Assessment of Cylinder Bores

NOTE: A visual checkup can be made with cylinder head in place by means of a cylinder illuminating lamp. For this purpose, the prechambers must be removed. Service and Repair

When evaluating scored or streaky cylinder walls, it is often difficult for a workshop to decide whether the damage is already extensive and requires removal or repair of the engine, or whether the evidence is harmless. The following instructions will help in making an expert and correct decision.






With regard to marks on cylinder walls, the first important difference is between "optical streaks" and "seizure streaks". As a rule, "optical streaks" are about 3 mm wide, they are produced by the piston ring gaps and do not destroy honing structure; "seizure streaks", however, obliterate honing structure.

With streaks in direction of "land" (in direction of piston pin) shaft streaks or seizures are not possible, since there is no contact between piston skirt and cylinder liner.