C-Series Book - Industrial Engine Service

5
AIR CLEANER
VALVE COVER
BREATHER Assy
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The air cleaner with clean oil/element will
protect the engine parts from abrasive dust
and dirt in the air. Every month, depending
upon the operating conditions, clean the
air cleaner in solvent and refi ll with clean
oil of the type used in the engine or paper
element, whichever is applicable.
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CRANKCASE BREATHER
NOTE: This section does not address the
EPA emissions compliant breather systems
- please call Customer Service at 1-800-331-
3662 if you have questions about this system.
The crankcase breather plays an important
role in assuring Arrow engines perform with
maximum efficiency. A simple poppet valve,
in the body of the valve cover breather, allows
crankcase pressure to be evacuated, and a
secondary fitting is located in the crankcase top
cover.
Each time the piston goes back from the
cylinder head, the piston compresses the
air in the crankcase chamber. This pressure
opens the poppet valve in the breather and, in
turn, this pressure dissipates. When the piston
travels back toward the head, the poppet valve
closes and a light vacuum is created in the
crankcase. Simultaneously, the smaller fitting
located on the top cover allows a small flow of
fresh air to enter the crankcase.
If excessive oil blows out either breather,
usually the disc valve is worn or has stuck
and should be replaced. A simple test of the
crankcase breathing system is to unscrew the
small fitting out of the crankcase top cover,
plug the hose off the air filter and place your
finger over the hole in the cover. If the breather
is working properly, you feel a definite vacuum
build up. If you don’t feel a vacuum but a
pressure build up, check the poppet valve in
the breather on the valve cover.
1-800-331-3662 ARROW ENGINE COMPANY
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