Vanguard BIG BLOCK M540000, Repair Manual, Page: 20 / 168

9. Insert feeler gauge between rocker arm and intake valve
stem. Verify that intake valve clearance is 0.004-0.006
inches (0.10-0.15 mm). If adjustment is necessary, see
step 8.
10. Repeat steps 6-9 on opposite cylinder.
11. Rotate crankshaft 3 full turns to seat valve train.
12. Recheck valve clearance and adjust if necessary.
13. Remove old gasket material from valve covers and
cylinder head flanges. Gasket material left on sealing
surfaces will cause leaks.
14. Install new valve cover gaskets.
15. Install the valve covers to the cylinder heads along with
any lifting bracket that was removed with the 4 valve
cover fasteners. Tighten fasteners, using a diagonal
tightening pattern, to 70 lb-in (7.9 Nm).
16. Install spark plugs into cylinder heads and finger tighten
until snug. Tighten spark plugs to 170 lb-in (19.2 Nm).
17. Install spark plug wires onto spark plug terminals.
Idle Speed Adjustment - Mechanical Governor
1. Obtain a digital tachometer. See SECTION 3 -
TROUBLESHOOTING - Special Tools List .
2. Follow the instructions included with the tachometer and
connect to engine.
3. Start engine.
4. Hold the throttle lever (
A , Figure 16) against the throttle
stop adjustment screw ( B ).
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5. Adjust the screw to bring the idle speed to the correct
RPM based on the specification of the engine. See The
Power Portal for correct idle speed RPM.
Depending on the configuration of your engine, a
governed idle spring may be present. If equipped,
proceed as follows:
1. Hold speed control against the low speed stop.
Make sure that there is no tension on the high speed
spring.
2. Bend the low speed adjustment tab ( A , Figure 17)
until engine RPM is near the specified speed.
3. Snap the throttle open and let the engine regain idle
to ensure there is no friction within the system.
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NOTE: If the idle speed is not specified, adjust to 1750 RPM .
If the engine has NO governed idle spring, and the idle speed
is not specified, adjust idle to 1200 RPM .
High Speed Adjustment - Mechanical Governor
1. Obtain a digital tachometer. See SECTION 3 -
TROUBLESHOOTING - Special Tools List .
2. Follow the instructions included with the tachometer and
connect to engine.
3. Start engine.
4. Hold the speed control against the high speed stop.
5. Bend the high speed adjustment tab (
A , Figure 18) until
the specified RPM is reached. See The Power Portal
for correct high speed RPM.
NOTE: Some engines may be equipped with a high speed
fine adjustment screw ( B ). This is used for fine adjustment of
the top-no-load speed.
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