Valve Lash & Overhead Detroit DD15 Verified Factory Specs

Detroit Diesel DD15 Valve Lash & Jake Brake Clearance Specs

Factory OEM cold valve lash adjustment specifications, feeler gauge sizes, and TDC cylinder firing order steps for Detroit DD15 heavy commercial diesel engines.

Selected Heavy Diesel Engine

Intake Valve Lash (Cold)

0.014 in

Feeler Blade: .014 in (0.35 mm)

Exhaust Valve Lash (Cold)

0.027 in

Feeler Blade: .027 in (0.70 mm)

Engine Brake (Jake) Lash

0.163 in

Feeler Blade: .163 in (4.15 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)

Bar engine to TDC Compression Cylinder 1 (Camshaft notch aligns with flywheel pointer)

Valves to Adjust in this Position:Cylinder 1 Intake & Exhaust, Cylinder 2 Intake, Cylinder 4 Exhaust, Cylinder 3 Intake

Engine Brake (Jake) & Injector Settings:Cylinder 1 & Cylinder 5 Engine Brake Rockers (.163 in / 4.15 mm)

Rocker Arm Lock Nut Torque: 37 ft-lbs (50 N·m)

Source: Detroit Diesel Service Manual DDC-SVC-MAN-0081 (DD Platform Engine Valve Lash & Head Installation)

Detroit DD15 Overhead Adjustment Sequence (GHG14 / GHG17 / Gen 5)

The Detroit DD15 features a dual overhead camshaft (DOHC) 24-valve layout. Intake and exhaust lash adjustments are performed cold using feeler gauges:

Step 1: TDC Compression Cylinder 1

Intake Valves: Cylinder 1, Cylinder 2, Cylinder 4 (.014 in / 0.35 mm)
Exhaust Valves: Cylinder 1, Cylinder 3, Cylinder 5 (.027 in / 0.70 mm)
Engine Brake Rockers: Cylinder 1 & Cylinder 5 (.163 in / 4.15 mm)

Step 2: TDC Compression Cylinder 6 (Bar 360°)

Intake Valves: Cylinder 6, Cylinder 5, Cylinder 3 (.014 in / 0.35 mm)
Exhaust Valves: Cylinder 6, Cylinder 4, Cylinder 2 (.027 in / 0.70 mm)
Engine Brake Rockers: Cylinder 6, Cylinder 2, Cylinder 4 (.163 in / 4.15 mm)

Locknut Torque: Torque rocker arm adjustment screw locknuts to 37 ft-lbs (50 N·m) using tool W470589022100.