Chevy went from 6.5 to 6.6, Dodge went from 5.9 to 6.7, but Ford has gone through 6.9 IDI, 7.3 IDI, 7.3 Power Stroke, 6.0, 6.4, and now 6.7. Did I miss any? Why do they keep changing so much compared to the others? Is there a specific reason?
Ford’s changes were mostly because they were using engines from International (Navistar) before they built their own. The 6.9 IDI and 7.3 IDI were similar, just with a bigger bore on the 7.3. The 7.3 Power Stroke was a whole new engine designed for direct injection and turbocharging. Then the 6.0 came out to meet emissions, but it had issues like head gasket failures. The 6.4 tried to fix those problems but ended up with catastrophic failures too. Since 2011, Ford’s been building their own engines, starting with the 6.7, which has been more stable.
Before 2011, Ford used International-designed engines, so blame them for the constant changes. The 6.7 was Ford’s first in-house design, and they’ve stuck with that displacement since. Also, Chevy had the 6.2 before the 6.5, so they’ve made changes too.
Chevy’s Duramax 6.6 has stayed the same displacement, but each generation (like LB7, LLY, LBZ) was a big redesign. Ford’s displacement changes were more dramatic, especially when moving from 7.3 to 6.0 to 6.4, but they’ve been more consistent with the 6.7.
The 6.0 and 6.4 Power Strokes caused so many headaches—failures, lawsuits, and even deaths when ambulances broke down—that Ford had to cut ties with International and make their own engines.
Each engine change was driven by emissions regulations and performance demands. The 6.9 to 7.3 was just a size bump, but the 7.3 Power Stroke was direct injection to meet power needs. The 6.0 and 6.4 were attempts to meet tighter emissions, but both had serious reliability problems. The 6.7 was Ford’s first in-house diesel, and it’s been pretty stable since 2011.
Ford used Navistar/International engines for years. The 6.0 and 6.4 were made to meet emissions standards but were unreliable. Ford dumped Navistar and built the 6.7 in-house, which is why displacement hasn’t changed in over a decade.
The 6.0 and 6.4 Power Strokes were disasters that cost Ford and its customers a lot. That’s why they started making their own engines with the 6.7.
Chevy’s older diesels like the 6.2 and 6.5 had their issues too. The 6.2 was Detroit Diesel, and it didn’t have a turbo, so performance was meh. The 6.5 was a step up but still not perfect before they moved to Isuzu’s Duramax.
Ford’s gas engines also went through lots of variations: 427, 428, 429, etc. It’s just their style to try different things, I guess.
Ford’s engine changes were largely due to International trying to meet emissions and power requirements. The 7.3 IDI was upgraded to the 7.3 Power Stroke, which was direct injection. The 6.0 and 6.4 were attempts at better emissions but ended up being unreliable. When Ford switched to the 6.7 in 2011, it was their first in-house diesel, and it’s been solid since.
Ford had to keep giving new names because most of the engines from International (except the 7.3) weren’t great. The 6.7 is a totally different story—it’s solid.
If you’re curious, here’s a breakdown of Ford’s diesel engine history: https://www.carthrottle.com/post/a-brief-history-of-the-power-stroke-diesel-engine/
Thanks for all the insights. I didn’t realize Chevy also went through different engines like the 6.2 before the Duramax. Makes sense that emissions played such a big role in all the changes.