Money Matters: Trucking Business And Beyond

Detroit 11.1 vs. Cummins M11 Engines

Editors note: Welcome to a new format for our Money Matters column, which has been submitted for several years by Kevin Rutherford, who also hosts a show on Sirius/XM Satellite Radio. This is the fifth month where we recap a listener question from his Trucking Business and Beyond program.

Kevin:  Let’s see, let’s head off to Tennessee. Barry, welcome to the program.

Barry:  Hey, Kevin. Thanks for taking my call. I’m a company driver and I’m thinking about buying a truck.

Kevin:  OK.

Barry:  I spec’ed two trucks that will meet my needs. I’m just looking to haul three or four car trailers, I’ve already got a line on freight and everything’s set up to go. I’ve just got to get the truck and the authority to go with it. I found two trucks that are single axle Freightliners. One has a 60 series Detroit 11.1 engine in it with a 20,000 pound rear axle that’s a 410 gear in it.

Kevin:  OK.

Barry:  It’s 390 horse, so it will still be able to do the job. The other one’s a Freightliner that has a Cummins M11 in it.

Kevin:  Oooh, easy choice for me.

Barry:  Yeah.

Kevin:  Easy choice, and I’ve got history with this. I ran the 11-liter Detroits for years in the early ’90s. Absolutely loved it; my favorite engine of all time.

Barry:  OK.

Kevin:  If you were in a slightly lighter operation, and I was pulling doubles, but we weren’t real heavy. That was a killer engine for fuel mileage; they lasted forever. They were just about bullet proof. They hardly ever broke down and when they did they were easy to diagnose and fix. In the mid-90s, many of the manufacturers stopped offering the 11.1 as an option, you had to get the 12.7. I really wanted to stick with an 11-liter engine. I started doing some research on the M11, and prior to that I’d had some L10s, but the M11. What I found out was most shops were telling me on the M11s they were doing the N-frames between six and seven hundred thousand miles. I was doing them on my 11-liter Detroits between a million and a million two. So for me, I really didn’t want to buy an engine that I was going to wear out so much sooner, and the M11s didn’t seem to do nearly as good in fuel economy.

Barry:  Should I worry about that rear axle only being 20,000 as opposed to 23,000 pounds?

Kevin:  No, don’t worry about that, either. Just to give you an idea; over the years I’ve bought several tandem axle tractors and converted them to singles to pull doubles with. The way I convert them is the front axle gets yanked out, the rear axle gets moved up, and that’s a 20,000-pound axle. When you spec a true single axle you get a 23, but I would just use the 20 because it was there and the last one I did was on my ‘99 which I still own. Truck’s got about 1.6 million miles on it and I had to do the axle at between 1.2 and 1.3 million when I did an axle.

Barry:  That 11’s got almost 900,000 miles on it, and the other, the M11 has I think close to 800,000 on it; so it’s kind of close.

Kevin:  Both of them, if I had to guess, if neither one of those engines have been touched, I’d be much more confident with the Detroit. I would be confident that if we did some testing and checked into a couple of things. The odds are it might have a good solid two years before we would have to do any major engine work. As far as that M11 goes, if we look at the averages, you might already be overdue.

Barry:  Yeah. OK. Well, thank you very much for taking my call.