Engine Break-In Secrets - True or False?

Not open for further replies.
Interesting! A lot of guys say if you break it in hard the engine will be faster. I like to do that
mainly because I can't wait to drive fast!
I just make sure to vary the rpms a lot, and to
never drive hard when the engine is stone cold. (I missed out on a street racing opportunity
yesterday because my engine was stone cold)
He does have SOME valid points but also a lot of mis conceptions.

example, he is correct about the sealing of the combustion for the most part, that gases and such do go on the back side of the rings and push out the rings.

He is incorrect about the cross hatch in a engine as it is there to provide minimal lubrication where the oil can shear into the cross hatch maintaining some lube where the rings cannot scrape it down on the down stroke. You cannot wear a cross hatch pattern into the rings, and is not there by design to wear rings down. Now if lubrication doesn't exist due to say too high of viscosity due to no warm up, then you will wear down the crosshatch prematurely, thus cause blowby and loss of compression, like he stated, one of the main problems in break in, not allowing enough time for warm up.

Just a couple of things that stood out, and many other things that do as well but wanted to show how some of the theroy he presents is a little off base, But over all he does present a good point about break in. I myself do not adhere to manufactures break in rules for some of the same reasons. Just a personal opinoin along simular lines.
Well reasoned for the most part, but I've read too many reports of cylinder cross-hatching being still evident at high mileage on hard driven engines-some even still looking almost like new.- to buy into "wearing away the hatching during break in". As Bob said, the old timers always told me that it was to hold oil. Still, some hard runs, well warmed up, early on may very well be the way to go.
I have always driven my new cars like I drive them after they have 50,000 on them. Just regular driving, but if I need to step on it, I do. It's always worked for me. If I took as good of care of my wife as I do my cars, she would probably make me a cherry pie. But for some reason all I get is store bought cookies.

I don't know what that statement has to do with oil, but it just came to my mind.
So, what is the verdict here then guys? Is the procedure valid and should be done rather than following manufacturer recomendations OR vice versa?

Also, what did you guys think about changing the oil very early AND the use of Dino oil rather than Synthetic?


I always do a 500 mile oil and filter change on every new car I buy, and make sure my family
members do the same. I go with dino oil at this point just because I like to do a second change
once again at 2k to get rid of even more break in materials.
The 500mile filter/oil change is good, but nothing is WORSE on an engine than breaking it in hard.

You'll never even see race engines being done this way! Heck, many engines take a full 10,000-30,000 to fully break-in...
Some engines do not require break-in. Others do. I know that most motorcycle engines require a pretty elaborate one, as does the Subaru WRX. My LT-1 did not require a break-in.
In the mid 80's a friend toured the Yamaha final assembly line in Japan,FJ1200s were lined up to run on rear wheel dynos and ran through the gears and ran hard for 2 minutes to make sure they were good for the go before shipping I was told,then the oil was drained through a strainer and put into the next bike engine.
I can't help but think Honda and Kawasakis are run prior to shipping out as well. It makes financial sense for warranty purposes to not have to ship a motor to a dealer if it failed very early after initial fire up and or the legal ramifications if a gearbox siezed on the hiway with it's new owner

As far as proper breakin? Far to many different engines and applications to tackle,each a different case

[ August 15, 2002, 07:37 PM: Message edited by: dragboat ]
Honda motorcycle break-in recommendation from the owners manual.

"Avoid full throttle starts and acceleration for the first 300 miles"

That's it. Nothing complicated about that. Fortunately my bike wheelies without full throttle.
I have to disagree with the idea of a hard break-in.
FIRST: I think the engine manufacturers must know something. My 2002 toyota book says for the first 600 miles:
-Don't exceed 62 mph
-Keep rpm between 2000 and 4000 as much as possible
-Don't accelerate hard
-Don't lug the engine
-Don't tow
SECOND, and more importantly: Unless it is an MS or some other specially prepared engine, there are always parts to be molded to their matching parts during the first "X" miles. That is why on analysis after 100 hours of operation on new engines I see:
-Fairly high levels of IRON
-High levels of Copper, Tin, and Lead: Soft metals used in the final layers on bearings to wear immediatly and leave a full smooth surface where oil can flow and give the hydrodynamic lubrication that Bob explains so well on this site, and boundary lubrication can work evenly.
If we have uneven surfaces, and push hard on the accelerator, the pressures will cause contact on the ridges and cause more heat, faster wear of those materials, probably in larger particles that might damage other things.
This is also why I believe in an early oil change. Get that stuff out of there.
Terry probably has more analysis like this, but here are my most recent two examples of those levels: Both CASE Diesel Tractor engines with 100 hours (will normally run 300 to 400 hours between changes)
Iron: 28 ppm -- 26 ppm
Copper: 56 ppm -- 44 ppm
Lead: 7 ppm -- 5 ppm
Chrom: 2 ppm -- 2 ppm
Alum: 3 ppm -- 4 ppm
Silicon: 19 ppm -- 23 ppm (probably from seals)
Theories are easy to put on the internet, but I think analysis helps define things.

what's an MS?

I've only bought 1 new car and 1 new bike in the last 30 years that I've had a drivers license. So I give some thought on how I should break-in an engine. I also consider the transmission, brake pads/rotors and every other working part needs to be "broken in".

Here’s my thoughts on a proper break-in:

I like to do lots of heat cycles early in the process. Metals deform a bit the first few times you heat cycle them. In addition heat cycling will relieve stresses in the metal caused by machining. I like to make sure I get that process over with before I start giving the engine a transmission a work out.

0-250 miles

Take short 20 miles trips and run through the rev range but a few grand below redline. I don’t use full throttle (50%max) and generally don’t use 5 and 6th gears very much. Let the engine cool completely between trips. Change the oil with petro based stuff.

250-750 miles

Take longer trips running the engine higher in the rev range for the lower gears and begin using 5 and 6th gears more. Lower gears get more throttle than higher gears but still no full throttle. Change the oil with dino.

750-1500 miles

Start running up to redline briefly in 1,2 and 3 gears under full load and using 4, 5 and 6 at 80% load. Use the transmission as you normally would. At 1500 miles change the oil, for cars change the gear box oil too. Synthetic is ok at this point for bikes but I’d go a little longer for low revving cages.
Good advice on the heat cycles! When I bought my 98 Formula new, I did that. I drove it for 20 miles, then I'd let it cool for a while, then I'd drive it 20 more, etc.

Although I did drive it hard, I was going 135mph plus, redlining it in 4th gear, with just 50 miles on the clock (was racing a 5.0 Mustang)

Then with just 700 miles on it, I took it to the strip and ran 16 runs.
I read somewhere that the engines that do not call for breakin such as the LT1 are "plateau honed" this cuts the tops of the cross hatching down just like breaking in the engine would. Apparently the rings seat ok this way too. Don't recall if I posted here but a long time ago I read in Mechanics Illustrated that an engine broken in with used motor oil broke in faster and cooler than with new oil. I pretty much subscribe to that theory, but not to the extent of filling my new truck with used oil. I did, however, run her till the oil change lite came on at 5711 miles. One more dino short change and now I have Mobil 1 in it. Think I wil get a test when the light comes on again. Regards, RW
As I've said before, break-in is a very engine specific thing. I say, follow your manual. My LT1 had no break-in in the manual.

My 87 Yamaha Fazer 700cc, a 124 HP/L(2.07 HP/ cubic inch) 20 Valve 4 cylinder, had a comprehensive break-in.

0-90 miles 4000 RPM limit (This engine's Power and Torque peaks are at 10.5k and 8k) Never stay at one RPM or throttle setting, shutdown and let cool off every 5-10 minutes.

90-300 miles, 6000 RPM limit, never use full throttle.

300-600 miles, Do not cruise over 8000 RPM, no prolonged full throttle.

600-1000 miles, no prolonged full throttle.

>1000 miles, have at it. 0-60 in 3.2 seconds
Not open for further replies.