Belarus 1221B.2 - Page 75

BELARUS-1221.2/1221В.2/1221.3 Description and operation
74
The adjusting parameters of the fuel pumps are shown in the Table below
Parameter description
Unit of measure-
ment
Value
РР6М10Р1f-
3492
(Д-260.2)
1. Average fuel feed per cycle through induction (high-pressure) pipe-
lines, at 100 min
-1
rpm, no less than
mm
3
/cycle
150
2. Camshaft rated speed min
-1
1050±10
3. Average fuel feed per cycle through pump high-pressure pipelines,
at rated RPM
mm
3
/cycle
80±2
4. Irregular fuel feed through induction pipelines , at rated RPM, no
more than
%
6
5. RPM at regulator action commencement min
-1
1080±10
6.Complete fuel-feed cutoff automatically by the regulator – within the
RPM range
min
-1
1170
not more than
7. Average fuel feed per cycle by pump sections, at diesel-engine
speed:
800 min
-1
500 min
-1
mm
3
/cycle
83±2.5
70±3.5
8. Pressure at pneumatic adjuster start/end action, at
n
= 500 min
-1
MPa
0.005…0.01
0.025…0.03
9. Average fuel feed per cycle, at 500 min
-1
and no-supercharging
pressure condition
mm
3
/cycle
55.5…64.5
Note: The parameters to be adjusted as per items 3…7 should be checked with the pneumatic ad-
juster arbitrarily disconnected (air pressure in the pneumatic adjuster is 0.05…0.06 MPa).
In case of a difficult engine start or
smoky exhaust, as well as after replacing
or installing the fuel pump after adjust-
ment and/or repair, be sure to check the
timing angle of the fuel pump.
To check the timing angle, proceed
as follows:
- set the regulator control levers to
a position corresponding to maximum fuel
feed;
- disconnect the injection pipeline
from the union of the first pump section;
connect a fuel injection timing meter
(momentoscope) instead (a female-swivel
nut with a short tube coupled through a
rubber pipe with a 1…2-mm inner dia.
glass tube);
- turn the crankshaft clockwise with
the help of a wrench, until fuel free of
bubbles flows from the device glass tube;
- remove some fuel from the glass
tube by shaking the latter;
- turn the crankshaft in the oppo-
site direction (counter-clockwise) through
30…40°;
- observe the fuel level in the glass
tube when rotating slowly the engine
crankshaft; stop the crankshaft rotation
the instant the fuel begins to rise;
- read the position of the locating
pin arrow on the valve control mechanism
cover.
If it is within “21…23” on the
graduated scale located on the vibration
damper housing, then the setting angle of
fuel injection advance is correct, i.e. the
first cylinder piston is in the position cor-
responding to 21…23° to TDC.
If the arrow is outside the stated
range, proceed with re-adjustment; to do
this:
- bring the locating pin arrow in co-
incidence with mark “22” of the graduated
scale on the vibration damper housing by
turning the crankshaft;