2. Lay out piston assemblies with connecting rods and new sets of piston rings in such a way that both when measuring gaps in the ring locks and when reassembling the engine, the sets of rings always correspond to the same piston and cylinder.
3. Insert the top ring into the first cylinder and press it into the cylinder using the piston head as a mandrel. This will force the ring to be perpendicular to the walls of the cylinder. Position the ring near the base of the cylinder, at the lower end of the ring travel zone. Keep in mind that the top and second compression rings are different from each other. The second ring can be identified by its cone; in addition, it has a step on the bottom surface.
4. Measure the gap in the lock of the ring with «fan» probe.
5. Repeat the procedure with this ring in the upper zone of the cylinder, at the upper limit of its movement (pic. 17.5) and compare the measurement results with the values given in «Specifications». If the joint clearances are incorrect, check that the rings are correctly selected for the specific engine and for the given cylinder size.
Pic. 17.5. Piston ring gap measurement
6. Repeat the procedure for checking each ring in the first cylinder and do the same for the rings in the remaining cylinders. Don't forget to keep the rings, pistons and cylinders aligned.
7. After checking the gaps in the locks, the rings can be installed on the pistons.
8. Establish piston rings, using the same technology, as at removal. Install the bottom first (oil scraper) ring, and then the rest of the rings in the direction from the bottom up. When installing the oil scraper ring, first install its expansion element (in the presence of), and then install the ring itself by turning its lock 180°relative to the expansion ring lock. Install the second compression ring, ensuring that the identification mark (paint dot or marking «TOR») was facing up, and the stepped surface was located at the bottom (pic. 17.8). Then install the top ring. Turn the compression rings so that the locks are located at an angle of 120°with respect to each other and relative to the oil scraper ring.
Pic. 17.8. Typical Piston Ring Arrangement
1. Oil scraper ring
2. Second compression ring
3. Top compression ring
Note. Be sure to follow the instructions that come with new piston ring kits. Different manufacturers may prescribe different procedures. Do not confuse the top and second compression rings as they have different cross sections.