Operating instructions

SERVICING
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Check, replace the sparking plugs
25 The sparking plugs should be removed every 10 000 km (6 000 miles) and the
electrode cap checked. The gap should be 0.7-0.8 mm (0.028-0.032"). After
20 000 km (12 500 miles) the plugs should be changed. This replacement should
preferably be carried out by a Volvo workshop where the plugs should be
tightened with a torque wrench. When fitting new plugs, be sure to fit the right
type (see page 54). Consult a Volvo workshop if you intend changing to a
harder or softer type of plug. The appearance of the old sparking plugs will
easily tell whether or not they were the right type for your driving.
26 Ignition system
27

The distributor contact breaker gap should be checked at a Volvo workshop
after every 10 000 km (6 000 miles).
All adjusting work to the engine ignition system should be done by the work-
shop which has the proper equipment for this purpose. The distributor is one
of the most sensitive units in the engine and careless handling can lead to de-
creased engine output and high fuel consumption or even serious damage to
the engine.
Fuel
The petrol used for fuel should be at least 97 (ROT)* octane for the B 20 A en-
gine. For the B 20 B type engine an octane rating of 100 (ROT)* is recommend-
ed. If petrol with too low an octane rating is used, knocking or pre-ignition
can occur.
However, if highway motoring is often involved, the octane rating should be
at least 97 (ROT)* even for the B 20 B engine.
* Research Method
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SERVICING
Electrical System
The electrical system in the car is equipped with an alternator. When changing
the battery or carrying out any other work with the electrical system, the follow-
ing should be observed:
When changing the battery or when carrying out work involving the electrical
system, the following should be observed:
1.
A battery connection to the wrong terminal will damage the rectifiers. Be-
fore the connections are made, check the polarity of the battery with a volt-
meter.
2. If extra batteries are used for starting, they must be properly connected to
prevent the rectifiers from being damaged.
The negative lead from the auxiliary battery for starting must be connected
to the negative terminal stud of the car battery and the positive lead from the
auxiliary battery for starting to the positive terminal stud.
3. If a rapid charger is used for charging the battery, the car battery leads should
be disconnected.
The rapid charger must never be used as an auxiliary unit for starting.
4.
Never disconnect the battery circuit (for example, to change the battery)
while the engine is running, as this will ruin the alternator immediately.
Always make sure that all the battery connections are properly tightened.
5. If any electrical welding work is to carried out on the vehicle, the earth lead
and all the connecting cables of the alternator must the removed. The weld-
i
ng unit should be placed as near the welding point as possible.
28
Check the battery electrolyte level
To ensure that the battery functions properly, the electrolyte level should be
checked regularly. A suitable time to do this is when the fuel tank is being filled.
The electrolyte level should be 5-10 mm
(3/16-3/g")
over the top of the cell
plates.
Top up with distilled water if necessary. Never add too much distilled
water since this can cause the acid to splash over and cause damage in the
engine compartment.
Never check the electrolyte level by lighting a match.
The gases
formed in the cells are highly explosive.
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