Vanguard BIG BLOCK M540000, Repair Manual

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Valve Springs
1. Inspect valve springs for broken or discolored coils.
Replace springs if either of these conditions are found.
2. Set the intake and exhaust valve springs on a level
surface and use a straightedge to check for proper
squareness and equivalent height. Too much height
may correspond to a reduction in spring pressure which
results in sluggish valve action.
Valve Spring Retainers/Tapered Keepers Inspection
1. Inspect parts for rust pits or corrosion. Replace as
necessary.
2. Inspect inside diameter of valve spring retainers for
damage or excessive wear. Center must be well defined
without distortion.
3. Inspect inside of tapered keepers for excessive wear.
Upraised center must be well defined and fit snugly in
valve stem grooves. Place keepers into grooves and
verify that they grip tightly without sliding.
Tappets, Push Rods, Adjuster Screws, and Rocker
Arms
1. Inspect tappet and valve adjuster screw sockets for signs
of scuffing, pitting or general wear.
2. Tappet faces may appear to have smooth surfaces, but
still have concave wear. Hold a straight edge across the
tappet face. Any concave wear found on the tappet faces
may also indicate worn camshaft lobes.
3. Roll push rods on a flat surface to determine if they are
bent. Replace push rods that are bent, dented, broken
or discolored. Replace the push rod if the ball ends show
signs of excessive wear or damage. For best practices,
replace push rods in pairs.
4. Check rocker arms for uneven wear or pitting where
contact is made with the valve stem tips. Replace
the rocker arm if excessive wear is found, or if pitted,
deformed, or scored.
Intake Manifold Studs
1. Inspect intake manifold studs ( A , Figure 114). Replace
studs if broken, bent, or if severe thread damage is
observed.
114
2. Replace stud as follows:
A. Loosen stud using a T-20 TORX bit.
NOTE: If stud is difficult to remove, apply a suitable
penetrating oil to threads, and then work stud in and out until
it moves freely.
B. Remove stud from cylinder head.
C. With the TORX recess on the outside, install
new
stud by hand, and then tighten to 45 lb-in (5 Nm)..
Assembly
1. Pack shop towels into the combustion chamber and
place cylinder head on bench with the combustion
chamber side down.
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