Piston Ring Set 1st Oversize 77.50

1st oversize piston ring set.
Bore: 77.50.
Ring size: 2.50 x 2.50 x 4.00.
Type 1 engines.

New piston rings should only be fitted if the cylinder is still within the wear limits regarding ovality (maximum 0.03 to 0.05 mm). The one-sided movement of the connecting rod leads to oval wear of the cylinder. Fitting your new piston rings in a cylinder above the wear limit increases the problem of oil consumption and higher crankcase pressure.

After fitting new piston rings, a running-in phase must be taken into account; the new piston rings have to adapt to the operating pattern of the old cylinder.

The most important thing is that you only renew piston rings if the end gap and the play in height are outside the wear limits and the ovality of the cylinder allows it. If the ovality is outside the wear values, fit a new set of pistons and cylinders.