Engine Break In - Freshly Rebuilt 3.3
 

I know this topic has been discussed ad nauseam but I’m trying to reconcile two, what appear to be contradictory steps in the engine break in process. I’m hoping to fire things up (not in the manner of Mark, mind you) this Friday afternoon or Saturday morning and, assuming I haven’t made some catastrophic assembly mistake, get my car back on the road.

I’ve already confirmed oil circulation and will do the same for pressure (as best I can by way of engine-cranking only) prior to the first start. I’m going to power up the fuel pumps and check fuel pressure this evening. Of course I’ll be watching for oil and fuel leaks during these processes. If things check out I’m (with more than a bit of trepidation, mind you) going to go for it.

But first …

… there’s the requirement of bringing the engine up to 2000 RPM as soon as it starts and keeping it there for 20 minutes in order to obtain the proper relationship between the rocker arms and camshafts.

Fair enough …

… except that we also have the start-the-ring-seating-immediately requirement which, according to many, is an absolutely critical part of both engine performance and longevity.

At this point, I’m planning on doing the 20 minute cam/rocker break in, then getting the car out on the highway for some acceleration/deceleration runs, all while keeping my fingers crossed that I haven’t crossed some (black) magical line-in-the-sand during those initial 20 minutes of running.

Thoughts (clean, appropriate and on-topic only please, Ronnie) and input welcome.

Norm, good luck with your non-Mark-style, engine fire-up! :D

I guess I can't answer your 20m/2000rpm 'v' ring seating because I was taught long ago, by a local engine builder that I admire & respect, that the 20 minutes at 2K RPM is bumpkis, so I don't do that step . . .

Also, is asking me to keep it "clean, appropriate, and on topic" code for "go ape-shat wild in this thread, please"?!?!?! :)

Knock yourself out, Pal.

We were always taught not to hold the engine at a constant RPM. Accelerate up through the gears getting to 4k or 5k RPM in a smooth progressive deliberate pace and backing off the throttle at different speeds as you go up through the gears. I have heard of rings not seating due to babying a new engine. I will be interested to see what others recommendations and experience with engine break-in is.

Norm, can you give some details on you engine build. I remember that you changed direction in your build plans.

Rahl

i am always curious about engine breakin. i did some reading about flat 6 airplane engine breakin a long time ago, just curious what you have to say about it.
dont worry, i have no opinion, just taking in others

I still do the 20 minutes at 2000 RPM on the classic air cooled 911 engine. I don't know what "proper relationship" means, but here is the engineering behind it.

Back in the day, before modern coated bearings and roller valve trains, it was shown via testing that low mile bearing scuffing and cam lobe wear were reduced if the engine was brought up to a high enough speed for the first 20 minutes to ensure plenty of oil pressure and oil volume to the bearings and valvetrain. This allows any high spots or minor surface roughness to be polished off without any localized heating and/or excessive metal to metal contact due to inadequate oil pressure or volume. That's all it is. It neither helps nor harms piston ring seating. That takes place over a few hundred miles, and running at a constant RPM is not good because you want the rings to wiggle around in the grooves.

Thanks, Speedy. Because brevity in the written work is not one of my strong suites, "proper relationship" was intended to convey the more eloquent description below...

... bringing the engine "up to a high enough speed for the first 20 minutes to ensure plenty of oil pressure and oil volume to the bearings and valvetrain. This allows any high spots or minor surface roughness to be polished off without any localized heating and/or excessive metal to metal contact due to inadequate oil pressure or volume. That's all it is. It neither helps nor harms piston ring seating. That takes place over a few hundred miles, and running at a constant RPM is not good because you want the rings to wiggle around in the grooves."

Breakin Oil is also an important consideration when breaking a motor in.
As well as changing the oil filter right after the initial 20 minute breakin.

There you go.. do the 20 minute non synthetic oil break in your new cams and rockers routine and then take it out and accelerate to around 5000 rpms around 10 times while trying to keep boost from going over .5 to .6 bar and decelerate closed throttle each time to seat the rings.

After that change the oil and filter using non synthetic oil again and go from there.
I like to change the oil and filter again after 500-700 miles and switch to synthetic 20w-50 at that point and use full boost and a 6500 red line when wanted.

The funny thing about this topic is that there are so many engine break-in methods out there, and each on is considered "the best" by the people who use them (including me :)), and the differences are often on opposite ends of the scale from one another. You see the exact same thing in aviation, BTW.

In my opinion, the best possible way to break an engine in is on a dyno - nothing compares to having such a controlled environment as that to work in - but that won't be an option for most people.

Regardless, here is my simple procedure (learned from an accomplished motorcycle engine builder in my area, and from aviation mechanics I know personally).

1) Three stand still heat cycles - combination of throttle blipping & idling around 1K rpm . . . do this until the oil temp comes up, shut the engine off, allow to cool somewhat, and repeat. Listening for troubling noises and checking for leaks done here, buttofcourse.

2) Lowish RPM run through the gears (either on the dyno or on the track/road) - listen for noises and check for leaks (after shutdown).

3) Full throttle runs after that - repeated bursts of full throttle/full engine RPM - again listening for noises, checking for leaks, and observing AFRs (adjusting them accordingly). The rings will typically seat during the first full throttle session unless there are problems (I've seen evidence of this on the dyno). For obvious reasons, this step is much easier to do on a dyno or track.

- First oil change done after a couple hours of operation (around 500 miles).
- Valve lash check done after several more hours of operation (1500-2000 miles).

Is the rationale for keeping the boost low: to minimize pressure stabilization of the rings in their grooves due to boost pressing the rings downward?

I babied mine the first 500 miles and the rings settled just fine.

No blowby at all.

But, I put WD-40 on the cylinder walls, not engine oil.

Getting closer. We'll engine dyno mine to tune and break in, then will go for a 400 mile drive on some very, very twist roads with massive elevation change... From sea level to 4000 ft. That'll do. ��

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Nice loop!