Contents: Cleaning ⬇ Inspection ⬇
Cleaning
For complete cleaning, remove the plugs if required. Drill a small hole in the plug, then insert a self-tapping screw and pull out the plugs with pliers. Remove all external parts (sensors, brackets, etc.).
Note that on some engines, a rubber plug located near the flange of the cone-shaped housing on the cylinder block covers the hole for installing the TDC diagnostic sensor.
Scrape all traces of gasket from the cylinder block, being careful not to damage the mating surfaces.
Remove all oil channel plugs where required. They are usually a tight fit - they may need to be drilled out and the holes tapped. Use new plugs when assembling the unit.
If the block is heavily soiled, it should be cleaned with a jet of steam.
After cleaning the block with steam, clean all lubrication channels and oil filling holes. Rinse all internal channels with warm water. Dry the block thoroughly and lubricate all machined surfaces with a thin layer of oil. If there is a source of compressed air nearby, blow out all lubrication channels and oil filling holes (wear safety glasses when working with compressed air).
If the block is relatively clean, cleaning can be done with soapy water and a stiff brush. After thoroughly cleaning the lubrication holes and oil filler holes, lubricate the machined surfaces with a thin layer of oil.
After coating the mating surfaces of the new plugs with the appropriate sealant, install them on the cylinder block. Make sure they are straight and seated correctly, otherwise a leak may occur.
If the engine must be left disassembled for a period of time, install the main bearing caps, tighten the bolts by hand, and cover the cylinder block with a large plastic bag to protect the engine from dirt and corrosion.
Inspection
Visually inspect the block for cracks, rust and corrosion. Check for thread damage. If defects are found, try to repair the block, otherwise the only solution may be to replace it.
Check the cylinder bores in the block for taper, ovality, scoring and scratches. Start with a thorough inspection of the top of the cylinder bore, where there may be "ridges".
Measure the diameter of each cylinder at the top (just under the comb), in the central and bottom parts of the cylinder parallel to the crankshaft axis.
Then measure the cylinder diameter at the same three points, but at a right angle to the crankshaft axis. Compare the results with the required ones. Repeat the operations with the remaining cylinders. If the cylinder wear exceeds the permissible limits or if there are strong burrs and scratches on its walls, it is necessary to bore it and select new pistons.
- a) At the factories the piston and cylinder diameters are closely matched. The actual piston diameter is indicated on the piston head; the same numbers on the engine crankcase indicate the cylinder diameter.
- b) After boring the cylinders, it is necessary to carefully measure and select the pistons to ensure the required clearance between the cylinder walls and the piston.
- c) The piston diameter is measured at the bottom of the skirt.
If the wear is at the limit and is within the tolerance range, new special piston rings can be installed to compensate for the wear.
In this case, the bores are honed to ensure that the new rings fit correctly and provide an effective seal.
Visitor comments