The Ford 6.9L & 7.3L IDI Diesel Engine

6.9L 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.

• 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.

Applications:

1. Ford Pickup 83-87
2. Ford Van 84-87
3. Commercial Applications
4. Custom Applications

7.3L IDI Ford Diesel:

By increasing the bore of the 6.9 L to 4.11 inches, the 7.3 L IDI was born. It replaced the 6.9 L in 1988. Like its predeccesor, the 7.3 L was naturally aspirated, indirect injected. In 1993, a turbocharged version of the IDI was introduced, but short-lived since the IDI was replaced mid-1994 by the 7.3 L Power Stroke. The 7.3 L Power Stroke was turbocharged, direct injected, and featured computer controlled engine & injection management.

• Though the 7.3 L IDI and 7.3 L DI Power Stroke share the same displacement, the engines are ultimately very different:
  

   

  	7.3 L IDI	7.3 L DI Power Stroke
  Displacement:	444 ci, 7.3 L	444 ci, 7.3 L
  Compression:	21.5:1	17.5:1
  Aspiration:	non-turbo, turbocharged in 1993	Turbocharged
  Injection:	Stanadyne rotary injection pump, indirect injection	HEUI injection system, high pressure oil pump, direct injection
  Peak Horsepower:	185 hp @ 3,000 RPM 190 w/turbo	275 hp @2,800 RPM
  Peak Torque:	360 lb-ft @ 1,400 RPM 388 w/turbo	525 lb-ft @ 1,600 RPM

   

 

• Ford introduced the turbochared 7.3 IDI in 1993 to stay competitive with GM’s turbocharged 6.5 L & Dodge’s turbocharged 5.9 L diesel powerplants.
• The 7.3 L IDI had very respectable performance for being a naturally aspirated diesel engine.
• Ford’s 6.9 L & 7.3 L IDI diesels proved extremely reliable powerplants during their 12 years of production, setting high standards for future designs by all manufacturers.
• Though a stock 7.3 L IDI seems lacking in performance, rumors exist of one enthusiast pumping 1,200 horsepower out of his IDI, using extensive modifications, proving the overall capability of these trucks.
• Aftermarket solutions have long existed that can transform a non-turbo IDI into a turbocharged, intercooled truck, boosting performance dramatically.

Applications:

1. Ford Pickup 88-94
2. Ford Van 88-94
3. Ford Pickup 93-94 Factory Turbo
4. Commercial Applications
5. Custom Applications

 

IDI Diesel Engine Timeline: