What should be done when the depth of a cylinder block liner counterbore varies 0.003 inches in four places?

What should be done when the depth of a cylinder block liner counterbore varies 0.003 inches in four places?

• A. Machine and shim the counterbore
• B. Install a tapered shim to even out liner height
• C. Nothing - measurements are acceptable
• D. Hone the block for an oversized liner

Answer: (A)

Uniform liner seating depth is essential for a proper seal and correct deck height. When the counterbore depth varies across multiple places, the liner won’t sit flush and the top of the liner can be uneven relative to the block deck, which can lead to head gasket leaks, distortion, or improper bore alignment. If you see a difference of 0.003 inches in several spots, you must bring all areas to a single, spec’d depth. This is done by machining the counterbore to a uniform depth and then using shims as needed to set the liner height precisely against the block. Trying to compensate with a tapered shim would create uneven seating and loading, and wouldn’t reliably restore a true, flat seating surface. Nothing should be left out of tolerance, and modifying the bore diameter with a hone won’t address the depth issue.

Uniform liner seating depth is essential for a proper seal and correct deck height. When the counterbore depth varies across multiple places, the liner won’t sit flush and the top of the liner can be uneven relative to the block deck, which can lead to head gasket leaks, distortion, or improper bore alignment. If you see a difference of 0.003 inches in several spots, you must bring all areas to a single, spec’d depth. This is done by machining the counterbore to a uniform depth and then using shims as needed to set the liner height precisely against the block. Trying to compensate with a tapered shim would create uneven seating and loading, and wouldn’t reliably restore a true, flat seating surface. Nothing should be left out of tolerance, and modifying the bore diameter with a hone won’t address the depth issue.