Page 1
VALTRA – VALMET
MEGA MEZZO HI-TEC
WORKSHOP MANUAL
Page 2
Service Manual
Tractors
Power
transmission
Brake
system
Steering system and Front
axle
Frame and
Wheels
Tools
Cab and
Shields
Hydraulics
Valtra Inc.
44200 Suolahti, Finland
Groups 10---100
General
Engine
Electrical
system
40
50
60
70
80
100
90
10
20
30
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25
ValtraValmet--tractors, Stanadyne injectors
Tra c t o r Typ e of
injector
Ordering
no of
compl. in-
jector
Ordering no of
nozzle
Nozzle ope-
ning pres-
sure, bar
Adjusting
pressure, bar
(value to be
used both with
new and used
nozzles).
Shims no 1,00...2,00 mm Code C
6000, 6100
6200 (---K41123)
6300 (---K42118)
6400 (---K42107)
6600, 6800 (---L23516)
8000, 8100, 8200
8400
103 kW ( --- K34331)
8050 (---L22533)
8150 (---L24138)
8450(---L24208)
8750, 8550 USA
S/736 8366 39956 8366 39957 230+10 240 8366 40104...8366 40122 736
6900, 8000R USA, 6200 USA, 6300 USA, 8150Hi
8150 (L24139---)
M/423 8368 54755 8368 54757 270+8 278 8368 62000...8368 62020 423
8550 (--- L24115) S/655 8363 40034 8363 39985 230+10 240 8366 40104...8366 40122 655
6250Hi, 6350Hi, 6750Hi, 6850Hi,8350Hi, 8550Hi
6200 (K41124---)
6300 (K42119---)
6400 (K42108---)
6800 (L23517---)
8550 (L24116---)
M/358 8366 59808 8366 59902 270+8 278 8368 62000...8368 62020 358
6550Hi, 6650Hi, 8050Hi, 8450Hi
6400 (L23506---)
8050 (L22534---)
8400
110 kW (K32135 ---L33320)
8450 (L24209---)
M/446 8368 54831 8368 54832 270+8 278 8368 62000...8368 62020 446
8950Hi M/876 8368 54791 8368 54792 270+8 278 8368 62000...8368 62020 876
8400 118 kW (L23130---) M/301 8368 54940 8368 54941 270+8 278 8368 62000...8368 62020 301
22. Fuel system
6000--8950
Model
220
Code15Page
1. 8. 2000
1. 9. 2002
Page 4
107
Model Code Page
22. Fuel system
1. 6. 1999
6000--8750 222 1
1. 4. 1997
Repair instructions
Fuel feed pump and fuel filter (Op no 222)
Bosch in---line pump
A. Bleeding fuel system
1. Slacken the bleeder screw on the filter head (8200, 8400,
8750 and 8950 have a double filter). Pump with the hand
pump until the fuel flowing out atthe bleeder screwis free from
air bubbles. Then tighten the bleeder screw.
3. Slacken the injection pump overflow valve. Pump with the
hand pump until the fuel flowing out is free from air bubbles.
Tighten the overflow.
4. W ipe off any fuel from the engine.
B. Bleeding thermostart system
Always remove air from the glow plug fuel pipe when thepipe
or reservoir has been emptied during repair work etc. This
preventsdamages to theglow plug causedby lack of fuel during starting.
1. If the reservoir is empty, fill it e.g. with a drip pot through the
breather hole on the reservoir.
2. Open the glow plug pipe connector and drain fuel from the
pipe. Connect the pipe.
C. Measuring fuel feed pressure
Note! Measuring equipment, see page 220/3.
1. Clean the fuel injection pump and the filter and the pipes
between them.
2. Fit the gauge at the banjo connection on the pump, as
shown above (between filter and injection pump).
3. Run the engine at low idling for a while and compare the
gauge reading with the prescribed value (0,6 ---1,0 bar).
N.B. If themeasured pressure is below the prescribed value,
this may be caused by:
--- faulty overflow valve
--- b l o ck e d fu e l fi l te r
--- faulty fuel feed pump
--- blocked or leaking fuel pipes or unions
Page 5
108
Model Code Page
22. Fuel system
1. 9. 1992
6000--8750 222 2
D. Checking overflow valve
If the fuel feed pressure deviates from the prescribed value,
check the opening pressure of the overflow valve.
1. Connect a pressure gauge to the banjo union in the same
way as in previous instruction C.
2. Pump with the hand pump until the overflow valve opens.
Compare the reading on the gauge at the moment the valve
opens with the prescribed value (0,6 ---1,0 bar).
3. If the recorded opening pressure deviates from the prescribed value, the overflow valve should be changed.
N.B. If the recorded pressure is considerably lower than the
prescribed value, there may be a fault in the hand pump or
the fuel feed pump valves.
E. Changing fuel feed pump valves
1. Clean the feed pump. Disconnect fuel pipes to the feed
pump. Remove the feed pump.
2. Secure the pump in a vice provided with soft jaws. Loosen
the tappet body from the pump and remove the piston, seal
rings, suction valve and the spring.
3. Detach from the pump body the outlet side threaded connector, in which is placed the pressure valve.
4. Rinse thevalves withclean fuel and check the functionand
possible wear.
5. Change the valve if needed and assemble the pump using
new o---rings and gasket
Page 6
109
Model Code Page
22. Fuel system
1. 6. 1999
6000--8750 223 1
1. 8. 1998
Fuel injection pump and injectors (Op no
223) (Bosch in---line pump)
Note! Concerning fuel injection pumps with a new type gov-
ernor, see page 223/8.
A. Checking injection timing
Note! Theexact time at which the fuel should be injected into
no. 1 cylinder is marked with a punch mark on the flywheel.
There is an inspection hole in theflywheel housingand ahole
for the locating tool. Due to the excess fuel flowing into the injection pump the control rod must be moved to the drive position when checking the injection timing. Otherwise the timing
will be incorrect!
Checking method:
1. Clean the injection pump and its surroundings carefully.
2. Remove the inspection hole rubber plug from the flywheel
housing.
9025 99100
3. Insert the locator (9025 99100) in the hole on the flywheel
housing front face.
4. Turn the crankshaft to a position where the 1st cylinder piston reaches its compression stroke top dead centre. Then turn
the crankshaft backwards until the timing mark on the flywheel passes the inspection hole.
9025 99000
5. Remove the protecting cap for the control rod on the injection pump front face. Fit adjusting tool (sleeve for limiting control rod travel) 9025 99000. The tool moves the control rod to
the ”running position”.
6. Disconnect the delivery pipe for thenumber one cylinder injector at the pump.
7. Clean the delivery valve of fuel. Slowly turn the crankshaft
in the correct direction of rotation until the fuel level in the delivery valve just begins to rise.
8. Check if the mark on the flywheel is at the point of the locator
which has been inserted into the flywheel housing. Repeatthe
check procedure. If the injection pump needs to be adjusted,
follow the instructions under heading B.
9. Fit the delivery pipe and the rubber plug in the flywheel
housing. Remove the locator and the sleeve which was used
to limit the control rod travel. Start the engine.
B. Adjusting fuel injecti on timing
Important! Adjusting fuel injection timing on 6800, 8750 and
8950 tractors, see page 223/8. Later on all tractors which have
Bosch in ---line pump (G4720 --- (320), G2358 --- (420) and
G5294--- (620, 634), the injection timing is adjusted according
to instruction on page 223/8.
If the timing is incorrect, adjust as follows:
1. Loosen the retaining nuts (17 mm) of the injection pump
and remove the delivery pipes (17 mm).
Page 7
110
Model Code Page
22. Fuel system
1. 9. 1992
6000--8750 223 2
8. 11. 1990
A
M
2. If the injection timing isretarded, turn the pumpanti---clockwise (viewed from the front end of the pump). If the timing is
advanced, turn the pump clockwise.
3. Check once again the injection timing and set again if
needed.
4. When the timing is correct tighten the retaining nuts of the
pump and fix the delivery pipes.
C. Removing fuel injection pump
1. Clean the injection pump and surrounding engine parts
and the pipes and connectors on the injection pump.
2. Disconnect the delivery pipes and the banjo bolts at the
supply and return fuel connections. Disconnect the lubricating oil line. Plug all connections.
3. Detach the oil filler pipe/cover from the front cover.Unscrew
the pump drive gear nut.
9052 48900
5. Use puller 9052 48900 and loo sen the gear from the injection pump camshaft front end.
6. Remove the injection pump attaching nuts (17 mm).
Remove the injection pump.
N.B. If the engine is not to be disturbed while the pump is removed, there is no need to secure the pump gear. The gear
rests against the idler gear .
D. Fitting fuel injection pump
1. Check the condition of the o ---ring between the pump and
the timing gear casing. Change the o---ring if necessary.
2. Lubricate theo ---ring andplace the injection pump so that
the key on the pump shaft aligns with the key slot inside the
gear. Tighten the pump attaching nuts.
3. Tighten the gear nut to 90 Nm . Fix the oil filler pipe/cover.
4. Connect the supply and return fuel lines.Connect the lubricating oil line. Use new sealing washers.
Page 8
111
Model Code Page
22. Fuel system
1. 9. 1992
6000--8750 223 3
5. Bleed the fuel system (Op no 222 A).
6. Adjust the injection timing (Op B).
7. Fit the delivery pipes.
8. If the injection pump is changed or if thelubricating oil has
been drained from thepump, fill the pump with lubricatingoil
before starting the engine. Open the hexagonal socket plug
on the governor housing and pour in oil.
Filling quantity: 320 ---engines 0,3 l
420---engines 0,4 l
620---engines 0,6 l
Same oil specification as in the engine.
E. Checking/changing delivery valve
1. Clean the injectionpump, injectors and surr ounding parts.
Disconnect the delivery pipes.
9052 47800
2. Connect the pressure gauge 9052 47800 to the delivery
valve holder which is to be checked.
3. Rotate the engine with the starter motor, until the gauge
reading is about 330 bar.
Note! Pressure rises fast, do not damage the gauge. Get
ready to pull the stopcontrol out as soon as the gauge reading
reaches an adequate pressure value.
4. Let the gauge reading lower at first about 30 bar. When the
gauge shows 300 bar, observe the reading during one minute. During this time the gauge reading must not lower too
much (max 30---50 bar). If the pressure lowers faster than
specified, the delivery valve must be cleaned or replaced.
Note! Thedelivery valveplunger and guideshould alwaysbe
replaced in pairs.
5. Open the delivery valve holder locking and holder. Remove
the valve spring, plunger and the guide.
6. Rinse the plunger and guide in clean fuel ortest liquid and
atthesametimerotatetheplungerinitsguideandpressthe
sealing surfaces against each other.
Page 9
112
Model Code Page
22. Fuel system
1. 9. 1992
6000--8750 223 4
7. Fit thedelivery valve into the fuel injection pump. Placethe
spring in place and tighten the holder.
Note! Renew the sealing ring and o---ring.
8. Tighten the holder as follows:
--- Tighten first to 30 Nm.
--- Open the holder about 1/2 a turn and tighten to 40 Nm.
--- Open the holder about 1/2 a turn and tighten to 45 Nm.
F. Adjusting low idling speed
If the idling speed of the engine deviates from the value given
in the specifications or if the engine revs vary at the idling
speed, adjust the idling speed as follows:
1
2
1. Unscrew the idling speed adjusting nutcap (1) and thecap
(2) on the idling speed additional spring adjusting screw.
2. Ensure that the throttle lever is in the idlingposition andthat
the engine is at normal operating temperature.
3. Start the engine and loosen the adjusting screw of the additional spring so that it does not affect the idling speed.
4.Adjusttheidlingspeedusingtheadjustingscrewtoabout
20 RPM below rated speed and lock the adjusting sc rew (10
mm).
5. Run the engine a few times and ensure that the idling speed
remainsasset.
6. Tighten the adjusting screw ofthe additional spring until the
idling speed rises to the rated value. Lock the adjustingscrew
(17 mm) in this position.
7. Fix the safety caps of the adjusting screws.
Note! Other adjustments (output and max. speed) of the injection pump can only be performed by a specially trained
person who has the necessary special tools and gaugesavailable.
Page 10
113
Model Code Page
22. Fuel system
1. 9. 1992
6000--8750 223 5
G. Removing injectors
1. Clean the injectors and the area around them. Disconnect
the delivery pipes and the leak---off pipes.
9051 71300
3. Remove the injector attaching nuts (13 mm) and remove
the injector from the cylinder head. Fit protective plugs to all
connections. If the injector does not rise by hand, use puller
9051 71300.
4. Remove the sealingwashers from the bottom of the injector
location in the cylinder head if they do no come out with the
injector
H. Inspecting injectors
N.B. When pressure testing the injectors, it is important to
avoid the nozzle end as the fuel jetting out easily penetrates
the skin. Also bear in mindthat the fuel ”mist” is dangerousto
inhale.
1. Clean the injector with cleaning fluid and a soft brush.
The carbon deposits must not be knocked off or removed in
anyotherwaywhichmaydamagethenozzle.
2. Secure the injectorin a test bench and checkthe following:
--- injector opening pressure
--- the properties of the chattering (creaking) sound and the
form of the spray pattern
--- sealing of nozzle valve against its seat
Opening pressure
Pump a few times to fill the injector. Increase the pressure in
the injector until the chattering (creaking) sound becomes
audible. Read off the opening pressure of the injector. If the
opening pressure deviates from the given value (230±5 bar),
the injector should be taken apart and checked.
Adjustment is achieved by changing the shims. The thickness
of the shims varies from 1.00 ---1,90 mm and they areavailable
in increments of 0,05 mm. A thicker shim will raise the opening
pressure while a thinner one lowers it. A difference in shim
thickness of 0,05 mm changes the opening pressure by approx. 5,0 bar. As the opening pressure of the injector drops
slightly after adjustment, the opening pressure should be set
toapproximately 10 bar above thevalue given in thespecifications. This value applies both to new and used injector.
Chattering sound properties
Testing with a hand powered pump does notcreate the same
circumstancesas when the injectoris fitted in the engine. Only
with new nozzles are the test results reliable. With used
nozzles, there is no chattering (creaking) sound when the
tester is pumped at a certain rate. This has to do with the design of the nozzles.
However, with arapid pumping on the tester handle, itshould
be possible to hear the chattering (creaking) sound or/and
see a mist of the fuel jetting out.
Page 11
114
Model Code Page
22. Fuel system
1. 9. 1992
6000--8750 223 6
Tightness of nozzle
Press down the tester pump lever until the pressure rises to
approx. 20 bar below the adjusting value. Maintain this pressure for approximately 10 seconds and check whether drops
of fuel are formed on the point of the nozzle. If the injector
leaks, it should be cleaned or the nozzle should be changed.
I. Reconditioning injectors
1. Secure the injector in a suitable way.
2. Unscrew the nozzle cap nut. Remove the nozzle and the
parts inside the holder.
3. Clean the no zzle in cleaning fluid both inside and outside.
4. Clean the nozzle holes with a needle (including in cleaning
set 8360 83288).
5. Test the movement of the nozzle valve as follows:
Rinse the parts thoroughly in fuel ortesting fluid. Pull the valve
out of the nozzle body to 1/3rd of its length. If the fit is correct,
the valve should be able to slide down in the nozzle body
under its own weight. Turn the valve slightly and repeat the
test. Should the nozzle valve bind slightly, it should be
changed.
1
2
3
4
5
6
7
8
9
Injector
1. Fuel inlet 6. Nozzle body
2. Leak---off fuel 7. Pressure chamber
3. Shims 8. Nozzle valve
4. Pressure spring 9. Nozzle hole
5. V alve stop spacer
6. Before assembling, all parts should be carefully cleaned in
clean fuel or testing fluid.
7. Put the same number of shims back as were fitted earlier.
Note possible adjustment of theopening pressure.Assemble
the rest of the injector. Note the position of the spring guide
andthevalvestopspacer.
8. Tighten the nozzle cap nut by hand and then to 60 Nm.
Page 12
115
Model Code Page
22. Fuel system
1. 9. 1992
6000--8750 223
7
J. Fitting injector in engine
1. Clean the injector sealing surface in the cylinder head. If
necessary use a reamer 9101 66000.
1
2
3
1. Washer
2. Rubber ring
3. Sealing washer
2. Fit the injector in the cylinder head using a new sealing
washer.
N.B. The spray pattern from the injector isnot symmetrical on
purpose. It is therefore important that the injector is fitted correctly in the cylinder head. The connection for the leak---off
line should be facing the valve mechanism.
3. Fit the attaching clamp and tighten the nuts (13 mm) evenly
to 15 Nm.
4. Connect the leak- --off line (10 mm) together with new sealing washers and connect the delivery pipes (17 mm).
N.B. The screw studs in the cylinder head for the injectors
should only be finger tight. If tools have to be used the studs
should be tightened only lightly.
Note! Make sure, that the injector is of a correct type. Wrong
injectors cause malfunctions and can damage the engine.
K. Fitting delivery pipes
1. Check the state of the pipes. If there are kinks, damage by
chafing, or if the tapered sealing end is damaged, the pipes
should be changed.
2. Fit the pipes without tension and check that they are at right
angles to the union.
3. Fit the clamps for the pipes.
Page 13
116
Model Code Page
22. Fuel system
1. 6. 1999
6800, 8750
8950
223
8
1. 8. 1998
L. Adjusting injection timing on
6800, 8750 and 8950 tractors
Important! Adjusting fuel injection timing on 6800, 8750 and
8950 tractors and later on all tractors which have Bosch in --line pump (G4720--- (320), G2358 --- (420)and G5294--- (620,
634), the injection timing is adjusted according to this instruction.
Note! On these tractors the injection starting point in the 1st
cylinder has been positioned with aid of an indicator pin inthe
pump governor housing.
9025 99100
1. Turn the crankshaft to a position where the 1st cylinder piston reaches its compression stroke top dead centre. Then turn
the crankshaft backwards until the timing mark on the flywheel is at the point of locator 9025 99100.
2. Unscrew the plug on the side of the injection pump. Take
out the indicator pin.
3. Turn the indicator pin and push it into the hole so that the
groove at the end of the pin points towards the pump.
4. If the pin groove fits on the boss on the governor weight
assembly, the injection timing is correct. Otherwise, turn the
pump to a position where the boss and the pin groove align.
Warning! Do not rotate the crankshaft when the groove end
of the pin is inside thepump, sincethe pin end damages easily and metal pieces remain in the governor housing.
5. When the adjustment is correct, turn the indicator pin so that
the groove points outwards (running position) and push the
pin into the hole. Refit the plug.
Note! When checking the injection timing, an electric testing
device can also be used, e.g. Bosch KDEP 1601 according
to the instruction manual of the device.
Page 14
Running position Starting position
1. Forced---feed solenoid
for starting
117
Model Code Page
22. Fuel system
1. 6. 1999
6800 223
9
15. 5. 1996
Manifold pressure compensator on
6800 tractor
(Bosch LDA)
Note! Boost control is fitted also on 8750 and 8950 tractors
which have SigmaPower system.
The boost control unit on the governor housing has been
connected via a hose to the engine inlet manifold. At low
revs the boost pressure is low and engine tends to smoke.
The boost control limits amount of injected fuel at low revs
so that exhaust gas emissions are below standard R24.
This adjustment starts at a certain, adjusted, boost pressure.
The boost control unit membrane is pre--- tightened and air
tight. A spring in the unit affects the lower surface of the
membrane; the other end of the spring rests against the
threaded guide sleeve (2). The spring tension can thus be
changed in certain limits (adjusted in factory).
With thread equipped pin (1) is attached to the membrane.
The lower end of the pin transmits movement of the membrane via an angle piece to the injection pump control rod
(3).
When increased boost pressure presses the membrane
downwards, also the pin moves downwards against the
spring force and allows the control rod to move towards the
greater fuel amount, which is injected into the combustion
chambers. When the boost pressure decreases, the control
rod moves towards the smaller amount of injected fuel.
Important! The boost control unit has been adjusted in the
factory, and adjustments afterwards are not necessary.
Cold start solenoid
Note! This solenoid is also fitted on 8750 and 8950 tractors.
When the engine is started, the control rod must move to
the starting position. This can be done by moving the boost
control lever in the direction of the axle, so that the lever
cannot affect any more the injection pump control rod.
The mechanism functions with aid of solenoid and a cross
shaft.
The solenoid is energised, when the ignition switch is
turned in a starting position. The solenoid is energised as
long as the starter motor is on. In the starting position, the
solenoid is magnetic. When the solenoid moves to the starting position, a click sound can be heard from the injection
pump.
1
2
Picture 1. Boost control
A. Adjustment screw with which is adjusted fuel amo-
unt, which the injection pump injects at low boost pressure.
B. The operating pressure is adjusted by removing the
plug and by adjusting wheel B with a screwdriver.
3
A
B
Page 15
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