6.9 L IDI Ford Diesel
International began development of the 6.9 L in 1978. It was not until 1983 that Ford offered the 6.9 Diesel option in its 3/4 & 1-ton trucks. The 6.9 L displaced 420 cubic inches, features indirect injection (IDI), and had no turbocharger. Horsepower & torque ratings peaked in 1986, producing 170 horsepower @ 3,300 RPM & 315 lb-ft. @ 1,400 RPM. The 6.9 was known for being simple in design & making great power at a low RPM (peak torque @ 1,400 RPM from a V-8 diesel). Though the performance of the 6.9 is far from today's standards, it was a solid performer of its time and has a history of reliability & dependability.
6.9 L IDI Specifications:
| Manufacturer: | International Harvester |
| Production Years: | 1983-1987 (for Ford Trucks) |
| Applications: | Ford F250, F350 |
| Configuration: | V-8 |
| Block/Head Material: | Cast-iron/Cast-iron |
| Displacement: | 420 cubic inches, 6.9 Liters |
| Compression: | 20.7:1 (1983) 21.5:1 (1984+) |
| Bore: | 4.00 inches |
| Stroke: | 4.18 inches |
| Injection: | indirect injection (IDI), Stanadyne rotary pump |
| Aspiration: | naturally aspirated, non-turbo |
| Weight: | 860 lbs. (approx) |
| Peak Horsepower: | 170 HP @ 3,300 RPM |
| Peak Torque: | 338 lb-ft. @ 1,400 RPM |
| Reputation: | Reliable, durable, powerful for time period |
Additional 6.9 L Information:
- The 6.9 was bored out to 7.3 L in 1987, eliminating it from the engine line-up in 1988.
- The 7.3 L & 6.9 L are almost completely identical in design, except that the bore of the 7.3 L was increased to 4.11 inches.
- The heart of the injection system on the 6.9 L was a Stanadyne DB2 rotary injection pump.
- By the time the 6.9 L reached production, engineers had tested the design for a combined 52,000 hours, and racked up 815,000 miles worth of field testing.