Forester F4-2.5L Turbo (2009)
3) When the piston is to be replaced due to general or cylinder wear, select a suitable sized piston by measuring the piston clearance.
4) Measure the outer diameters of the cylinders. Measure the outer diameter of each piston at the height as shown in the figure. (Thrust direction)
NOTE: Measurement should be performed at a temperature of 20°C (68°F).
Piston grade point H: 38.2 mm (1.50 in)
Piston outer diameter:
Standard:
A: 99.505 - 99.515 mm (3.9175 - 3.9179 in)
B: 99.495 - 99.505 mm (3.9171 - 3.9175 in)
0.25 mm (0.0098 in) oversize: 99.745 - 99.765 mm (3.9270 - 3.9278 in)
0.50 mm (0. 0 197 in) oversize: 99.995 - 100.015 mm (3.9368 - 3.9376 in)
5) Calculate the clearance between cylinder and piston.
NOTE: Measurement should be performed at a temperature of 20°C (68°F).
Cylinder to piston clearance at 20°C (68°F).
Standard: -0.010 - 0.010 mm (-0.00039 - 0.00039 in)
6) Boring and honing
1) If any measured value of taper, out-of-roundness or cylinder-to-piston clearance is out of standard or if there is any damage on the cylinder
wall, rebore the cylinder for replacement to an oversized piston.
CAUTION: When any of the cylinders needs reboring, all other cylinders must also be bored at the same time, and replaced with oversize
