High performance engine break-in

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I read an article last year you wrote about breaking in a new rebuilt engine. This is a high performance engine that will be installed next month. I cannot find that article. Can anyone help? It stated to run it hard for about 20 miles, then change the oil or something similar to that. Since I just finished reading all the chapters on oil, I guess I need to start with 0W20 synthetic and check the pressure by the 1000 rpm example you used. Since it holds 9 quarts experimenting is very costly. This car is not driven a lot,but fairly hard when it is. Thanks for any help.
 
Need MUCH more info. Cam and springs used? Usually you run in the cam unless the builder already did so - which I would recommend he does. The cam has to be run in with a break-in light pressure spring set if it's a flat tappet cam. The Dyno should wear-in the rings for you also. If not you HAVE TO load them up pretty good with open throttle (stay under 3500-4000 rpm) with cool down cycling for the first 2 hours. You only get ONE change to wear in the iron/moly rings - I assume you are not running chrome with the chrome specific hone. That 20 weight better be high moly high zddp conventional oil or have break-in lube in there. Dont even THINK about using passenger ILSAC GF4/5 naked in there. Have fun.
 
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Hey the facts are simple.

The rings are set in minutes at most, and the rotating assembly is either right or wrong. Running that engine at full throttle with good oil and proper coolant temps will be the BEST way to break it in if you want the best power output and lowest oil consumption.
 
Originally Posted By: ARCOgraphite
That 20 weight better be high moly high zddp conventional oil or have break-in lube in there. Dont even THINK about using passenger ILSAC GF4/5 naked in there.


As ARCO said. With that sized sump, you might be better off using a lighter HDEO, because you might get it at a reasonable price. If using a GF-4 or GF-5 oil, I'd use a ZDDP additive, at least for break in. The HDEO option tends to be a bit cheaper.
 
Thanks to all for all the info. It is going in my 65 Mustang. It is a 1993 EFI 302 HO roller motor with Comp roller cam, TrickFlow Twisted Wedge heads, 1.6 roller rockers, 75mm throttle body, 24 lb. injectors, TrickFlow intake and plenium, long tube headers, T5 trans, 9",3.92 posi rear, Melling high volume oil pump, MSD box and coil. I can give you the cam and head specs if you need them. Engine has less than 200 actual miles on it so the bottom end was left stock for the time being.
 
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Originally Posted By: 1965Mustang
Thanks to all for all the info. It is going in my 65 Mustang. It is a 1993 EFI 302 HO roller motor with Comp roller cam, TrickFlow Twisted Wedge heads, 1.6 roller rockers, 75mm throttle body, 24 lb. injectors, TrickFlow intake and plenium, long tube headers, T5 trans, 9",3.92 posi rear, Melling high volume oil pump, MSD box and coil. I can give you the cam and head specs if you need them. Engine has less than 200 actual miles on it so the bottom end was left stock for the time being.


Oh dude, that thing is MILD! Just run M1 0w40 in it.

BTW, why the HV pump and huge pan? And what intake are you running?
 
Originally Posted By: JAG
You are best off forgetting everything you read by AEHass.

I think that's a little unfair.
The basic jist of what Ali Haas says is true, namely not to run an oil heavier than necessary and since you have an oil pressure gauge you can certainly start with a 20wt oil.

Since you will likely want to change out the oil after 500 miles or so I would run the cheapest 20wt oil you can find on sale and that will likely not be a synthetic 0W-20 but rather a 5W-20 dino. During this short run interval you'll have plenty of time to make note of you oil pressure levels when the oil is fully hot and if it is more than adequate then yes you can then use a 0W-20 for next oil change.
 
I concur... JAG's comment was unfair and, unlike most of Haas' work, completely worthy of being forgotten.

I like the idea of breaking in an engine with a light oil and light exercise followed by a 500 mile oil drain. From there, go to the oil you will use and up the work level to moderate for another thousand miles followed by drive "normal" (whatever that is to you) and a 3-4K interval. Follow that by the normal interval. It's just "what I do" and not based on a lot of study. May not be right or efficient but it can't do any harm either.

Some people say an engine breaks in better on a mineral oil, citing the higher friction aids break in. I guess that implies the mineral oil is like using a "medium grit polish" to start a valve lapping job followed by finer paste and a smoother finish. I've always followed that oil axion but have never seen any scientific "proof" that it's best (but would like to see proof of something one way or another). Sounds logical but I have seen (not close up) engines broken in on synthetic and they seem to be fine.

I do know that the relationship between ring material and the type of hone used on the bores plays a part in ring seating. In those cases where a mismatch has occurred in this area, the oil plays a big part and that's were a less slippery oil helps. Anyone else used BonAmi or Comet to seat rings that just wouldn't?

I'm not following my own advice on my latest overhaul on a diesel truck. Because it has a bypass oil filtration system, I'm going to run a normal interval from day one.

These days, I'm beginning to think the "run normally from day 1" crowd is right, at least as it applies to a newly manufactured engine. I have been to a number of engine plants and watched engines being built and tested. The DMax plant in Moriane, Ohio, stands out. At the time I did my tour three years ago, literally every engine was hot tested. They said they'd been doing that since day one and I presume they still are. It's all pretty much automated. A robot cart carries the completed engines to one of a long line of dyno cells. Robots attach the engine to a dyno, a human makes a few of the hookups, it's started, warmed up for a couple of minutes, run lightly for a few and then tested at full rated power. Total time under 15 minutes. If the engine passes all it's tests, it goes into a crate. If not, it goes to a diagnostic area for repair. The above is similar to other plants, though not all of them hot test every engine.

You gotta figure that if it's OK to run a brand new engine at full power when the paint on the block is barely dry....

But I don't thing this would apply to a rebuild or a home job, because the standards of cleanliness are usually not as high as I've seen in a modern engine factory. The standards of machining may not be as good either (I've see my share of what you might call "loose tolerance" machine work). It's the built in dirt and break in materials you need to get out ASAP because it can be a killer. I know guys that will run an engine 30 minutes and change the oil and filter. It's hard to argue against that given some of the junk you see in the drain pan.
 
Caterham and Jim, my comment was no more unfair than yours and really, there are no ethics involved here. You like an article that I think has too many flaws. You have the right to say what you want about it, as do I.
 
Our cylinder kit guru at Cummins stated that if a new engine (he was talking specifically about Cummins engines) did not get up to rated power within the first 20 minutes of operation, the liners would glaze, and the rings would not break in properly. It is important to get the engine up to temperature and get to high load in order to seat the rings in their grooves and force the wear faces against the liners.

Other parts of the engine have different needs:
Hydrodynamic bearings require an oil film to work, so oil must be present at first startup. But as long as they have oil, they don't require special treatment at break-in.

Slider-follower cams shouldn't be run at low speeds for very long when they're new. Variable speed operation around 2500 rpm actually reduces contact loads between the tappets and lobes compared to idle speed, and provides more oil for lubrication.
 
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