The ATC-8040 / PT-8040 Lower Press-Fit Counterbore Bushing is a high-precision repair insert engineered for Cummins diesel engines, including 250, 335, 350, 855, and 5½″ NH / NTC inline-6 / V-12 platforms. This standard-size bushing (dimensions: 6.299″ OD × 6.754″ ID × 0.751″ thick) is designed to restore worn or damaged counterbore surfaces, allowing blocks to be reused rather than scrapped.
Constructed from durable, wear-resistant Spun Cast Iron, this press-fit bushing ensures a precise, interference fit for enduring performance. As a direct replacement for PT-8040, the LS-8040 helps preserve linear alignment, sealing integrity, and reliable engine rebuilds by providing a new, true counterbore surface.
This insert is suitable for use in professional engine machine shops, diesel rebuild operations, and heavy-duty service environments where cost-effective block restoration is essential.
Key Features & Benefits
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Designed for Cummins 250 / 335 / 350 / 855 / 5½″ NH / NTC engine families
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Standard dimensions: 6.299″ OD × 6.754″ ID × 0.751″ thick
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Press-fit installation forms a permanent, concentric counterbore surface
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OEM replacement for PT-8040
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Reduces rebuild costs by salvaging serviceable blocks
Applications & Use Cases
Use the ATC-8040 for repair scenarios where the original lower counterbore or liner support area is worn, corroded, or out of tolerance. Ideal for engine overhauls, fleet rebuilds, remanufacturing, or block remediations in Cummins heavy-duty applications.