Overhaul

DISASSEMBLY
1. Using piston ring expander, remove two compression rings (Top and 2nd) and oil ring from piston.
2. Remove piston pin from connecting rod.





- Ease out piston pin circlips, as shown.





- Force piston pin out.

CLEANING
Clean carbon from piston head and ring grooves, using a suitable tool.

ASSEMBLY

NOTE: Two sizes of piston are available as standard size spare part so as to ensure proper piston-to-cylinder clearance. When installing a standard size piston, make sure to match piston with cylinder as follows:





a. Each piston has stamped number 1 or 2 as shown. It represents outer diameter of piston.
b. There are also painted color of red and blue on the cylinder block as shown.





c. Stamped number on piston and stamped mark on cylinder block should correspond. That is, install number 2 stamped piston to cylinder which is identified with mark blue and a number 1 piston to cylinder with mark red.
Piston:
Number At The Top (Mark): 1
Outer Diameter: 83.98 - 83.99 mm (3.3063 - 3.3066 inch).
Number At The Top (Mark) 2
Outer Diameter: 83.97 - 83.98 mm (3.3059 - 3.3062 inch).
Cylinder:
Mark: Red
Bore Diameter: 84.01 - 84.02 mm (3.3075 - 3.3078 inch).
Piston-to-Cylinder Clearance: 0.02 - 0.04 mm (0.0008 - 0.0015 inch).
Mark: Blue
Bore Diameter: 84.00 - 84.01 mm (3.3071 - 3.3074 inch).
Piston-to-Cylinder Clearance: 0.02 - 0.04 mm (0.0008 - 0.0015 inch).
Also, a letter A, B or C is stamped on piston head but ordinarily it is not necessary to discriminate each piston by this letter.





1. Install piston pin to piston and connecting rod: After applying engine oil to piston pin and piston pin holes in piston and connecting rod, fit connecting rod to piston as shown in figure and insert piston pin to piston and connecting rod, and install piston pin circlips.

NOTE:
^ The "77E" mark on connecting rod should come on crankshaft pulley side.





^ Circlip should be installed with its cut part facing as shown in figure.





2. Install piston rings to piston:
- As indicated in figure at the left, 1st and 2nd rings have "RN" or "R" mark respectively. When installing these piston rings to piston, direct marked side of each ring toward top of piston.
- 1st rings differs from 2nd ring in thickness, shape and color of surface contacting cylinder wall. Distinguish 1st ring from 2nd ring by referring to figure.
- When installing oil ring, install spacer first and then two rails.





3. After installing three rings (1st, 2nd and oil rings), distribute their end gaps as shown in figure.