Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Block and Piston Inspection
- Remove the crankshaft and pistons (see CRANKSHAFT AND PISTON REMOVAL ).
- Check the piston for distortion or cracks.
- Measure the piston diameter at a point 13 mm (0.5 in) from the bottom of the skirt. There are two standard-size pistons (No Letter or A, and B). The letter is stamped on the top of the piston. Letters are also stamped on the block as cylinder bore sizes.
Piston Diameter
Standard (New):
No Letter (or A): 86.980-86.990 mm (3.4244-3.4248 in)
B: 86.970-86.980 mm (3.4240-3.4244 in)
Service Limit:
No Letter (or A): 86.930 mm (3.4224 in)
B: 86.920 mm (3.4220 in)
Oversize Piston Diameter
0.25: 87.230-87.240 mm (3.4342-3.4346 in)
- Measure the wear and taper in direction X and Y at three levels inside each cylinder as shown. If the measurements in any cylinder are beyond the Oversize Bore Service Limit, replace the block. If the block is being rebored, refer to step 7 after reboring.
Cylinder Bore Size
Standard (New):
A or I: 87.010-87.020 mm (3.4256-3.4260 in)
B or II: 87.000-87.010 mm (3.4252-3.4256 in)
Service Limit: 87.070 mm (3.4279 in)
Oversize Bore
0.25: 87.250-87.260 mm (3.4350-3.4354 in)
Reboring Limit: 0.25 mm (0.010 in) max.
Bore Taper
Limit: (Difference between first and third measurement) 0.05 mm (0.002 in)
- Scored or scratched cylinder bores must be honed.
- Check the top of the block for warpage. Measure along the edges, and across the center as shown.
Engine Block Warpage
Standard (New): 0.07 mm (0.003 in) max.
Service Limit: 0.10 mm (0.004 in)
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.