Downsized engines=shorter life?

[Retiredguy2]

Seems like the engines in new vehicles constantly get smaller to increase mpg and I wonder how downsizing will affect service life. I began pulling travel and boat trailers back in the early 80's and the understanding then was that a small engine straining to pull a load would consume about the same amount of fuel as a larger engine that could comfortably handle the same load, and the bigger engine would have a longer service life. My last Ford F-150 pickup had the 5.0 V8 and I used it to pull a 7000 pound travel trailer...it did the job okay but had to work hard at times. Today's F-150 is available with an engine as small as the 2.7 Ecoboost and they are rated to tow more than the 7000 pounds my truck used an engine almost 2X the size to pull.

I would have reservations about using such a small engine for 7000 pound towing because I would wonder about the service life. Thank you for any input on the subject.

 

[MMagis]

I think one thing you're not considering is the amount of HP produced in a smaller package these days. Have you compared the HP of your old truck to that of the newer 2.7? Also keep in mind that a vehicles rated tow capacity is a fine example of creative accounting. If there's one thing that can be said about engines of today, it's that they last a lot longer than those from 30 years ago.

 

[Retiredguy2]

I think one thing you're not considering is the amount of HP produced in a smaller package these days. Have you compared the HP of your old truck to that of the newer 2.7? Also keep in mind that a vehicles rated tow capacity is a fine example of creative accounting. If there's one thing that can be said about engines of today, it's that they last a lot longer than those from 30 years ago.

Sorry but I think you missed my point...I know today's engines produce much more horsepower. Look at a drag racing engine, for example...it produces huge amounts of horsepower but the service life may be only one or two trips down the strip. AND...does anybody really know for certain today's downsized engines WILL last longer?

 

[HHR]

I've pulled a 12,000 pound trailer load of hay with a 1991 F350 with the 460 V8 and one fuel injector wire chewed off by a rodent. The truck still pulled the load fine and other than a slightly rough idle, it was hard to notice the "dead" cylinder. If you dropped a cylinder on a 2.7L EcoBoost under load, the thing would probably go into limp mode and cut all the boost. Do you think a 2.7L V6 short one cylinder and without any advantage of forced induction would pull a loaded trailer very well?
The margin for error on these smaller engines simply isn't there.

 

[MMagis]

How did I miss your point? Maybe you missed mine? The only reference to engine size you gave was the liters, not the HP. HP is all that matters in this discussion.
I don’t know how you can even question whether engines of today last long than they used to. It’s common knowledge that they do, and not by a small margin.

Edit: Maybe I’m starting to get what you’re asking. Personally, I think you’re grasping at straws trying to make the argument. I don’t know the answer, maybe no one does. But there’s nothing to even suggest the “smaller” engines won’t last as lone, quite the contrary.

 

[KennyG]

I wouldn't be concerned about it. The smaller engines can get higher output in two ways - higher engine speeds and higher internal pressure. Horsepower is a function of torque and RPM and torque is directly related to the "brake mean effective pressure" inside the cylinders. New engines like the ecoboost are torque engines, not rpm engines (although they will rev when needed). The engine internals have been beefed up to take the increased pressure. The reliability problems with earlier turbo and supercharged engines was that they were essentially normal engines with boost added. When you design for boost to begin with, no problem. Diesels solved this problem years ago by beefing up the internals which is why they cost more and last longer.

 

[r8nger]

Today's engines are also producing power more efficiently. They also are burning cleaner, less contamination. Lubricants are also better, contributing to longevity.

 

[DarkBlack]

I've pulled a 12,000 pound trailer load of hay with a 1991 F350 with the 460 V8 and one fuel injector wire chewed off by a rodent. The truck still pulled the load fine and other than a slightly rough idle, it was hard to notice the "dead" cylinder. If you dropped a cylinder on a 2.7L EcoBoost under load, the thing would probably go into limp mode and cut all the boost. Do you think a 2.7L V6 short one cylinder and without any advantage of forced induction would pull a loaded trailer very well?
The margin for error on these smaller engines simply isn't there.

True.
The opposite view of it though, is that an 8 cylinder engine is more likely to drop a cylinder than an engine with 4, or 6..

 

[DarkBlack]

I've pulled a 12,000 pound trailer load of hay with a 1991 F350 with the 460 V8 and one fuel injector wire chewed off by a rodent. The truck still pulled the load fine and other than a slightly rough idle, it was hard to notice the "dead" cylinder. If you dropped a cylinder on a 2.7L EcoBoost under load, the thing would probably go into limp mode and cut all the boost. Do you think a 2.7L V6 short one cylinder and without any advantage of forced induction would pull a loaded trailer very well?
The margin for error on these smaller engines simply isn't there.

True.
The opposite view of it though, is that an 8 cylinder engine is more likely to drop a cylinder than an engine with 4, or 6..

 

[bigdeano]

How long they're going to last would depend on how beefy the bottom end is, like diameter and width of bearings. More boost equals higher bearing loads.