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break in period..is there even one?

514 Views 17 Replies 13 Participants Last post by  ownedbyaz
my car is totally fresh...it will still be a few weeks before i drive it. but lately i have been hearing that there is no such thing as break-in. jeffp's post about no break-in on clutches..and iheard that there really isn't a required break-in on engines....what's the truth here? i know the clutch "was" 500 miles of moderate stop and go traffic. just wondering...maybe turn the boost down to 6-7 psi for a little while..then openher up to 16-17 later down the road.
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There are actually two hottly debated sides on this issue. One is that you break an engine in by granny driving for the first 1,000 or so miles and the other is that you run the engine hard (like race conditions) for the first 20 miles. The reason behind the hard break in is that it helps the rings seat evenly creating a much better seal. Check out this address for the harsh break in method:

Post Edited (Oct 5, 1:27pm)
Regardless you still have to break in your cam.
On our motors, it does not make a huge difference. Just change the oil after 500 miles or so and it will go another 200K miles. Gotta love a Nissan L6.

so black lines out of the garage, down the driveway, and down the road! my neighbors will know my wrenching is done!
http://www.mototuneusa.com/break_in_secrets.htm seems to be air-cooled engines on motorcycles and snowmobiles. I can see how getting high pressure is needed to seat the rings in thos engines since they are "looser" in tollerances since the barrels have to ramp from ambient to 450F.

In our water cooled engines, things only vary between ambient and 200F so things ane probably close tollerance so high pressure is not needed to "help" seat the rings.

Just a thought.

i was reading that...said break in is done in the first few miles. what about my car...i had a hard time getting it to run right when i tries using the stock electronics. it idled for a litle while while i tested various parts trying to find the problem. it prob has 30 min of idle on it now.
Last engine I rebuilt the break in time was 10 minutes and the rings were sealed with no further blue smoke. 180 compression on all six. So it depends on your rebuild skills. Regardless chnge your fresh oil within 500 miles and then again at the thousand mark. Then change every few thousand or so. Congradulations on your rebuild efforts and final assembly. Its why this forum is so important to Z owners.
If I were you I'd just still perform the "hard engine break in" In 30 minutes it probably didn't even get totally warmed up. I believe the article says that in order for the procedure to work properly the engine has to be up to operating temp.
yeah 30mins at idle isn't going to satisfy the "hard engine break in" method. So you still have time to do that method.
required break-in on engines....what's the truth here?>>>>>>

Well unlike my take on the clutch, there is in fact a breakin on engines!
You see there are different sources of friction going on in the engine unlike the clutch.
You have to create a wear pattern in the cam, and this 2000K for 20 minutes is ok, but not really required, that is just a disclaimer for the cam grinders to cover their own butts.
The one thing that needs to be addressed is most importantly dirt in the oil, I dont mean big clumps of oil, but particulates none the less, and if you cdont think it is a real issue, take a sample of your new engine oil build and have it analyzed for particulates and I am quite sure you will be very surprised at what is floating in the oil.
Then there is the ring breakin, and this is the most important issue for an engine breakin. You must run the engine up to temp and maintain the temp/rpm's for a number of hours before the rings are totally seated to the cylinder bores. When I built my engine, I was gettin blow by on my rings, now I have total seal rings and I was not to happy about that. I also noticed I was using a high amount of engine oil.
What I did was to take a nice long 525mile trip to my mom and dads house with the car, just driving normal speeds 75-80 all the way there. My engine oil consumption went down by 50% and that was good. Now when I turn the engine over by hand, even after sitting for a number of weeks I dont hear the blow by anymore. The rings seated and everything is happy.
My take on hard driving/easy driving really is not the issue for me, but running the engine, bringing it up to temp that it will see every time you drive, and maintain that temp and running for a number of hours. That is a good engine breakin for an engine. Make sure the oil is clean, and change it after some running to get all the crap out of the oil. You can be the most cleanest machine shop in the world, but I will guarantee you there is going to be particulates in the oil after any rebuild, and no matter how precision you machine a part, the part that mates to that part will need some running time to find its final operating place.
Dont confuse a clutch with an engine, totally different contact materials. Dont worry about a hard/easy breakin, the engine will do both if built properly, but rather try to fire the engine and run it for as long as possible bringing it up to operating temp the first few thousand miles.
That is my take on the deal, it has worked every time for me.
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The 2000RPM to break in camshfts is for ==V8== engines. They oil the cam lobes by drain back from the heads only and at idle there isn't enough oil. These engines don't have that problem.

My break in for a fresh engine is:

Idle till it warms up fully. This gives you some time to check for leaks, set the timing etc. This takes about 20 minutes or so ussually.

Then I go drive it normally with some "spunky" acceleration to around 4000 RPMs. I don't run the crap out of it, but I don't baby it either. The WORST thing you can do is run the engine at a steady state. You should vary the speeds and avoid hiway type steady speed driving for at least 100 miles. Don't rev it past 4000 or maybe 5000 for 300-500 miles. Then change the oil and let it rip.
My break in procedure is very similar to steves280's. The one thing I'll add is that I use 30 wt. non-detergent oil for the first 1500 miles then switch to oil of your choice. Do not use a synthetic oil during the break in.

Post Edited (Oct 5, 6:26pm)
Break- in or not,my engine ran hot for about the first 300 miles.After that the temp stablized and the power went up.When you build your own engine the break-in is more dramatic,you really get the new engine smell.Engines from the factory are pretty much run in ahead of time so you dont notice the conflict thats going on inside the motor.But once all the parts are in agreement the power really comes on.
nice...i like the <1200 mile break in! i would go crazy!

Even if it were a 1200 mile break in, I'd only have to drive it to work for 2 weeks! LOL

I'm glad this question was asked... I've read about it done 20 different ways, and now we have some experience talking. That's ALWAYS a good thing.
i have for the last 30 years started the engine and run it for 30 minutes then changed the oil/filter.

then fire it up again and go for a drive varying rpms from idle to 1500 short of redline whatever that might be for that particular engine for about 20 miles. change the oil/filter again.

then from then on i drive it like i stole it.
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