Belarus 1523, Operating Manual

Page: 61 / 312

BELARUS- 1523/1523В /1523.3 /1523В.3 Construction and Operation
61
rod caps are not interchangeable. Be-
sides, the connecting rods have group
designations of the mass groups of the
top and bottom ends; these are marked
on the end-face of the top end of the
connecting rod. The engine shall be
equipped with the connecting rods of the
same group only.
Liners of the Main- and Crankpin
Bearings of the crankshaft are thin-
walled parts made of a bimetal strip. The
liners are manufactured in two sizes as
to their inner diameter in accordance with
the nominal size of the crankshaft necks.
The
Flywheel is made of cast iron and
bolted to the crankshaft flange. A steel
toothed rim is pressed onto the flywheel.
The
Valve Control consists of the timing
gears, camshaft, inlet and outlet valves
as well as their fitting and driving parts.
The
Camshaft is driven from the crank-
shaft through valve timing gears and
rides on four supports.
The
Tappets (2) are steel members with
spherical bottoms. The camshaft cams
are made with a slight tilt; hence, when in
operation, the tappets are forced to ro-
tate.
The
Tappet Pushrods (5) are made of a
steel bar. The downwardly concave part
of the tappet and the push-rod cup are
hardened.
1 – piston; 2 – insert of a “non resist” type; 3 –
top compression ring; 4 – compression ring; 5 –
oil wiper ring with an expander.
The Valve Rocker Arms (7) are made of
steel and rock on the rollers installed in
supports. The rocker-arm roller is hollow,
with six radial bores for arm lubrication.
Displacement of the rocker arms along
the roller is restricted by spreader
springs.
The Inlet and Outlet Valves (4) are
made of high-temperature steel and free
to move in their guide bushes. The
bushes are press-fitted in the cylinder
heads. Each valve closes under the force
of two springs: the outer (12) and the in-
ner (11), respectively, fixed on its stem
by means of a valve spring retainer (9)
and valve locating split cones (10).
Sealing collars (18) installed on the valve
guiding bushes keep oil from leaking
down into the engine cylinders through
gaps between the valve stems and the
guiding bushes.