Cylinder block of a 4-cylinder petrol engine
1 – cylinder block; 2 – rear cover of the crankshaft; 3 – front crankshaft cover; 4 – engine support bracket; 5 – front crankshaft seal ring; 6 – rear crankshaft sealing ring; 7 – oil pan gasket; 8 – main bearing cap; 9 – guide pin; 10 – threaded plug; 11 – technological plug
Cylinder block of a 4-cylinder diesel engine
1 – cylinder block; 2 – cylinder liner; 3 – main bearing cap; 4 – oil pan; 5 – front crankshaft cover; 6 – rear cover of the crankshaft; 7 – rear crankshaft sealing ring; 8 – front crankshaft seal ring; 9 – oil pan gasket
Cleaning
Removal the nozzle from the cylinder block
Using a tap to clean a threaded hole in a cylinder block
1. Remove all parts and electrical sensors from the cylinder block. For complete cleaning, remove the process plugs. To remove the plugs, drill small holes in them and screw a self-tapping screw into the holes. Pull the screw head to remove the plug.
2. Remove the oil sprayers on the inside of the piston. To remove the sprayer, unscrew the bolt, remove the sealing ring and remove the sprayer from the cylinder block (see Fig. Removing the nozzle from the cylinder block).
3. Install oil sprayers.
4. Remove all traces of gaskets from the mating surfaces of the engine block.
5. Remove all oil line plugs. Use new plugs when installing.
6. Clean the dirtiest areas with steam.
7. Clean all oil holes and oil lines. Flush all internal passages with warm water until the water runs clear. It is necessary to completely dry the cylinder block and lubricate all mating surfaces with a thin layer of oil to prevent corrosion. Also lubricate the engine cylinders. If compressed air is available, use it to speed up the drying process and blow out all oil holes and lines.
8. Thoroughly clean all threaded holes using a tap with the appropriate thread size, then blow out the holes with compressed air.
9. Install the plugs into the oil line in the engine block and tighten them securely.
10. If the engine is not to be reassembled immediately, cover the cylinder block with a large plastic bag to protect it from contamination.
11. Visually inspect the cylinder block for corrosion. Check the integrity of the threads in the threaded holes.
12. Check the engine cylinder bore for wear by looking for a step at the top of the cylinder.
13. If you have a measuring tool, measure the diameter of the liner of each cylinder at the top (under the wear step) in the center and at the base parallel to the crankshaft axis. Then make the same measurements perpendicular to the crankshaft axis and compare them with the technical data. Repeat the measurement procedure on the remaining cylinder liners. If the wear exceeds the permissible values, it is necessary to bore the cylinders and install new pistons of a larger size.
Checking piston protrusion on diesel engines
1. Check the piston protrusion from the engine block when the piston is installed at top dead center, as this is especially important if the cylinder head surface has been machined. If the piston protrusion exceeds the permissible limits, the pistons may hit the swirl chamber during engine operation, which will lead to serious engine damage.
2. Measure the piston protrusion at the level of the top plane of the cylinder head gasket. If the piston protrusion exceeds the permissible limits, consult a Mercedes-Benz dealer and it is likely that the engine block will have to be replaced.