Piston Ring Positioning for the 477 BB kit (84mm piston)

The chrome ring is on top, the black ring is second.
The orientation does not matter (which side of the ring is up).

Position the gap at 10 o'clock and 2 o'clock for the top 2 rings, the oil ring ends need to be over the piston pin so as to away from the oil holes.
The spacer ends of the middle part of the oil ring face upwards.

If there is markings on the rings, they definitely are meant to be on the top!
Second rings are often chamfered also and need correct orientation.
Look carefully at the ring ends, some have definite angles requiring the correct positioning.

sam2019 said:

The chrome ring is on top, the black ring is second.
The orientation does not matter (which side of the ring is up).

Position the gap at 10 o'clock and 2 o'clock for the top 2 rings, the oil ring ends need to be over the piston pin so as to away from the oil holes.
The spacer ends of the middle part of the oil ring face upwards.

Click to expand...

Which brand of rings are being referred to here?

These are the rings that come with the BB set we sell now (2024). Above instruction refer to them only.

Guide to Piston & Ring Clearance for Optimum Performance:

Piston ring clearances mainly consist of three types: side clearance, end clearance, and back clearance. Side clearance, also known as side gap, refers to the gap between the side of the piston ring and the groove in the piston when the piston ring is installed, with a standard range of 0.04-1.10mm.

End clearance, also called end gap, is the gap between the ends of the piston ring when the piston is at the top dead center inside the cylinder, with a standard range of 0.25-0.50mm.

Back clearance refers to the gap between the inner cylindrical surface of the piston ring and the bottom of the piston ring groove, with a standard range of 0.50 mm-1.00 mm.

Methods for Measuring the Three Clearances of Piston Rings:

1：Side clearance: Remove the piston ring from the piston, then press its side into the piston ring groove and secure it with one hand, while using a feeler gauge to measure the gap between the piston ring and the groove with the other hand.

2：End clearance: Place the piston ring flat on the piston, then push the piston towards the top dead center of the engine, and use a thickness gauge to measure the gap at the opening of the piston ring.

3：Back clearance: Insert the tail of a vernier caliper into the piston ring groove, measure the depth of the groove, then measure the cross-sectional value of the piston ring with the vernier caliper, and subtract the groove depth from the cross-sectional value of the piston ring.