[HPA Q&A] Engine break-in myths dispelled | Performance Engine Building

[HPA Q&A] Engine break-in myths dispelled | Performance Engine Building

– Naden has asked, what’s the proper way to break in a freshly built engine and what type of oil should be used for that period? Again this is an area where there’s a huge amount of confusion and a huge amount of misinformation. For this reason we actually have included a module in both our practical and our fundamentals course on engine break in. And it’s a process that I’ve sort of gone through and developed in my own career. I’ve got a process that works exceptionally well and as with most engine builders I tend to be a little bit superstitious, once I’ve found something that works, I stick to it, and I don’t vary. The important part about engine break in first and foremost is understanding what we’re actually trying to do. And this is where a lot of the misinformation comes from. A lot of people think that we are trying to bed in the bearings or the crankshaft, and that’s just not the case. If we ever end up with metal to metal contact between the bearings in the crankshaft journals, we’re going to end up instantly causing damage, and once that occurs, no amount of gently running is going to help the situation. We’re going to end up with damage that needs to be fixed. The main area that we are trying to deal with during engine break in, is to bed the rings against our freshly honed bores. And we have a relatively narrow window in order to do this. So what we’re trying to do is bed those rings so that they achieve a correct seal against our cylinder walls. And if we achieve this we’re going to end up with an engine that produces good power, low blow by, and has low oil consumption. So what we’re trying to do there is use the rough surface of that hone pattern to abrade the rings and make them seat. And we only have a narrow window as I’ve said before that hone pattern will be broken down. So the worst thing we can do when we’re breaking in an engine is to baby it or to allow it to idle for extended periods particularly when it’s hot. This will place almost no load on the rings and it will allow that hone pattern to be broken down without it actually performing its job. So what we want to do is use moderate amounts of load and moderate amounts of RPM. Then what happens is when we use moderate amounts of load, combustion pressure gets in behind the rings and it forces them out against that fresh hone pattern. So this forces the rings against the wall and helps the bedding in process. Of course because that hone pattern is a little rough to start with it also causes a lot of friction and hence a lot of heat. So we need to be careful, we don’t wanna go straight to wide open throttle and 8500 RPM. That’s going to cause the rings to overheat. So we want to vary between periods of moderate load and then periods of low load and that’ll allow the rings to cool back down. The bedding in process is normally completed within about the first 100 or 200 kilometres of use. So those people who have heard engine builders requiring 1000 or even 5000 kilometres of running in, it’s absolute rubbish, it’s simply not necessary. After the first couple of 100 kilometres of use, your rings, your engine is as bedded in as it’s every going to be and after that, it’s all downhill so you may as well get out and start enjoying your engine. The other thing just talking about there, you’ve mentioned oil. There are some specific running in oils. I’ve used those myself but now I’ve tended to go away from them. The reason for this is the running in grade of oil tends to be incredibly thin. It’s almost a little bit like water. And the idea here is we’re providing an oil that’s going to allow the rings to bed in correctly. So for example, it’s common in performance engines to use high quality full synthetic oils. Those are actually so slippery that they make it harder for the rings to bed in, so we clearly don’t want to be using a full synthetic oil during break in and that’s where these running in oils come in. More recently what I’ve done is gone away from running in oils and I actually use a good quality mineral based oil. That’s still going to provide the protection I need, because even during break in, these engines are still producing reasonably high power levels, we want to protect all of those components with a good quality oil. But the mineral based oil is not so slippery that it will prevent the rings from bedding. That question was taken from one of our free live lessons. If you like free stuff, and you’re the type of guy who wants to expand your knowledge, click the link in the description to claim your free spot to our next live lesson. You’ll learn about performance engine building and EFI tuning, and you’ll also have the chance to ask your own questions which I’ll be answering live. Remember it’s 100% free so follow the link to claim your spot.


  1. You may forgot about heat cycling.
    Bearing caps and shells will expand and shrink. During test assembly they go apart little bit better than after a teardown. I hear offten the modular/progressive method. 100/500/2000 km , mineral/ semi/full synthetic oil. During this method you add more and more load. Did my enginie that way. Even compression, little blowby and oil consumption .

  2. Most informative no bullshit answer I’ve ever heard on the topic! Thanks Andre! Do you think additives like ZDDP run in addition to the mineral oil provide any benefits during break in?

  3. good information but old news to aircraft people. Standard practice these days is straight mineral oil for first 25-50hrs or until oil consumption stabilizes. Then go to your preferred oil – synthetic or whatever. Don't use an oil with detergents or friction modifiers during run-in, as you say. Run in above 75% power if temps are under control, vary throttle setting, keep the rings seated on the bores. I own old Alfas (2L Nord engine), notorious for being smoky and burning oil. My theory is that the factory recommended running-in schedule is exactly the worse thing you could do! Drive it like you stole it.

  4. Very controversial topic. I build VW engines for Formula Vee’s and suggest that my engines are run in quickly on a mineral oil. Usually it’s 3 laps, spanner check and then go for it. Today I will be running a new motor at Barbagallo raceway in Perth. It will be run in during qualifying and raced there after.

  5. Dang great lesson, I also want to know going with conventional oil just to breakin the piston rings is a good idea. Other than the Dino oil thats typically in the breakin oils like amsoil or drivenracing, i wonder does it have zinc and thats all? 30W single viscosity motor oil is what everyone uses i hear.

  6. A very touchy topic with about as many opinions are there are engine builders. Fortunately, modern tolerances and materials make this less critical for long engine life than it used to be.

    For ME, usual practice is to start it at a fast idle, usually taken care of by the cold start/choke, and a quick visual check for leaks then drive it a shortish distance and recheck as it comes up to temp'. If everything still seems OK, then continue driving it with load and rpm increasing a bit to around 1/3rd throttle (depends on car) and up to half max' rpm then after 25-30 miles(40-50kms) return and, for my own vehicles, change the oil and filter and recheck everything, make adjustments as required and continue driving it until around 300 miles (500kms) I'm using full throttle and rpm, when I'll give it another oil and filter change with the good stuff. Seems to work OK so far and oil consumption on the engines seems to be low with good torque.

    That said, different honing methods (finish, plates used, etc), ring materials and design, bore materials, even pistons – especially if gas ported, etc, can make significant differences in the proceedure required. Oh, and intended use – a high end drag engine will be rebuilt between runs and the 'break in' is done between firing it up and staging for the run, but a commuting vehicle may be expected to last hundreds of thousands of miles with low oil consumption.

    So best practice, I guess, is to go by the recommendations of the various manufacturers.
    Remember, with a build it is up to YOU to do your research and get as much information as you can then YOU have to make the best call you can because if it turns to crap, it is YOU that is going to have to pay to remedy it.

  7. I've always tended to err on the side of caution rather than going hell for leather. I have noticed those people who thrash it from the start are more prone to blowing smoke after a short time, whereas I never seem to have that problem. I don't baby it, but I also don't hit WOT until it has had a real good chance to break in.

  8. These same principals and theories match the break in procedure from the shop I just got my engine from, good stuff! After 50 miles my break in is complete, send it!

  9. Great video! Makes me feel better knowing that I run my engines in, in a very similar procedure👌

  10. There are alot of "opinions" about how to break in a 2 stroke dirt bike properly also. Do the same principals apply in a 2 stroke with regards to using a mineral oil in the fuel or a synthetic or a castor based oil?

  11. Good video. But I've got a question. I see this happen to a lot of friends. New engine they put about 500 miles on it shortly after they spin a bearing.. Why do new engines spin bearings so easy??

  12. I did an engine in my younger years (20+ years ago) with Mobil 1 synthetic . The rings never did seal that well, always alot of blowby. The following engine I used running in oil and aggressive initial run for several hundred km and clearly had less blowby.

  13. I have always broken in my engines with fully synthetic oils, never had blow-by or other related issues.

  14. But if the manufacturer reccomends 1500km break in period then surely I would follow that guidance since they are afterall not wanting people to return engines with issues because that would cost them money and bad reputation. I would rather follow manufacture, who builds millions of engines, specs than some mechanic that builds a couple thousand engines in his/her lifetime.

  15. Another thing I like doing during break in is to use engine breaking as much as possible. This way the negative vacuum forces the oil between the rings just the right amount to help polish the roughness of the cylinder wall.

  16. Love your videos, thank you so much, when i have time ill will take your full courses, to lean more about engine building and tuning.. 🙂 Thanks again for the free videos, this is a great service for all, and so needed!

  17. what are your thoughts about break-in when new rebuilt engine had cylinder walls honed then WPC treated, piston rings too! and piston skirts/wall were WPC treated?  still same 100 or 200 km ?

  18. I already feel like a star, 2 of my questions have been answered the proper way and made separate topics out of… Thank you Andre and HP Academy team, you guys rock! As a self educated car entusiast all the info I can get my hands means alot and is greatly appreciate. Keep it up, I enjoy wathing every video you guys release! Cheers from small country of Bulgaria.

  19. The way I do it is first start up I rev to between 2 and 3000 revs so cams get plenty of lubrication and if new valve springs putting a heat cycle into them with the engine up to temperature. I then switch off and leave engine for 24hrs. I then next day get it up to temperature then go up and down with the throttle and rev it to not more than 4000rpm. I load the engine now and again but mostly just up and down with the revs. The vacuum of coming off throttle pull the rings onto the bore. I do this for 50 miles but it will be tricky if you have no where to do this for obvious reasons. I then change oil and filter but cut open old one looking for metal particles that are not supposed to be there. If ok I then go and do the same up and down with revs but rev it to 5-6000 revs and load the engine more by finding hilly roads to do it on. There is no blow by after the engine has done high mileage and after a engine strip down old rings are reused if bore is ok. This method I have done on bikes also but rev them slightly higher. Other methods can work but this way is proven to work well for longevity of engine components. Mineral oil is used up to the 1000 mile mark then whatever oil after that. Oil filter and oil is also replaced at 500miles then again at 1000.

  20. I just bought my new 2018 Honda CR-V and I have drive home on the highway which is 80mph for around 45 miles. Should I be worry? I have put in over 1000 miles now.

  21. Doesn't breaking in the engine also harden all the metal surfaces like the cam isn't that why they use zinc in the "break in" oils

  22. You had me until you got to the point about "synthetics being too slippery for break in" That's a total myth and pretty readily dispelled one. https://www.youtube.com/watch?v=6VLMfUz34R0&t=438s The viscosity of oil is completely unrelated to the way it is constructed. Construction is mainly a factor of punishment. This is frustrating man, does that mean the other stuff about moderate use and break in period of 500 miles may not be true? Just holding you to the quality of standard I found with this channel. I've been going back and watching everything you made since I found this channel a month ago. Love the work.

  23. 22 year BMW master tech here. One thing also to add is the programming on almost every make of cars since 2010 on limit power until you reach a certain milestone in miles or hours . A lot of customers will complain of bad fuel economy and then all of an sudden it improved after the ecm is satisfied of your break in period. Now your car will apply max power when you floor it.

  24. For how much it took me to clean the oil pan of burned mineral oil, now I have to put mineral break-in again, for break in? Common …

  25. All sound advice. I use dino oil for break in, there's already assembly lube in there from putting it together. Idle long enough for fan to cycle twice, then slowly start revving. Gently up to just above idle and close throttle, then slowly work it up just a little higher each time up to about halfway to redline. Then switch to snapping the throttle, staying under halfway to redline. (Bikes, I have to get the ecu measuring the nasty American fuel I put in it.) Then I gently ride to just outside town and thrash the shit out of it to make sure everything went right. Whole time you're watching temps and the exhaust, and there's so many little things. We've all got our superstitions lol, my personal ritual costs me about 5 or 6 tenths of an hour, not including the actual ride/flush/check.

  26. If people saw how Sport Bikes and Dirt bikes are "tested" at the factory before being put in a crate, they would likely never argue a hard break in procedure again. These vehicles are very high revving, high performance machines with incredible reliability and they are broken in by DYNO runs to verify output! =)

  27. So I understand that modern engines are made from different materials and machining equipment is different than it was years ago.
    Back in the days I was always told to throw some cement bags in the trunk or pull a trailer and baby the new engine while putting it to work under load.
    So how do I break in a Isuzu 4ZE1 4 cylinder 2.6 liter for a 1986 Trooper that was just re-manufactured in a big reputable machine shop?

  28. Or 10w40/0w40. Most w40 have no added friction modifiers. It’s will not say “energy efficient” or “
    Energy conserving” on the back circle like most other car oil weights. We break in most motocross engines with 10w40 the switch to synthetic. Just my 2 cents.

  29. Problem is always to explain to others why they should do like this, and not what the manual of their new bike says?

  30. I have a question that I’d love your help with regarding the break-in period. I just bought a brand new 2019 Subaru WRX STI Limited. The only problem is that I bought it at a dealership 130km away from my house, and most of the drive back is via highways. So, I’ll be struggling to alternate the loads on the engine. Will I be fine doing this? Should I try to alternate loads as best as possible while driving on the highways? Or should I REALLY look for alternate routes that aren’t on the highway? It’s making me nervous to be quite honest.

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