hey my rebuilt sunfire just hit 322 miles on it today and i was talkin to some guys with srt-4's today and they said that they were told by the dodge dealer when they got theirs to drive it like your gonna drive it all the time to break it in and my machine shop guy told me to drive it for 250 miles before getting on it. what do you guys think is a good way of breaking a rebuilt engine in?

i found this link that says it goes for bikes and car engines, http://www.mototuneusa.com/break_in_secrets.htm , theres so many things ive been told that i had to make a post and see what everyone thought a good way to break in a engine was.

I always vary the driving conditions for the first 500 miles or so by driving how I normally would in the city, and on the highway , but never coming close to the redline. I like to make sure everything is seated and broken in before driving it like I stole it.




Gotta keep on livin', L-I-V-I-N

I have been told with the newer engines siimply tak eit on the highway and go through the gears varying your rpms but not goign to redline and then you should be ok...dont run synthetic foir a bit and take it easy for a couple weeks..should be good..it sucks when the rings dont seat tho..i have new engines that smoke,,lol..phil

Yeah keep away from redline, but dont totally baby it.

The latest information from almost every engine companies (from GM to Mazda),
new motors don't require a break in time, and you can use synthetic oils (motor, transmission, power-steering, brake fluid) anytime even from day one of the engine build.

I have yet to actually test this new information out, but I have spoken with a few engine builders/designers from GM and Ford, and they say breaking in a new engine is not needed.

But when rebuilding a motor I still suggest giving 300 miles to re-seat all rings, bearings and seals, you can drive them at high speeds, but do not romp on it from a stand still until 300+ miles from rebuild.

go through a tank of gas modestly, then have fun. thats all that needs to really be said.

When i got my 05 Sunfire last year, the damn car WOULD NOT go over 55MPH for the first 250 miles, then 65 untill i hit 500!

I'd have the gas pedel MASSED to the floor and it's stay at 55 for a few minutes thsn drop to 50, al;l the while the RPMs never went over 4500

I was told by 2 different stealerships that this was part of the engine break in programming. Basically the governer was set low so the engine seals could properlly seat. then at milage points, the governer would automatically raise to a new point

^^

DeadBob wrote:When i got my 05 Sunfire last year, the damn car WOULD NOT go over 55MPH for the first 250 miles, then 65 untill i hit 500!

I'd have the gas pedel MASSED to the floor and it's stay at 55 for a few minutes thsn drop to 50, al;l the while the RPMs never went over 4500

I was told by 2 different stealerships that this was part of the engine break in programming. Basically the governer was set low so the engine seals could properlly seat. then at milage points, the governer would automatically raise to a new point

ski-doo have a programmed break in period, not a gm econobox.... I've been easy for the first 800km of the car. I guess the break in period is up to the driver, I've seen brand new engine pushed to their limits on the dyno, but it's better to be easy at first so everything take it's place correctly.

after the 20minute cam/lifter break in the engine is prettymuch broken in, after that 20min @ 2000-3000rpm varying i do an oilchange, then hit the highway verying speed and rpm and also downshifting and letting the car slow from 55-60mph back down to 20mph a few times just by compression (no brakes, it creates a vaccum and sucks oil up into the cylenders for better lubrication) basically after that 50km of driving like that i do an oilchange, then head out again and do 2 or so moderate acceleration runs up to about 90 mph then i stop and check everything again, then head out and go for full out runs making sure to hit redline.

after that initial 20min of running your basically only seating the rings, if you baby it you'll never seat them, i'm normally hitting redline by 150-200km and if its a boosted engine around 500-750km of hard driving before boost/nitrous to let the bottom end loosen up alittle.


_______________________
** Flat Broke Racing Inc.**

I had a GM 8.1L that I swear had a computer break-in period.
My 02 Eco Cavalier also seemed like that.
My 02 Camaro couldn't tell you. I re-programmed the PCM the day I got it.

I have heard that GM car now have a computer break-in. As to what models I couldn't tell you. It seems like a good idea to me.

Motors are ran before you get the car to test them. They have been slightly broken-in from that. However, I doubt they hit every RPM and load combo. Why not play it safe?


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Yea, ummmm. I used to have a J-body...

that computer stuff is weird. i just test drove a 06 cobalt SS and had it up to 100.


anyways, glad to hear the new engine is up and running good

after cam break in , im usually easy for the first 20-30 miles , just to make sure there is no leaks , and the plugs read ok


then i redline it each gear , then i pretty much drive it like normal


but you do not want to make a trip on the freeway at a steady speed


driving at different speeds , kinda speed up then let it coast , then speed up then coast


what that does is wash the cylinders down with fuel , and allow the rings to seat in


and that takes a few hundred miles , depending on the ring type you used

the crate engine (fuel injected gm 350 v8) i bought a few months ago recommended a 300 mile break in period, where you're supposed to run it at varying speeds and loads, never coming any closer to within 200 rpms of the redline. but ive also heard that some engine shops (inclding a machine shop that builds nascar engines near me in woodstock, vt, will run it once or twice on the dyno easy, mid throttle, letting it cool all the way down each time, changing the oil, and then running it HARD. just my .02

then you want to try and change you oil may be after about 1000-1500 miles.


2004 Grand Prix GTP (Competition Group)
SOLD-->1999 Z24 5M-#30 to register on JBO
"You can please some of the people some of the time but you can't please all the people'
all the time

damn.... after my engine is built, i need to go back home (300km away)
now i read that highway should be avoid. i think i'll have to drive all day long during 2-3 days before going back home. maybe i can drive 200km/day.

me and a friend just finished up on a 383 stroker motor for his 69 skylark. a buddy of ours owns a performance shop and he builds motors for top fuel dragsters and much more. he helped us a bit with the block and tuning. from what we have learned and have tested drive it like your gonna. dont over rev it . or rev it out first run. a few hrs of running its good to go. took it to the track 2 days after we got it in the car ran 12.2 thrusting past the line. at 2500 rpm both feet on the brake. tryin to hold it down. but nehow . weve raced it quite a few times and hell its runnin great. i personally built a 3.1 for my 89 z balls to the wall 24/7 never had a problem with it . sold it after putting 35k on it. and as far as i know it still runs top dog.


PJ

I tend to agree with mototuneusa's website, but no matter what it's a highly debated subject and like anything else will stay that way. till the one decides what path they will take, personally i will after my fresh rebuild, drive mine hard, w/o synthetic oil even if it doesn't matter and change it between 300-800 miles to discharge the metal shavings, then drive it normal. To baby it or drive it hard is like 2 religions they both can tell you different storys that both can sound true for either way. I choose the mototune religion till my engine blows and I rebuild again

Chris.

Start the engine and bring it up to temperature, shut it down, change oil/filter. Then go around the block varying RPM and Load, also doing 10 accelerations and decelerations without braking on decel.

I've also heard it would be a good idea to take the engine up to or close to redline once you do that first 20 minute warm up/drive around. Drive it like you would with moderate load. If its built for boost, break it in with LOW boost settings. (So I'm told)

As WhiteDog said there are 2 theories to breaking in an engine, and the above is what I'll be doing. Of course it will be supervised by a fellow j-body guy who's built numerous SBC's over the years who have done the same break in.

Once you've done the 10 up/10 down (and changed the oil), I think you can go 300miles with varying load/rpm/speed, to be sure the rings are seating. Once you do that, you can go another 1000miles without an oil change. From there on in the engine should be broken in for the most part. I'm a bit skeptical as to whether or not I'll switch to Synthetic oil at this point, so I'll wait a bit longer before I change over. (but not too long)

don't listen to your friends and what they said about their SRT-4's. The owners manual clearly specifies the break-in procedures for the SRT-4.

There is also a big difference between an engine from the factory vs. a rebuilt engine.

Good luck with the new engine.


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'97 Z24
2004 JBO Bash Quick 8 Qualifier