OEM Initial engine break-in procedure.
OEM Initial engine break-in procedure.
(OP)
Greetings,
I would like to know the initial engine break-in procedure used by major automobile manufacturers or their suppliers.
I am intimately aware of the procedures employed by race and performance engine builders. What I am looking for is what do the big guys (Toyota, GM, Honda etc) do to break-in an engine before it leaves the factory.
Any help would be appreciated in this matter
Regards,
Bryan Carter
PS – I know what the owner's manual says...
I would like to know the initial engine break-in procedure used by major automobile manufacturers or their suppliers.
I am intimately aware of the procedures employed by race and performance engine builders. What I am looking for is what do the big guys (Toyota, GM, Honda etc) do to break-in an engine before it leaves the factory.
Any help would be appreciated in this matter
Regards,
Bryan Carter
PS – I know what the owner's manual says...





RE: OEM Initial engine break-in procedure.
These short start-up runs don't even come close to qualifying as a 'break-in' period. So far as I know (atleast with N.A. cars) the break-in is left to the end user. AKA- the customer.
*Without data, you're just another person with an opinion.*
Hydroformer
RE: OEM Initial engine break-in procedure.
As hydroformer says, it isn't really a break-in.
Cheers
Greg Locock
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.
RE: OEM Initial engine break-in procedure.
This is on par with what I expected. I had hoped for something a little more comprehensive on the part of the factory. Oh well.
Regards
RE: OEM Initial engine break-in procedure.
When Rover first started to commit technical suicide by going into partnership with Honda, they sent us over some prototypes.
We phoned them up, asking what the running-in procedure was. Hasty conference at the other end of the phone, and the result was "Oh, we just let them idle for a minute before loading them up".
With the exception of scuffing the cylinder liners it's a bit hard to see what running-in really accomplishes, and I would have thought that scuffing was best accomplished at variable loads and speeds.
That being said, where I work, we run every engine on the dyno before it goes into the car. I'm not sure for how much longer we'll do that.
Cheers
Greg Locock
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.
RE: OEM Initial engine break-in procedure.
seems like a few diesel oems do a "hot check" where they run the engines up to thermostat temp and check for leaks, odd noises, etc, then confirm/set the power output.
at least one major automotive oem in the US "cold checks" engines by motoring them and measures friction as a way of telling whether everything got put in the right holes.
RE: OEM Initial engine break-in procedure.
Normal practice is to start engine, confirm oil pressure and rev to 2000 for 1/2 an hour to break in the camshaft and lifters. Then drive with varying load and revs. This is what i was taught years ago. The new engine is LPG only, so i asked around and most answered load it up straight away to seat the rings!!
What has myself confused is, whats the difference with a factory built engine that doesnt need the cam run in, and an aftermarket cam needing to be run in????
Ken
RE: OEM Initial engine break-in procedure.
Regards
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RE: OEM Initial engine break-in procedure.
RE: OEM Initial engine break-in procedure.
Rod
RE: OEM Initial engine break-in procedure.
An initial dyno and motoring dyno is performed at the OEM stage, but this generally lasts no more than a couple of minutes at most. At a major US OEM engine assembly plant in the early 70’s, I saw a carousel dyno, where 8 engines are worked at once, run on a dry gas (this one used natural gas) while oil leaks, oil pressure, and initial run in were performed. As each engine was completed, it was removed and another installed.
Oil leaks can be checked by vacuum/pressure drop with 5 psig air pressure, oil pressure can be checked statically too. Originally, with manually adjustable ignition timing, that was performed at this stage, along with engine balance.
If the engine is built right and the human factor removed (the dreaded “Monday morning, and Friday afternoon” engine scenario) there is no reason the engine should be almost ready the moment it is installed. A site visit with a major piston ring manufacturer will show the research being done to allow rings to seal almost immediately, providing the proper cylinder wall finish is provided.
As a real life example: In the 60’s, where each engine was assembled by hand, with individual build up stations, and 60’s metallurgy, it was expected for an engine to last less than 100,000 miles, frequently with at least one valve refresher during that period. When emission restrictions became enforceable, the engine manufacturers had to tighten up the production processes and refine the build procedures. With today’s emission mileage warranty requirements, it is rare to see an engine ready for the scrap heap in less than 100,000 miles, with 200,000 not uncommon. Imagine the warranty costs if an OEM had to rebuild engines routinely at 60,000 miles. We still see smokers at less mileage than that, but a simple check of the required routine service shows that little attention has been paid. By simple observation, it appears that one manufacturer in particular seems to have a problem with smoker engines in vehicles approaching 5 years in age (I would guess about 75,000 miles).
Franz
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RE: OEM Initial engine break-in procedure.
About the aftermarket cams, I suspect they are not micro finished like the better OE cams thus the need for extended breakin. My experience with aftermarket producers is they do not have the same level of engineering, QA or production technology as OE. I know that is a gross over-generalization and there are exceptions but the general poor quality in the aftermarket is astounding.
RE: OEM Initial engine break-in procedure.
Rod
RE: OEM Initial engine break-in procedure.
Regards
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RE: OEM Initial engine break-in procedure.
RE: OEM Initial engine break-in procedure.
i think you hit the nail on the head with the higher spring pressures and more aggressive lifts!. now what is the best way to seat the rings? OEM dont seem to worry about this, so my guess is modern manufacturing is precise enough that a good seal is almost instant.
Ken
RE: OEM Initial engine break-in procedure.
RE: OEM Initial engine break-in procedure.
RE: OEM Initial engine break-in procedure.
RE: OEM Initial engine break-in procedure.
RE: OEM Initial engine break-in procedure.
RE: OEM Initial engine break-in procedure.
I am sure 2000 rpm is not appropriate for all engines. It is the benchmark rpm for typical American V8 car engines.
I doubt there is much demand for hotrod cams for big diesels.
It might be better to say run at 2 to 3 times standard idle with no load to break in the cam, then short bursts from idle to half maximum speed, then progressively increasing rpm for short duration full load runs with short rests between to stop localised overheating. The indicator of how long this takes will be the reduction in blow by.
It really does depend largely on many factors like compression ratio, ring materials, ring dimensions, bore accuracy, bore surface finish, bore material, bore stability, piston speed, cylinder pressure, piston to bore clearance, ring grove clearance etc etc
Regards
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RE: OEM Initial engine break-in procedure.
Pat, i agree with your comment on having more oil flying around at higher than idle RPM.
Ken
RE: OEM Initial engine break-in procedure.
My offhand thoughts behind why 2000 or a little higher is used for performance cams is to reduce the loading as the follower goes over the nose. You get to use the cam's negative acceleration to your benefit this time - instead of worrying about floating the rest of the valvetrain clear of all contact with the cam you're using a very mild case of this to overcome just a portion of the spring load. Valve train inertia will use up more of the spring force at any given position if you let the cam profile accelerate linearly out from under the follower faster, and more rpm helps this. Perhaps 2000 rpm or so provides a good balance between decreased loads over the nose and increased loads on the opening flank. And/or maybe it represents a good compromise between minimizing camshaft lobe wear and wear elsewhere within the engine (bearings, rings, journals, etc.).
If I'm not mistaken, the recommendation for breaking in double and triple spring cams is to use only one of the springs; obviously another means of reducing loads over the nose.
Norm
RE: OEM Initial engine break-in procedure.
2004-01-2917 (SP-1894) "Effect of Break-In and Operating Conditions on Piston Ring and Cylinder Bore Wear in Spark-Ignition Engines"
RE: OEM Initial engine break-in procedure.
RE: OEM Initial engine break-in procedure.
What, no changes at the ring/groove interfaces?
Did you mean sealing gas in, or oil out, or both? Do the peaks on a plateau-honed cylinder liner really have any lasting effect on sealing? Does the answer depend on what you meant by "sealing?" Is gas-sealing so detrimentally affected by the presence of "initial peaks" on the liner that a customer would notice any sort of performance degradation while waiting for them to wear off?
RE: OEM Initial engine break-in procedure.
As demonstrated above I'm a bit of an agnostic when it comes to running in, but, I am frequently told that the fuel consumption in cars improves rapidly over the first few thousand kilometres.
So, what's wearing in? Maybe it's the trans or the diff?
Cheers
Greg Locock
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.
RE: OEM Initial engine break-in procedure.
Ring tension can be reduced by the rings taking set in the compressed position, wear in the bore, wear in the rings and wear in the ring groves.
Gear boxes and final drive gears probably contribute more in my opinion, especially crown wheel and pinion.
On my engines, the blow by reduces considerably within a minute or so of power runs.
Regards
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RE: OEM Initial engine break-in procedure.
For blow by to reduce, something must change somwhere, and the ring/cylinder wall seal and to a minor extent ring/ring groove is it.
I would say its a form of lapping, so the parts mate together to live a long and happy life!
Ken
RE: OEM Initial engine break-in procedure.
Rod
RE: OEM Initial engine break-in procedure.
Are you sure that reductions in mechanical friction are to blame (if you halved mechanical friction, what fuel econ benefit would you expect to see)? Could the performance of the fuel injectors, or some other part of the combustion system, be changing as well?
All of the "soft" bearings within the engine will change shape slightly during this initial period, and the bearing clearances will increase (some more than others) - this may account for a fraction of the friction reduction (hydrodynamic rather than mechanical).
blow by reduces considerably within a minute or so of power runs
By blow-by, do you mean the flow rate of all gases from the crankcase, or just the visible portion (many people refer only to the visible portion)?
When you say power runs, are you refering to only the initial few minutes that the engine runs near full power output, or every subsequent run at high power as well? Blow-by should drop temporarily every time the engine returns from high power to a lower setting, due to gap shrinkage (ring thermal expansion relative to bore) and piston clearance reduction (piston expansion). It should "grow back" as the piston and rings cool. Is this consistent with what you've observed, or are you talking about a permanant change?
Ring tension can be reduced by:
1) rings taking set in the compressed position people often refer to this happening, but at Tmax<250degC I can't see much tempering happening in steel rings. I've also never noticed a significant change in tension between new and slightly-used rings.
2) wear in the bore yes, this does happen, but in a 100mm bore you'd need ~0.75mm of wear (diametral) to give you a ~5% change in ring tension - so I'm guessing this effect is pretty slight
3) wear in the rings ignoring the change in cross-section, you'd again need about 0.75mm of wear to get 5% change in tension (with that much wear, you couldn't ignore the change in x-sec, but the real initial wear is more like 0.005mm and is limited to a portion of the ring face)
wear in the ring grooves Sorry, I have no idea whatsoever how groove wear can affect ring fitted tension. Wouldn't the ring fitted tension be the same even if the piston was entirely absent, and the ring was just sitting (properly oriented) by itself in the bore?
I'll take a leak down after assembly, after initial warm up and, after the dyno runs. I'll post them here later, maybe in a couple weeks. Do you lube the rings or bore during assembly (might make a big difference in the results)? I know that many people "clock" the rings in the bore when they're building an engine, believing that this reduces blow-by. I would agree that this may slightly improve sealing on initial startup, but after that the ring gaps go wherever they please, negating the effect. Anyone have any comments on that? Is clocking the gaps important for initial startup, because compression would otherwise be too low? Is the lack of a somewhat-evenly-spread oil film on the cylinder wall the missing ingredient for initial compression?
RE: OEM Initial engine break-in procedure.
In my observations, the rings fit closer to the piston, or hang further out of the groves with the piston removed after the engine has done a few passes. The rings are easier to compress and refit to the bores as well on a slightly used engine.
Re grove wear vs tension. OK I was grasping at straws there.
No matter what the reason, engines do turn easier by hand after they have been run.
Regards
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RE: OEM Initial engine break-in procedure.
...Or is it the case that after every power run, you have a certain amount of visible mixture coming from the crankcase, and as the engine continues to run and cool the visible fraction declines, but then at the end of the next power run the cycle repeats?
I would also note that visible blow-by may not be a useful indicator of "ring seal" at all, since it doesn't necessarily correlate to the amount of gas passing the rings. In some select situations the two can be related (if, for example, the concentration and size distribution of oil droplets in the crankcase were relatively constant, and breather performance was not influenced by total blow-by volume, and piston temperature was constant, and cooling jet flow was constant, then I would expect that more gas flow means more visible stuff, and vice-versa. In other cases, more gas flow means less opportunity for droplets to clump together into a visible size. It can also happen that visible CCV constituents are most closely related to piston temperature and cooling jet flow, with next-to-no relationship to blow-by gas flow. Changing ring-groove clearances, perhaps due to wear, can also affect the size of droplets in the blow-by stream, making them more or less visible, without having a big effect on total gas flow, as can carbon and "gunk" accumulation at key locations on the pistons).
In any case, it has been my experience that blow-by (total, measured with a flow meter in a big duct) and oil consumption of an engine vary somewhat during the first 50 hours of running (or so), then tend to level out for a while, before heading off in whatever direction they eventually drift in (usually for the worse). There is usually an initial period of "rapid" change (although the magnitude of the change is generally pretty small compared to the magnitude of the parameters in question - 10% or less), after which changes happen at a much slower rate. Running at higher cylinder pressures would tend to make the "rapid change" period shorter, by a bit, than it would be if lighter load was used. There is a measurable change in bore surface finish, and the peaks do get smoother. The tops of the "plateaus" become more like plateaus and less like pincushions. I doubt that gas flow past the ring faces changes much as a result of these bore surface finish changes - the peaks aren't THAT big, and they should be pretty "mooshy" when the gas-loaded ring rubs across them. The ring and groove flanks both become smoother during this period as well, and regions where loads are concentrated tend to get "rubbed down" a bit - I would tend to attribute gas sealing improvements to better ring-groove contact and reduced groove runout. Then there's the accumulation of oil in the inter-ring volumes and in the backs of the grooves, which also likely helps to reduce gas flow past the rings.
RE: OEM Initial engine break-in procedure.
My method is purely subjective using the only tools I have for this, which are my eyes.
I have no means to measure cylinder pressures, nor internal temperatures. I do monitor oil and coolant temperatures to make sure they are "normal" but normal probably covers 85 to 110 deg C.
for coolant and 90 to 120 deg C for oil.
Regards
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RE: OEM Initial engine break-in procedure.
At one time in my life I succombed to the 'drag racer mentality' and pushed the pistons in dry or on one particular 394 Hemi, used a fine 'jewelers rouge'...not these days. Now I liberally oil the cylinder AND the piston/rings before assembly. The new piston never runs on a dry cylinder and I have seen no unusual anything in the last twenty or thirty engines save a broken ring on a street Ford Fiesta 15 years ago.
[Another, sorta related question to explore...Why do I still run my engines in on paraffin based lube instead of just going to synthetic to start? The OEM's that use syn don't bother?]
Firstly (or lastly), ring tension is ring tension until the fire is lit...then, especially on Dykes or drilled pistons, the tension increases, a lot.
Secondly(or firstly) from my experience, when the ring groves begin to exceed a certain wear limit, expecially the top ring, blowby increases dramatically. I see it as a result of "ring flutter" whereby the ring no longer makes a square, perpendicular fit to the cyl. I come by this opinion from some tests I was privy to on some 'dykes ringed' versus 1/16" versus 1mm versus zero gap top ringed Cosworth pistons in a Lotus Twincam 1594cc engine many years ago (sorry, I don't recall the specifics of each type. I do recall that the Dykes and 1mm were about the same.) I have a set of JE's with 1mm's (for that 10,000rpm "one of these days" engine) and a set of Venolia's with Deves 1/16" for the vintage engine (run in quickly and last a long time). One BIG difference in ring type is overall bore clearance...the smaller the ring the more critical the fit.
Sorry this post got a little longer than I had intended.
Rod
RE: OEM Initial engine break-in procedure.
But, I think it might be a bit special since our darling customers tend to skip or delay the first (1000 mile) service, so it has to stand up to regular use as well.
Cheers
Greg Locock
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.
RE: OEM Initial engine break-in procedure.
RE: OEM Initial engine break-in procedure.
Rod
RE: OEM Initial engine break-in procedure.
Rod
RE: OEM Initial engine break-in procedure.
Cheers
Greg Locock
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.
RE: OEM Initial engine break-in procedure.
when I had responsibility for engine tear-downs at Chrysler engine development, we often disassembled new production engines to use as bases for test engine build-ups.
Zer-mile engines that had only seen the engine plant hot-test run of 30 seconds or so.
I was horrified to see the amount of swarf that was left in the oilpan - a mixture of metal shavings, core sand, and just plain dirt.
Since that time I have immediately changed the oil and filter upon getting home with any new car, truck or motorcycle.
-----------
And on a related note, I have observed that vehicles that had been used extensively for passby noise testing had much lower oil consumption than one might have expected. I attribute this to the brief high-rpm/light-load operation they saw in the noise tests.
RE: OEM Initial engine break-in procedure.
Leak down after about a minute of turnover on the starter motor, sans sparkplugs, (oil pressure was 35psi) gave about 15%.
Leak down after a couple minutes to set ign. timing then about 15 minutes of high idle > 2000 rpm (oil press 95 psi) to warm up stuff (set valve lash warm) and another 5 minutes of 1500 to 6000 full throttle "pops" then to a low idle (barely) for a minute and shutdown...< 5% ! This indicates that, along with the fact torque to turn it over (sans plugs) is 10 ft/lb to break and <5 ft/lb to keep it rotating !!!!!!!
Man, I'm hoping for good things here. Leak down should drop to <3% and cranking pressure will probably still be in the mid 260 psi range, even with the 310 cam (CR is 13.87:1).
Can't get dyno time until next week (short notice, I did not think I could get this much done this soon)...nothing a handfull of Excedrin extra strength won't cure.
Rod
RE: OEM Initial engine break-in procedure.
Soooo---it sure did not take long to run in, did it?
Oh yeah, I changed the oil from Castrol 20W-50 to Mobil 1 after the dyno runs. Surprising how much stuff comes out in such a short time even though I treat engine building like surgery!
Rod
RE: OEM Initial engine break-in procedure.
The starter was engaged (sparks flying) and baby takes first breath. Run time was under 2 minutes and involved a prelube run up. I think there was some sort trash rinse before the pan was installed but a lot of small metal trash, manufacturing residues, core sand and misc FOD. I visited a northstar plant recently and it was clean enough to eat off the floor let alone the engine assembly.