Removing And Replacing Cylinder Head
1. Dismantle the air filter with holder, disconnect the induction pipe from the air compressor and the fuel line from the torch heater. Unscrew the clip on the induction pipe securing the fuel pipe leading to the torch heater. Dismantle the exhaust manifold, induction manifold, air cowling, leak-off lines and fuel delivery lines.
NOTE: Immediately the pipes are disconnected, plug the bores and fit caps over the connecting stubs of the fuel system.
2. Dismantle the cover plates for the cylinder head studs, back vertical plate, upper cover plate, exhaust air plate, rocker chamber covers and rocker arm shaft support. Remove the pushrods. Unscrew the plugs. (Use socket spanner No. 120040 and square-recess socket No. 120060).
NOTE: On recent engines the square head of the plug is of modified design. The use of a regular tool is, however, possible.
3. To dismantle the cylinder head of the final cylinder, disassemble the screw securing it to the front vertical plate.
4. Slacken the cylinder head studs in stages, in diagonal sequence. (Use socket spanner No. 120040).
5. Remove the cylinder head and push-rod sheaths.
1. Align the cylinder.
NOTE: Check/adjust piston crown clearance (see Section 2).
NOTE: Where provided, install gasket.
2. Mount cylinder head after measuring length of head bolts.
3. Renew those cylinder head studs that have stretched beyond the permissible maximum stated in the specifications.
4. Assemble and slightly tighten the studs fitted with washers. Align the induction and exhaust flanges of the cylinder heads without disturbing the alignment of the cylinders.
5. Tighten and lock down the studs in accordance with the instructions for tightening bolts and studs. (Use socket spanner No. 120040 and angle-of-turn indicator No. 101900).
6. Fit brass screwplugs with new gasket in the cylinder head.
The tightening torque for the brass screw-plugs is 80 + 10 Nm.
7. Assemble and tension the spring on the pushrod tube. (Use spring tensioning tool No. 125300).
8. Place on the profile washer with the domed side facing towards the spring. Fit a new sealing ring with the flat side facing towards the end of the pushrod tube.
Fig. 3-10, left
9. At the opposite end of the tube, fit a new sealing ring with the flat side facing towards the shoulder.
Fig. 3-10, right
10. Insert the spring ends of the two pushrod tubes in the pushrod holes in the crankcase and locate the upper ends with gaskets in the cones of the cylinder head. Remove the spring tensioner.
Fitting Pushrod Cover Tubes On Engine Provided With Exhaust Air Heating
11. Fit O-seals between the two grooves of the pushrod cover tubes as well as cover plate with gasket adhered thereto. Fitting order see Fig. 3-12.
12. Put springs on pushrod cover tubes and tension springs. Spring tensioner No. 125300 (2x).
13. Fit sectional washers and gaskets.
14. Insert spring ends of both pushrod cover tubes with cover plates in the pushrod holes of the crankcase and locate the upper ends with gaskets in the cones of the cylinder head.
NOTE: Insert cover plate between 2nd and 3rd upper fin of cylinder bearing in mind the difference in width of the cover plates. After their fitting, the plates must overlap. (see arrow)
15. Install the pushrods.
16. Mount the rocker arm shaft support.
17. Adjust the valve clearance.
18. Apply jointing compound to a new gasket and stick it in position on the rocker arm cover. Mount the rocker arm cover, align and secure with a screw fitted with a new gasket. For tightening instructions, see Specification Data.
19. If the cylinder head of the final cylinder was dismantled, assemble the screw in the front vertical plate.
20. Mount the exhaust-air plate.
21. Position the upper cover plate on the cylinder heads.
22. Place the rear vertical plate in position.
23. Secure upper cover plate and rear vertical plate.
24. Connect the fuel delivery lines. Install injection piping.
NOTE: Assemble the fuel delivery lines complete with a new rubber mounting strip and new rubber sleeves.
25. Assemble the leak-off pipes fitted with new gaskets.
26. Fit long banjo bolt.
NOTE: Location of banjo bolt:
- 3-cyl. engine: in No. 3 cylinder4-cyl. engine: in No. 4 cylinder5-cyl. engine: in No. 4 cylinder6-cyl. engine: in No. 6 cylinder.
27. Hook the air cowling to the upper cover plate and close.
28. Fit new gaskets, flat end upwards, for the induction and exhaust manifolds.
Provided for recent engines are modified gaskets for the air intake manifold, which must not be used for the exhaust manifold. New gasket design.
Fig. 3-24 (arrows)
29. Mount the induction manifold. Fit the washers and assemble the nuts.
30. Place the exhaust manifold in position. Fit the washers and assemble the tall brass nuts.
NOTE: If the engine is an F6L 912/913, check the gaskets on the exhaust manifold. They must seat freely in their grooves and be taut. If necessary, renew. Assemble the exhaust manifold.
31. If the engine has a flame-type heater system, connect the fuel line to the heater and fix with clips to the induction pipe.
32. Install the air filter, should one be necessary.
Removing And Replacing The Cylinder
It is assumed that the cylinder head is dismantled.
1. Position the piston at the bottom dead centre.
2. Turn the crankshaft to lift the cylinder out of the crankcase. Remove the cylinder.
NOTE: Do not knock the piston against the crankcase or connecting rod. Remove the rubber O-seal and shims from the cylinder.
3. Check the joint surface for the cylinder on the crankcase.
4. The cylinder joint surface must be level and free from indentations. If necessary, dismantle the adjacent cylinder and baffle plate. Turn the joint surface in accordance with the special instructions, see Section 4.
5. Adhere to cylinder by means of grease at least one shim of 0.2 mm thickness.
6. Place the piston on two wooden slats. Oil the working face of the cylinder and the piston. Position the rings so that their gaps are equally spaced around the piston.
7. Mount and tension the piston ring squeezer No. 130530.
8. Install the cylinder with the cutouts facing the pushrod bores.
9. Bring the cylinder into alignment with the adjacent cylinders.
Inspecting The Cylinder
Cylinder is removed.
1. Inspect cylinder for defects. If necessary, replace complete with piston.
2. Set precision gauge to the basic standard or oversize bore (see Specification Data).
3. Gauge cylinder bore at levels 1 to 4 of engine centre line "a" as well as cross-line "b".
Figs. 3-34 and 3-35
4. Compare readings with the Specification Data. If the wear limits are reached, replace the parts concerned. Pistons and cylinders are available in two oversizes.
5. Check that cylinder top and bottom joint faces are flat.
Repairing Cylinder Head
1. Bolt the cylinder head to the swivel clamping stand. Dismantle both valves with springs, valve rotator and washer. (Use clamping stand No. 120900 with plate No. 120910, valve spring compressor No. 121120).
2. Clean the cylinder head and inspect for external damage or cracks; renew if necessary.
3. Check the cylinder head seating surface. It must be flat and square. It can be refaced provided the distance from the cylinder head sealing surface to the cylinder head crown is not less than the low limit given in the specifications. Fig. 3-38
NOTE: Measurement to be made with intermediate ring inserted.
4. Slight damage to the cylinder head seating surface can be removed by grinding cylinder head on cylinder with fine abrasive paste. If the cylinder head seating area is more severely damaged, recut with plate mill No. 124480, Fig. 3-39, or rework in the turning fixture No. 125500.
5. Chuck cylinder head with fixture in lathe and align.
NOTE: Remove only so much material as is necessary for obtaining a perfect sealing surface, while taking into consideration the permissible tolerance.
6. Check that the intermediate ring is in good condition before placing it in recess of cylinder head.
7. To determine the wear of the valve seat rings, take a new valve and measure the distance between valve plate and cylinder head seating surface (with intermediate ring placed in position).
For valve recess, see Specification Data.
8. Renewing valve seat rings.
a) By means of mandrel No. 122450: Fit mandrel No. 122450 to the cylinder head for turning out the valve seat rings on a lathe. Chuck cylinder head with mandrel in lathe and turn out the worn rings.
b) Fit the drilling device No. 122460 to a drilling machine for cutting out the valve seat rings. Place on the cylinder head and insert the pilot pin with drilling bushes No. 122461.
9. Drill out the valve seat rings by means of the hard-metal special cutter No. 122463.
10. Heat the cylinder head uniformly in a heating cabinet or oven to a temperature of 220 deg. C. Slip the new ring (available in oversizes) chamfered side first on the drift and seat it. (Use drift No. 123960 for inlet valve and No. 123950 for exhaust valve, respectively).
To replace valve seat rings and valve guides, cylinder head should be heated up only once.
11. Reface the seating rings that are not to be renewed. The maximum permissible distance from the centre of the valve head to the cylinder head seating surface must not be exceeded. (Use drift No. 122305, reseater with holder for inlet and exhaust valve No. 122302.
12. Check the clearance of the valve stems in the guides of both valves. If it exceeds the permissible maximum given in the specifications, fit new guides.
Removing and installing a valve guide.
13. Uniformly heat the cylinder head in an oven to a temperature of 220°C. Do not heat for longer than 30 minutes. Drive out valve guide from the seating ring side (Assembly arbor No. 123310).
Fig. 3-48 left
14. Renew the valve guide. (Valve guides are also available in oversizes). Fix new securing wire.
15. With the cylinder head heated to 220 deg. C, drive in from the rocker arm support side the longer end of the valve guide until it seats on the securing wire.
16. Allow the cylinder head to get cold. Then ram the valve guide. (Use reamer No. 123510).
Fig. 3-48, right
17. Remove, if necessary by pulling, the injector gasket remaining in the cylinder head. (Use puller No. 120630)
18. Check whether the valve rotators work freely; renew if necessary.
19. Install the valve rotators.
20. Measure length of valve springs (Technical Data).
21. Insert valves.
Note for installation:
In the case of engines with two-stage combustion, FL 912 W, fit valve stem seals (see sketch).
Before fitting the valve stem seals, ensure that there are no sharp edges in the zone of the groove for the collets (see arrows).
22. Position the valve springs with the close coils facing the rotator. Install the valves. (Use valve spring compressor No. 121120)
NOTE: Regarding the renewal of cylinder heads, see Technical Circulars.
Overhauling The Rocker Arm Bracket
1. Dismantle bracket.
2. Replace any worn parts.
3. Press in the bearing bushing, making sure that the lubrication oil holes are in register.
Note for Refitment:
The rocker arms are provided with an oil metering screw, the chamfered face of which should point to the thrust pad (Fig. 3-55). Check that one thread turn of the screw projects beyond the locknut.
When the screw is finally adjusted under idling conditions on the engine test bench or in a vehicle, the position of the chamfered face is irrelevant. All you have to make sure is that a small oil flow toward the thrust pad is still visible.
Checking Pushrods, Pushrod Tubes And Tappets
1. Check that rod ends are tightly seated and free from wear.
2. Check that rods are straight and oil hole is free.
3. Check that tubes are straight and free from defects.
4. Check that tappets are not worn and oil hole is free.
Replace parts as required.
Dismantling And Installing Piston
It is assumed that the cylinder in question has been dismantled. It should be noted that to enable the final piston to be dismantled, the blower and front vertical plate must be removed in the case of F2/3/4/5L models and the front vertical plate in the case of an F6L.
An adjacent cylinder must be removed to permit one of the other pistons to be dismantled.
1. Heat piston to about 80° C by means of piston heater No. 139000. Remove circlip and withdraw the gudgeon pin.
2. Remove the piston.
3. Fit the circlip in the boss that is to face the cylinder that has not been dismantled.
4. Heat piston with the piston heater No. 139000 (temperature approx. 80 degrees C). Position the piston so that the exhaust side (marked with an arrow on the piston crown) faces the pushrod bores.
5. Press the gudgeon pin into the piston bosses and the small end of the connecting rod.
6. Install the second circlip for location of the gudgeon pin.
Checking The Piston
1. If the cylinder is renewed, a new piston must be fitted. Normal and oversizes are given in the specifications.
2. Inspect the piston for damage or visible wear, including the bosses.
3. Remove the compression rings and bevelled scraper ring. (Use piston-ring expander No. 130300)
4. Open and remove the expander spring for the bevelled scraper ring.
5. Clean the piston-ring grooves.
6. Measure axial piston ring clearance by using commercial tools.
Fig. 3-63, left
Measure first piston ring groove, if trapezoidal, by means of trapezoidal groove wear gauge No. 130360.
Fig. 3-63, right
NOTE: If, when measuring a piston with trapezoidal ring groove, a gap "S" (Fig. 3-64) is found to exist between the inserted gauge and the piston, this means that the axial piston ring clearance is within the tolerances stated in the Specification Data and the piston is fit for further use.
But if the gauge contacts the side of the piston (see Fig. 3-65), i.e. without gap, the piston has to be renewed.
7. Insert all the piston rings singly in the cylinder and press down with the piston to a distance of 30 mm from the cylinder head contacting surface. Measure the gap clearance of the piston ring.
8. Compare the gap clearances of the piston rings with the values given in the specifications.
9. Renew defective pistons together with gudgeon pin and rings. Renew also cylinders.
10. When installing the piston rings start by fitting the expander spring for the bevelled scraper ring in the bottom groove.
11. Assemble the piston rings with the aid of piston-ring expander No. 130300, in the following sequence:
- No. 3 (No. 4) Slotted, double-chamfered oil-control ring, chromium-plated.(No. 3) Tapered compression ring, ferrox finished; install with face marked "top" upwards.No. 2 Tapered compression ring, ferrox finished; install with face marked "top" upwards.No. 1 Top, double-trapezoidal compression ring, chromium-plated. "top" upwards.
NOTE: Place the rings so that the gaps are evenly spaced around the piston.
12. Check piston pin for wear using a bevelled steel straight edge or measuring angle, Fig. 3-69.
NOTE: Secure the opposite end of the gudgeon pin in position. Place the piston on the small end of the connecting rod so that the exhaust air side of the piston (marked on the piston crown) is in the same direction as the open side of the connecting-rod bearing. Press in the gudgeon pin.
Checking The Connecting Rod
Gauging and replacing piston pin bush
1. Set inside micrometer to starting dimension using a micrometer frame (see Technical Data).
2. Measure the piston pin bush at points one and two in the planes "a" and "b".
Compare recorded values with those specified in the Technical Data.
3. Pull out old piston pin bush with fixture No. 131310 and pull in new piston pin bush with the same device.
Note for installation:
Pull in the new piston pin bush flush, making sure that the oil bores in bush and connecting rod coincide.
Gauging And Replacing Big-End Bearings
The big-end bearings are of finished type. They are made of two half shells and correspond to the possible repair sizes of the crankpins. They are available in six sizes (see Technical Data). They cannot be reconditioned. The standard wall thickness "W" increases by 0.125 mm per undersize step.
4. Assemble the big-end bearing cap to the connecting rod, making sure that they bear the same identification number.
5. Mount bearing caps and tighten bolts according to instructions.
6. Set the precision gauge to the basic inner diameter size by means of a micrometer frame (see Technical Data).
7. Measure big-end bearing bore at the points 1 and 2 in the planes "a" and "b".
Fig. 3-77 and 3-78. Note any contraction, out-of-roundness or conicity.
8. If the readings keep within the limits of the Technical Data, the respective bearing bores are in acceptable condition and the necessary preload will be obtained after installation of new bearing shells.
9. If the recordings at the bearing bore deviate only slightly from the specified values, the measurements have to be repeated when the new shells are installed.
10. Remove bearing cap and insert new bearing shells.
11. Refit bearing cap then preload and tighten down according to instructions. Repeat measurement.
12. If the recordings show that the bearing tolerances remain up to a maximum of 0.020 mm above the values indicated in the Technical Data, the connecting rod is still fit for use. Otherwise it has to be replaced. It is not permissible to restore the preload by reworking the parting faces on the big-end bearing bore or shimming the shells.
13. Mark matching bearing shells and connecting rod.
14. Check connecting rod with mounted small-end bush, but without big-end shells, on a connecting rod tester for parallelism, Fig. 3-79.
When measuring the parallelism with the plug gauge, the deviation may not exceed = 0.08 mm over a distance of A = 100 mm.
15. Check connecting rod for squareness. "A" and "B" should be equal.
16. Weigh the connecting rods.
NOTE: The set of connecting rods for an engine should be of the same weight class. When renewing connecting rods, observe the colour-code (arrow) indicating the weight class. The permissible weight tolerance within a certain weight class is ± 15 g.
Removing And Installing Flame-Type Heater Plug
1. Detach electric cable and fuel pipe from flame-type heater plug.
2. Unscrew flame-type heater plug.
3. Spread thread of flame-type heater plug with DEUTZ DW 47. Screw in plug and align relative to the fuel pipe. Tighten counternut.
Note for installation:
Replace nut washer.
4. Connect fuel pipe on flame-type heater plug.
5. Connect electric cable on flame-type heater plug.