Piston Rings

GENERAL INFORMATION

Piston ring installation diagram

1. For SR20DE model

2. For SR20Di and SR20De models

Piston ring end gap positioning

1. Top compression ring

2. Oil control ring expander

3. To the front of the engine

4. Bottom compression ring

5. Oil control ring lower rail

6. Oil control ring upper rail

Installation

PROCEDURE

1. Before installing new piston rings, check the ring end gap. Arrange the pistons assembled with connecting rods and the new piston rings in such order that each ring set corresponds to the cylinder in which the end gap will be measured and in which the rings being checked will be installed.

2. Insert the top ring into the first cylinder and push it in with the piston crown so that the ring is square to the cylinder axis. Push the ring to the depth where the edge of the piston skirt is level with the cylinder block mating surface, then remove the piston.

3. Measure the end gap with a feeler gauge and compare the result with the specification given in subsection 3.2.1.

4. If the gap is too small (which is unlikely if Nissan rings are being installed), it must be increased. Otherwise, the rings may close during engine operation and cause serious damage. The best solution is to select new rings with the specified end gap. As a last resort, the gap can be increased by carefully filing the ring ends with a fine file. To do this, clamp the file in a vise with soft jaws, place the ring so that the ring ends are on either side of the file, and slowly move the ring to remove excess material. Note that the ring is very fragile and can break easily.

5. It is unlikely that the end gap of new rings will be too large. If the gap is above specification, make sure the ring matches this engine and the cylinder size group.

6. Repeat the procedure for each ring of the first cylinder, and for the rings of the other cylinders. Keep the rings and pistons belonging to the same cylinder together.

7. After selecting the rings, measuring and adjusting the end gap, the rings can be installed on the pistons (see Piston ring installation diagram). WARNING: Always follow the ring manufacturer's instructions, as different manufacturers recommend different ring installation procedures. Do not confuse the top and bottom compression rings, which have different cross-sections.

8. Install the oil control ring first (the lowest ring on the piston). This ring consists of three parts. Install the expander into the groove.

9. Then, between the expander and the groove faces of the piston, install the oil control ring upper and lower rails in order.

10. Next, install the bottom compression ring.

WARNING: The top and bottom compression rings differ in cross-section.

11. Before installing, orient the ring correctly (the identification marks on the compression rings must face up) and install the ring into the middle groove of the piston. Do not expand the ring excessively.

12. Install the top compression ring in the same way, after orienting it correctly. If the ring has a symmetrical cross-section, position it so that the identification mark (indicated by the arrow) faces up.

13. After installing the rings on the piston, position the ring gaps according to the figure. Piston ring gap positioning.

14. Repeat these procedures to install the rings on the remaining pistons.