The M20165 Counterbore Shim Cutter Plate is a precision-machined fixture designed specifically for service and rebuild of Cummins L10, M11 and ISM series engines. This cutter plate is a direct replacement for the OEM part number 3823569, and is used in conjunction with the cutter bit (such as PT-2210-12M) to remove material from the counterbore ledge in the engine block, enabling accurate liner shim installation. Works with M50134 Counterbore Tool
When a Cummins engine block’s counterbore surface is worn, machined, or out of specification, installing liner shims demands a precise, flat, and concentric ledge. The M20165 fixture guides machining so that the shim sits perfectly and supports proper liner protrusion. Using this tool helps avoid head gasket failures, liner misalignment, and premature engine wear.
Key Features & Benefits
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Compatible with Cummins L10, M11, and ISM engine blocks—covers widely used heavy-duty fleet applications.
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Direct cross to part number 3823569, ensuring compatibility and correct specifications for shim placement.
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Designed to work with a matching cutter bit (such as PT-2210-12M) enabling full machining of the liner seat counterbore to install shim tools or inserts.
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Improves rebuild quality by restoring correct ledge geometry for shims, supporting proper liner protrusion and deck sealing.
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A durable fixture built for shop use—reducing risk of off-center cuts, tapering or re-work during engine rebuilds.
Applications
Use the M20165 during full block overhauls or when the counterbore ledge is damaged, machined beyond spec or needs shim installation. Suitable for L10, M11 and ISM platform engine rebuilders, heavy-duty service shops, and fleet remanufacturing operations to maintain OEM-level build accuracy.
