Engine break in tips/advice?
JK Super Freak
Joined: Feb 2009
Posts: 1,488
Likes: 1
From: Sydney, Australia
I read an opinion on this from a guy who builds & races motorcycles. He claimed there actually was some merit to the "drove it like you stole it" theory on break-in.
I'm no automotive engineer myself, but the way I remember he explained it is: even though conventional wisdom advises against use of WOT (wide open throttle) during the early stages of break-in he suggested that short bursts of this actually helps the piston rings to seat. He theorized that although most people would think that the use of WOT would put pressure on the rings forcing them inwards towards the piston surface causing combustion gas blow-by between the outer surface of the ring and the cylinder wall before the rings had seated properly, the opposite is actually the case.
These high-pressure combustion gasses at WOT, rather than trying to force themselves between the rings and the cylinder wall, instead try to work their way in between the inner surface of the rings and the groove in the piston surface, forcing the ring outwards and thus providing a tight fit between the outer ring surface and the cylinder wall. What he did suggest though was that the net benefit of this effect was achieved within the first hour or so of the engine's running time after initial startup, so by the time most people recieve their new vehicle with 10miles or so on the clock from factory testing and from being driven on & off transports & around lots, the opportunity to influence this effect on the rings may already be lost. I remember he had photos comparing shiny pistons that looked brand new that he had pulled from motors he'd raced that had recieved this run-in treatment with ones with the surfaces stained from combustion gas blow-by from conventionally run-in motorcycle engines.
As I said, I'm no engineer so I don't personally have an opinion on his theory, just interested what the engineers & mechanics out there think of this? I'll try to find the article & post the link here.
OK: I think this is it...
http://www.mototuneusa.com/break_in_secrets.htm
Her's another that goes into a little more detail...
http://www.ntnoa.org/enginebreakin.htm
I'm no automotive engineer myself, but the way I remember he explained it is: even though conventional wisdom advises against use of WOT (wide open throttle) during the early stages of break-in he suggested that short bursts of this actually helps the piston rings to seat. He theorized that although most people would think that the use of WOT would put pressure on the rings forcing them inwards towards the piston surface causing combustion gas blow-by between the outer surface of the ring and the cylinder wall before the rings had seated properly, the opposite is actually the case.
These high-pressure combustion gasses at WOT, rather than trying to force themselves between the rings and the cylinder wall, instead try to work their way in between the inner surface of the rings and the groove in the piston surface, forcing the ring outwards and thus providing a tight fit between the outer ring surface and the cylinder wall. What he did suggest though was that the net benefit of this effect was achieved within the first hour or so of the engine's running time after initial startup, so by the time most people recieve their new vehicle with 10miles or so on the clock from factory testing and from being driven on & off transports & around lots, the opportunity to influence this effect on the rings may already be lost. I remember he had photos comparing shiny pistons that looked brand new that he had pulled from motors he'd raced that had recieved this run-in treatment with ones with the surfaces stained from combustion gas blow-by from conventionally run-in motorcycle engines.
As I said, I'm no engineer so I don't personally have an opinion on his theory, just interested what the engineers & mechanics out there think of this? I'll try to find the article & post the link here.
OK: I think this is it...
http://www.mototuneusa.com/break_in_secrets.htm
Her's another that goes into a little more detail...
http://www.ntnoa.org/enginebreakin.htm
Last edited by JKlad; Sep 29, 2010 at 08:18 AM.
JK Jedi Master
Joined: Feb 2008
Posts: 12,907
Likes: 185
From: Maine
I read an opinion on this from a guy who builds & races motorcycles. He claimed there actually was some merit to the "drove it like you stole it" theory on break-in.
I'm no automotive engineer myself, but the way I remember he explained it is: even though conventional wisdom advises against use of WOT (wide open throttle) during the early stages of break-in he suggested that this actually helps the piston rings to seat. He theorized that although most people would think that the use of WOT would put pressure on the rings forcing them inwards towards the piston surface causing combustion gas blow-by between the outer surface of the ring and the cylinder wall before the rings had seated properly, the opposite is actually the case.
These high-pressure combustion gasses at WOT, rather than trying to force themselves between the rings and the cylinder wall, instead try to work their way in between the inner surface of the rings and the groove in the piston surface, forcing the ring outwards and thus providing a tight fit between the outer ring surface and the cylinder wall. What he did suggest though was that the net benefit of this effect was achieved within the first hour or so of the engine's running time after initial startup, so by the time most people recieve their new vehicle with 10miles or so on the clock from factory testing and from being driven on & off transports & around lots, the opportunity to influence this effect on the rings may already be lost. I remember he had photos comparing shiny pistons that looked brand new that he had pulled from motors he'd raced that had recieved this run-in treatment with ones with the surfaces stained from combustion gas blow-by from conventionally run-in motorcycle engines.
As I said, I'm no engineer so I don't personally have an opinion on his theory, just interested what the engineers & mechanics out there think of this? I'll try to find the article & post the link here.
I'm no automotive engineer myself, but the way I remember he explained it is: even though conventional wisdom advises against use of WOT (wide open throttle) during the early stages of break-in he suggested that this actually helps the piston rings to seat. He theorized that although most people would think that the use of WOT would put pressure on the rings forcing them inwards towards the piston surface causing combustion gas blow-by between the outer surface of the ring and the cylinder wall before the rings had seated properly, the opposite is actually the case.
These high-pressure combustion gasses at WOT, rather than trying to force themselves between the rings and the cylinder wall, instead try to work their way in between the inner surface of the rings and the groove in the piston surface, forcing the ring outwards and thus providing a tight fit between the outer ring surface and the cylinder wall. What he did suggest though was that the net benefit of this effect was achieved within the first hour or so of the engine's running time after initial startup, so by the time most people recieve their new vehicle with 10miles or so on the clock from factory testing and from being driven on & off transports & around lots, the opportunity to influence this effect on the rings may already be lost. I remember he had photos comparing shiny pistons that looked brand new that he had pulled from motors he'd raced that had recieved this run-in treatment with ones with the surfaces stained from combustion gas blow-by from conventionally run-in motorcycle engines.
As I said, I'm no engineer so I don't personally have an opinion on his theory, just interested what the engineers & mechanics out there think of this? I'll try to find the article & post the link here.
I have no experience with motor cycle engines. (Except the 3 1/2 horse Clinton I put on my Schwinn, back in '66)
JK Enthusiast
Joined: May 2009
Posts: 214
Likes: 0
From: Woodridge, Illinois
I read an opinion on this from a guy who builds & races motorcycles. He claimed there actually was some merit to the "drove it like you stole it" theory on break-in.
I'm no automotive engineer myself, but the way I remember he explained it is: even though conventional wisdom advises against use of WOT (wide open throttle) during the early stages of break-in he suggested that short bursts of this actually helps the piston rings to seat. He theorized that although most people would think that the use of WOT would put pressure on the rings forcing them inwards towards the piston surface causing combustion gas blow-by between the outer surface of the ring and the cylinder wall before the rings had seated properly, the opposite is actually the case.
These high-pressure combustion gasses at WOT, rather than trying to force themselves between the rings and the cylinder wall, instead try to work their way in between the inner surface of the rings and the groove in the piston surface, forcing the ring outwards and thus providing a tight fit between the outer ring surface and the cylinder wall. What he did suggest though was that the net benefit of this effect was achieved within the first hour or so of the engine's running time after initial startup, so by the time most people recieve their new vehicle with 10miles or so on the clock from factory testing and from being driven on & off transports & around lots, the opportunity to influence this effect on the rings may already be lost. I remember he had photos comparing shiny pistons that looked brand new that he had pulled from motors he'd raced that had recieved this run-in treatment with ones with the surfaces stained from combustion gas blow-by from conventionally run-in motorcycle engines.
As I said, I'm no engineer so I don't personally have an opinion on his theory, just interested what the engineers & mechanics out there think of this? I'll try to find the article & post the link here.
OK: I think this is it...
http://www.mototuneusa.com/break_in_secrets.htm
Her's another that goes into a little more detail...
http://www.ntnoa.org/enginebreakin.htm
I'm no automotive engineer myself, but the way I remember he explained it is: even though conventional wisdom advises against use of WOT (wide open throttle) during the early stages of break-in he suggested that short bursts of this actually helps the piston rings to seat. He theorized that although most people would think that the use of WOT would put pressure on the rings forcing them inwards towards the piston surface causing combustion gas blow-by between the outer surface of the ring and the cylinder wall before the rings had seated properly, the opposite is actually the case.
These high-pressure combustion gasses at WOT, rather than trying to force themselves between the rings and the cylinder wall, instead try to work their way in between the inner surface of the rings and the groove in the piston surface, forcing the ring outwards and thus providing a tight fit between the outer ring surface and the cylinder wall. What he did suggest though was that the net benefit of this effect was achieved within the first hour or so of the engine's running time after initial startup, so by the time most people recieve their new vehicle with 10miles or so on the clock from factory testing and from being driven on & off transports & around lots, the opportunity to influence this effect on the rings may already be lost. I remember he had photos comparing shiny pistons that looked brand new that he had pulled from motors he'd raced that had recieved this run-in treatment with ones with the surfaces stained from combustion gas blow-by from conventionally run-in motorcycle engines.
As I said, I'm no engineer so I don't personally have an opinion on his theory, just interested what the engineers & mechanics out there think of this? I'll try to find the article & post the link here.
OK: I think this is it...
http://www.mototuneusa.com/break_in_secrets.htm
Her's another that goes into a little more detail...
http://www.ntnoa.org/enginebreakin.htm
i am no expert either but i think that break in procedure might apply to those high performance, high compression, 15K RPM + race engines
JK Junkie
Joined: Nov 2008
Posts: 3,297
Likes: 8
From: Cabot, Ar.
What I think is, it's best not to be hard on a newly assembled engine for a while. Run it up and down the lower two thirds of the power band. This is how I treat automotive and aircraft piston engines. No reduction in longevity so far.
I have no experience with motor cycle engines. (Except the 3 1/2 horse Clinton I put on my Schwinn, back in '66)
I have no experience with motor cycle engines. (Except the 3 1/2 horse Clinton I put on my Schwinn, back in '66)
JK Newbie
Joined: Jun 2010
Posts: 84
Likes: 0
From: Perth, Australia
Don't baby the engine.
The worst thing you can do.
In the morning or when 1st starting it up let it idle for a bit.
Let the fluids start flowing.
Give it a minute or two.
Then take off slowly and don't rev the crap out of it until it warms up to temp.
After that rev through the entire range. Keep it moving.
Drive it and enjoy the hell out of your new pride and joy.
The worst thing you can do.
In the morning or when 1st starting it up let it idle for a bit.
Let the fluids start flowing.
Give it a minute or two.
Then take off slowly and don't rev the crap out of it until it warms up to temp.
After that rev through the entire range. Keep it moving.
Drive it and enjoy the hell out of your new pride and joy.
JK Freak
Joined: Mar 2009
Posts: 747
Likes: 0
From: Arvada, CO
Drive it like you are going to drive it, with some occasional WOT in there. That IS straight out of the owners manual. Just don't keep a steady speed and RPM for too long. Accelerate, brake hard, etc, etc. Just avoid WOT in first gear. For the first 500 miles or so avoid high speeds, above 55 mph.
But if you want to break it down into only two options, baby it or drive it like you stole it - then drive it like you stole it. Change the oil a little early, 1000 miles or so, and then keep up that occasional WOT every once in a while forever.
But if you want to break it down into only two options, baby it or drive it like you stole it - then drive it like you stole it. Change the oil a little early, 1000 miles or so, and then keep up that occasional WOT every once in a while forever.
JK Freak
Joined: Apr 2010
Posts: 973
Likes: 1
From: Englewood, CO
Varying the engine speed is the most important, making sure you use all of the rpm's for a short period of time.
Your setting the rings and trying to avoid scarring the cylinder walls.
Warming it up slowly then gradually going hard on it is the best method. That includes motorcycles. The hig rev bikes need to hit the limiter once in a while to keep max HP in the higher RPM's
Your setting the rings and trying to avoid scarring the cylinder walls.
Warming it up slowly then gradually going hard on it is the best method. That includes motorcycles. The hig rev bikes need to hit the limiter once in a while to keep max HP in the higher RPM's
JK Freak
Joined: Jul 2009
Posts: 590
Likes: 1
From: State College, PA
I would assume the "best" is highly dependent on the type of engine. I can tell you that with my Jeep I just drove it normally (how I still drive it to this day) right off the lot and changed the oil only once the "change oil" message came up on the dash at ~2500 miles (so I don't see a need to change the oil super early like many do). My first change was with Mobil 1 5W-20 (due to the lack of availability of Royal Purple at the time). My engine currently doesn't burn oil and is powerful enough I always wonder what people are adding to complain about the power and torque of the 3.8. I hauled a half-ton of concrete in the back of my JKU the other day in the very hilly central PA terrain including using 6th gear for everything but the steepest grades with my 3.21 gears and the only thing I noticed was the ride was a bit more comfy since the extra weight damped out a lot of the bumps 
I would NOT change to synthetic oil too early as I have read a couple posts about people's Jeeps consuming oil by switching to synthetic too early. This was actually backed up when I was reading Royal Purple's website the other day where they say right on the website "do not switch to synthetic oil before 2000 miles"
...just something to think about
I would NOT change to synthetic oil too early as I have read a couple posts about people's Jeeps consuming oil by switching to synthetic too early. This was actually backed up when I was reading Royal Purple's website the other day where they say right on the website "do not switch to synthetic oil before 2000 miles"
...just something to think about
JK Super Freak
Joined: Mar 2010
Posts: 1,006
Likes: 0
From: San Marcos, CA
my .02cents
avoid driving driving at freeway speeds for long periods of time for the first thousand miles or so, if you do drive on the freeway vary your speed. I'd drive it around town for at least 500 miles. Change your oil at 3K miles.
avoid driving driving at freeway speeds for long periods of time for the first thousand miles or so, if you do drive on the freeway vary your speed. I'd drive it around town for at least 500 miles. Change your oil at 3K miles.
JK Jedi Master
Joined: Feb 2008
Posts: 12,907
Likes: 185
From: Maine
Something else to think about:
Millions of people do nothing to break in their engines. They just drive like they normally do.
There doesn't seem to be a problem with that, on a world-wide basis.
Millions of people do nothing to break in their engines. They just drive like they normally do.
There doesn't seem to be a problem with that, on a world-wide basis.