Proper engine break-in technique
 

This is probably useful information since some of these builds no doubt cost a small fortune.

i followed FM guideline and am going to break in by driving 200 miles under varying yet high load while keeping out of boost. proper ring seat needs high load, but the added boost fro the turbo can be excessive and leed to improper seating of the rings.

this method appears to be debatable. what is the ideal method for breaking in a turboed miata engine?

thread jacking f***ers , you know who you are.

I think that sounds great.

http://www.mototuneusa.com/break_in_secrets.htm

Thats a great article, similar to the method FM has. Vary the load, vary the throttle, no highway driving, dont be a pussy.

If you already have a good base tune. Run it once to full temp while still on stands, check for leaks, change oil, then put it on the road and beat the fuck out of it. Lots of high rpm and then let out the throttle to let it engine break and pull mega vacuum. This is how I've done it for years. I get perfect ring seal every time.

My breakin procedure was:

1) start it in the garage, check everything for 5 minutes.
2) drive around the block for 5 minutes, pull back into garage, check everything again.
3) drive around for 30 miles staying out of boost, doing the high-vacuum coast down thing.
4) change oil.
5) drive around another 270 miles at 7 psi.
6) 30 pulls on the dyno at up to 15 psi, added about 30 miles to the odometer doing this.
7) Laguna Seca. :)

--Ian

My break-in
1) idle for about 3-minutes on shitty Castrol GTX
2) cut cheapo filter to check for metal, smile at results, put a wix on
3) 5-7 runs of 4500rpm-1000rpm overrun
4) change oil and look for metal
5) road tune at 14psi
6) taking about 100-miles until 7000rpm
7) at 500 miles put in synthetic Rotalla, tune that bitch, track it, get bitches, make money

It appears that I may have made a mistake by using synthetic oil fromt he start. I wonder if this causes the ring seating process to take longer?

Break in for the past 2 motors I built:

1) Warm up, change oil and check filter
2) Disconnect wastegate, several WOT runs to 6k, then coast to 1k in second or third.
3) Change oil, check and change filter.
4) Reconnect wastegate, turn boost up and tune.

The break in happens in the first 20 or so minutes of you driving, after that, if shit is going to break, it *usually* would have done so. What I was referring to in the other thread was the 200 miles with no boost, there is no reason to do that. The rings need to seat, then after that, it is all over. Bearings don't need a wear in period.

Well then, I'm at 100 miles. When I get back from Indianapolis I will change the oil and start tuning boost. Should I run the boost in stages, i.e. run at 12psi for a while, then 18psi, then 22psi. Or just tune for 22psi and be happy? Honestly, if rings seat in the first 20 minutes, then I was not hard enough on the engine in the first 20 min. I was waiting to see/hear if anything was going to break while I was driving around during the first 20 min.

That is the mentality that most people have, but think of it like this. If something is going to break, it's going to break either way. You might prolong it by babying the motor, but the first time you go WOT, if it isn't put together right, you'll know :).

Most modern cars have synthetic put in from the factory. So even though that is a "myth", it's not true.

Good thread! I think this will be helpful to a lot of people.

Any break-in procedure should use graduated engine speed steps. You want to see high load and high vacuum, but set an rpm ramp up schedule. For the bikes my brother and I have always done something like 50% redline for 50 miles, then an additional 25% for another 25 miles.

It was helpful to me. I'm going to be breaking mine in soon

Explain to me why this matters. After the motor is warmed up, does the motor care what rpm its at? What empirical evidence do you have that shows that you need to graduate the rpms?

To explain my point using your numbers Go. Say you stay at 50% throttle for 50mi. Assume that you have a redline of 10k, not unusual for a bike, and you cruise at 50mph at a constant rate of 5k rpm. You would complete that graduated step in 1hr. In that time your engine would have made 300,000 revolutions. If you think that the rings have not seated well into that count then you are on crack.

I've heard the "step up the RPM" thing before too, but once again, after 20 miles (probably less actually) the rings are seated. The bearings don't need that kind of special treatment either, they are floating on a film of oil and don't need a 'break in' at all, aside from warming up the car the first time to ensure the clearances are correct.

Well, hopefully you ensured your bearing clearances well before first start, or assembly for that matter :P

Also, I disagree that things don't continue to break in after the first like 5min. Although, I would rather use the term "wear in". Sure your motor will continue to loosen up, but the initial ring seal is achieved mostly during initial warm up, then you get it on the road and beat it (with a good tune) with high rpm/very high vacuum to get maximum seal.

You can verify this simply with a compression tester. The last motor I rebuilt, in the miata I sold to nate the snake, I ran a compression test on it before I ever even started it for the first time while verifying that the tbelt was on properly. I achieved 150 or 160 (cant remembet) on all cylinders with no deviation before it was ever even started.

Indeed, but say you assembled your engine in your unheated garage, in the winter, warming the car up for the first time could actually bring things out of spec.

Just look at F1 motors, they run clearances to tight that they have to heat the motor up before they start it or they'll spin bearings.

Are you kidding? Engine speed kills everything. You're talking about flexing non-seated rings at twice the frequency. Simple dynamics, you're increasing the cycle of forces for a set amount of time on a parts that have not completely mated.

No, I don't have any empirical evidence, and it's only theory coupled with common sense, so feel free to disprove it.

I will admit that one good case for going across the whole rev range is to avoid ring ledges in the cylinder from forming. But that won't happen in 50 miles, and I still recommend varying the rpms, a lot, to aid that. Gradually stepping it up will see slightly more rod stretch and form a nice, smooth ramp at the top and bottom of the stroke as opposed to a ledge. I definitely don't recommend sitting at any given rpm, and it's better to really make it an analog increase, not a step-wise one as suggested by the manufacturer.

Regardless I think we can both agree that the more important aspect of a break in is load. BMEP is what really determines how well the rings seat. This can easily be achieved within a smaller portion of the rev range since peak cylinder pressures remain the same, only with lower frequency. Once the ridges have begun to wear down it would be prudent to increase that frequency, and prepare the motor for it's intended operation.


EDIT: A few other posts were made while writing...I definitely don't recommend just sitting on the highway at 5K rpm for an hour. That would be the stupidest possible way to break-in a motor. But if you seriously thing that engine speed doesn't have a negative impact on part wear you my friend are the one using the crack. There is absolutely no reason to "rev it up" from the get go. Yes, vary rpm, yes, increase rpm, yes, you need to be using the whole rev range in less than 100 miles, but have you done any real research on just how many revolutions it takes to seat the rings? I've seen UOAs from 250mile break ins that were still showing cylinder wall material removal.

I'm not kidding at all, the rings will not flex more at first start than they will during the duration of their lifetime. The purpose of getting high RPM soon and quickly is because the principle that ring seal works on is applying gas pressure to the top and back of the ring through load. The more load the more pressure.

Point taken, things will wear for sure (otherwise engines would last forever :) ). The point I try to get across though is that after that initial warmup and seating period, its either going to work or it isn't.

Agreed.

What's the correlation between load and rpm?

Go, the entire fucking point of an engine break in is you want the fucking rings to wear.... So yes, I do think engine speed impacts wear, but not negatively.

ve

Right, and that's it...and it varies maybe 5% across the rpm band we're discussing. Therefore you still have sufficient BMEP to do the job. You kept stating load load load. I agree. Full load is available at any rpm.

Now consider how engine speed does affect the rings as they glide (or are dragged) across the cylinder walls. How does the friction vary? Wouldn't you want to condition the rings, and smooth the ridges for every range of engine speed. And my arguement for starting at normal speed ranges is that this is where the motor will spend most of it's life unless it's a race motor.

Now consider harmonics and how much they will play into proper piston ring seating. Where do the uglier vibrations come out? Do we even know? We can safely assume they're higher up the rev range.

Now consider lubrication. When new, the grooves are still deep, and the rings aren't yet functioning in their "hydroplaning" fashion, but skipping across the tops of the ridges. Yes, you want it to wear, but without work hardening. If you do work harden the tops of those ridges you will actually work against the wear you desire, and likely damage the rings.

Again, all speculation, and you've apparently had success (and not puked any rings). But it's something to consider, and I don't see a downside to prudence in this case.

I wish we still had the chat, waiting for your replies is killing me....

No shit. Fucking firefox crashed while typing that last post.

Fuck it, im going to lunch. Go break in ur ringz!!!!

I have found a continuing theme where new "performance oriented" rings (material used) seem to seat very rapidly. Some suggest that the rings are practically seat before the first start simply from rotating the engine to align the crank and cams. Others say 5 min and some say up to 50 miles of driving. The real debate seams to arise with level of load that should be place don the motor. I would agree with high load with no turbo i.e. keep out of boost with a turbo engine.

Maybe a better question is: How much pressure does it take to seat a ring for a given initial gap. At some point a threshold will be crossed where you are just creating more wear on the rings and cylinder walls. This is why a turbo engines running high boost are not expected to last as long as an NA version of the same engine.

This pretty much summed up what I was going to type.

While I respect the theory behind what you propose, in the real world I've yet to encounter a problem with my method of breaking a motor in.

In reality there isn't much difference between our methods. Not using enough load will do much more harm for your break-in than any level of rpms, save lugging the motor.

I'm simply saying don't go straight to redline.

And djp:

The guideline for wear I've always heard is 50-100 miles for the rings to finish seating, although they continue the process for another 1000 miles or so to some extent.

The most important part of this all is to vary load, to both extremes, cover the rpm range withing that period, and then drive it as you intend.

I guess that is the question, but arguably one that can only be answered by trial and measurement.

It looks like I might end up putting together 2 engines this summer. If that happens, I'll have to break them in differently. One will be my low comp high-boost monster, which I'm planning on breaking in around 5psi and 6k-1k overrun. The other will probably be a ~9:1 1.8l block. If I can, I'll try to break that one in using your method and then compare results.

edit: Although this won't necessarily be apples to apples, I can compare the resulting compression #s against the factory spec, which will tell how well the rings seated in.

This.

Since some of my background is in piston engined aircraft, I knew that manufacturers were specific about the need for high load and varying engine speeds to be applied to an engine during break-in (run-in). So, I did some digging. The specific procedures were a bit dry, but this overview from Lycoming is insightful. http://www.factoryengines.com/docs/H...20Break-In.pdf

One of the specifics that was common to both Continental and Lycoming's break-in procedures was the bold print insistence that the engines not be run in a high vacuum condition during initial break-in. It was stated that high vacuum conditions promoted ring flutter which stressed the rings and could cause failure. I knew you were supposed to descend gradually without cutting power much after a break-in flight, but have not heard of ring flutter being the reason until now.

Please delete this double post.

When I worked for Griggs racing we would fill the engine with GTX and run 3 laps then pit and change to synthetic.

After reading all these break-in methods I think my new motor is ready for its street tune ;D

250miles so far

Two major considerations for break in.
Cylinders- Cylinder prep and ring pack choice need to be considered. Using high precision rings with well prep'd straight cylinders should be "broke in" by the time the motor is fully assembled. Going back a few decades. Cast rings adn cylinders you could sharp[en your fingernails on took a bit of low load "break-in" to wear in the ring to the cylinder.

Camshafts - Since most here likely use precision rings, the break-in would most likely be about the camshafts. This will vary with the cam type. If not roller cams they most certainly need to wear in before they are exposed to high RPM. (Many a bike cam was severely damaged due to this). V8 cams need the 20 minute run then a 24 cool down to work harden the cam. They run 2k on those for proper oiling during the run. Sometimes a light spring is ran for breakin then heavier springs that belong in the motor. Point is with proper cylinder prep rings really dont need a breakin. Other parts can though.

My builder told me that he burnished the cylinder walls and there was no real break-in other than pulling some vaccum with some RPM. He told me to drive it to the dyno, tune it and change the oil, then race it the next day...and after a few days at the track it will make about 20% more on the dyno than the first time you tuned it.

They guy has a pretty solid record with FI engines in general, everyone around here uses him.

last motor i built was a 408 ford small block and i put new pistons and rings in let it warm up then cool down changed the oil and stuck it on the dyno. We did one motor pass to make sure timing and a/f was correct which it was then we did about 4 nitrous pulls starting with a 150 shot ending with a 300 shot. motor ran perfect no leakdown and lasted longer then it ever should have with a stock 95 f150 block making over 700hp.
everyone told me i was an idiot for not breaking it in but i have witnessed that the rings continue to rotate around on the piston throughout the engines life so to think that the rings are going to wear into the slight groves that might be in the cylinder walls is incorrect.
our cam had been in the engine already but in the event that the valve train was new a few heat cycles and some time spent holding it at around 2k-2500 rpms would prolly have been a good idea. im not sure if this applies to miata cams though since they ride in the head with no bearings and there are no rockers. i would still do it though its not going to hurt, and heat cycling new springs is important in my opinion.

The first heat cycle is key to the cams. Only takes once to work harden it. Many of us have broken the rules and gotten lucky. Sucks to be the unlucky one. As for Miata cams. Old pushrod v8s have higher stresses (stock). V8s have a much greater leverage disadvantage and much more weigh to manage. I have not done any Miatas so this is just an opinion, however I would expect to break these in as I would a bike. Managing RPM as the motor wears in. I have replaced more than one rocker assembly on a bike for this reason. btw - avoiding a set RPM on bikes is also for the cam to rocker pad/ bucket breakin.

I envy the 408. The terror I could have caused in high school with my 68 fastback.

Corky's Procedure for breaking in a motor:
http://www.bellengineering.net/artic...rticles_id=263

Stephanie

breakin
 

rings wont seat properly with synthetic.

proper oil break in:

use any regular cheap oil, start engine, warm it up, go rip on it, varying the rpms, doing lots of vacuum coasting from high to low rpm's. do this for about 30 miles.
go home, change oil, again put regular cheap oil.

drive it for another 500-1000 miles, and then change over to synthetic.

Thank you. I have 2 new items that are going to be a first start. I did the 99 motor and bought the MSPNP Pro for the 96/97 version 3 they just released. I have to get the new motor to idle first but need to set the MS for base timing. I converted to 36-2 trigger wheel. I am hoping i can get the rings to seat on the bases tune.

If not, do I use the stock ecu? I have eliminated 02, EGR, MAF all not going to be used with MS and stock trigger wheel. It's seems I have to get the MS to run and break-in the motor.