In the article, we will consider the operations for disassembling and repairing the engine cylinder head
Cylinder head disassembly
We wash the cylinder head and install it on a workbench or disassembly tool
We remove the valve lifters from the cylinder head and mark their position relative to the cylinder head
Using the tool, we compress the valve springs and remove the crackers with tweezers
We press out the valve stem seals using special pliers or an inertial puller
Checking the height of the cylinder head
Height H, (drawing) cylinder heads must be 125 mm
Using a straightedge and a set of feelers, we check the flatness of the surface of the cylinder head mating with the cylinder block
Maximum allowable flatness of the mating surface of the cylinder head 0.1 mm
Check the diameter of the supports for the camshafts, for this:
We install centering bushings, camshaft bearing caps on the cylinder head
Tighten the cap bolts to 9.0-11.0 Nm (0.9-1.1 kgcm)
We measure the holes for each cover with a bore gauge NI 18-50-1
The diameter of the holes for the first cover 1 (picture) should be 28.000-28.021 mm, for the holes 2 of the remaining covers 25.000-25.021 mm
After that, unscrew the mounting bolts and remove the camshaft bearing caps and centering bushings
Checking the diameter of the holes in the valve guides
The maximum allowable diameter should not exceed 5.03 mm
Checking the diameter of the nests for pushers in the cylinder heads
The diameter of the sockets should be 30.000-30.021 mm
Checking the outer diameter of the valve lifters
The diameter of the tappets must be between 29.977-29.987 mm
On the surface of the pushers there should be no signs of wear and cracks in the coating
Checking the valves
One-sided wear of the valve stem on the working surface is not allowed
We visually determine the wear and condition of the valve discs. Chips, cracks and one-sided wear are not allowed
We determine the wear of the end of the valve stem, if necessary, you can grind the end
Permissible dimensions of valves according to the drawing and according to the table
Permissible valve sizes
Inlet valve:
Valve disc diameter D, mm 31.6±0.15
Valve stem diameter d, mm 4.965 - 4.980
Valve length L, mm 101.48
Height of the cylindrical part of the valve disc t, mm 1.00
Exhaust valve:
Valve disc diameter D, mm 25.3±0.15
Valve stem diameter d, mm 4.955 - 4.970
Valve length L, mm 102.24
Height of the cylindrical part of the valve disc t, mm 1.00
Checking the valve springs
Spring free length - 42.26 mm
Spring length under load 145 ± 9 N (14.5 ± 0.9 kgf) - 34.4 mm
Deviation "t" (picture), spring from perpendicularity should not be more than 1.6 mm
Checking the valve seats and lapping the valves
After that, we wash and blow through all the holes and parts of the cylinder head
Collecting the goal Cylinders
Install intake and exhaust valves into the cylinder head
To do this, install the cylinder head on fixture 67.7823-9567 for cracking and cracking valves
Lubricate the valve stems with engine oil
Using a mandrel 67.7853-9732, we press the valve stem seals all the way into the bearing surface of the cylinder head
Installing the spring washers into the cylinder head
Installing valve springs and spring plates
Lubricate the outer surfaces of the tappets with engine oil and install the tappets into the cylinder head according to the marking
Using a stud driver, we screw new exhaust manifold mounting studs into the cylinder head, with a short part into the body of the head
Remove the cylinder head from the fixture
Installing the cylinder head
We press two centering sleeves of the cylinder head into the cylinder block (if they are not installed).
Protrusion of the sleeve above the mating plane of the cylinder block 6-8 mm
We apply two dots of sealant to the surface of the cylinder block on the timing side, as shown in the figure
We install a new cylinder head gasket on the cylinder block and apply two dots of sealant to the gasket on the timing side, as shown in the figure
We use silicone sealant TB1217L, consumption rate - 1 gram
We screw the crankshaft pulley bolt into the crankshaft and install the pistons in the middle of the stroke
We install the cylinder head, washers of the cylinder head bolts, new mounting bolts on the cylinder block.
We twist and tighten the cylinder head bolts
Tighten the cylinder head bolts in the order shown in the figure in the following sequence (replaceable head 11, knob, extension, torque wrench, head for measuring the angle of rotation):
- - tighten the bolts with a tightening torque of 35.0…44.0 Nm (3.5…4.4 kgf.m);
- - tighten the bolts by an angle of 60º…65º.
- - unscrew all bolts;
- - tighten the bolts with a tightening torque of 35.0…44.0 Nm (3.5…4.4 kgf.m);
- - tighten the bolts by an angle of 75º…80º.