Volvo 242 1977 Manual page 55

1977 Volvo 242 244 245
I Engine Mechanical Components
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Torque cylinder head bolts
The cylinder head bolts should be torqued at the 600 mile inspection to ensure proper sealing of the head
gasket.
Torque manifold nuts
The manifold nuts should be torqued at the 600 mile inspection. A loose manifold could alter air/fuel
ratio and cause an increase in emission and/or poor driveability.
Valves
The valve clearance should be checked every 15,000 miles.
Camshaft drive belt
The camshaft drive belt tensioner should be adjusted every 15,000 miles.
Replace the drive belt every 45,000 miles.
An incorrectly tensioned drive belt will impair exhaust emission as the valves will open and close
incorrectly.
Vacuum fittings, hoses and connections
Unstable idle, misfiring or poor emission control is often caused by leaking vacuum hoses or
connections. Check hoses and connections on distributor vacuum unit, EGR valve and connections,
heater control servo systems and hydraulic brake servo.
II Engine Fuel System
Fuel
91 octane RON (Research Octane Number) unleaded fuel permitted for all models and required for
certain models (with catalytic converter).
A label on the instrument panel and on the rear fender, near the filler inlet, will remind of this
requirement. It is unlawful to dispense leaded fuel into a vehicle labeled "unleaded gasoline only".
CI system
The B21F engine is provided with a fuel injection system called the CI system (Continuous Injection),
which means that the injectors are open and inject fuel as long as the engine is operating.
This system has few moving parts, is reliable and meets the exhaust emission standards at maximum
efficiency.
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Air supplied to the engine is continuously measured and determines the amount of fuel injected.
The air flow is regulated by the throttle valve.
The air flow sensor and the fuel distributor are integrally built as a single unit. A lever is actuated by the
air flow to produce continuous fuel distribution.
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