Diesel Engine Service Manual Library
Complete US military technical manuals for classic diesel engines, republished as fast, searchable HTML — free forever. These are US government works (public domain, Distribution Statement A: approved for public release) that get harder to find every year. Original PDFs are downloadable on every manual's page.
Cummins NTC-400 Big Cam I & III
Full rebuild-level manual for the 14-liter Big Cam six: troubleshooting, disassembly through assembly, fuel pump calibration, torque and wear limits, and the complete repair parts list. As fitted to M915–M920 trucks.
GM / DDA 6.2L & 6.5L Diesel
Direct/general support engine manual for the 6.2L and 6.5L V8 diesels used in CUCV and HMMWV family vehicles — disassembly, inspection, rebuild, and specs.
Detroit Diesel Series 60 (M915A2/M916A1)
Truck-level DS/GS manual covering Series 60 DDEC engine work — cylinder head, turbo, injectors, cam bearings, Jake brake — plus the rest of the M915A2 chassis.
Why these manuals?
Military technical manuals are the best-documented service literature ever written for these engines — written for trained mechanics, illustrated step-by-step, and in the public domain. The engines they cover (Big Cam Cummins, the GM 6.2/6.5 diesel V8s, Detroit two-strokes and early Series 60s) power classic trucks, military-surplus rigs, equipment, and swaps that are still on the road decades later, while the paper manuals go out of print and the PDFs rot on dying forum links.
Every manual here carries its original distribution statement. Where an engine has no public-domain manual (Cummins N14 and 6BT, CAT 3406, 7.3 Power Stroke/T444E — all OEM-copyrighted), we don't republish it.