Yaroslavl ???-236, Maintenance Manual

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no more than 2 drops a minute at the nominal rotation rate of the crankshaft.
- coolant leakage or its mixture with the sealant from the drainage hole of the water pump at
any operation mode as well as at the engine stop is allowed no more than one drop in 3 minutes.
- leakage of the separate drops of fuel and oil mixture from the induction manifolds in the
period of running-in.
6.3.9 Hammering and noises coming from the total noise of the operating engine and which
are not specific to the normal running of the engine at this heat mode are not permitted during the
engine operation at the stand.
If necessary, engine listening should be carried out at the idle run at different speed rates.
Sudden change of loading and rotation rate of the crankshaft are not allowed during the running
and listening of the engine at the stand.
If there is hammering coming from the general operation of the engine it is necessary to
reassemble the engine to define the reasons and eliminate them.
6.3.10 To perform fivefold test of the starter start up for each engine. Engines
ЯМЗ-236М2-6,
ЯМЗ-238М2-8 and ЯМЗ-238М2-9should not be checked for start up.
The starting up of the starter is not allowed when the engine running or was not turned
off.
6.3.11 After the replacement of the main parts, nods, devices and elimination of the defects
engine should be run up and tested repeatedly at the mode of the repeated tests.
6.4 Timing of the engine
6.4.1 One should check and time the heat clearances of the valve operating mechanism prior
to begin and finish the running up but no earlier than in 15 min after the engine was turned off.
Before the timing of the clearances of the valve operating mechanism one should turn on the
fuel feed using the adjusting clamp, to take off the covers of the cylinder heads, to check bolt
tightening of the fastening of the rocker pivots which should be Мкрfrom 118 to 147 Nwm (from 12
to 15 kgf·m). Technical requirements for the tightening according to the OST 37.001.031-72.
6.4.2 Clearance adjustment in the valve operating mechanism:
Heat clearance in the valve operating mechanism provides the sealing of the valve seating at the
seat and compensates head extension of the mechanism parts during the engine operation.
Dimension of the heat clearance of the eduction and induction valves should be equal and it is
adjusted within 0.25-0.30 mm. Checking the trip valve gear at the engine because of the runout of the
joining parts heat clearances after the rotation of the crankshaft should be within the limits 0.20-0.40
mm.
Adjusting valve operating mechanism and inspecting the heat clearances of the valve rocker