Checking cylinder bores

The clearance between the cylinder and the piston can be determined by measuring the cylinder and piston separately. This clearance cannot be measured with a feeler gauge set.



To measure a cylinder, a dial gauge is required for measuring internal dimensions, the scale of which must first be set to a predetermined value (see table).



Insert the probe about 10-15 mm below the inner edge.

If, when measuring the piston and cylinder, it is found that the gap is about 0.2 mm, then the piston and cylinder are replaced with a pair of the same size group. The difference of pistons by weight in the engine should not exceed 10 grams. A piston whose corresponding cylinder shows signs of wear cannot be replaced separately. If, on the contrary, the cylinder of the damaged piston shows no signs of wear, it is often sufficient to install a new piston of the same size group.

Attention: Only cylinders and pistons of the same size group should be installed in the engine. When deciding whether to replace pistons and cylinders, oil consumption plays a larger role in addition to wear marks. If the oil consumption exceeds 1 l / 1000 km, an overhaul of the engine is generally required.