GOPONYGO

I need some advice on breaking in my 05GT. There seems to be two schools of thought...baby the engine for the 1st 1000 miles but vary your speed and keep the RPM's low the other method is too drive the car harder by varying the RPM's and speed.
I only have about 200 miles on my new stang and have been pushing the RPM's for short bursts by shifting gears later. It burns more gas but oh the sweet sound!!!

Any comments????

Also, how many miles should I put on my car before changing to synthetic oil???

I never had to worry about these issues when I drove a mini van.. lol.

Thanks[&:][]

hawgman

Have you been through this thread yet?

The other engine break in thread going right now on this board

JC74

I was told don't start using synthetic until at least 5,000 miles.

COBERA

Engine brake in is a very interesting discussion... and at times is somewhat of a religious discussion. Hard to put you finger on and thus requiring some amount of faith.

What I have done in the past with my engines is to treat the break in period as perhaps 3 distinct periods: ie: early, middle and late.

In the early break in period, 0 to 500 miles, I would thermal cycle the engine. Start the car and when it gets up to normal operational temperature I would pull off the road and then let the engine cool. In the mean time you can busy yourself with setting radio pre-sets, and heaven forbid, read the owners manual. Two or three cold to warm to cold thermal cycles will allow the engine parts to release tension and also allows the suspended metal particles to settle.

During the early break in period it is important to vary engine speeds as much as possible. Try not to drive at the same speed all the time (Ie: long drives on the turnpike in 5th is not a good early period break in regime). Try not to heavily accelerate your engine but take it easy and try to shift up and down thru the gears covering as many allowable RPM bands (and high end) as you can so that cam lobes, and bearings and rings will seat well. You do not want to LUG the engine eary so let it hum freely by being in the correct gear. Try to not feather the brakes but rather apply them with somewhat of a moderate pressure so that they bed correctly and do not glaze. Try not to use downshifting to slow the car down during this time period unless you heal and toe the engine speeds so that you are not glazing the clutch and flywheel. The key in the first 500 miles is to try to vary the speeds and the gears. Read you owners manual for RPM limits.

Now, some may disagree with me but at the end of the 500 mile period I would change the oil in the engine (lite oil normal dyno juice) to flush out the metal particles in the oil and i would perhaps put a oil filter screen on the new oil filter to trap big particles and allow me to see what is going on. Additionally, I would make sure the oil drain plug was a magnetic type and if not change to a magnetic type.

The Middle period of brake in goes from 500 miles to 2000 miles. Again try to vary speeds, begin to get on the engine. Try not to slam you gears. I would not dump the clutch at this point with RPMs on the tach. At 2000 miles I would change the engine oil and filter again, insert another screen and pay attention to the particles on the first screen and the magnetic oil plug.

The last stage of break in runs from 2000 to 5000 miles. Where I would begin to perhaps downshift and raise RPMs. At the 5000 mile interval I would change the Engine oil and filter, and the trannie oil as well. If really ****, the differential oil too.

I have been around Ford and Shelby V8s since the mid 1960's and this approach of break in has done well for me.

Of last note, if the engine is supplied with Synthetic from the factory (like the Corvette and Mercedes and Porsche) then you can use it in the break in process, if not then don't. I do not know what the oil is that is supplied in the V8 Mustang. You should try to use the same oil and weight as supplied by Ford as the newer engines have very close tollerances in the cam bearings. If you can get Ford break in oil from your dealer for the 500 and 2000 oil changes, then by all means do that.

Lugn

It comes with a Motocraft blended oil. I changed after about 800 miles and put the same blend in.

Shifty

Drive it like you stole it.

ChristopherCamel

i wouldnt be to worried its under warranty for 3 years at least...remember "built ford tough"

MustangBuddha

My thoughts on the breaking in an engine...

One major component of a break-in period is ring seating. The premise is that the crosshatching on the cylinder walls and the intentional roughness of the new rings need to wear on each other at a specific rate - the cylinder walls need to "polish" the ring faces. The idea behind varying engine speed is that an engine under load will press the rings harder against the cylinder walls as combustion gasses are forced into the space between the piston and the ring, forcing the ring outward. The deceleration also helps to load the ring with oil, among other things. Keeping the engine at a constant RPM will not produce enough of these pressures to wear the ring faces in the amount of time that it takes for the crosshatching to wear down, and what's left is (essentially) a rough ring face scrubbing on smooth cylinder walls.

This is the root of why there are two distinct schools of thought on breakin (disregarding the notion that breakin isn't necessary - after all, it isn't actually *necessary* that we brush our teeth, right?). The more controversial approach is designed to specifically address the ring seat. For the best ring seating possible, the engine needs to run fairly hard, but in a controlled manner - repeating cycles of controlled hard accelleration and smooth deceleration. This method can achieve an amazingly efficient ring seat - so much so that the combustion chambers and piston crowns will not even turn black from the significant blow-by that is present in most improperly broken engines. The downside of that thought is a trade off of the potential for non-seasoned component failure for a great ring seat. A perfectly seated ring is useless if block turns to swiss-cheese because time wasn't allowed for the residual manufacturing stress to disperse throught the rods. That is what the more conservative approach to engine breakin is for - gently stressing the internals to "work out" the stresses that are inherent in manufacturing. For example, one region in a rod will have more stress, while another will have less - the boundary between these two regions is a weak point. If too much overall stress stress is applied to the rod, the weak point will fail. With controlled application of stress to the rod, the internal stresses will actually flow through the rod like a liquid and will reach a more general state of equilibrium. Then there are no more stress boundaries, or least the ones that remain are less dramatic, which miniumizes the weak points. This is where the constant vs. varied RPM comes back into play. With a consant RPM, there is insufficent stress to the components to smoothing out the boundary regions, so the weak points remain. The trick is to apply enough stress to achieve this without stressing to the breaking point. Hence, the general guidlines: accelerate and decelerate smoothly and constantly.

Having said all that, it is true that today's manufacturing processes and materials seem to produce components that are far superior to those of days gone by, so the imperative of a breakin period is certainly less than it has been in the past. I think this is why more aggressive ring seating has become more popular - the internal stress variations are much less of a factor now. It is evidently possible to rip a double stripe out of the dealership all the way home without breaking anything. The engine may never display obvious signs of trouble, but I guarantee the problems are there just waiting to crop up. Be it in the form of substandard long-term performance (which wouldn't be noticable because it will be so gradual), or in the form of a piston waving like a queen in a parade as it flies through that aluminum hood, which most people would notice right away...

Red69Sportsroof

I wouldn't waste my money. The engine is designed for a certain grade oil, just use that, it will not make any difference if you use something that costs much more. Just change it every 3,000 to 4,000 miles along with the filter and you will be just fine.

GOPONYGO

Thanks for all your replies and wisdom on this topic!