Block and Piston Inspection

2008 Chevrolet HHR LT, 2.4 P, AutomaticSECTION Block and Piston Inspection
WARNING: This page is about a different car, the 2011 Honda Insight and 2010 Honda Insight. However, it is still accessible from the selected car via links, so may be relevant.
  1. Remove the crankshaft and the pistons (see CRANKSHAFT AND PISTON REMOVAL  ).
  2. Check the piston for distortion or cracks.
  3. Measure the piston skirt diameter (A) at a point 16 mm (0.6 in) from the bottom of the skirt.

    Piston Diameter 

    Standard (New): 72.969-72.979 mm (2.8728-2.8732 in) 

    Service Limit: 72.967 mm (2.8727 in) 

    Oversize Piston Diameter 

    0.25: 73.219-73.229 mm (2.8826-2.8830 in) 

    Fig 1: Measuring Piston Skirt Diameter
    G06428987Courtesy of AMERICAN HONDA MOTOR CO., INC.
  4. Measure wear and taper in direction Y at three levels in each cylinder as shown. If measurements in any cylinder are beyond the oversize bore service limit, replace the engine block. If the engine block is to be rebored, refer to step 7 after reboring.

    Cylinder Bore Size 

    Standard (New): 73.000-73.015 mm (2.8740-2.8746 in) 

    Service Limit: 73.065 mm (2.8766 in) 

    Oversize 

    0.25: 73.250-73.265 mm (2.8839-2.8844 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) 

    Fig 2: Measuring Cylinder Bore Size
    G06428988Courtesy of AMERICAN HONDA MOTOR CO., INC.
  5. Hone any scored or scratched cylinder bores.
  6. Check the top of the engine 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) 

    Fig 3: Checking Engine Block Warpage
    G06428989Courtesy of AMERICAN HONDA MOTOR CO., INC.
  7. Calculate the difference between the cylinder bore diameter and the piston diameter. If the clearance is near or exceeds the service limit, inspect the piston and the engine block for excessive wear.

    Piston-to-Cylinder Clearance 

    Standard (New): 0.021-0.046 mm (0.0008-0.0018 in) 

    Service Limit: 0.05 mm (0.002 in) 

    Fig 4: Identifying Piston-To-Cylinder Clearance
    G06428990Courtesy of AMERICAN HONDA MOTOR CO., INC.
RENDER: 1.0x

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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.