Chevrolet 70 1969 Series, Shop Manual

Page: 691 / 913

E N G IN E 6-20
Figure 3 1 — Sectional V ie w of C y lin d e r H e a d on 4 0 1 M a n d 4 7 8 M E n ­
gin e s
1. Exhaust Valve Seat 5. Valve Spring Cap
Ring 6. Valve Key
2. Exhaust Valve 7. Oil Seal
3. Valve Rotator 8. Intake Valve
4. Valve Spring 9. Cylinder Head
bolts (9). Try turning pum p shaft which should turn
freely. If shaft cannot be turned or if binding occurs
when shaft is turned, disassemble pump and make
necessary corrections.
OVERHAULING OIL PUMP
(ENGINES WITH HYDRAULIC GOVERNOR)
Key numbers in text refer to Figure 30.
Disassembly
rotor and shaft assembly in operating position. Check
clearance between outer roior and body and clearance
between edge of inner rotor lobe and outer rotor with
feeler guauge (fig. 29). If clearances are greater than
specified in “ Specifications" at end of this section, re­
place parts as necessary. Inner rotor and shaft assem ­
bly and outer rotor are furnished for service in
matched sets. With rotors in pum p body, place
straightedge across rotors and body, then with feeler
gauge measure clearance between rotors and straigh­
tedge (fig. 29). Clearance should be 0.001 1 to 0.0064
inch.
5. Use straightedge (fig. 29). check rotor side of rotor
cover and spinner housing for flatness. Also look for
grooves and other evidence of wear on pump cover.
Replace if not in good condition.
6. Clean relief valve parts (fig. 28) and check fit of valve
in its bore in pump. Valve must slide into bore freely.
7. Cheek fit of spinner valve shaft (4) in cover and spin­
ner valve housing (11) and in cover (6). If excessive
clearance is evident, replace parts as necessary.
8. Inspect thrust washer (8) for wear.
9. Clean passages through spinner shaft (4) and passages
including relief orifice in spinner cover (6).
10. Soak spinner valve (5) and shaft in solvent, then note
fit of valve in shaft. It should be possible to push
valve (5) endwise and spring (9) should move valve to
closed position. If valve sticks or appears to be loose
in shaft, obtain a new preadjusted valve
assembly
from service stock for use when assembling pump
unit.
C AU TIO N : Since special eq u ip m en t is requ ired
for testing spin ner valve operation, the valve
adjustm ent should not be d istu rb ed at norm al
overhaul periods.
Assembling Oil Pump and Spinner
Valve Components
Key numbers in text refer to Fiuure 30.
1. Remove bolts which secure spinner valve cover (6)
and rotor cover and spinner housing (11) to pump
body (3). Separate parts.
2. Remove outer rotor (13) and shaft and inner rotor as­
sembly from pum p body.
3. Remove relief valve spring cap (15), then remove re­
lief valve spring and valve (fig. 30).
Inspection of Oil Pump Parts
1. Wash all parts of pump and spinner valve assembly in
solvent.
2. Inspect ends of drive shaft which engage distributor
and oil pum p shafts. Replace drive shaft if worn or
damaged.
3. Check fit of inner rotor shaft in body (3). If wear is
indicated at either the shaft or body, replace worn
parts.
4. Place the outer rotor (13) in body (3) and insert inner
Figure 3 2 — Use of Special Tool for R e m o v in g E x h a u st V a lv e S e a t Ring
CHEVROLET SERIES 70 80 HEAVY DU fv t r j C K SH O P M AiM UAi