Proper Break In Procedure

[spartan786]

Proper Break In Procedure

1. Best Practices For Breaking In a New Car


So, congratulations, you’ve bought a brand new car. It's a great feeling, and you're justly proud of your new vehicle. You want to take the best possible care of your new car, and you want to know the best way to break it in. Break it in right, and you maximize the car's life expectancy.

Who Am I?

Before I get started, I should present my credentials. I’m about 50 years old. I rode my first mini-bike at age 6, my first shifter bike at age 8, began to drive at age 12 (on a ranch), and was racing circle track at 16. I am a former licensed FAA Airframe & Powerplant mechanic, which required two years full time training (back then it was 2,001 hours of classroom theory and hands on training). I went on to engineering school and worked happily in the aeronautical field for many years. I was better on engines (turbines and reciprocating) than airframes.

I raced stock cars, sports cars, and motorcycles for over 20 years. I have built/rebuilt hundreds of piston and turbine engines over my career. And I’m nuts about all things mechanical, I read and talk and listen to anyone and everyone. My approach is scientific, with my engineering background, I want data and study results, not anecdotal evidence from someone's uncle.

Rule #1--You're Breaking In The Entire Car, Not Just The Engine

It's very important to keep in mind that you aren't just breaking in the engine, you are also breaking in the transmission, rear axle, brake rotors/pads, wheel bearings, and all other moving parts. The approach discussed in this article is a holistic, entire car break in method.

Rule #2--There's Mechanical Break In, And There's Thermal Break In

There are two primary concerns for break in, mechanical break in issues (for example, rings sealing to their cylinder bores) and thermal break in issues (for example, crank and rod bearings hardening through multiple heat cycles). Both break ins require time (which is the same as racking up miles) and heat cycles (which is going from cold to operating temperature and cooling down again).

[spartan786]

2. The First 50 Miles

If you have the good fortune to get to put the first 50 miles on your vehicle, great.

Take it Easy! Or, Heat is the Enemy!

During the first 50 miles, critical mechanical break in (wear) is occurring between your piston rings and their cylinders, your camshaft and it's tappets or lifters, and your connecting rods and crankshaft and their bearing surfaces and journals. During the break in period, as amazing as modern machining techniques are, there are microscopic high spots on various parts. These micro high spots can cause very local increases in friction (and thus heat) until they wear down. If you take it easy on the car, and keep the overall temperatures reasonable, no worries. If you go zooming around at high revs and full throttle before they wear in, then it's bad, bad news.

For The First 50 Miles:

* Do not exceed 50% of the engines rev limit (if it redlines at 6,000 rpm, stay under 3,000 rpm).
* Do not exceed 1/4 throttle unless there's an emergency (if a truck is about to hit you, the heck with the car, floor it and get out of the way!).
* Use the brakes gently, again unless there's an emergency. Look ahead, drive easy and brake slowly and evenly. Avoid hard use of the brakes if you safely can. You have to heat cycle the brakes for awhile to achieve maximum braking efficiency.
* If you have a manual transmission, shift gently. Don't force the trans into gears quickly, you've got to wear in the synchros for a while. Be easy on the clutch, it needs to both wear in and heat cycle for a while.

Avoid Cruising At One Constant Speed. Or, Variety Is Good!

Your car's engine needs variable RPM's and pressures during break in. The worse thing you can do is to drive from the dealer's onto the freeway, turn on the cruise control and just motor down the highway at a steady and constant state.

Certain parts of your engine need to vibrate at different frequencies and rotate around, your valves and lifters for example. Your cylinder rings will also walk back and forth in their lands a bit, and this is a good thing as it brings varying parts of the rings into contact with varying parts of the cylinder bore.

City mileage is great for break in, as long as you can avoid heavy bumper to bumper traffic on a hot day. City driving lets the engine run up and down its RPM range as you accelerate and brake, and subjects the cylinders to various pressures as you apply the throttle on and off.

If you have to drive on the highway, avoid driving at one speed. Slowly speed up and down in a safe range (if the limit is 65 mph, then keep doing 55-65 mph for example). Every now and then slow down (safely of course) a little bit and downshift one gear for a short distance. Keep up the variety! And get off the highway as soon as you can--take the scenic route home!

[spartan786]

3. The First Week And 500 Miles

OK, you've got the first day or two and 50 miles under your belt. Now what?

Take It Easy, But With A Little Enthusiasm Now!

During the first week of break in, it's all about thermal cycling the engine/transmission/rear axle and brakes. Mechanical wear is still occuring, but at a lesser rate than the first 50 miles.

BRAKES:
For the first week or so, continue to be gentle on the brakes. What you're doing is called "seasoning" the brakes. Nope, we're not talking salt and garlic here. Seasoning refers to cycling the brake rotors (or drums as some cars still have those on the rear) from cold up to operating temperature and then cooling back down to cold. This evens the temper of the rotors (temper is the hardness of a metal, you can harden most metals by heating them up and then quickly quenching them in cold liquid--except for copper, its weird and heating and quenching actually softens copper--but I digress). Over the first week of use, seasoning will evenly temper the rotor/drum metal and help provide strong braking and increased reliability.

ENGINE:
OK, this is a little complicated, but hang in here. From 50 to about 500 miles, you still need to be gentle on your engine, but with brief bursts of enthusiasm within certain parameters. What you get do now, is every so often (every five to ten minutes of driving or so) is to accelerate a little harder with a little more throttle. The key concept here is cylinder pressure. Within your engine, as you press the accelerator down (opening up the throttle more) you let more air into the engine which raises the pressure of the combustion chamber. The reason this is good (within limits) is that the only thing that really seals the piston rings to the cylinder walls is combustion chamber pressure. After the first 50 miles, you actually want to increase this pressure now and then to "push" the rings into harder contact with the cylinder and continue to improve the wearing in of the rings to the cylinder.

The best way to do this is with second gear acceleration. In a manual tranmission car, accelerate away from a light normally in first gear and shift at a normal time into second gear.

* If you have between 50 and 100 miles on the car, when you shift into second, give it about half throttle (that is push the accelerator pedal half way to the floor).
* Between 100 and 500 miles, go ahead and give it 3/4 throttle (press 3/4 to the floor).
* Limit the RPMs to 75% of redline (if redline is 6,000 RPM, shift at 4,500 RPM).

The reason you do this in second gear is because in a low gear you have a lot of mechanical gear ratio working for you, you can safely do this without putting a high load on the engine bearings and creating detrimental temperatures and pressures.

If you have an automatic tranmission, do the same thing, just wait until you've gently accelerated to aobut 15-20 mph before you give it half or 3/4 throttle per the above.

Your engine will love you for this!

TRANSMISSION:
If you have a manual tranmission, continue to shift easily and be genlte with the clutch. Don't force your shifts quickly, and don't slip or abuse the clutch.

[spartan786]

4. Bedding In The Brakes And The First Oil Change

Good, you've seasoned the brakes. Now you get to bed them.

Bed Your Brakes And Enjoy Maximum Brake Performance

Modern general purpose brakes are amazing. They have tremendous stopping power (did you know that your brakes are about 4-5 times more 'powerful' then your engine?), and last a long time. You don't have to bed modern brakes, but as many of my friends have discovered after I've done this for them, the brakes do work better afterwards.

What Is Bedding?
Bedding is drastically increasing the friction between the brake pads and the rotor for a very short period of time creating high temperatures. Bedding finishes the brake pads "curing" process which increases the brakes resistance to fade, and equally importantly, transfers and embeds pad material to the rotor surface, significantly increasing the brake's stopping power.

How To Bed The Brakes:
You need to scout out a location where you can accelerate up to 60 mph, brake heavily to 5 mph, repeat several times and then hop onto a highway for about 10 minutes of cool down driving. I have a couple of stretches of road that have a freeway entrance at the end that I use for this.

Once you've found the location, and you've got about a week of using the car behind you, plan on a time of day or night with little or no traffic on the road. Accelerate to about 60 mph (ensuring that there are NO cars behind you!) and apply the brakes very hard and firmly (NOT slamming them on suddenly, but pressing hard) until the car slows to about 5-10 mph. Do NOT come to a complete stop, you want to keep the rotors turning. Also try to avoid pressing so hard on the brake that you engage the anti-lock brake system (if you have one) or lock up the brakes if you don't have ABS.

Repeat this process about five or six times. I usually just keep turning around and going back and forth over the same stretch of road. It is OK if you see or smell smoke, that's not unusual. You will probably find that the car takes a little longer to slow each time you do this procedure, that's normal too--you're experiencing brake fade.

After five or six repetitions, hop on the highway and drive for at least 10 minutes. Try to avoid using the brakes as much as possible during this ten minutes. You're just trying to get airflow over the brakes to cool them back down, and using the brakes heats them up. I usually drive five miles in one direction, and then get off and head back. it's OK to use the brakes a little, just try to get the first five minutes in braking free, and be gentle on them if you have to use them.

After the cool down drive, head for home. Be gentle on the brakes on the way. When you get home, it at all possible, park on a flat and level place. Shut down, and if it's a manual transmission, leave it in first gear, if it's automatic put it in park. Do NOT apply the parking brake--you don't want the rear pads in contact with the rotors or drums, this can lead to uneven cool down. Let the brakes cool down completely, over night is best.

You will be impressed with how well your brakes work after this. It's not a bad idea to bed the brakes every six months or so, it removes any glazing that may have occurred.

First Oil Change

No doubt your owner's manual says your first oil change should occur after thousands of miles of use. If you love your car, don't believe the manual. It is still a good idea to change your oil after you've put 500-1,000 miles on the car. There are tiny particles of metal suspended in the oil from the mechanical wearing that has occurred (small enough to pass through the filter). The oil has also seen micro hot spots that wear the additives and break down the oil. Be safe, change the oil and filter.

A Note About Synthetic Oil:
There is absolutely NO question about this, synthetic oil is better for your car than standard mineral oil. Synthetic oil resists break down to much higher temperatures, reduces friction better, and just flat out lubricates your engine better. If you decide to use synthetic oil, you can safely go 6,000 miles between oil changes. And I mean 100% safely with a large margin of safety left! Your engine WILL last longer and produce better mileage and horsepower for a longer time.

If you decide to go with standard mineral oil, again, ignore your manual. Change it every 3,000 miles without fail. If you want maximum life and performance out of your car that is!

If your car comes from the factory with synthetic oil, then it's fine to break in your car with it and your first oil change should be at around 1,000 miles. And stay with synthetic if your manufacturer recommends it! If your car comes from the factory with standard mineral oil, then I would strongly suggest you change it at 500 miles. It is absolutely OK to switch to synthetic oil after 500 miles, you've done the vast majority of the engines break in, don't worry about the old stories of synthetic oil being too slippery.

[spartan786]

and finally the link where i got all this information from : http://www.novustechnic.com/breakin_4.htm

[Fayvir]

great read! thx for sharing

[vinnierap]

Wow!!! lot of info, im sure this will help a lot of people. Good write up.

[krimsalt]

Thanks for the information. One suggestion however; would have prefered this in KM rather than miles lol

[sammyboi36]

if only i read this a few months ago. i just babied the car for a 1000km