How to break in an engine?

[slickwilly]

This has probably been addressed before but it's still a topic of controversy. I'm rather curious (as I'm sure many are) what the proper way to break in a newly built engine.

It came up on another forum today and here a couple responses, to get the ball rolling.


I've heard varying opinions on how to break in a car. Some say you should be extra gentle to it while others say you should get on it a few times to help the rings seat.


I hear opinions on both ends of the spectrum, some say to break in an engine under conditions it will normally see. example; break in a forced induced engine under boost. others say thats wrong and to not boost until broken in.. whatever floats ppls boat.

[Car Guy]

This is one of those topics to where it depends on who you talk to.....






:3gears::3gears::3gears:

[Windsors 03 Cobra]

8 thousand different ways to do it.

[05caddyext]

I would have to say that one of the biggest things to make sure of is not driving around at the same rpm for long periods of time. When I broke in my last mustang motor, I did it very slowly, all through the lower rpm band. I also changed 4 times before I hit 2,000 miles to make sure it was all clean. There is some theory that it doesn't really matter what you do, hell cars from the dealer are "new" and those get the living crap beat out of them all the time on test drives and those are under warranty. So it's really up to what you believe. Safer is better that sorry.

[slickwilly]

I would have to say that one of the biggest things to make sure of is not driving around at the same rpm for long periods of time.

Why is that?

[lit666]

http://www.mototuneusa.com/break_in_secrets.htm

[Prince Valiant]

The key to any break-in is really what happens, and how well the engine was prepared for the initial fire up...and will depend on a couple different things if it's a flat-tappet or roller cam.

But, for the first 50 miles i like to keep it sane, not too hard, but occassional full-rpm romps. I've put it down to the floor right as I was pulling out with a new engine on a couple of occassions....but not so much that you'd think I was beating it. I keep an eye on things like oil pressure at all times and all temps, temp gauge, and I avoid super long excursions for the first 200 miles or so, until I'm confident in the engine. Sometimes I'll do lower rpm, high load, and sometimes i'll floor it and let the engine run up a bit, if not to the "redline" per se.

Break-in theories are generally overwraught with overthinking. It's pretty basic.

[HY35F2T]

drive it like you stole it.if its under warranty.

use your brain dont beat the shit out of it but dont baby it and change the oil.

[juicedimpss]

The key to any break-in is really what happens, and how well the engine was prepared for the initial fire up...and will depend on a couple different things if it's a flat-tappet or roller cam.

But, for the first 50 miles i like to keep it sane, not too hard, but occassional full-rpm romps. I've put it down to the floor right as I was pulling out with a new engine on a couple of occassions....but not so much that you'd think I was beating it. I keep an eye on things like oil pressure at all times and all temps, temp gauge, and I avoid super long excursions for the first 200 miles or so, until I'm confident in the engine. Sometimes I'll do lower rpm, high load, and sometimes i'll floor it and let the engine run up a bit, if not to the "redline" per se.

Break-in theories are generally overwraught with overthinking. It's pretty basic.
i agree with this.

[Car Guy]

Will a compression test tell you if the rings have seated properly...???

I just fired a reman'd 5sfe in a `97 Camry and had to 'modify' the break-in process because it was making 'funny' noises for the first 10-15 minutes. I didn't want to grenade the thing so I was a lot more easy on it than I normally would have been.....

I am just worried that I didn't seat the rings properly because of it.....






:3gears::3gears::3gears:

[juicedimpss]

compression test will show MAJOR problems,but will not nessecarily tell you if the rings are seated. A leakdown tester is the correct tool for that duty.

Is the car smoking or consuming large amounts of oil?

[Car Guy]

compression test will show MAJOR problems,but will not nessecarily tell you if the rings are seated. A leakdown tester is the correct tool for that duty.

Is the car smoking or consuming large amounts of oil?


No not really, just concerned.....

After the 10-15 minutes of 'funny' noises when warming it up I let it idle for another 30 minutes just to make sure it wasn't going to grenade on me. It then coughed a plug wire and in return it cooled down while I got another wire.....

I let it warm up again (10-15 minutes) and then ran it between 2-3000 RPM's for another 10-15 minutes. After that I took it for a ride and started opening it up but not as much as I nomally would because I was hesitant from all the noise it was making.....

Maybe I'm just overreacting but I've never had an engine make that much noise on start up.....






:3gears::3gears::3gears:

[juicedimpss]

hydraulic lifters are lazy and noisy sometimes.
if its quiet now and doesnt use an extreme amount of oil,i dont think id be too concerned.

[Car Guy]

hydraulic lifters are lazy and noisy sometimes.
if its quiet now and doesnt use an extreme amount of oil,i dont think id be too concerned.

I know part of it was the lifters but the 'funny' noise was still there after they quieted down, and I couldn't pinpoint it before it finally went away. The main thing that I was worried about was that I let it idle too long before getting on it to seat the rings.....

I've heard the window of opportunity to seat the rings is anywhere from 20 - ??? miles of driving after you warm it up. Just not sure how that translates to idling time.....







:3gears::3gears::3gears:

[Prince Valiant]

I wouldn't worry...must every engine prior to using roller lifters essentially idled (albeit at a high speed ~2000rpm) for 10-20 minutes before it ever truely developed a compressive load that, in "theory", seats the rings.

It's fine.

[slickwilly]

http://www.mototuneusa.com/break_in_secrets.htm
Good article. :thumbsup

[Windsors 03 Cobra]

Speaking of rings and seating them I honed a couple dozen prototype ductile iron jugs for harley davidson some time back and there were very very faint horizontal lines in the bore that could not be picked up with any measuring device, just visually. A young woman engineer claimed that this caused the engines to whistle when the rings passed over that void at higher speed, they did later say they were fine and used them.

The nice finish I put in the harley jugs I hone is not the greatest considering the finish once the rings smooth the cylinder out over say 50,000 miles, where most are like glass inside or 150k even