Adjusting The Valve Clearance
The engine must be cold.
1. Dismantle the rocker chamber covers.
2. Rotate the crankshaft so as to close the valves of the cylinder to be adjusted. Note that this adjustment will depend on the individual engine.
2.1. Turn the crankshaft in the direction of rotation until the valves of the cylinder to be adjusted overlap. Mark this position of the crankshaft on the vee-belt pulley and rotate the crankshaft one complete revolution (360°).
2.2 Turn the crankshaft in the direction of engine rotation until the valves opposite the cylinder to be adjusted overlap.
Fig. 2-1 and table below
Note for Refitment:
The exhaust valve is left-hand as viewed from the exhaust air side.
3. Release locknut of adjusting screw and adjust rocker arm/valve stem clearance.
4. Recheck clearance and readjust if necessary.
5. Apply sealing compound to new gaskets for rocker chamber cover(s) and fit cover(s).
Checking The Compression Pressure
The specified pressure applies to min. 150/min starting speed of engine and 20°C reference temperature at sea-level. Prior to checking, run up engine briefly to medium speed, so the combustion chamber will be sufficiently sealed by an oil film. Perform check at zero delivery of injection pump.
1. Remove injector and in its place insert and secure adapter with seal.
Fig. 2-5, left
In the case of FL 912 W, remove heater plug and in its place insert adapter for compression pressure recorder.
Fig. 2-5, right
2. Connect compression pressure gauge.
3. Take the compression pressure reading.
Check that the individual compression pressures are within the range specified and about equal for all cylinders. Any deviations in pressure between cylinders should not exceed 15%.
Determining TDC With Setting Device
1. Remove No. 1 rocker chamber cover.
2. Turn crankshaft until valves overlap, then give crankshaft another half turn.
3. Mount setting device. Using pressure screw of device, press down one rocker arm through 5-6 mm.
4. Fit dial gauge with preload.
5. Secure graduated scale to V-belt pulley and fix pointer to dowel sleeve.
NOTE: If engine is installed in vehicle, use graduated dial segment No. 100940.
6. Set pointer to "O" on scale.
7. Turn crankshaft carefully in nominal direction until piston pushes up the valve. Slowly turn farther until gauge pointer changes the direction. Set gauge at "O"
8. Turn back crankshaft through about one revolution of gauge pointer, then again in original direction up to 0, 1 mm (10 graduations) from O-position. Read crankshaft position from scale and record.
9. Turn crankshaft in running direction beyond "O" through about one revolution of the gauge and turn back up to 0.1 mm (10 graduations) before "0".
10. Read crankshaft position again from scale and record. The middle of the two crankshaft positions is the TDC (=OT) mark.
11. Turn crankshaft so that the mark found agrees with the pointer. The piston is now in TDC position.
12. Set pointer to "0" position of scale.
Determining TDC W/O Graduated Scale
Mounted are tuning unit No. 100640 and dial gauge No. 100400. Dial gauge is pre-tensioned.
1. Extend dowel sleeve by a piece of wire.
2. Turn crankshaft carefully in normal direction until piston pushes up the valve. Slowly turn farther until gauge pointer changes the direction. Set gauge at "0".
3. Turn back crankshaft through about one revolution of gauge pointer, then again in original direction up to 0.1 mm (10 graduations) from 0-position. Provide an V-belt pulley a mark agreeing with dowel sleeve.
4. Turn crankshaft in running direction beyond "0" through about one revolution of the gauge and turn back up to 0.1 mm (10 graduations) before "0". Provide second mark on belt pulley.
5. Measure and mark the half-way position between the two marks.
NOTE: The mid-way mark will be the dead centre mark. When it is opposite the retainer sleeve, cylinder 1 will be in the top dead centre position.
Checking Beginning Of Delivery (FB) (by H.P. test unit or hand pump)
The TDC (=OT) has been determined. The graduated scale is secured to the belt pulley, the pointer to the dowel sleeve.
1. Turn the crankshaft backwards through 90 deg., then in the direction of engine rotation until the indicator points to the value given in the specifications for the FB point ahead of the zero position.
NOTE: The piston of cylinder 1 will be exactly at the FB point.
1. Connect the pressure line of the high-pressure tester.
2. Dismantle the fuel filter. Disassemble the fuel line of cylinder 1 connecting with the pumping element and the leak-off line connecting with the fuel-injection pump cover. Plug the leak-off hole and connect the pressure line of the instrument to the threaded sleeve for the fuel filter.
NOTE: The hand pump can also be used if a blanking cover with hollow screw instead of the delivery pipe with H.P. unit is provided. The hollow screw can be fabricated locally (see drawing on last page).
3. Connect the overflow pipe with funnel and the return line to the stub for the fuel line to cylinder 1.
F2/3/4/5/6L (with Bosch injection pump):
3.1. Disconnect inlet pipe and backleakage pipe. Plug up one of the ports (arrow) and connect delivery pipe of test pump to second port.
4. Turn the crankshaft in the direction opposite that of engine rotation through 90 deg. from the point of fuel delivery (FB).
4.1. Switch on H.P. unit (F2L with Deutz injection pump) or operate H.P. hand pump (F2/3/4/5/6L with Bosch injection pump), until fuel comes out of the overflow pipe. Turn crankshaft slowly in normal direction, until only droplets come out at intervals of 5-8 seconds.
Fig. 2-20 and 2-21
5. Check that FB mark on belt pulley agrees with pointer, so that the fuel delivery timing is correct.
6. Turn off the high-pressure tester.
7. If necessary, correct the point of fuel delivery in accordance with the separate instructions. Note that the procedure is not the same for all types of engine.
Setting Beginning Of Delivery (FB) (As from 3-cylinder engine)
1. Turn the crankshaft in the direction opposite to that of engine rotation, through 90 deg. from the point of fuel delivery (FB) and then in the direction of engine rotation until the FB mark on the vee-belt pulley registers with the retainer sleeve or timing indicator.
2. Dismantle the vee-belt idler or cover. Slacken the screw on the injection pump drive with special spanner No. 110310.
3. Slowly rotate the injection pump shaft in the direction of normal rotation until the pump starts to deliver fuel. (Use double spanner No. 110330 or a 19 mm socket spanner)
Fig. 2-31 and 2-32
4. Check that fuel comes out from overflow pipe (when operating test unit or pump) only in droplets at intervals of 5-8 seconds.
5. Retain the injection pump shaft in this position and tighten the screws on the injection pump drive, using special spanner No. 110310.
6. Re-check the fuel-injection point and correct, if necessary. Turn off the high-pressure tester.
7. Assemble the vee-belt idler or cover with a new rubber O-ring. Dismantle the timing device. Connect the fuel lines, free from tension, and assemble the cover on the injection pump.
Testing The Injection Nozzle (by testing outfit)
Injector is removed.
1. Connect injector to outfit.
2. With pressure gauge cut in, press outfit pump lever several times. Read opening pressure (Fig. 2-35) and inspect spray pattern. Compare readings with Specification Data.
At 25 - 30 bar below specified opening pressure, check that no fuel will dribble from nozzle.
3. Adjust nozzle opening pressure by shims below the spring (adding shims increases pressure and vice versa). Shims of the following thicknesses are available: 1.0; 1.05; 1.1; 1.15; etc. up to 1.95 mm.
Note for Refitment:
By adding shims the pressure will be increased; by removing them the pressure will be decreased.
For FL 912W, adjust release pressure by means of set-screw. By turning in screw, release pressure is increased; by turning it out, pressure is decreased.
4. Repeat test and recheck spray pattern. The jet(s) should be solid without surrounding mist. Fig. 2-38
FL 912/W: one jet only
5. Check that there is no after-dribble.
6. If nozzle works unsatisfactorily, replace.
Testing The Injection Pump (by special outfit)
The test is confined to making sure that the delivery valves and pump elements are free from leaks. The fuel feed pump intake is connected to the fuel tank or a receptacle containing filtered fuel. Proper fuel delivery is a prerequisite.
1. Disconnect injection line(s) on the fuel-injection pump. Evacuate the air from the fuel injection pump. Connect the tester to the pump element to be checked.
2. Open the second connection of the tester and evacuate the air. When the escaping fuel is free from bubbles, close the second connection.
NOTE: The manual operation of the fuel-injection pump elements differs from one type of engine to another.
F2L: Rotate the crankshaft until the air is evacuated or until the pressure has built up.
As from 3 cylinder engine: Lower the tappet of the element to be checked by turning the crankshaft and then pump with a lever.
3. To check a pressure relief valve, generate a pressure of 150 bar. The indicator of the pressure gauge may not drop back more than 10 bar during a minute.
4. Generate a pressure peak of 350 bar. This must be clearly indicated by the pressure gauge.
5. A faulty injection pump should be repaired by specialists or replaced.
Checking Piston Crown Clearance
(Direct injection and 2-stage combustion system)
Cylinder head(s) removed.
1. Apply grease to a piece of lead wire of 2 mm thickness and stick wire to piston crown.
Check that piston is below TDC.
2. Mount cylinder head and insert securing bolts with washers.
3. Preload bolts by above wrench through 30 Nm (see tightening procedure) and tighten through one stage (45°) with the aid of device No. 101900.
Rotate crankshaft by one revolution (360 degrees).
4. Unscrew bolts and remove head. Mark heads relative to cylinders.
5. Take out wire and gauge at weakest point. (Compare reading with Specification Data).
For piston crown clearances see Technical Data.
6. Adjust clearance by shims of 0.2 mm and 0.5 mm.
Note for Refitment:
This is the easiest method of getting the correct clearance:
If the clearance is too small, remove cylinder and place the number of shims required below the cylinder.
In the case of a distance of 0.6 mm, instead of using several thin shims, use either one shim of 0.5 mm or one shim of 0.5 mm plus 0.2 mm, taking into consideration the piston crown clearance with appropriate tolerance.
If the clearance is too large, raise cylinder, cut through the surplus shims with side-cutting pliers and remove.
Removing And Installing Exhaust Gas Thermostat
1. Disconnect pressure oil pipes and breather pipe from exhaust gas thermostat.
2. Loosen counternut, screw thermostat out of exhaust gas elbow.
3. Apply film of Deutz S1 Never-Seez paste to thread of thermostat.
4. Screw thermostat into exhaust gas elbow and align with the connection for breather pipe. Tighten counternut.
Then lock down counternut with a torque of 15 - 20 Nm only.
5. Connect pressure oil pipes at front end and at lower connection of thermostat.
NOTE: Renew joint washers for banjo bolts, connect pipes free from tension.
6. Tighten clip securing breather pipe.
Checking Exhaust Thermostat
(possible only with engine under load)
Should the red pilot lamp (for indicating the engine temperature) light up in the case of engines with exhaust thermostat, check whether the cooling fins of the cylinders are clean and whether the cooling blower is properly controlled by the exhaust thermostat. If the cooling fins are clean, the next step is to by-pass the thermostat. Stop the engine. Remove the copper gasket from under setscrew "d", Fig. 2-60. The thermostat is thus switched over to full-flow, that is to say, the cooling blower then operates uncontrolled. Restart engine. If the cooling blower is now heard to run at higher speed, and the pilot lamp no longer lights up, this means that the thermostat is defective and must be renewed.
Exhaust thermostat uncontrolled. The copper gasket has been removed from under the setscrew "d".
Exhaust thermostat controlled. The copper gasket is in place under the setscrew "d".