The Engine Break-In Debate

[MUSThavaSTANG]

Since many of us will soon be driving shiny new Stangs, (about a year for me) I'm curious to get some opinions on how people break-in their engines. I used to think you should baby them, but after some research I'm starting to think the opposite. I found this article in Popular Mechanics, which I would consider a pretty reliable source.

It basically states what I've seen several on-line mechanics and other sources say: Get the rpms high regularly during the first few hundred miles so the rings develop a good seal against the cylinder walls.

Engine Cylinder Walls

Piston rings don’t rely on their spring tension to seal against the cylinder bores. Instead, combustion gases work their way between the rings and the piston and force the rings outward. During the first few minutes of engine operation, it’s important that the throttle be opened pretty far at lower rpms [think he meant to say lower gears] to provide this high pressure. Otherwise, the rings won’t burnish the cylinder walls properly, and the engine will have high volumes of blow-by—which means excessive oil consumption and shortened engine life. If you’ve ever seen the car jockeys who drive new cars off the end of the production line into the storage lot, or the transporter drivers zipping up and down the car-hauler ramps, you’ll realize that this all-important step has been performed for you many times. If you’re installing a new engine, simply give it a few seconds of wide-open throttle in a high gear. For the first thousand miles, avoid constant speeds and throttle settings. If you commute in normal stop-and-go traffic, you’ll be fine. I advise against cruise-controlled sojourns across Nebraska.

Thoughts?

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[Nitro]

I'll do whatever the owners manual says. That info should be right from the engineers themselves.

 

[TheOneDoubleN]

Owners Manual = Limit Manufacturer's Liability = Instruct Owner to Never Push Engine Hard.

The Owners Manual's opinions on engine break-ins are unfortunately one of the worst resources.

I've generally ascribed to the philosophies detailed below, make sure the engine gets some good loads on it in the first 1,000mi but try not to be seeing redline on a regular basis

http://www.mototuneusa.com/break_in_secrets.htm

http://amsperformance.com/attachments/article/74/EngineBreakInInstructions.pdf

 

[MUSThavaSTANG]

The debate begins...

 

[Todd15Fastback]

I have had 3 Cobra's and 5 GT's...All of them have had mixed driving. Some low RPM jaunts along with high RPM acceleration. Just mix up the driving and don't baby the car. Drive it hard and take it easy. All of my cars had zero engine issues and made great reliable power.

I will drive my 2015 GT in this same fashion.

 

[mustanghobo]

I've read that most manufacturers break in the engines prior to installation so they're ready to go once they leave the factory? Anyone able to confirm or debunk this?

I revved my fr-s to 7k as soon as i drove it off the lot and on to the highway. I mostly babied it from there but would rev up to 5-6k getting on the highway, only hit redline about a month later.

Engine has yet to explode, I think its a liability thing with the manuals always asking drivers to baby it. They can't state in there for people to enthusiastically be rev happy because we all know people would be revving the engines to death and citing the manual as the reason.

 

[scottpe]

I'm just going to say that there is no way this debate will result in any conclusions as to what the 'right' answer is. But it will be entertaining I'm sure. ;)

That being said, here's my thoughts on the subject...

I think in general that modern manufacturing processes and the parts tolerances have resulted in much less need for the types of break-in procedures that many learned and employed decades ago, and still swear by.

As far as the idea of running the car to its absolute limits right away, I don't care what anyone says, I'm going with my gut. Despite the improved tolerances, common sense tells me that rapping a brand new engine up to red line when I drive it off the lot is probably not a good idea. The forces applied to the internals of the motor at those high RPMs are extreme. I'm giving that motor a few hours of operation to let everything settle in before I lay into it that much.

I think the most important thing with running in a motor -- and I think most agree -- is to vary the RPMs and load on the motor while driving it for the first couple hundred miles. I think it's also a good idea to leave the factory supplied oil in it for at least a few hundred to a thousand miles before switching to synthetic.

 

[deeps29]

I've read that most manufacturers break in the engines prior to installation so they're ready to go once they leave the factory?

They are but the tolerance is still very low thus you wont get the full open throttle response.
Best way to brake-in, IMO, is rev your engine at different RPMs time to time for first 500 miles. Do some low RPM driving then some high RPM push once a while. You should not continuously drive it at one constant RPM (a very narrow range, I mean).

 

[Taneras]

They are but the tolerance is still very low thus you wont get the full open throttle response.
Best way to brake-in, IMO, is rev your engine at different RPMs time to time for first 500 miles. Do some low RPM driving then some high RPM push once a while. You should not continuously drive it at one constant RPM (a very narrow range, I mean).

This is what I did, unfortunately I bought mine from out of state, and the drive back was, of course, all interstate. Still, I did my best to adjust speed and use the automatic in sports mode, playing with higher and lower gears the entire way.

So far so good.

 

[tbonez3858]

Dyno break in and be done with it.

 

[5.0GT]

I broke my 13 in by leaving two long black marks from the dealer lot. I drove it hard after that. Ran a 12.6 on stock tires.

 

[c3po]

I would say....if breaking in an engine is high on your importance list I'd order the 2015 'stang instead of buying one off the lot. We all know how those things are going to be driven.

 

[Rob WH]

Drive it like ya STOLE IT!

 

[HGFireHazard]

My plan consists of a fair amount of WOT in 5th-6th gear at low speeds (25-30) and a lot of variation in RPM. No cruise control for the first 1,000 miles and then change the oil.

I will likely keep it away from the limiter most of the time, but I will probably take it to higher RPM's once in a while.

After that first oil change I plan to drive it like I stole it.

 

[Tim Hilliard]

There is no such thing as a break in period on modern engines. All the parts have 'met' each other by the time it rolls off the assembly line. It will never be as good as when it's brand new. Let it come up to temperature before driving it hard. Car's that are not driven (garage queens) will need to have the oil changed more often due to moisture and acids that build up in the oil. Don't over change the oil, you introduce more contaminants to the engine every time you open it up, i.e. remove the filter, oil cap. It's 2014 not 1970, the machining, assembly, materials and engine oils are light years ahead. The days of 3K mile oil changes are long gone. Modern engines have a very low reciprocating resistance meaning they don't make metal, even the first oil change will have very low wear metals in the oil sample and really doesn't need to be changed sooner than what Ford sets the oil life at (10K miles?) My rule of thumb is if its at operating temperature it doesn't matter how its driven. If Ford didn't want you to drive it at 7000 RPM they would have set the limit lower, think about it, it's just a mechanical device, it has no feelings. If mine comes in before the snow does it's getting "broken in" on a road course

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