Inspection
1. Check cylinder bores for taper, ovality, and scratches. Inspection start from the top of the cylinder channels. If they are worn, a small ridge will be visible on the thrust side. It indicates the top of the piston ring travel. The wear of the cylinder channels can be determined without disassembling the engine, and without removing the cylinder head. If there is excessive oil consumption accompanied by blue smoke from the exhaust, this is a sure sign of worn cylinder bores and piston rings.
2. Measure the bore diameter across the block, but just below the wear ridge. This can be done with an internal micrometer. Compare this to the diameter at the base of the cylinder bore, which is not subject to wear. If there are no measuring instruments, use a piston without rings, and measure the gap between the piston and the cylinder wall with a feeler gauge. Cm: Specifications. If the cylinder wear exceeds the allowable limits, the cylinder bores must be rebored, but note the following points:
- a) The pistons and cylinder bores are closely matched during manufacture. The actual piston diameter is indicated by a number at the top; the same number is printed on the crankcase and indicates the diameter.
- b) After boring, the bores of the cylinders must be accurately measured and oversized pistons must be selected from the available ones in order to provide the gap between the piston and the cylinder wall specified in the Specifications.
- c) The piston diameter is measured across the base of the skirt.
3. If there is marginal wear within tolerance, you can simply install new special piston rings.
4. Carefully inspect the crankcase and cylinder block for cracks and damage, check all lubrication and cooling channels with a piece of wire so that they are not clogged.
5. Please note that the rubber plug, located next to the clutch housing flange on the cylinder block, closes the hole for installing the TDC diagnostic sensor. The sensor is connected to the diagnostic unit, and indicates the TDC from the position of the group of pins in the counterweight of the crankshaft.
Visitor comments