Valve Lash & Overhead
Verified Factory Specs
Heavy Commercial Diesel Valve Lash & Jake Brake Clearance Directory
Factory OEM valve lash adjustment specifications, feeler gauge blade selections, and TDC cylinder firing order steps for Cummins ISX15, Detroit DD15/DD13, Cat C15, and PACCAR MX-13 commercial diesel engines.
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Intake Valve Lash (Cold)
0.014 in
Feeler Blade: .014 in (0.36 mm)
Exhaust Valve Lash (Cold)
0.027 in
Feeler Blade: .027 in (0.69 mm)
Engine Brake (Jake) Lash
0.070 in
Feeler Blade: .070 in (1.78 mm)
Cylinder Adjustment Stepper (Firing Order: 1-5-3-6-2-4)
Click Step 1 or Step 2 to highlight which valves to set based on crankshaft timing mark.
Step 1 of 2: Cylinder 1 at Top Dead Center (TDC)
Line up Engine Timing Mark at 'A' or '1-6 TOP' (Cylinder 1 at TDC Compression)
Valves to Adjust in this Position:Cylinder 1 Intake & Exhaust, Cylinder 2 Intake, Cylinder 3 Exhaust, Cylinder 4 Intake, Cylinder 5 Exhaust
Engine Brake (Jake) & Injector Settings:Cylinders 1, 2, 3 Jake Brake Slave Pistons (.070 in)
Rocker Arm Lock Nut Torque: 35 ft-lbs (47 N·m)
Source: Cummins QuickServe Online Service Manual Bulletin 003-004 (ISX/X15 Overhead Set)
Master Heavy Diesel Valve Lash Quick Reference Matrix (Cold Engine)
All valve lash measurements MUST be taken with the engine completely cold (coolant temperature below 140°F / 60°C). Setting overhead on a hot diesel engine will cause loose clearances and severe valve train wear once the block cools.
| Engine | Intake Lash (Cold) | Exhaust Lash (Cold) | Jake Brake Lash | Firing Order | Dedicated Page |
|---|---|---|---|---|---|
| Cummins ISX15 / X15 | .014 in (0.36 mm) | .027 in (0.69 mm) | .070 in (1.78 mm) | 1-5-3-6-2-4 | View Step-by-Step → |
| Detroit Diesel DD15 (GHG14 / GHG17 / Gen 5) | .014 in (0.35 mm) | .027 in (0.70 mm) | .163 in (4.15 mm) | 1-5-3-6-2-4 | View Step-by-Step → |
| Caterpillar C15 & C15 ACERT (6NZ / BXS / MXS) | .015 in (0.38 mm) | .030 in (0.76 mm) | .027 in (0.69 mm) on Jake Slave Piston | 1-5-3-6-2-4 | View Step-by-Step → |
| PACCAR MX-13 (EPA10 / EPA13 / EPA17 / EPA21) | .016 in (0.40 mm) | .028 in (0.70 mm) | .055 in (1.40 mm) | 1-5-3-6-2-4 | View Step-by-Step → |
| Detroit Diesel DD13 | .014 in (0.35 mm) | .027 in (0.70 mm) | .163 in (4.15 mm) | 1-5-3-6-2-4 | View Step-by-Step → |
| Caterpillar 3406E (5EK / 2WS / 1MM) | .015 in (0.38 mm) | .030 in (0.76 mm) | .027 in (0.69 mm) | 1-5-3-6-2-4 | View Step-by-Step → |
| Detroit Diesel DD16 (Heavy Haul 600 HP) | .014 in (0.35 mm) | .027 in (0.70 mm) | .163 in (4.15 mm) | 1-5-3-6-2-4 | View Step-by-Step → |
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Related Heavy Diesel Engineering Tools
Cross-reference other factory specifications and diagnostic tools for commercial diesel engines:
Technical Reference Citation: Cummins QuickServe Bulletin 003-004, Detroit DDC-SVC-MAN-0081, Cat SIS RENR2306, PACCAR MX-13 Manual