a) Use a scraper to remove carbon deposits and other carbon deposits from the piston crown.
b) Clean the piston grooves from deposits using a part of the broken ring.
c) Using solvent and a soft brush, thoroughly clean the piston.
Note: Do not use a wire brush.
2. Check the piston and piston rings.
A. Check the clearance between the piston and the cylinder.
a) Using a micrometer, measure the piston skirt diameter as shown in the figure.
Note (K20A): There are 2 types of pistons: Type 1 - pistons with or without the "A" mark on the bottom, Type 2 - pistons with the "B" mark on the bottom. There are also size marks on the cylinder block.
Size "L":
- D15B, D17A — 13 mm
- K20A - 11 mm
Piston diameter:
D15B, D17A:
- nominal size - 74.98 - 74.99 mm
- 1st repair size (0.25) - 75.23 - 75.24 mm
- 2nd repair size (0.50) - 75.48 - 75.49 mm
- minimum size - 74.97 mm
K20A:
Nominal size:
- 1 type - 85.98 - 85.99 mm
- 2 type - 85.97 - 85.98 mm
- 1st repair size (0.25) - 86.23 - 86.24 mm
Minimum size:
- 1 type - 85.93 mm
- 2 type - 85.92 mm
b) Find the difference between the diameters of the piston and the cylinder. Determine the size of the gap.
Nominal clearance:
- D15B, D17A - 0.010-0.040 mm
- K20A — 0.020 - 0.040 mm
Maximum clearance: D15B, D17A - 0.05 mm
If the clearance is greater than the maximum, replace all pistons. If necessary, replace the cylinder block.
B. Check the end clearance "compression ring - piston groove" by measuring it with a flat feeler gauge as shown in the figure.
Nominal clearance:
D15B, D17A:
- compression ring No.1 - 0.035 - 0.060 mm
- compression ring No.2 - 0.030 - 0.055 mm
K20A:
VTEC Rocker Arm Block:
Type 1:
- compression ring No.1 - 0.050 - 0.075 mm
- compression ring No.2 - 0.030 - 0.055 mm
Type 2:
- compression ring No.1 - 0.035 - 0.075 mm
- compression ring No.2 - 0.030 - 0.055 mm
Type 3:
- compression ring No.1 - 0.045 - 0.070 mm
- compression ring No.2 - 0.040 - 0.065 mm
Maximum gap - 0.13 mm
If the clearance is greater than the permissible limit, replace the piston.
B. Check the piston ring gap.
a) Insert the piston ring into the cylinder.
b) Use the piston to push the ring away from the cylinder block surface as shown in the figure.
c) Use a flat feeler gauge to measure the gap in the ring lock.
Nominal clearance:
D15B, D17A:
- compression ring - No.1 0.15 - 0.30 mm
- compression ring No.2 - 0.30 - 0.45 mm
- oil scraper ring - 0.20 - 0.70 mm
K20A:
compression ring No.1 - 0.20 - 0.35 mm
compression ring #2:
- models with rocker arm block type 3 - 0.50 - 0.65 mm
- the rest - 0.40 - 0.55 mm
oil scraper ring:
- models with rocker arm block type 3 - 0.20 - 0.70 mm
- the rest - 0.25 - 0.65 mm
Maximum clearance:
D15B, D17A:
- compression ring no. 1 - 0.60 mm
- compression ring #2 - 0.60 mm
- oil scraper ring - 0.80 mm
K20A:
compression ring no. 1 - 0.60 mm
compression ring #2:
- models with rocker arm block type 3 - 0.75 mm
- the rest - 0.70 mm
oil scraper ring:
- models with rocker arm block type 3 - 0.80 mm
- the rest - 0.75 mm
If the gap in the lock is greater than the maximum, replace the piston ring.
3. Check the alignment of the connecting rod heads. Check the piston pin oil clearance.
a) Using a bore gauge, measure the inner diameter of the connecting rod upper head in the "X" and "Y" directions, as shown in the figure.
Nominal diameter:
- D15B, D17A - 18.96-18.98 mm
- K20A - 21.97-21.98 mm
b) Using a micrometer, measure the piston pin diameter in the "X" and "Y" directions as shown in the figure.
Nominal piston pin diameter:
- D15B, D17A - 18,996-19,000 mm
- K20A - 21.961-21.965 mm
Minimum piston pin diameter:
K20A - 21.953 mm
c) Determine the oil clearance: subtract the piston pin diameter from the inner diameter of the connecting rod upper head.
Nominal clearance:
- D15B, D17A - 0.016-0.036 mm
- K20A — 0.005-0.015 mm
Maximum clearance:
K20A - 0.02 mm
Replace the piston or piston pin if necessary.
4. Check the piston pin oil clearance and the piston pin holes in the piston boss.
a) Measure the diameter of the piston pin hole in the piston boss.
b) Find the difference between the diameters of the piston pin and the hole for the piston pin.
Nominal oil clearance:
- D15B, D17A - 0.010 - 0.020 mm
- K20A - -0.005 - +0.002 mm
Maximum oil clearance:
K20A - 0.005 mm
If necessary, replace the piston and piston pin assembly.