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(d) The exhaust system should be as short as possible and with a
minimum of bends, otherwise a serious reduction of power will result.
(e) A short length of flexible exhaust pipe should be included between the
engine and main run of piping
4. Air intake
Air is taken in through an air cleaner
Engines installed in confined spaces require good ventilation to ensure a
plentiful supply of cool. clean air.
5. Cooling
(a) Open system
(i) Salt water must NOT be used for cooling unless a corrosion
inhibitor is fitted, and it is important that brass or copper pipes
and fittings are kept to a minimum UNDER NO CIRCUM-
STANCES may brass or copper pipes or fittings come into
contact with the aluminium on the engine.
(ii) The cooling system must not be connected directly to a main
water pressure supply unless a control valve is fitted in the inlet
side of the system. The control valve must at all times prevent
the system being pressurized
(iii) The cooling system must be so arranged that water remains in
the Jacket when the engine is shut down or the water flow is
interrupted
(iv) IT IS IMPORTANT that the vertical distance between the water
pump. if fitted, and water supply is no more than 2ft (61.0 mm).
By fitting a small reservoir to the suction side of the pump, and
supplying water through a hose of no more than 3/8 in (9.5mm)
bore. the distance may be increased to 10ft (3m) A suitable
reservoir and hose is available from Petters Ltd or their agents.
(v) To ensure correct circulation, the cooling water inlet should be
fitted to the side of the cylinder head on AB1W engines, to the
cylinder on AC1W engines and the outlet taken from the top of
the cylinder head.
(b) Closed system (thermosyphon) (Fig 1)
(i) Water tanks may be used for cooling and should be filled with
clean fresh water (see Technical Data)
(ii) It is recommended that 3/4in (19mm) bore pipes are used to
supply water to and from the engine
(iii) The water outlet pipe (A) from the engine should be connected to
the top of the cooling tank (B) in a steadily rising manner. The
bottom of the cooling tank should be level with or slightly below
the bottom of the cylinder Pipes should be as short as possible
with a minimum of bends.
(iv) The water level must NOT fall below the top connection. To
reduce evaporation a loose fitting lid should be fitted