The cylinder head and the timing
Removing and installing cylinder head fitted with engines
The following description describes the work that is required if installed cylinder head and timing gear. Description also includes the removal and installation of camshafts. Because of differences between the carburetor and the injection engine operation are described separately. The main difference between the carburetor and the fuel-injected engine is the use of a fuel-injected engine timing chain, carburettor and the two chains. In the following description are only some of the work in the form of guidance. To carry out specific operations should read the relevant section of the manual.
Vehicles with a fuel-injected engine
Elements of timing gear injection engine
- Reduce the pressure in the feed system, as described in Section Removal and installation of the motor. To do this, remove shown in fuse.
- Remove all panels under the front of the vehicle.
- Replace the front part of the car on supports, remove the right wheel and unscrew the plate on the front right-hand wheel arch.
- Drain the coolant as described in Chapter Cooling and heating systems.
- Remove the radiator.
- Remove the intake air hose to the inlet pipeline.
- Loosen and remove the drive belt on the front side of the engine. Remove the water pump pulley.
- Remove the generator.
- Remove the power steering pump.
- Remove the throttle cable.
- Remove all spark plugs.
- Remove the cylinder head cover. In order not to drag the cover should observe a certain sequence when loosening the bolts. It is shown in the illustration below. On the side of the cylinder head is slinger, which should be removed.
Sequence of easing of bolts of the cylinder head cover. Tightening in the reverse sequence
| || 1 - head cover |
2 - slinger
- Remove all support the inlet pipeline. The engine supports several SR20DE used, as shown in The engine SR20Di used only one support.
- Remove the oil filter cartridge and console power steering pump.
- Rotate the crankshaft (setting a socket on the crankshaft pulley bolt) until the mark on the belt pulley is not located next to the pointer on the timing gear cover (see. Illustration below). In this position, control labels each camshaft drive gears are in the position shown in the illustration.
The control label (1) on the camshaft sprockets must be in the specified position when the piston cylinder 1 is at TDC
| || 1 - control labels |
2 - right asterisk
3 - left asterisk
- Remove the nut and bolt and remove the timing chain from the cylinder head. Tensioner is laying and compaction of circular cross-section. Both parts must be replaced.
- Uncover the distributor head and check valve. Rotor, distributor will be in the position shown in the illustration. To remember this position should be on the distributor hold prescriber line opposite the middle of the slider. Then, remove the two bolts (arrows) and remove the valve.
| || Before removing the distributor (2) to the housing (arrow) in front line of the slider (2). |
- Loosen the two screws and remove the chain guide.
- Loosen the two bolts of asterisks of camshafts. This shaft must be held against rotation. For an asterisk shaft has a hex on which you can install the wrench as shown in the illustration below.
| || Loose bolts stars camshafts. |
- Remove the camshaft bearing caps, camshafts, oil line and a conductive plate. With the weakening of the bearing cap should be some consistency. It is shown in the illustration below.
Sequence of easing of bolts of covers of bearings of camshafts
| || And - right camshaft |
B - camshaft bearing caps
On - left camshaft
D - conductive plate
E - oil line
- After loosening the hose clamps, disconnect the following hoses: hose to the cylinder block, hoses from the heater and, if you have a water hose from the oil cooler.
- The engine SR20DE remove the starter. Also on this engine should unscrew the water pipe.
- Remove the cylinder head bolts on the outside. They are in the places indicated in the illustration below, the three near the water pump pulley and the one next to the ignition distributor.
| || The situation outside the cylinder head bolts. Three-side pulley of the water pump (1) and one on the side of the distributor (2). |
- Loosen the cylinder head bolts from the outside to the middle of the parallel passes and lift the cylinder head. An inlet manifold and outlet manifold are on the head. The illustration below shows the sequence of loosening bolts. If the head is stuck to the unit, you can knock on it with a rubber mallet. Under no circumstances should you try to insert a screwdriver between the sealing surfaces. Put your head on the bench, if it is to disassemble or repair.
| || Sequence of easing of bolts of the cylinder head. The arrow facing forward. |
- Remove the pan (Head of System of cooling and heating).
- On the underside of the crankcase and remove the oil suction grid masloprovodyaschuyu plate.
- Loosen the bolt of the crankshaft pulley. To lock the shaft from turning, you can enable the transfer. Press the two pulley mount. Firmly seated camshaft can be removed with a special tool. To set shown in the illustration below a stripper in a belt pulley there are two threaded holes.
| || Remove the crankshaft pulley. |
- Now, the engine should be lifted from the supports. You can use a mobile lift with a suitable steel plate to plate rested against the frame of the crankshaft main bearings.
- Remove the front engine mount.
- Unscrew the timing gear at the end of the engine. There should be weakened 9 bolts.
- Loosen the illustration below screws and remove the right (1) and left (2) guide chain.
| || Setting the right (1) and left (2) guide chain. |
- Remove the drive chain, if required, remove the crankshaft sprocket. Remember, she is wearing. Carefully clean and check all parts especially the details of timing gear. Worn sprockets are recognized by very brilliant places, which can be seen and roller chain. Checking the details of a head of cylinders, including camshafts, discussed later. When installing the timing gear parts and cylinder head, proceed as follows. All the necessary tightening torques on the they also stated in the text.
- Score on the crankshaft sprocket. Collar Stars must face the crankshaft. Make sure the key is properly seated.
- Rotate the crankshaft to key in an asterisk standing vertically. Management on an asterisk mark is set to "4 hours". Inspect the circuit and find the marked link. On one side of the circuit can detect two marks, spaced apart by 20 units. They serve for the camshafts. If you count 48 units, you can find a label for the crankshaft. This unit also has a color different from the other two. Put the chain on the crankshaft sprocket to coincide tags.
- According to the install and tighten the chain guide. Hang the top of the chain in a weakened state.
- Remove the old gasket from timing gear cover and sealing surface of the cylinder and apply sealant to the sealing surface (strip width of 2-3 mm). Put the remote unit (20) the oil pump and screw the cover to the cylinder block. All displaced remove sealant.
- Reinstall the front support of the engine and remove the lift.
- Score a crankshaft pulley on the shaft and tighten the bolt. At the same time hold the crankshaft from turning. Mark "0" on the pulley should be located next to the pointer in the timing gear cover (compare
- Install the oil suction grid and masloprovodyaschuyu plate.
- These activities are described in Chapter Cooling and heating systems.
- Lubricate the joints between the timing gear cover and the cylinder block a small amount of sealant and place the cylinder head gasket.
- Install the cylinder head with the intake manifold and the exhaust manifold and face down with a rubber mallet.
- Before installing the cylinder head bolts should be measured. If the distance from the end of the thread to the underside of the bolt head is greater than 158.2 mm, corresponding to the bolt to be replaced.
- Tighten the cylinder head bolts in the reverse order shown in Grease the bolt threads and the lower part of the bolt head with oil and tighten all the screws with your fingers. Tightening is carried out as follows:
The sequence of tightening camshaft bearing caps. Large cap belongs to the left camshaft
| || And - right camshaft |
B - Left camshaft
C - oil passage plate
D - oil line
| || Type of homemade protractor. It should be used when tightening the cylinder head bolts. |
- Put the template on the power strip and plug an extension cord into a socket.
- Wear on the bolt head (10) (see. and align the point of "0" to any point on the cylinder head.
- Now tighten the bolt until it reaches the mark of 90 - 100 ?°.
- Likewise other tighten the bolts as much as possible maintaining the angle as accurately as possible.
- Likewise, tighten the bolts another 90 - 100 ?° C. In no case can not be dovorachivat bolts directly to the 180 - 200 ?° r. E. A half turn. Dovorachivanie a predetermined angle should be carried out in two passes.
- Screw the 4 cylinder head bolts on the outside.
- The engine SR20DE install a water pipe. Also this engine replace the starter.
- Connect all water hoses. Check whether you can reuse the hoses and clamps.
- Clean the surface of the lid bearing the extreme left of the camshaft sealant residue and clean as a mounting side of the cylinder head. Then cover the mating surfaces sealant.
- Good neck camshaft bearing grease and insert into support holes. Rotate camshafts until guide pins terminal surfaces will not take the following provision:
- Pin the right shaft should stand straight up (12 o'clock)
- The pin of the left shaft must also face upwards (but at 10 hours)
- Now tighten the camshaft bearing caps. This work is quite complicated and should be performed, guided by the illustrations sequence tightening camshaft bearing caps. Large cap belongs to the left camshaft and specifically mentioned in the text of the bolts are designated by letters A through D below. In one illustration of a sequence of tightening on the other illustrations showing various bolts, which have different torques. Proceed as follows:
| || The individual referred to in the text of the bolts are designated by letters A through D. |
- Put the camshaft sprocket (connected to the guide pin) at the same time setting circuit. The marks on the sprockets and the chain links must be the same, as seen from the
- Screw bolts holding the camshafts (see. tighten the bolts to 14-16 N m.
- Install the chain guide (6) (see.
- Establish the ignition distributor. The receiving slot in the camshaft must be positioned horizontally. After installing the valve compare with
- Install chain tensioner. It should be guided by an illustration to pull tensioner. To do this, press the locking latch (1) inward and slide the piston (2) in the tensioner until the hook (4) can not be snap over the pin (3). Screw tensioner arrow to the front of the engine. After tightening the tensioning hook (4) is released and the tensioner is automatically triggered.
Elements to lock chain tensioner
| || 1 - retainer |
2 - piston
3 - pin
4 - hook
- Screw the cap of the oil filter and the console power steering pump.
- Install the support or the support of the inlet pipeline.
- Remove all traces of gasket from the sealing surfaces of cylinder head and cylinder head cover and cover both surfaces of the sealant.
- Place the gasket and tighten the nuts in the sequence reverse First, tighten the nuts are in the middle since the nuts (4) (3) (1) and (6) to 4 N m. Then tighten all the nuts in the reverse order to force 8 - 10 N m. Again, in the middle of the nut is tightened first.
- All the other works in the reverse order of removal.
Vehicles with a carburetor engine
Elements of timing gear carburetor engine
The position marks of upper and lower chains
| || 1 - 16 units between marks (2) and (3) |
2 - the label chain (silver color)
3 - the label chain (silver color)
4 - link 22 between the markers (3) and (6)
5 - 16 units between marks (2) and (6)
6 - tag chain (silver color)
7 - mark the bottom chain (silver color)
8 - lower drive chain
9 - mark on the intermediate shaft sprocket
10 - upper circuit
11 - mark the bottom chain (silver color)
- Remove all installed under the front of the vehicle panel.
- Replace the front part of the supports, unscrew the right wheel and unscrew the plate on the front right-hand wheel arch.
- Drain the coolant as described in Chapter Cooling and heating systems.
- Remove the drive belts of the generator and the power steering pump. Unscrew the pump together with the console from the engine. Do not disconnect the hoses.
- Completely remove the front exhaust pipe.
- Connect the motor cables to the lift and remove the front engine mount. This bracket is shown in
- Remove all spark plugs.
- Remove the cylinder head cover. In order not to drag the cover by loosening is necessary to observe a certain sequence. She is depicted in the illustration below.
| || Sequence of easing of bolts of the cylinder head cover. |
- Rotate the crankshaft (putting an end to the bolt head, crankshaft pulley) until the mark on the belt pulley will not rise next to the pointer on the timing gear cover (see. Illustration below). In this position the crankshaft piston cylinder 1 is in the TDC.
| || When the piston of 1st cylinder is at TDC, the pointer (1) and the "0" mark on the belt pulley (2) must be the same. |
- Uncover the distributor head and check valve. Rotor must be in the position shown in To remember this location for the installation should be carried out on the edge of the body of the distributor line opposite the middle of the slider. Then remove the ignition distributor.
- Remove the camshaft sprocket covers.
- Remove the water pump pulley.
- Remove the thermostat housing.
- Remove chain tensioner. It is secured by two bolts.
- Guided by the illustration below, make sure that both the control labels of asterisks of camshafts were opposite each other. Then remove the inner chain tensioner on the left side and the chain guide on the right side.
Kind established stars, tensioner and chain guide. The arrows indicate the screws
| || 1 - control labels of asterisks of camshafts |
2 - chain guide
3 - chain tensioner
4 - intermediate sprocket
- Loosen and remove bolts of asterisks of camshafts. This should keep the shaft from turning. Remove both asterisks at the same time removing the chain. Camshafts no longer be rotated, as otherwise the valves will encounter pistons. If you want to remove only the cylinder head should pull the chain and fasten it.
- Loosen the camshaft bearing cap bolts in several passes in the order indicated in the illustration. Mark the position of the caps and remove them. Remove both camshaft.
| || Sequence of loosening the camshaft bearing caps. |
- Loosen the cylinder head bolts from outside to inside in several passes in the order shown in the illustration and remove the cylinder head. Intake manifold and exhaust manifold are at the cylinder head. If the head is stuck to the strip, you can knock on it with a rubber mallet. In no case do not try to remove the head by inserting a screwdriver between the sealing surfaces. Carefully place the cylinder head on the bench, if it is to disassemble or repair.
| || Sequence of easing of bolts of the cylinder head. |
- On the reverse side, remove the intermediate shaft sprocket.
- Remove the timing chain.
- Check that the engine is securely hung on the lift and remove the high beam engine.
- Remove the oil pan and the oil suction screen (Section Removal and installation of the oil pan).
- Hold the crankshaft from turning (including transfers), loosen the screw of the crankshaft pulley. Press the two pulley mount.
- Install the engine under the mobile lift and raise the engine. Put between the elevator motor and a wooden lining. Unscrew the front engine support from the suspension.
- Unscrew the timing gear. One bolt is inserted into a water pump.
- Remove items from the end of the engine shown in the illustration below.
View installed lower circuit
| || 1 - lower drive chain |
2 - chain guide
3 - remote ring oil pump drive
4 - intermediate sprocket
5 - chain guide
6 - the crankshaft sprocket
- Install timing gear and a head of cylinders in the following sequence. In the depicted the individual elements of timing gear with a torque.
- Check that the piston of 1st cylinder is in TDC position. The two keys to the crankshaft must stand upright.
- Install the chain guide.
- Score crankshaft sprocket and apply the lower drive chain. Asterisk has a label and silver unit must stand on the tooth with the mark.
- Tagged with asterisk must be installed outside. Other silver link located symmetrically, so that the chain can be applied by anyone. Tighten the chain and tie at the top, that it can not slip off.
- Install timing gear cover:
- Cover the surface of the lid sealing.
- Once again, make sure that the marks on the chain and sprocket match.
- Align the remote element of the oil pump with the pump.
- Press down on one side of the chain guide, so she could not touch the seal cap.
- Insert two new seal round section inside the cover.
- When replacing the cover, making sure not to damage the oil seal.
- Install the front engine mount.
- Install the oil suction grid and pan (Section Removal and installation of the oil pan).
- Install the crankshaft pulley and tighten the bolt.
- Set high beam engine (see.
- Line a large asterisk of an intermediate shaft so that the mark on the sprocket coincides with silver chain links. Then, guided by
apply a top chain, the label on the small sprocket coincides with the upper link silver chain.
- Both labels of asterisks of an intermediate shaft should be turned outwards. Insert the shaft of the intermediate stars behind.
- Install the cylinder head with a new gasket. In the cylinder head bolt washers are imposed that the flat side facing the head. Establish a head with the intake manifold and the exhaust manifold and face down with a rubber mallet. Replace all screws.
- Tighten the cylinder head bolts in sequence of return to that shown in the Oil the bolt threads, the lower part of the head bolts and washers and tighten all screws by hand.
- Tightening follows:
- Tighten all bolts according to the diagram to with a force 29 N m.
- Tighten all bolts according to the diagram to with a force of 60 N m.
- Fully release all bolts.
- Tighten all bolts according to the diagram in the illustration 4.78 with effort of 30 N m.
- Tighten all bolts by a certain angle in the sequence shown in the
- All bolts should be tighten on a corner 50 - 55 ?°. In order to properly sustain the angle template needs to be made independently. Cut a circle out of cardboard and divide it into four equal segments of 90 ?°. Divide a segment to get an angle of 45 ?°. Label area 50 - 55 ?° below the line of 45 ?°, as shown. Similarly, in the middle of the template cut a square hole about the size of a socket and used an extension cord. When tightening, proceed as follows:
- Put the template on the power strip and plug an extension cord into a socket.
- Wear on the bolt head (15) (see.
and align the point of "0" to any point on the cylinder head.
- Now tighten the bolt until it reaches the mark of 50 - 55 ?°
- Likewise other tighten the bolts as much as possible maintaining the angle as accurately as possible.
| || View improvised corner template for gasoline engines. |
- If you do not use a template, you can tighten the bolts to 60 N m after they are tightened to 30 N m. Then tighten the screws on the outside (bolts 1 to 5 on the
with a force of 6.5 - 8.5 N m.
- Lock the chain drive and tighten a bolt of an intermediate gear.
- Install the camshafts, the camshaft cover and the ignition distributor. Tighten the camshaft bearing cap bolts in the reverse order to that shown in Good grease neck camshaft. After the replacement of parts of valves or camshaft, valve clearance must be adjusted as described below.
- Insert the camshaft sprocket in a chain and screw them onto the shafts. At the same time, guided by the illustration and consider the number of links between the silver links on the upper side. Each star has a single tooth with a tag that must be inserted into a silver link. Also mark on the intermediate shaft sprocket must be aligned according to the illustration, respectively, t. E. Marks on the camshaft sprocket and idler shaft should coincide with silver links. The guide stars within the camshaft will be in the position shown.
Properly assembled top drive chain with established stars
| || 1 - 16 units |
2 - left mark
3 - 22 level
4 - right mark
5 - 16 units
6 - the bottom label
7 - marks on the sprockets
- Carefully turn the two camshaft (crankshaft must also be rotated, so that the valves can not stumble on the pistons), until the two guide pins occupy the position shown in the illustration. In this position, slide the sprockets onto the shafts (pins must be logged in to guide sprockets) and insert the bolts. Tighten bolts with demanded effort. Recheck to match the mark in the illustration below.
| || The two guide pins have to stand in this position before putting them stars. |
- Install the inner chain tensioner and chain guide according to the Make sure the hook to lock the tensioner was free.
- Screw the chain tensioner on the outside. Slowly turn the crank to check that the drive of the crankshaft can rotate freely. Establish the piston of 1st cylinder TDC.
- Lubricate the thermostat housing gasket sealant and screw it.
- Screw the water pump pulley.
- Establish the ignition distributor. The receiving slot at the end of the camshaft must be positioned horizontally.
- Screw the cover stars camshafts.
- Grease a semicircular sealing strip sealant 3 mm and insert it into the bed of the cylinder head. Good align them with the top side is flush with the surface of the cylinder head.
- Cover the cylinder head cover gasket sealant and replace the cover.
- Tighten the bolts in the reverse of the one shown in the
- The rest of the work make in sequence, return to removal.
Disassembly of the cylinder head and valves
Both are described in this manual have the engine cylinder head with camshafts mounted in it, but the similarity of their ends. Therefore, the work described separately. The injection engine uses levers that rely on hydraulic tappets for valve clearance compensation. In the carburettor engine cams both camshafts act directly on the inverted hollow cylindrical pushers. Also, different camshafts and support.
Remove levers of valves, shims, guide levers and hydraulic jacks according to the illustration below.
Details of the mechanism of the valve injection engine
| || 1 - guide arm |
2 - the valve lever
3 - Compensation washer
4 - hydraulic jack
Elements of the cylinder head of the injection motor
- The engine SR20Di remove the valve return pipe exhaust gases.
- Remove the heat shield from the exhaust manifold and loosen the manifold. Thus loosen starting from outside to inside.
- The engine SR20DE unscrew the fuel.
- Loosen the intake manifold from the outside to the inside. The engine SE20DE unscrew the pipe from the intake manifold.
- Remove the water outlet pipe and the thermostat housing with a water pipe.
- Remove the valves. To do this, squeeze the valve springs with the help of the detrusor. The illustration shows suitable for this engine constrictor. Remove the valve crackers, cup springs and valve spring. If detrusor not, put a piece of wood into the combustion chamber under the plate valve and slide section of pipe on top of the valve plate. Tap pipe for a hammer, and the crackers pop out of the valve slots and remain within the pipe.
| || Removing injection valves of the engine. |
- Remove the valve stem caps on valves using forceps. Caps should always be replaced. For shows individual elements of the cylinder head with an arrangement of individual parts. The second cam is supported on the same elements but one of the end caps more.
The cylinder head of the engine carburetor even when shot in one way or another is broken down into individual elements, t. E. In the cylinder head leaving only the valves. They also removed, as described above. Remove pushers and adjusting washers of pushers and connect according to the number of the valve. Supports the camshaft of the engine shown in the illustration below.
Camshafts and their bearing on the carburettor engine
A partition of a head of cylinders
The mechanism of the valve (injection engine)
- Check the levers for wear.
- Measure the diameter of the hydraulic elements and replace if it lies outside the 16,690 - 16,994. With the help of an internal micrometer, measure the opening elements (17.000 - 17.020). The difference between the resulting value gives the size of the backlash that should be in the range 0.07 - 0.040 mm.
| || Knocking out the valve guide. Knock it on the indicated side. |
- For all these measurements the appropriate size is specified in the Specifications. Dimensions for individual engine models are different, the difference is even between the two injector engines. Saddles in the cylinder head to be processed to the desired angle by means of milling or grinding stone. Sharp corners of facets of saddles of valves are listed in the Specifications in the beginning of Chapter. The width of the chamfer of the valve seat is different for carburetor and injection engine. Watch out for the correct size.
- To reduce the width of the seat chamfer cutter with there different angles, which are also listed in the Specifications in the beginning of Chapter.
Valves should grind in the usual way, to be used for grinding is good, but not for installation valve.
- If chamfers valve seats are worn out, you can install the new seat, while the cylinder head must be drilled to the corresponding size. This work should be carried out in the workshop Nissan, as the valve seats should always be mounted concentrically valve guides.
- Check valve stems for wear, cracks or the formation of grooves. Apply to perfectly clean the valve stem steel ruler and check that the rod was straight. Bending unacceptable since the valve will stick in the guide. Check valve plates for the presence of soot or cratering. Between the upper surface of the valve and the upper edge of the valve face needs to be a certain distance. This size is designated as the width of the valve and must lie within certain limits. In no case do not belittle the minimum size. Valve plates can be sanded special machine, with the proviso that retain the desired edge thickness.
- If the ends of the valve stems do not smooth (they can no longer properly actuated rockers or pusher) can be sanded, provided that they are ground off by not more than 0.2 mm.
Valve guides pressed into the cylinder head. If the gap between the rod and the valve guide is too large (more than 0.10 mm), the guides can be replaced. First, check the clearance. To do this, insert the valve into the head, as shown in the illustration below, and remove the 15 mm. Set the dial indicator show the image and move the valve from side to side. If the clearance is more than 0.2 mm, the guide has to be replaced. In this case, install new valves.
| || Check valve stem wear in the hole. |
- To repair guides are oversize (various diameters for injection engines) and a hole in the head should be deployed appropriately to install new rails.
- Be sure to maintain the required size to ensure accurate landing site. Before pressing in new pilot holes should be deployed to the specified size.
- Again, heat the cylinder head to a temperature of 110 - 130 ?° and drive in a new guide on the upper side in the head, while the protruding portion (the size of in the illustration below) will have a length of 14.0 -14.2 mm for the injection engine, or 11.5 - 11.7 mm carburetor motor. This work should be done very slowly and carefully so as not to score the guide too deeply. After all guides scored, cool head, and then expand the guide holes scan the appropriate size. Work with a special oil, always from the combustion chamber.
| || Size "L" - size of protrusion guides. |
- Exact backlash valve rod can be calculated by measuring the outer diameter of the rod and the inner diameter of the guide.
| || Measure the diameter of the valve stem. Measure at three locations along the entire length. |
- To measure the inside micrometer holes is required as shown in the illustration below. To get the value of play need to subtract one from the other dimension.
| || Measure the valve guide holes dial indicator. |
- After boring the guide should always treat the bevel valve seats to maintain match guides and seats. Otherwise, the valves will not close tightly.
It is always recommended to replace the valve springs, if the engine has high mileage. The spring can be checked by putting on a bolt abut the old and new spring and tighten the nut with the corresponding washer. Tighten the nut until the springs are compressed and measure the length of the springs. If the old spring is shorter than the new 10%, replace the entire set. To accurately test the springs requires a special screening device. If there is such a device, it is possible to check the mounting loads and the associated spring length. Install the spring one by one on a flat surface (glass) to a vicious spiral was downstairs. Install the spring steel angle (see. Illustration below). Measure the gap between the square and the upper part, which shall not exceed a predetermined value. Otherwise, the spring is bent and must be replaced.
Check valve spring bending. Install the spring as shown, and to check deviation of the upper side.
Springs of valves should be installed so that the closed end at the bottom. If we look at the spring, one can see that on one side of the coils are further apart than on the other side.
- On gasoline engines in this test also includes check valve lifters. Light damage cams or bearing journals can be smoothed touchstone. Scratches and cracks even require replacement camshaft.
- Cervical camshaft bearings are measured with a micrometer to check the diameter and roundness. These values compare with preformed holes values camshaft bearings. To measure set all bearing caps and tighten with the appropriate Specifications effort. Measure by an internal indicator separate the bearing bore as shown in the illustration below.
| || Measuring holes camshaft bearings. This shows for gasoline engines. |
- On the basis of the Specifications to determine the condition of the parts. To determine the exact diameter of the camshaft bearing journals are placed on two prisms, as shown in the illustration below.
| || Measure the diameter of the camshaft bearing journals. All cervical measured at 90 ?°, to obtain the correct value. |
- Measure using a micrometer height cams. To do this, cheeks micrometer between the tip and the back side of the cam, to obtain the maximum amount (see. Illustration below). Compare the result with the data of the Specifications. Worn cams affect the control valve, which is why not enough filling of cylinders.
| || Measuring the height of the cam using the indicator. |
- Measure the camshaft runout, putting two camshaft journals in the prism and the probe attaching a dial indicator to the middle neck of the bearing as shown in the illustration below. Slowly rotate the camshaft and read the display. If the value at the two speeds is greater 0.10 mm, the shaft must be replaced.
| || Check the camshaft runout. The camshafts are not subject to straightening. |
- To check the endplay paste it into the cylinder head and secure the bearing caps. Set at the end of the shaft and move the dial indicator shaft from side to side as shown in the illustration below. If the value is more than 0.20 mm, check the surfaces of the cam-shaft and the inside of the lid. If necessary, replace the relevant part.
| || Checking axial clearance of camshafts. Results for the injection engine. |
- On the carburettor engine, measure the diameter of the push rod and the diameter of the holes in the cylinder head. The difference between these values gives the play. If it is too large, the pushers or the cylinder head must be replaced.
Cylinder Head Inspection
- The surface of the cylinder head must always be checked for deformation. When burning the cylinder head gasket may be that the surface is deformed.
- To control apply to the surface of a steel ruler and using a feeler gauge, measure the deformation in the directions indicated in the illustration below.
- If unable to insert the probe of a thickness exceeding 0.10 mm, the head should be given to the grinding.
- The cylinder head can be ground by up to 0.2 mm, but in this case, the cylinder block can not be sanded. Otherwise block and cylinder head can be sanded for a total of not more than 0.2 mm. After polishing, measure the height of the cylinder head. To do this, use a large caliper which reaches to both surfaces. The cylinder head can be used as long as it is permitted height. After polishing head camshaft is possible that jam. In this case, the cylinder head needs to be replaced.
| || Check the surface of the cylinder head for deformation. Perform the measurement in these areas (total 6). |
Assembling the cylinder head
- If the valves are replaced, cylinder head, guide levers and / or valve seats should determine the thickness of shims under the new lever. For this to work you need a special tool to measure the height of the installed valve. If there are doubts about the choice of goals, it is recommended to carry the cylinder head to the studio Nissan, where they can pick up the necessary goals.
- Thoroughly clean the valves, valve seats chamfer, channels and sealing surfaces. Clean the inside of the valve guides, prodernuv through them soaked rag in gasoline. This is especially necessary if the valves grind to a grinding paste residues could not get into the hole. During assembly, proceed as follows.
- Replace the valve stem seals. End valve with slots for biscuits should foil wrap (packs of cigarettes). Valve stem caps worn by a piece of pipe, after installation of the valve spring cup. Caps without damage.
- Plug valves into the holes. The valves are initially produced engines were not signs. New valves in the middle may be labeled "53J" (inlet valves) or "5J" (the exhaust valves of the engine SR20DE) or "64Y" (the exhaust valves of the engine SE20Di). Designated way valves can be installed in place of the old ones.
- Set closed valve spring coils to the cylinder head. Also the lower part of the valve spring is color designation. This side facing the cylinder head.
- Put on top of the cup springs and compress a spring despreader or press to be inserted into the slots of the valve crackers. In the shows how to set constrictor valve springs.
- Release constrictor and tap on the valve spring with a hammer to ensure the strength of planting crackers.
- If the cylinder head studs are replaced, they must be securely screwed to the head, for this one-Tighten the two nuts and replace the top nut wrench.
- Install the valve levers, compensation washers, guide levers and hydraulic jacks according to the Now check the compensation elements. If the lever can be pressed down by 1 mm when the lever on the opposite side is pressed down in the corresponding element is air. The air has to be removed because he did not come.
Checking the hydraulic compensating element. Push the piston in the direction of the two arrows down, while the metal rod in the direction of the arrow will put pressure on the ball
| || 1 - metal core |
2 - motor oil
- Despite the fact that the work is connected with some difficulties, the air from the element to be removed, because otherwise when the engine he will knock. To remove the air again, remove the item, insert filled with motor oil container so that it rested against the bottom side of the bottom. Press your finger on the piston and insert a small pin in the valve opening. Move the rod up and down. When the rod presses the non-return valve and displaces the air. The air is removed when the piston is no longer moving. The illustration above shows the elements of this work. The rest of the cylinder head assembly is identical with its installation and have been described previously.
To assemble the cylinder head of the engine carburetor is only required to install the valves and the removed parts. Keep in mind that you need to adjust the valve clearance as described in subsection valve guides. The valves are installed in accordance with the instructions above. Further assembly of the cylinder head and the adequacy of its installation is described in Section Check and adjustment of backlashes of valves of the Head Current leaving and service.