Late last year, Ford shelved plans to introduce a new 4.4-liter diesel V8 into its light duty F150 pickup trucks and full-size Expedition SUV. Ford has apparently continued to work on a larger diesel V8 that it has developed to replace the troublesome 6.4-liter Power-Stroke in its Super-Duty trucks. The Power-Stroke is supplied to Ford by Navistar and has caused the automaker no end of grief, in spite of its good performance.
The new 6.7-liter Scorpion has been spotted being tested in a prototype Super Duty pickup and reportedly incorporates some of the same ideas in the recently-shelved General Motors 4.5-liter Duramax diesel. Like the Duramax, the Scorpion uses a reverse flow layout for intake and exhaust. A pair of turbochargers lie in the valley of the V8 where they are fed by very short exhaust manifolds coming from the inboard side of the heads. This has multiple advantages. The short exhaust runs mean better response and reduced turbo lag as well as more energy available to drive the turbos since the exhaust doesn't cool. The intakes are on the outboard side of the heads although its not clear if they feed through the top like the GM engine or from the outside.

According to, the new engine should yield more power than than the Navistar engine as well as a 3 mpg improvement in efficiency. In the big trucks, where mileage ratings are often in the single digits, that's a significant jump.


Share This Photo X