Engine Break In

Over the years I have heard the debates on engine break in. FSMs say break them in easy, while performance oriented individuals say break it in the way you intend to run it. I have heard ALL the arguments and counter arguments over the years.
Now for the first time in my life I have a fresh engine to break in that actually belongs to ME, not a customer. So now I have this internal debate. I've done both hard and soft. I have taken a brand new Saturn Sky Redline Turbo fresh off the truck and beat it like it owed me money. I have also meticulously followed Subaru's break in procedures. I've done many in between. However I have never had the opportunity to see too much of the long term effects.
Well this man makes the best argument for either side I have ever come across. I'm convinced. Drive it like its stolen.
Break in secrets

 

[broxma]

His argument is valid and is also part of the reason I do it that way. Break in at the ring/wall contact is negatively exponential, meaning you will probably do 50-75% OF the break in the first 20-40 miles and the other 50-25% will happen over the next several hundred. A road test of a Nissan Maxima showed an increase in HP by about 2%(Margin of Dyno error, but still) after 2000 miles. I think there is something for the hard and fast approach. I also know that the top fuel drag cars do break in on their motor in only 1 mile, 4 1/4 passes. Something to be said about a several thousand HP motor running 300 MPH in the quarter on a 5280 break in.

The idea that pressure in the cylinder pushes against the rings and that this is time critical makes sense to me. This isn't a frying pan I am looking to season slowly over time. You need it done, and the window to do so is short, so do it now.

Just my .02. I will however be happy to pull compression numbers from my car. I am only 215 miles into break in and have not given it an ounce of rest from the get go.

/brox

 

[mitsuturbo]

Many people have followed this procedure. I dont think a single one has expressed any "complaints" about this method afterward, although i could be wrong. I've done it both ways, and i prefer "this" way you've linked.

 

Quoting broxma:
I also know that the top fuel drag cars do break in on their motor in only 1 mile, 4 1/4 passes. Something to be said about a several thousand HP motor running 300 MPH in the quarter on a 5280 break in.



Yeah the NHRA argument has been used in favor of this method, but the fact that the engine is disassembled after every pass and has a rather short life expectancy counters that pretty quickly. I was never fully convinced until reading this article. Sure I have never seen adverse effects from a hard break in, but I have heard complaints of "compromised break in" especially referring to Evo's and STI's being either denied for warranty work or in need of warranty work. But that was merely anecdotal evidence, and we all know how douchy dealerships try to squirm their way out of warranty work on performance oriented cars.
Even though I live in town, Lorane Hwy, which leads to Wolf Creek rd, one of my favorite mountain passes is just a couple hundred feet from my driveway. Lorane hwy is twisty with some off camber surprises. That is where my break-in is going to happen /ubbthreads/images/graemlins/grin.gif I'm really looking forward to it. I was not looking forward to being extra gentle for the first few hundred miles.

 

[MitsuDriver274]

I spoke with my machinist about the concept of a hard vs soft break in. He basically told me that with the tolerances that today's engines are machined too, the break in period is actually very short, usually over with by the time your done burping the cooling system, adjusting timing and anything else.

 

[bazeng]

I don't think that would relate to rings. That does make sense with bearings/cams etc. the rings will still need to wear or bed in against the bores

 

[Dan D]

I followed the break it in hard method because to me, with modern plateau honing profiles, the physics make sense.

At 1500 miles, compression is 209,210,210,211 (9.0:1 Wisecos). Car is now tuned pretty well running 22 psi with no blow-by, oil consumption or other unwanteds.

I did this modified version of the motoman drive it hard method:
1. Always bring engine to FULL operating temperature before high revs.
2. Drive the car easy for the first 10 miles or so, varying the rpm's from 2,000 - 5,000.
3. Then, start bringing the engine up to maximum rpm's and letting the engine bring the revs back down by coasting in gear.
4. Repeat several times in order to create maximum heat in the cylinders.
5. Drive around at lower RPM's for several more miles, remembering to vary the speed of the engine every couple of miles.
6. Repeat number 3, 4 and 5.
7. Park car and let the engine cool down overnight.
8. Repeat all the above 2 or more times.

I followed that procedure pretty closely taking four or five purposeful test drives to rack up 100 miles. The loaded portion of the break-in runs was usually 2nd and 3rd gear acceleration runs using as much gas as I could while keeping the boost gauge hovering around 0 and the revs below 6.5k. A couple other points - I made sure to only decelerate in gear, pulling vacuum; I changed my oil at 25,50,100,250,500,1k with a new filter and valvoline dino oil. I proceeded to drive it pretty easy until 500 miles to ensure my new centerforce got the required break-in. Once I hit 500 miles, the boost controller went back on and the hammer went down! So far so good

 

[broxma]

Those are really high compression numbers even for 9-1. My Evo brand new never pulled more than 180.

I have some seats arriving in the mail tomorrow but after I'm done throwing them in I plan on pulling some compression numbers. With the Webb Cams, I'll honestly be happy with anything above 150. That would be after about 300 miles since the re hone and a not so easy break in. I'll post some numbers as a way of adding premise to the assertion. Right now it is pulling around 20 in/hg at idle with those very cams which gives me some indication that I am getting a good seal.

/brox

 

[thecman02]

Depends on the gauge measuring too. Main thing is that the numbers are even. My 9.1 stroker got 185 across the board after rebuild. I guess I should check it since its been 1000's of miles after break in.

 

[broxma]

I just changed the break in oil tonight. I'll be running the comp test tomorrow. Steve is also just a few miles into his break in on new rings and a fresh hone and I know he is using the drive it hard method, mainly because he is unable to keep his foot out of it. I'll run another comp test on his machine once he does his first oil change as well.

/brox

 

Learn something new everyday /ubbthreads/images/graemlins/worthy.gif /ubbthreads/images/graemlins/worthy.gif.

 

[524of1000]

Quoting broxma:
I just changed the break in oil tonight. I'll be running the comp test tomorrow. Steve is also just a few miles into his break in on new rings and a fresh hone and I know he is using the drive it hard method, mainly because he is unable to keep his foot out of it. I'll run another comp test on his machine once he does his first oil change as well.

/brox



/ubbthreads/images/graemlins/devil.gif

 

[broxma]

I ran the compression test today and it confirmed two things. One, the hard break in seemed to have worked. I got a max of 157 in my number 1 cylinder. This is after 400 miles, 8.8-1 with 272 Webb Cams. Two, there is a physical issue with the block and it needs to be pulled. My previous numbers were 130,80,125,85 and now they are 157,105,45,110.

Seems I have two cylinders out of round so once I sell my Evo I'm going to go fully forged inside and be done with it.

/brox