how many miles till break in

suprarcr89

The Juggernaut has my old
alot of engine builders say start it up let it come up to operating temp. then turn the engine off and let it cool... After it has cooled completely start it back up let it come back to operating temp and take off in it and go.. the engine(7mgte) I rebuilt for a buddy we went 500 miles on it before getting on it hard... but the machine shop i used to machine the head and block told us to do like above and the car would be fine... I have seen alot of engines with fresh rebuilds put right on the street and driven hard without any issues at all.... there are many opinions out there on this but main thing do what makes you feel safe....

Me myself I would put 500 easy intown miles on it.not really babying it but not flat out racing it either... then change the oil and filter. Do a headretorque... check compression and if all is well your good to go.. but like I said above there are many opinions out there....
 

Dan_Gyoba

Turbo Swapper
Aug 9, 2007
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www.gyoba.com
I've heard that you give it about 500 miles, with the important thing being not to use the cruise control. Allow the engine RPM to vary a bit.

The biggest thing with "break-in" is seating the piston rings and bearing surfaces. Maybe replacing that assembly lube with regular oil.

During and after this period, an oil change is recommended, as seating the rings and bearings leaves tiny metal shavings in the oil, so you want to clear that out.
 

Mr.PFloyd

I am the Super Devil
Jun 22, 2005
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you're not supposed to attempt to seat the rings 24/7 with a new engine.... seat them in properly (3rd gear 30km/h to 80km) and repeat about 20 times till they are seated.
 

wardog

R.G.V WARDOG
Jan 19, 2006
564
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ALTON, TX
I just finished breakin in my rebuilt 7mgte. First of all use staright 30 dyno oil with no additives, i used the one they sell at walmart for 1.25 a bottle and a supertech filter it was less than 10 dollars. Did about 500 miles on this oil then changed to an autozone special 5 quarts :icon_biggof mobile clean 5000 5w-30 and stp filter and thats were im at. I break in my rings by doin 4th gear 2000 rpm to 5000 rpm pulls on the freeway with no traffic . The first 50 miles your engine is on the road is very critical good luck this was just my 2 cents.... :naughty:
 

dbsupra90

toonar
Apr 1, 2005
2,374
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indiucky
some of you may or may not know, but they actually make a "break in oil filter". it is more expensive than standard, but it filters much smaller particles. you arent supposed to drive with it, it is just used for first start up.
 

Dirgle

Conjurer of Boost
Mar 30, 2005
1,632
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Pauma Valley, CA
Dan_Gyoba;884725 said:
The biggest thing with "break-in" is seating the piston rings and bearing surfaces. Maybe replacing that assembly lube with regular oil.

During and after this period, an oil change is recommended, as seating the rings and bearings leaves tiny metal shavings in the oil, so you want to clear that out.

You don't want to "break-in" your bearings. ;)

If you have metal debris coming off your bearings you have a bigger problem.
 

Supracentral

Active Member
Mar 30, 2005
10,542
10
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Whoa, whoa, whoa!

How a motor is built has as much to do with how you break it in as anything else.

For example. My drag motors? Built on the loose side of the tolerances. They get 5-10 minutes of running on break in oil. They get an oil change, they go to the dyno and lay down 1,500 + rwhp when they have less than 15 minutes of run time on them.

My street motors however, are built to the tight side of the tolerance. I use an extended break in for those, where there is lots of varied driving and engine loading to micropolish the bearings, etc.

It all depends on what your goals are, how much break in you can afford, and how long you want the motor to last.

Anyone giving you a simple "drive it hard" or "drive it soft" answer isn't giving you a good (or complete) answer.

Your machinist should be able to tell you what's appropriate for your engine. If he can't, you should have picked a better machinist.
 

KMinAF

Old Man
Sep 15, 2006
291
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American Fork, UT
As an aside note, between 500 and 1500 miles I noticed power increased as the engine "broke in" and loosened up. It ran smoother and was more responsive and free-er reving
 

Supracentral

Active Member
Mar 30, 2005
10,542
10
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KMinAF;888186 said:
As an aside note, between 500 and 1500 miles I noticed power increased as the engine "broke in" and loosened up. It ran smoother and was more responsive and free-er reving

I've had that on a few builds. It's the piston rings seating.