1, remove the cylinder head
2. Remove the cylinder head gasket.
3. Remove the camshaft (camshaft brackets should be arranged in sequence)
4. Remove the cylinder head and remove the valve (special tools are needed when removing the valve).
5. Remove the oil pan and the piston at the same time (special tools are needed to install the piston ring).
6, notify the referee to check
7. Install the engine according to the above steps.
8, notify the referee to check
9, finishing tools
10, notify the referee to stop the watch.
Second, the engine disassembly matters needing attention
engine parts
As the heart of the car, the engine plays an important role in the structure of the whole car, providing the driving force for the car. Moreover, many other parts of the car, such as steering oil pump, generator, water pump, etc., need to be driven by the engine to run directly, so that the whole car can work according to the design working conditions. All these directly lead to the complexity of the engine structure.
1 valve disassembly process
The power source of the engine is nothing more than oil and gas. The function of the valve train is to open and close the intake valve and exhaust valve regularly according to the working cycle and ignition sequence of each cylinder of the engine, so that the fresh charge can be discharged in time even if it enters the cylinder.
Disassembly sequence
1) Remove the valve cover, take out the oil baffle, gasket and semi-circular plug, and observe the structure and arrangement of the valve group and the structure of the valve drive group. Remove the fastening bolt of the toothed pulley at the front end of the camshaft. Remove the camshaft toothed belt pulley and key (if necessary, use a puller), remove the cylinder head (cylinder head bolts are removed from the periphery to the middle) and cylinder gasket, turn the engine sideways, remove the oil pan, and remove the oil pump and oil filter.
2) Lay the removed cylinder head flat on the workbench.
3) Loosen the fastening nut of the camshaft support cover and remove the support cover (put it away according to the installation mark).
4) Remove the camshaft (handle it carefully to avoid damage).
5) Remove the hydraulic tappet subassembly (make installation marks).
6) Use the special tool (special tool code 2037) to remove the valve key, spring seat, inner and outer springs of the valve, valve oil seal and valve.
Illustration (Special tool for removing valve and piston)
installation procedure/program
1) Install the valve oil seal on the valve guide, press it into place, then install the valve spring and valve spring retainer ring, and install the valve key with special tools.
2) Install the valve hydraulic tappet. Hydraulic tappets must be installed in the original installation holes. If you want to change it, you should change a set.
3) Install the camshaft. Apply lubricating oil to the bearing seat and journal, and put the camshaft on the bearing hole so that the two cams of the first cylinder face upwards. It should be noted here that after the cylinder head is installed on the cylinder block, the crankshaft cannot be placed at the top dead center of any piston when rotating the camshaft.
4) Install the bearing caps in sequence. First, alternately tighten the second and fifth bearing caps diagonally, and then tighten the first and third bearing caps diagonally with a tightening torque of 20Nm.
5) Install the camshaft oil seal, but do not press it to the bottom to avoid blocking the oil return hole.
6) Install the camshaft timing gear. Install the semicircle first, then press the timing gear, and tighten the fixing bolt with a torque of 80Nm.
7) Clean and straighten the cylinder block, put the piston of the first cylinder at the top dead center, put the cylinder pad on it, and install the cylinder head. Then, tighten the cylinder bolts in strict accordance with the requirements, and tighten the cylinder bolts in four times: the first tightening torque is 40Nm, the second tightening torque is 60Nm, the third tightening torque is 75Nm, and the fourth tightening torque is to continue to turn the wrench for a quarter turn.
Disassembly experience
1) valve disassembly process
The key is how to use the special tool 2037 safely and skillfully. Due to the great pre-tightening force of the valve spring, it is easy to have dangerous accidents if you are not careful. When installing the spring locking piece, please handle it carefully with tweezers.
2) Camshaft Support Cover
Before removing the camshaft bearing cover, it should be noted that each bearing cover has a number, starting from the timing gear end, that is, bearing cover number 1, 2, 3, 4, 5, and each bearing cover has a convex angle on one side. Before taking it off, pay attention to the direction in which it is aligned with the cylinder head, and do not install it in the wrong order or in the opposite direction.
Pay attention to the tightening sequence of nuts during installation, and tighten them several times according to the principle of diagonal intersection from the middle to both sides to prevent uneven installation of camshaft.
2 piston ring disassembly method, piston ring installation cut, cut problem.
Piston rings are divided into gas rings and oil rings. Generally there are two gas rings and one oil ring from top to bottom. Special tools are needed for disassembly and assembly: piston expansion pliers and piston ring compressor. In practice, what we see is a forward-twisted gas ring, but it is a lower external cut, so we must pay attention to the installation direction when installing. The upper inner cutting ring is 45 oblique cutting, and the lower outer cutting ring is 90 rectangular cutting.
Disassembly steps of piston ring
1) Remove the piston.
2) Remove the piston ring with the piston ring caliper.
Installation steps of piston ring
1) After cleaning the selected piston ring, separate the gas ring from the oil ring, and pay attention to the section structure and installation sequence. Santana car piston ring marked "top" side must be installed upward.
2) Install the oil ring first. For the combined oil ring, first install the liner ring, and then install the scraper.
3) Installation of gas ring: Install the gas ring into the ring groove according to the installation requirements and direction with special piston ring flaring pliers (according to the requirements of the ring manual, the chrome-plated ring should be installed in the first row), and the openings of each ring are staggered.
4) The openings of three piston rings should be staggered by 120, and the openings of four piston rings should be staggered by 90o. The openings of the upper and lower blades of the combined ring should be staggered by 180o, and the openings of the lining ring should be staggered by 45o~90o. During installation, all piston ring openings should be staggered in the direction of piston pin hole and piston maximum side pressure.
3 Disassembly and assembly method of piston
Disassembly steps of piston
1) Fix the cylinder block on the turning table and turn it 180 degrees.
2) Check whether the direction marks and corresponding cylinder numbers on the piston and connecting rod are complete and clear. If the marking is not clear, re-mark it for installation. Starting from the end of the timing gear, the numbering sequence should be 1, 2 and 3. ......
3) Turn the crankshaft, turn the piston connecting rod group to the bottom dead center, remove the connecting rod nut, remove the connecting rod cover, and take out the piston connecting rod group from the cylinder. Be careful not to knock or pry hard during this process, so as not to damage the cylinder; If the connecting rod bearing is not replaced with a new one, the upper and lower bearing shells cannot be interchanged.
4) Connecting rod cover and connecting rod are connected in pairs according to marks.
5) Remove the piston ring with the piston ring caliper.
6) Remove the piston pin snap ring, and then remove the piston pin.
7) Remove the piston.
Installation steps of piston
1) The cleaned piston connecting rod shall be inspected before being assembled into an assembly. The inspection contents include: piston wear inspection, piston ring inspection and selection, connecting rod bushing and pin inspection, connecting rod and connecting rod bearing shell inspection, etc.
2) Clean the selected piston, piston pin and connecting rod bushing.
3) When installing the fully floating piston pin, the piston should be heated to 80℃ in water, and then taken out for installation; When installing the semi-floating piston pin, the small end of the connecting rod should be heated to about 230oC, and then press in the piston pin with a special tool.
4) Apply clean grease to the connecting rod small head bushing, then put the connecting rod small head between the two pin holes of the piston so that the bushing hole of the small head is aligned with the pin hole, quickly push the piston pin into the seat hole at one end of the piston, then put it between the connecting rod small head and the two seat holes of the piston, and finally push the piston pin into the connecting rod bushing until the other hole end of the piston, and install the locking ring. Be careful not to knock hard in the process.
5) Install the piston ring.