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Cummins 855 Thread Insert Installation Procedure: LS-8705 Professional Guide

By Blog Admin •
Cummins 855 Thread Insert Installation Procedure: LS-8705 Professional Guide

This 10-phase procedure uses the LS-8705 insert to repair stripped bolt holes on Cummins 855 / NH / Big Cam engine blocks—restores strong, reliable threads for head bolts and liner applications.

LS-8705 thread insert installation in Cummins 855 block deck hole LS-8705 Cummins 855 repair insert 11/16-16 internal 13/16-16 external

Introduction: Reliable Bolt Hole Repair for Cummins 855 Engines

The LS-8705 provides deep, full-strength repair—critical for maintaining head torque, gasket sealing, and engine integrity.

Phase 1-3: Preparation & Damaged Hole Assessment

  1. Secure engine block – Fixture or stand support
  2. Remove head / components – Full access to damaged hole
  3. Inspect & measure threads – Confirm stripping & depth needed

Phase 4-6: Hole Preparation & Insert Installation

  1. Drill & tap to 13/16"-16 – Clean, straight, full depth (use kit reamer/tap)
  2. Apply high-strength thread locker – On external threads of insert
  3. Install LS-8705 insert – Torque to spec with proper tool

Phase 7-10: Finishing & Verification

CRITICAL: LS-8705 Insert Protocol

  1. Trim excess insert if needed – Flush to deck surface
  2. Chase internal 11/16"-16 threads – Clean & true for bolt fit
  3. Reassemble head / components – Torque sequence to Cummins spec
  4. Pressure test & run engine – Verify no leaks or issues

Critical Warnings: Thread Insert Installation Hazards

AVOID THESE CATASTROPHIC MISTAKES:

  • ❌ Misaligned tap/drill – Crooked insert & bolt bind
  • ❌ Shallow tap depth – Weak thread hold
  • ❌ No thread locker – Insert loosening under load
  • ❌ Over-torque insert – Block cracking risk
  • ❌ Skip internal thread chase — Bolt seizure

Why LS-8705 Beats Alternative Repair Methods

Alternative Risks:

  • ❌ Heli-coil → Limited strength & failure risk
  • ❌ Oversize bolt → Misalignment & uneven torque
  • ❌ Block replacement → $10K–$22K cost

LS-8705 Advantages:

  • ✅ Deep 3.25" engagement
  • ✅ Accepts standard 11/16"-16 bolts
  • ✅ Full-strength repair
  • ✅ Saves block & thousands
  • ✅ Bulk pricing to $32.48
  • ✅ Proven Cummins 855 solution

Repair Cummins 855 Head Bolt Holes Professionally. OEM-Strength. Save Blocks. Boost Rebuild Profits.

Get LS-8705 – $56.00

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