The Engine Break-In Debate

[Tim Hilliard]

Just to add something about this "varying engine speed" for the first few hundred miles. This is inaccurate, load is what you are trying to vary. Again this is old school thinking back when cylinder bores where machined rough and heavy thick iron piston rings needed to machine themselves to the bore to seal. The rings in a modern engine seat instantly, they have to otherwise they would never be emission certified.

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[qwkcoupe]

How about the Q&A on breaking in Gears?

The ring and pinion guys mentioned going easy for a few hundred miles to micro-polishe the faces of the gears where they touch one another to reduce friction and thus increase gear life because they retain their intended tolerances. Ring and pinion mostly, transmission likely, probably other ones too like in the engine.

 

[Tim Hilliard]

How about the Q&A on breaking in Gears?

The ring and pinion guys mentioned going easy for a few hundred miles to micro-polishe the faces of the gears where they touch one another to reduce friction and thus increase gear life because they retain their intended tolerances. Ring and pinion mostly, transmission likely, probably other ones too like in the engine.

Again, let it come up to temperature before driving it hard, same for trans. Once it's up to temp it doesn't matter. Hopefully Ford uses clean oil and no micro-polishing takes place? :shrug: Gear sets should be ready to run out of the box, they run in gear lube so theoretically they do not actually make metal to metal contact when they mesh, same principle as an engine bearing. They, over time wear due to lube breakdown and the tolerance will change. It should be perfect when new.

Basically it comes down to common sense, if it's 0F outside you don't jump in any vehicle hold it on the rev limiter and dump the clutch. Drive the car as it was intended it will be fine.

 

[qwkcoupe]

True and very close. Okay my bad for not better supporting my memory banks.....looks indeed there are more parts than instant seating piston rings....

Bolding parts about supporting the notion that hundreds and thousands of miles are needed to break-in gears, best, as in I guess, ideal-world purposes I suppose ......

2014 Ford Mustang Owner's Manual says:

Calculating Fuel Economy
Do not measure fuel economy during the first 1000 miles
(1600 kilometers) of driving (this is your engine’s break-in period); a
more accurate measurement is obtained after 2000 miles–3000 miles
(3200 kilometers–4800 kilometers).

ESSENTIAL TOWING CHECKS
Follow these guidelines for safe towing:
• Do not tow a trailer until you drive your vehicle at least 1000 miles
(1600 kilometers).

Driving Hints
BREAKING-IN
You need to break in new tires for approximately 300 miles
(480 kilometers). During this time, your vehicle may exhibit some unique
driving characteristics. Avoid driving too fast during the first 1000 miles
(1600 kilometers). Vary your speed frequently and change up through
the gears early. Do not labor the engine. Do not tow during the first
1000 miles (1600 kilometers).

Note: In order to allow a break-in period for your vehicle, you may not
be able to create a Vehicle Health Report until your vehicle odometer has
reached 200 miles.

/2014 Mustang Owner's Manual said ^

Maybe someone can find pictures comparing good versus bad gear break-in. In the meantime

Team Rip (T.R.E) REAR DIFFERENTIAL RING & PINION BREAK-IN PROCEDURE:

The greatest damage to any new ring & pinion gearset usually occurs during the first thousand miles. During this time, the new gears are bedding-in which generates quite a bit of heat and if driven hard you will raise this temperature even further and may cause irreversible damage to the gears. This is because the gears need some run-time to allow the machine surface finish to wear itself to its final match. The ring & pinion gears are now lapped in but they still must have sufficient run-time to allow the surface finish to properly develop.

Over the course of a few thousand miles the gears will bed-in, increasing the load bearing surface area while polishing themselves up nicely to where they are smooth and shiny. This improved MSF (machine surface finish) reduces the heat that is generated and the larger load bearing contact area increases the overall durability of the gearset. It is wise to let the transfer case ring & pinion gears bed-in before pushing them to their material limits. This process takes about 3000 miles before the ring & pinion have fully bedded in. Think it takes only 500 miles? WRONG! It takes much longer than you think. If you take apart a freshly rebuilt rear differential after 500 miles the gears hardly show any signs of bedding in.

Recommend procedure for breaking-in your ring & pinion:

Follow the transfer case filling instructions provide on the FAQ section of this site. Vehicle speeds should stay below 60 mph for the first 100 miles. Drive the vehicle 10-20 miles, stop and let cool for 30 minutes. Repeat this process at least 5 times before driving the vehicle at highway speeds. Do not abuse or dump the clutch or do any hard acceleration, let the ring & pinion bed-in gently. If you take it easy on a new ring & pinion and perform regular oil changes it will last much longer. Use caution when letting out the clutch, as aggressive high rpm clutch dumps can fatigue parts and may lead to eventual failures.

New or recently rebuilt transfer cases should have the oil changed after the initial first 500 and again after 2000 miles. TRE adds a Moly assembly additive, do not be alarmed by the color of the oil when you first change it. Vehicles that are being road raced require race car maintenance and all drivetrain oils should be inspected after each race and changed if the oil is dark or stinky. Road racing applications may add an additional 1/2 pint of oil to the transfer case for added lubrication and cooling.

So for the next new purchase, I'll marvel at the piston rings have already instantly seated; and then trade out my WOT smiley face for my longevity smiley face per above.

 

[Tim Hilliard]

Interesting advice....I won't be following

 

[derieuz]

The dreaded break-in period

I feel like the want to put the pedal to the floor is going to be worse than wanting to itch a huge mosquito bite for the first 500 miles of break-in once we all receive our mustangs for those who ordered:rant:

 

[IGJoe2192]

Not going to hurt a thing. GIVE HER HELL! then change the fluids.

 

[Wild Stang]

I'm more dreading that if I order a limited edition, the out-of-state dealership I'm ordering it from will take it for a joy ride (before the break in period) because it will probably be the first 2015 they see. There isn't really any way for me to know what they do with it.

 

[derieuz]

Not going to hurt a thing. GIVE HER HELL! then change the fluids.

I don't believe the internals of the engine are lubricated to its full extent before the break-in period, or thats what i've always read/learned

 

[derieuz]

I'm more dreading that if I order a limited edition, the out-of-state dealership I'm ordering it from will take it for a joy ride (before the break in period) because it will probably be the first 2015 they see. There isn't really any way for me to know what they do with it.

luckily for me, im ordering mine from a family friend who owns the dealership, hes a hardcore italian guy, and would probably hire the mafia to take down his own man if he took a joyride in my car

 

[mmhmmustang]

500 mi under 3000 rpm, next 500 not above 4500, avoiding constant engine speeds. i.e. on the highway with a 65mph speed limit, 6th gear changing speed from 60-70 instead of cruising.

that's my choice and ill stick to it

 

[IGJoe2192]

I don't believe the internals of the engine are lubricated to its full extent before the break-in period, or thats what i've always read/learned

Learned > Reading

 

[nak302]

the last car i bought brand new was a high performance Australian GT. the drive home from the dealer was a touch over 200kms and in that time the engine was used throughout it's rev range, but never on cruise control. this engine, after over 100,000kms has never used oil in between services. this has and always will be my prefered method of "running in". i believe the key to engines staying strong is thorough servicing, not the running in method.

 

[Grimace427]

http://www.mustang6g.com/forums/showthread.php/engine-break-in-1961.html


I don't drive my new cars any differently when they have less than 500 miles.

 

[JoeDogInKC]

I'm more dreading that if I order a limited edition, the out-of-state dealership I'm ordering it from will take it for a joy ride (before the break in period) because it will probably be the first 2015 they see. There isn't really any way for me to know what they do with it.

Tell them in advance what you want and be there, if you can, on delivery day... EARLY. Tell them that if you suspect it's been driven before pickup that you'll refuse to buy it and ask for your (hopefully) refundable deposit back.

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