Valves, Inspection; Valves, Refacing - Ford LRG-423 Service Manual

01-30 Engine Service 01-30
SERVICE PROCEDURES (Continued)
A23881 -A
Item
Part
Number
Description
1 - Valve
A - Valve Seat Angle
B - Seat Width and Proper
Location on Valve
c -
Bottom Narrowing Angle
75 Degrees
D - Top Narrowing Angle
30 Degrees
E - Valve Face Angle
F - Valve Margin
A6802-B
If the valve seat width exceeds the maximum limit,
remove enough stock from the top edge and/or bottom
edge of the seat to reduce the width to specification.
On the intake and exhaust seats, use a 6O-degree
angle grinding wheel to remove stock from the bottom
of the seat (raise the seats). A 30-degree angle wheel
is used to remove stock from the top of the seats
(lower the seats).
The finished valve seat should contact the
approximate center of the valve face. It is good
practice to determine where the valve seat contacts
the face.
To do this, coat the seat with Prussian Blue and set the
valve in place. Rotate the valve with light pressure. If
the blue is transferred to the center of the valve face,
the contact is satisfactory. If the blue is transferred to
the top edge of the valve face, lower the valve seat. If
the blue is transferred to the bottom edge of the valve
face, raise the valve seat.
Valves, Inspection
The critical inspection points and tolerances of the
valve are illustrated below.
Inspect the valve stem for bends, and the end of the
stem for grooves or scoring.
Inspect the valve face and the edge of the valve head
for pits, grooves or scores. Inspect the stem for a bend
condition and the end of the stem for grooves or
scores. Check the valve head for signs of burning or
erosion, warpage and cracking. Minor pits, grooves,
etc., may be removed. Discard severely damaged
valves.
Inspect the valve spring (6513), valve spring retainer
(6514), valve spring retainer keys (6518) and discard
any visually damaged parts.
DIAMETER AN D
I
BENT STEM
VALVE
FACE
ANGLE
,794 MM (l/32 INCH)
THIS LINE PARALLEL
WITH VALVE HEAD
1
I
Al 4139-D
/
Valves, Refacing
NOTE: Discard any excessively worn or damaged
valve train parts.
Minor pits or grooves may be removed. Discard valves
that are severely damaged if the face runout cannot be
corrected by refinishing or if stem clearance exceeds
specification. Refer to specifications section for valve
specifications.