1956 AMC Hudson Technical Service Manual Supplement

ENGINE V-8 5
Valve Refacing
The intake valves are faced to a 29° angle and the exhaust
valves to a 44° angle. Valves may be refaced until remaining
margin is down to 1/32"; then the valve must be replaced.
The valve stem tip when worn can be resurfaced and
rechamfered. However, never remove more than .010".
Valve Seat Refacing
Valve Springs
1. Exhaust Valves 2. Intake Valves
FIGURE 3—Valve Arrangement
Whenever valve springs are removed, they should be tested
according to the specifications listed below. Use valve
spring tester and replace all springs not within specifications.
Intake or Exhaust Valve Springs:
Valve Closed 85-91 Lbs. @ 113/16"
Valve Open 150-160 Lbs. @ 17/16"
Valve springs are installed with the inactive (closed) coils
against the cylinder head.
The valve spring retainer serves the purpose of holding
the valve and spring together. The seal is mounted onto the
valve guide. At valve service periods, the valve stem oil
seals should be replaced to insure good oil control at this
point.
The half conical shaped valve locks can be removed after
compressing the spring.
Valve springs are 2.20" long free length. They are .938"-
.953" inside diameter.
Grind the valve seats to the following specifications:
Seat Angle
Intake Valve 30°
Exhaust Valve 45°
Seat Width
Intake Valve .078"-.093"
Exhaust Valve .093"-.104"
Narrowing stones should be used to obtain the proper
seat widths when required.
Control seat runout to a maximum of .002".
Valve Tappets and Push Rods
The hydraulic valve tappet consists of a body, plunger,
plunger return spring, check valve assembly, push rod socket,
and lock ring (Fig. 4).
Valve Stem to Guide Clearance
The valve stem to guide clearance is maintained through
replacement of valve guides. The valve guides are an
interference fit in their bores in the cylinder head and can
be replaced by driving out the old guides and driving in the
new. The new guides are driven, to a depth to permit 3/4"
+ or —1/44" to remain exposed above the cylinder head.
Measure from top of the guide to flat machined surface for
lower valve spring retainer.
New valve stem to guide clearance is as follows:
Intake .0013"-.0028"
Exhaust .0018"-.0033"
Valve guides are reamed to .3430"-.3440" inside diameter,
after installation.
Rubber valve stem oil deflectors are provided on the
valve guides to aid in preventing oil consumption between
the valve stem and guide.
FIGURE 4—Sectional View of Hydraulic
Tappet Assembly
The tappet operates in a guide bore which has an oil
passage drilled into the adjoining main oil galleries.
When the tappet is on the heel of the cam lobe, the
plunger return spring indexes an oil hole undercut in the
plunger with the oil supply admitted through the tappet
body. Oil under pressure flows into the body- through the
check valve assembly maintaining the tappet fully charged.
This cycle of operation occurs when tappet leaks off some
oil during the normal valve opening events. Opening movement
of the cam lobe causes tappet body movement, closing
the check valve and transmitting "zero-lash" movement of
the push rod to open the cylinder valve.