Cummins ISX Cam Timing Procedure: Complete Workflow Using ATC Master Kit

ISX cam timing is the most critical procedure in any Cummins rebuild. This workflow guide covers the complete timing process using the ATC ISX Master Cam Timing Tool Kit—from crankshaft locking to final verification. Follow these steps for factory-perfect timing on every ISX.

ISX Timing: The Stakes Are High

Incorrect ISX cam timing causes:

• Valve-to-piston contact – Catastrophic engine failure
• Poor emissions – Failed DOT inspections, fines
• Lost fuel economy – 2-5% efficiency loss per degree off
• Reduced power – Customer complaints, comebacks
• Premature cam wear – Expensive repeat repairs

Phase 1: Preparation & Crankshaft Locking

1. Position engine at TDC #1 – Rotate crankshaft clockwise until TDC mark aligns.
2. Verify TDC – Check camshaft lobes are in neutral position for #1 cylinder.
3. Install timing pin – Insert ATC2892174 timing pin into block to lock crankshaft.
4. Confirm lock – Engine should not rotate with pin installed.

Phase 2: Cam Gear Removal (If Required)

1. Mark existing timing – Scribe marks on cam gear and housing for reference.
2. Remove cam gear bolts – Follow OEM sequence, save hardware.
3. Install ATC3163069 puller – Thread puller into cam gear hub.
4. Extract cam gear – Turn puller bolt to press gear off camshaft taper.
5. Inspect gear and cam – Check for damage, wear, or corrosion.

Phase 3: Timing Wedge Installation

1. Select correct wedge – Refer to service bulletin for required degree (4°, 4.25°, 4.5°, 4.75°, 6°, or 7°).
2. Clean mating surfaces – Remove all debris from cam gear and housing.
3. Position wedge – Install ATC20161 wedge between cam gear hub and timing housing.
4. Verify wedge seating – Ensure wedge is fully engaged, no gaps.
5. Install cam gear – Seat gear on camshaft taper against wedge.
6. Torque cam gear bolts – Follow OEM sequence and torque spec.

Phase 4: Final Verification

1. Remove timing wedge – Carefully extract wedge from housing.
2. Remove timing pin – Extract ATC2892174 pin from block.
3. Rotate engine – Turn crankshaft 2 full revolutions by hand.
4. Return to TDC #1 – Verify timing marks align correctly.
5. Reinstall timing pin – Confirm pin engages at TDC position.
6. Final check – If pin engages correctly, timing is verified.
7. Document – Record timing setting, wedge used, and date for warranty.

Timing Wedge Selection Guide

Troubleshooting: Common ISX Timing Issues

Master ISX Timing with the Right Tools