O.S. Engines 21VZ-M - Manual (Page 4)

6
Piston
Cylinder Liner
Crankshaft
ENGINE CONSTRUCTION
With this engine, the piston will
feel tight at the top of its stroke
(TDC) when the engine is cold.
This is normal.
The cylinder bore has a slight
taper.
The piston and cylinder are
designed to achieve a perfect
running clearance when they
reach operating temperature.
Near TDC
Slight taper
When the engine is cold. When the engine is hot.
7
Notes on installing flywheel
Do not use a tool which
locks piston when
installing a flywheel, or
top of the piston may
be damaged. Also, do
not insert a screw
driver or the similar
into the exhaust port.
It is recommended to use Crankshaft
Clamp 1521 (Code No.71530200) available
as an optional tool.
It is made of durable engineering plastic
and locks the crankshaft without risk of
damage to any part of the engine.
Application is as follows:
Remove the crankcase rear cover plate from the
engine and rotate the crankshaft to the bottom
dead center (BDC) position.
Insert the crankshaft clamp so that its grooved
portion surrounds the crankpin and lower end of
the connecting rod and securely tighten the fan
or clutch onto the crankshaft.
Insert this groove onto
the connecting rod.
BDC position
Rotate the crankshaft so that the
connecting rod comes to this position.