.
After grinding, lap
valves in place until a uniform ring will show entirely
around the face of the valve. Clean valves and wash
block thoroughly with a hot solution of soap and
water. Wipe cylinder walls with clean lint free rags
and light engine oil, especially if cylinders were
rebated and honed.
Valve guides in the cylinder block are easily re-
placeable by use of Wisconsin DF-72 driver tool.
In reassembly; mount guides with inside chamfer
down. The valve stem has a clearance of .003
to .0054 in the guide. When the clearance becomes
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