First of all, I did search. I came up with tons of threads but almost not useful info, so I decided to start this thread in an attempt to compile the different views on break-in times.
I have seen everything from take it easy for 1000 miles then its broken in, to keep it below 4k rpms for a few thousand miles then gradually raise the "redline" until 4000 miles.

So I want to know: how do you think engines should be broken in?
Please state your reasons, and whether this pertains to engines using new parts or used parts.

Thanks, everyone!

 

How about 1000 miles n/a, staying below 4k, gradually bring it up over the last 250 miles? 13bt i would think would be the same except, 1500-2000 miles, don't boost before 1000 miles, gradually bring revs up after that.

 

I would just follow what Kevin Landers says:

http://www.rotaryresurrection.com/2n...p_breakin.html

 

Yep. Personally, I just keep ithe revs low as long as my will power allows.

 

QFT! My will power doesn't let me study unfortunately

 

Break in time all depends on whats been replaced in the rebuild.
If I'm just replacing apex seals, I've had no problems with just going a couple hundred miles at low revs. Change the oil for a second time and give it hell.
If youre replacing the bearings as well, its a different story. Make sure to change the oil very early also to get rid of all the shavings.

 

i did 2500 miles. no boost. under 4k. all ive got to show for it is a large streetported engine that idles pulling 17-19 hg

 

Make sure you're a little rich and go easy for the first 500 miles new or used. Change the oil and so long as your tune is right, let her rip! stephen.

 

Yeah, I'm currently following the guidelines from Kevin, since thats about the only concrete info I could come up with. My engine only has new apex seals, so I suspect is already broken in (750 miles) but I'm gonna give it a little while longer before I push it too hard.

Edit: I have also been told not to drive it on the highway during break-in. Is this just if you get new bearings?

 

Can someone clarify on the highway thing?

 

wtf take it out for a spin and beat the **** out of it change the oil and REPEAT

 

Isn't that breaking the car and not breaking-in the car?

 

meh, lots of people do very little to break in a car other than get it started, drive it a bit, and change the oil. I was to impatient to baby my car for 500 miles, but I did make it a couple hundred.

 

I did it the Kevin Landers way and I'm happy. I think the time, energy, and money that goes into a new engine, it might be worth waiting those 2,000 miles before opening it up.

Now a good question to ask might be, "Who here has blown up an engine just after rebuilding? And was beating on it prematuring the cause?"

Brian

 

^Ha!
I havent "blown" one up, but I did manage to overheat mine within 2 hours of getting it running thanks to a nice air bubble in the coolant system.
That was before ever getting over 4k though.

 

This is how mazda broke-in their competition motors. A good baseline I guess.



600 miles instead of 60 all the way to 3000miles?

 

If you have a standalone, anyway to just set up a rev limiter really low that won't allow you to rev any higher than say, 4k.

 

Like many things, breakin can be a factor of opinion.

I generally drive the engine easily for 500 miles, then start beating on it.

 

Although that would be great for keeping the motor under low revs, it could also be really dangerous.
In an emergency situation(pulling out in tricky intersection and couldnt see that truck barreling towards you) I would rather rev my fresh motor past 4k once rather than have my car smashed because it cut revs at 4k.

 

http://fc3spro.com/TECH/FAQ/breakin.html


-Ted

 

Sooooo... can the car be driven on the high way during break in?

 

I generally follow Ted's recommendations (http://fc3spro.com/TECH/FAQ/breakin.html) if there is used unlapped plates, or used housings and seals.

If the majority of the motor is new, then I follow the Mazda OEM guidelines of no hard starts and vary engine RPM for the first 1000 miles.

 

I had to dig into this, since it piqued my curiosity...

This is what the 1987 owners manual has to say about break-in:

That's it.


-Ted

 

the highway thing its that you hold the car at almost the same rpm range all the time cause its a long road with no stop and go,On a rebuild motor you want the engine to be able to rev at diferents ranges so the motor see every diferent scenario(low revs,mid range revs,vacuum,temp changes,even some low boost)so that way all the seals(soft and hard seals)will start adjusting and getting used to this changes,i do this for around 1000 miles after that its just hell.

 

Is 1000 miles in three days the same thing as 1000 miles in one week?

Meaning. Is time a factor to break in?