M4R engine
H4J engine
Checking the clearance between piston grooves and piston rings
- A: Wrong probe position.
- B: Correct probe position.
Measure the gap between the rings (5) and undercuts on the piston using a set of feelers (6) (must be measured at three points at an angle of 120°to each other).
M4R engine:
- upper compression ring - the gap lies in the range from 0.04 to 0.11 mm;
- lower compression ring - the gap lies in the range from 0.03 to 0.10 mm;
- oil scraper ring - the gap lies in the range from 0.015 to 0.185 mm.
H4J engine:
- upper compression ring - the gap lies in the range from 0.04 to 0.08 mm;
- lower compression ring - the gap lies in the range from 0.03 to 0.07 mm;
- oil scraper ring - the gap lies in the range from 0.045 to 0.125 mm.
If the clearances are out of range, replace the piston with piston pin or piston rings.