ATC-8705 / PT-8705 Bolt Hole Thread Insert – Cummins 855 / NH / Big Cam

The ATC-8705 thread insert is engineered for restoring worn or damaged head bolt holes in Cummins 855 / NH / Big Cam engine blocks. This insert features a long internal thread of 11/16"-16 TPI and an exterior dimension of 13/16"-16 TPI, with an overall length of 3.25". Designed for use with Apex, Monaco, and Porta-Tool thread repair kits.

Used when original threads are stripped, corroded, or otherwise compromised, the ATC-8705 allows technicians to install a durable internal thread that maintains proper bolt retention and alignment—restoring structural integrity without excessive machining. This insert is ideal for rebuild applications where preserving block strength and maintaining OEM specifications is essential.

Key Features & Benefits

• Restores original 11/16"-16 internal threads in Cummins 855 / NH / Big Cam engine blocks
• 13/16"-16 TPI external thread for secure installation using standard reamer and tap from kit
• 3.25" length ensures deep thread engagement in long head bolt holes
• Repairs stripped, worn, or cross-threaded holes while retaining block integrity
• Professional-grade solution for engine rebuilders and heavy-duty diesel repair facilities

Typical Applications

• Repairing head bolt holes during overhaul of Cummins 855 / NH / Big Cam engines
• Salvaging engine blocks with damaged bolt threads without full re-machining
• Heavy-duty diesel rebuilds where proper bolt torque retention is critical