The "mysticism"of engine break in

[guydoc77]

Since the issue of engine break in continues to come up, I thought I'd start this thread to see what people understand or don't understand about engine break in. Some of the notions out there continue to baffle me. "Go put 1000 miles on it then we'll tune it." "Should I break it in on the dyno?"
What is break in actually?
How long does it actually take?
Why wouldn't you want to "break in" on the dyno?

Let's attempt to remove the apparent black magic some seem to associate with engine break in.

[K4FXD]

I've been breaking them in the same since I started. Assuming roller cam, warm them up, let cool, warm up again, hit the drag strip. Opps, that was our race car motors.

Bike motor, Warm up, let cool, warm up again and hit the road. Change oil and ride.

I figure if its going to blow let it blow right away.

[kd]

Here's a good read to start the conversation. For the reasons stated in this article, it is also my preferred method if we are counting votes. That comes with the provision that the tune is absolutely correct. An example would be for a rebuild of a stellar tuned engine or an AFR and timing check before rolling down the road.

While I was typing K4FXD responded and (without hearing the actual details of his procedure) I somewhat agree with that approach. In fact I just yesterday fired my hopped up 120 motor and after a quick Moto tune run through I am riding it hard. 

[bigfoot5x]

We have bought all of our Harley's new except one. My thinking is that if the manufacturer wants to have a good reputation, they will  determine what is best for their product. I always break in following guidelines in the owners manual for that reason. I do regular maintenance and get lots of miles out of all my vehicles. Nothing really special.

[Deye76]

IMO breaking in on the dyno takes all the "mystery" out of it.

[kd]

IMO breaking in on the dyno takes all the "mystery" out of it.

I agree, "when possible it would be the best approach). A dyno is not always available or an option.

[jmorton10]

I can tell you one thing, if a bike is bought brand new from a dealer there is no reason to baby it.

I worked at a dealer for a few years & when we test drove new bikes we made sure the rev limiter worked correctly on every test ride LOL.

~John

[prodrag1320]

IMO breaking in on the dyno takes all the "mystery" out of it.

as long as its done by a tuner that knows how to properly break a motor in on a dyno

[TXChop]

I can tell you one thing, if a bike is bought brand new from a dealer there is no reason to baby it.

I worked at a dealer for a few years & when we test drove new bikes we made sure the rev limiter worked correctly on every test ride LOL.

~John

Not to mention if a bike wasnt sold for a while it was started and driven across the parking lot in the morning and shut off.
And then the same at night. So some bike were run for about 1 minute a day for months if not sold right away.

[Deye76]

IMO breaking in on the dyno takes all the "mystery" out of it.

as long as its done by a tuner that knows how to properly break a motor in on a dyno

Agreed, I assumed anyone on this site knew who the good tuner/operators are.

[Trouble]

Fifty miles of regular riding to determine how everything sounds, tune, etc.,  then start throwing some heat at it to seat the rings. Done this way, more power, less oil loss, lots of smiles. JMHO

[PoorUB]

Fifty miles of regular riding to determine how everything sounds, tune, etc.,  then start throwing some heat at it to seat the rings. Done this way, more power, less oil loss, lots of smiles. JMHO

Fifty?? More like ten miles! By fifty miles it's too late!

I don't ride regularly the first few miles. I run it through the gears near full throttle but never over 4,000 RPM, do it over several times. Around fifty miles it's done, ride it like you stole it!

[guydoc77]

To me "break in" is the seating of the rings in the bore.
And I agree, it takes only minutes to do.

Things that WILL ruin the break in are not warming the new motor sufficiently prior to first operation, but, most importantly, running it with literally no idea what the air fuel ratio is and with too much or too little timing or extremely rich or lean AFR.

The perpetuated notion that some sort of "starter" map is "safe" is what baffles me. If good ring/bore seal can be established in minutes, doesn't it also follow that it can also be permanently harmed too some degree if AFR and timing are way off?

To me that is the risk involved in "starter map" break in.
These are the builds with all the correct parts that never run like expected.
I have personally seen AF ratios in the high teens when "starter map" builds finally get on the dyno.
I have listened to new motors ping and detonate as the owner "breaks them in" for 1000 miles prior to dyno.
I have seen canned map motors shell out with limited miles, never having actually been properly tuned.

I get the lure and seemingly cost effectiveness of self tuning with the stock EFI narrow bands. I get that.
If the build is not extremely close to the build of whatever canned map was developed by whomever, what sort of damage is done to ring seal during the self tuning? Can we be certain of the AFR or timing while the tuning device "learns"? And, if there are parts of the map that are close, what does the adaptive fueling and timing do to those areas of the map while the tuning device and ECU compete to correct the way off parts of the map?

These are the thoughts and questions I have on this topic.

[smoserx1]

IMO this subject is way over analyzed, much like an oil discussion.  When I bought my one and only FLHT (which I still ride regularly) nobody said anything to me about break in.  My maiden voyage was about 70 miles home, I would shift at about 3500 RPM cause it felt about right.  When I got home I read the owners manual and worried that I caused damage by going over 2500 RPM the first 50 miles.  Actually the recommended gear/RPM recommendations in the owners manual seem like lugging.  Anyway the engine did fine.  It went 16 years and 179000 miles on the original top end, and even survived a cam bearing failure.  It did gradually use more and more oil, but in the end it was still no more than a quart per 2000 miles or so.  Then one of the base o-rings started leaking.

Two years ago I fixed the leak with SE 95 inch cylinders, flat tops and low mileage stock heads from ebay.  Did it all myself.  I remember thinking the stuff I removed looked pretty good (and was certainly running fine).  I did the "MotoMan" break in this time.  A warm up then 4 or 5 5000 RPM shifts the first couple of miles with high RPM throttle chops (yes that is radical as hell).  Two years later and 11000 more miles all seems well.

Just ride your bike normally and it should break in fine.

[bigfoot5x]

Every Harley is started and run on rollers in the factory before shipping as the final test. My dealer runs each bike on a 7 mile test loop and I don't know how they ride the bike but I would hope that the mechanic is treating somebody's new ride with some respect and kid gloves. I still maintain that Harley has established a break in pattern that they feel is best for the engine they designed. They have to stand behind the product. Not us.

[Hossamania]

I was assuming the OP was talking about a custom or aftermarket build on a motor. Not a factory new bike and motor. That is what I was basing my input on.

[harleytoprock]

It's amazing that there is such extreme recommended break in procedure differences. Where one side says redline it from the get go, others recommend mild break in's like S&S. S&S recommends staying under 2500 rpm for first 500 miles and then under 3500rpm for the next 500 miles. No drag racing, excessive speed, dyno runs, trailer towing or sidecar operation for the first 1000 miles. So if you dyno your new S&S motor with less then a 1000 miles, will that void their warranty?

[K4FXD]

Maybe I'll figure out how to quote people someday.

The method S&S stated, is how we used to break in motors with coarse hone jobs and chrome or cast rings. Outdated technology. It used to take 500 to 1000 miles to completely seat rings.

Today's hones are much finer and the ring material is different. The rings are 95% seated after 25 miles, give or take.

Break in however you like.

For me with a non stock FI motor I would break in on a dyno, but I sure as hell wouldn't baby it once the afr's were sorted out.

[hbkeith]

I ride with constant rolling the throttle low to higher RPM for 50 miles , then ride it normal , never a problem

[1FSTRK]

One good thing about the break them in fast guys is they post the best info on how to modify your breathers to outside the air cleaner and where to mount the catch cans.

[FLHRI_2004]

One of the big no-no's for break in is not to lug the engine.  Well, you should never lug it, but you certainly don't want to lug it while breaking it in.

[Don D]

So what about drag bikes? They rely on low leak numbers for top performance. What do the racers do for instant success?

[K4FXD]

Not sure about the racing bikes, but with our race car motors, BB Chevy's, we warm them up, shut down, fix anything that needs attention, warm up again and run a full pass down the strip. Or if available do the same thing on a dyno.

Leakdown runs around 5% avg. Most are less.

My Twin cam motor was broke in the same way. (I didn't run it down a drag strip but I hit the road and gave it full throttle through all gears) I don't have any oil in my breather.
I might do a leak down test just for giggles.

[Don D]

EFI is a game changer however and fuel and timing by program VS demand is very different.

[K4FXD]

FI, unless a stock re-fresh, yes a dyno is almost a must. However once the map is sorted, LOAD IT. Do a couple of full pulls and let the dyno slow the thing, pull high vacuum.

Anyway that is how I do it.

YMMV

[harleytuner]

I do the 500 mile before a full tune break in on my builds.  After heat cycles I do a break in on the dyno so I can give it a tune to 4000 RPM's, then I set the limiter at 4K and let the customer go for 500 then it's back for a full and final tune.  For me it's not so much about the rings seating, I agree with others here that with modern fluids the rings seat pretty quick.  I do it this way because of the changes that are made after 500 miles.  In other words the Delta differences in the MAP from the break in tune to the final tune are significant.

[1FSTRK]

Can anyone tell us why a race engine break in would be different from a touring engine break in?

[prodrag1320]

So what about drag bikes? They rely on low leak numbers for top performance. What do the racers do for instant success?

about 4 heat cycles.then run it.but understand,everything is set a lot sloppier than it would be on a street bike

[Don D]

Have heard of racers dry lapping the rings

[1FSTRK]

Or just dry lube the cylinders with Quick seal on every engine you build and be done with it.

[Don D]

I do that already.
And agree that it works

[PoorUB]

Dry lapping?

I will take piston rings and run them over a piece of glass and some 400 grit wet or dry to take off the high spots on the top and bottom surfaces before slapping them on a piston.

Years ago I knew a mechanic at a local car dealership. He had a customer bring in a car that was just overhauled and was burning oil like crazy. The guy was traveling through on business and had to keep going but needed the engine checked too. The mechanic checked it over and decided that the rings never seated properly. After a discussion with the customer he sprinkled about a tablespoon of Bonami,
http://www.bonami.com/index.php/products/powder_cleanser/
down the carburetor while the engine was idling. he told the customer to run it 50 -100 miles and change the oil. He said about a week later the customer stopped in and said the engine was running fine and using very little oil so he was pleased with the "repair" and just wanted to thank him for his help.

[1FSTRK]

I do the 500 mile before a full tune break in on my builds.  After heat cycles I do a break in on the dyno so I can give it a tune to 4000 RPM's, then I set the limiter at 4K and let the customer go for 500 then it's back for a full and final tune.  For me it's not so much about the rings seating, I agree with others here that with modern fluids the rings seat pretty quick.  I do it this way because of the changes that are made after 500 miles.  In other words the Delta differences in the MAP from the break in tune to the final tune are significant.

This is one of the best posts on this subject from someone that has obviously tuned many Harleys and paid close attention to details. I know of one tuner that has been tracking the the difference in tunes from fresh engine to 2000 miles for almost twenty years now.

[Hossamania]

I have to agree, that is the first time I've seen someone state a reason to come back and do a final tune. And, the bike isn't just ridden with a canned map, but actually tuned, ridden, and returned for final tune.
Thanks for that info.

[K4FXD]

I admit I don't know much about FI, but if the delta of the tune changes at 500 miles, Why don't I need to rejet my carb after 500 miles??

Changed the miles due to mis-reading the post

[Don D]

Dry lapping?

I will take piston rings and run them over a piece of glass and some 400 grit wet or dry to take off the high spots on the top and bottom surfaces before slapping them on a piston.

Years ago I knew a mechanic at a local car dealership. He had a customer bring in a car that was just overhauled and was burning oil like crazy. The guy was traveling through on business and had to keep going but needed the engine checked too. The mechanic checked it over and decided that the rings never seated properly. After a discussion with the customer he sprinkled about a tablespoon of Bonami,
http://www.bonami.com/index.php/products/powder_cleanser/
down the carburetor while the engine was idling. he told the customer to run it 50 -100 miles and change the oil. He said about a week later the customer stopped in and said the engine was running fine and using very little oil so he was pleased with the "repair" and just wanted to thank him for his help.

Used Bonami on diesels with chrome rings in the 60s, a few spoons in the intake. This was with all new parts from Caterpillar. It worked but even then at my young age I thought it was voodoo. The Okie mechanics I worked with swore by it but they also dipped new piston assemblies in a bucket of oil and STP mixture. Never did that again.

By lapping I am saying, NOT SUGGESTING ANYONE SHOULD RUN OUT AND DO THIS, that the rings are put on the pistons and they are installed dry and then the pistons manually run up and down the cylinders a number of times. Clean everything, oil and put them in and go down the strip. I was told by a well known VTwin racer this is what he does.

So what about the valves? Everyone seems to agree that rings seat rather quickly or they don't and never will due to problems from the beginning. What else would influence the MAP profile after 500 miles of road use?

[PoorUB]

I rebuilt a Wisconsin V-4 air cooled engine years ago. The owner brought it in because it was burning oil and pushing oil out all the seals and gaskets in the crankcase. I tore it down and checked it over. Those Wisconsin blocks were hard as hell, a lot of nickle in them I was told. Everything was in spec so I run a rabbit turd hone through the cylinders, new rings, bearings and gaskets and sent it on it's way. The owner called me a couple months later, still blowing and burning oil. I got it back to my shop, looked it over, replaced a couple gaskets and seals and gave it the Bonami treatment. I never mentioned the Bonami treatment to the owner, figured he would not understand! I called him a few weeks later and he said whatever I did worked, no more oil leaks and using very little oil. I probably could have given it the Bonami treatment right off, but I did not know the condition of the engine.

[tomcat64]

accelerate till ya see God,,, then brake!!

I actually do the 3 full heat cycles, and then give her hell!!

[harleytuner]

I'm just posting my findings and my reasoning for my break in procedure.  It's been very good to me for going on 19 years and it's the same procedure we used when I was at Roeder Racing and they've never had a problem either.  I'm in no way saying it's the only way to do it but it's my way and I have no plans on changing. 

[Don D]

Chad, I have no doubt or problem with what you posted and in fact it just sparked some curiosity.

[harleytuner]

Chad, I have no doubt or problem with what you posted and in fact it just sparked some curiosity.

I know Don.  I've done my form of testing on it is all, and for me it's worth it to do it my way.  It would be a lot easier for me, and definitely more convenient for my out of state customers if I just did a final tune right off the lift.  I should note that there is no charge for the second tune and it gives me a chance to go over the bike thoroughly after 500 miles and do an oil change.  For me to stand behind my work it's the way it is done.

[1FSTRK]

I admit I don't know much about FI, but if the delta of the tune changes at 2000 miles, Why don't I need to rejet my carb after 2000 miles??

If you run a carb with more than two jets and you do a very good tune the first time some builds will require a jet change. One thing to remember is a carb jet is a fairly coarse adjustment compared to EFI and often you will have one cylinder on a Harley at the top of one jet and the other at the bottom of the same jet because of the engine design. With a Mikuni on an early twin cam build with cams and head work you will change jetting and timing after break in most of the time.

[1FSTRK]

I asked this in the dyno break in thread and it was ignored, If the engine is broke in after the rev it style break in then why do most of you do short mileage oil changes at 500 and 1000? If your engine is all broke in at 50 miles why not dump the oil and the cylinder/ring debris as well as anything else that was in the engine from the build at 50 miles and go straight to the regular 2-3000 mile oil change interval?

[K4FXD]

From what I have been reading here, it seems there are as many ways to break in an engine as there are opinions.

What that tells me is break in is not very important in a well built motor. Pay attention to the build and it will perform well with almost any break in method.

Harleytuner, that is a good service you offer, if something is wrong it should show up by 500 miles. A local shop owner bought a S&S motor, broke it in like S&S said then put it on his dyno and it dropped a valve. I told him,"better on the dyno than on the freeway"

I'm not real sold on S&S after this as he is a dealer for them and had to jump through hoops to get warranty. (Not a hyjack or a bash, he got a new motor)

We all have our way that works, and like in a large oil thread here, it's hard to change from something that works to something new.

[K4FXD]

One fast trike,

Most of the break in takes place in the first 50 miles give or take. The last 5 % takes 500 to 1000.

I think the several oil changes deal is "because we have always done it that way"

[1FSTRK]

One fast trike,

Most of the break in takes place in the first 50 miles give or take. The last 5 % takes 500 to 1000.

I think the several oil changes deal is "because we have always done it that way"

I am not singling you out or trying to change anyone's mind, but in response to your response where did you get the percentage numbers? This is what happens on the internet someone post numbers form some where and they become gospel.

I do disagree with this post as well

What that tells me is break in is not very important in a well built motor. Pay attention to the build and it will perform well with almost any break in method.

This site is full of people that have engine failures and many of them are break in related, they just do not get correctly diagnosed. 

[K4FXD]

I get my percentage by leakdown numbers.

If there was only one correct way to break in a motor, why do so many have success with many different ways?

[Don D]

Shops vary their cylinder finishes. This does have an effect on the time and method best to break in the new top end.

[K4FXD]

The cylinder finish should match the type of ring used.

Sorry should have put a disclaimer on my percentages. 

[1FSTRK]

I get my percentage by leakdown numbers.

If there was only one correct way to break in a motor, why do so many have success with many different ways?

This does add to the confusion, I did not say there is only one correct way to break in an emgine, but that does not mean there are no wrong ways.

I take the devil's advocate approach when looking at break in methods and if they include things detrimental to engine parts or longevity then the method is flawed. Things that work on a specially prepped race engine are not good on a touring engine, and vise versa. A given cylinder finish and a given set of rings will take a given number of strokes to wear in but while doubling the rpm of the engine will get those strokes done in half the minutes the heat generated from the friction of the process will be more than double and the ability of the the ring to transfer the heat to the ring land stays the same. We see far more engines posted with high heat damage, cylinder and piston scoring, over heated valve seals, and heat related guide failures than we do with oil glazed cylinder and unseated rings. The most common cause posted here for blow by and oil carry over is not glazed cylinders but scored and burnt rings and cylinders.

Anyone with a way that works for them should stick with it, unless your definition of works includes catch cans, oil consumption between changes or leakdowns of more than 2% on health new engines, then you need to redefine the word "works"

[Don D]

There are some things to do that are not critical but considering the investment and potential damage why not take all possible precautions?
The process detailed by Harley tuner is just that. A good tuning / break-in solution.
I also agree with Eric that an early oil change is wise.
I have witnessed the dry lapping I described and the metal precipitated is quite a bit. That goes into the oil along with the assembly lubes and other crud. Remember the best oil filter are the lifters and right after the oil filter in the circuit. If the filter bypasses then the lifters can catch contaminants.  Play it safe, stack the deck to win.

[01fxdxt]

Owners manual has all you need to know.It is not a mystery..........

[1FSTRK]

Owners manual has all you need to know.It is not a mystery..........

The owners manual applies to stock engines that come to the customer completely tuned and are at a performance level that is so restricted that they are almost indestructible, almost.

[FlaHeatWave]

'Always thought that the initial "no blip" heat cycles were more for the benefit of the Head Gaskets than anything else

[gordonr]

Dry lapping?

I will take piston rings and run them over a piece of glass and some 400 grit wet or dry to take off the high spots on the top and bottom surfaces before slapping them on a piston.


I do a process similar but if there are high spots and the ring isn't flat I toss it. Using a procedure like that is similar to lapping a valve and seeing that its bent. You toss it.

[1FSTRK]

Dry lapping?

I will take piston rings and run them over a piece of glass and some 400 grit wet or dry to take off the high spots on the top and bottom surfaces before slapping them on a piston.


I do a process similar but if there are high spots and the ring isn't flat I toss it. Using a procedure like that is similar to lapping a valve and seeing that its bent. You toss it.

I know of at least one ring manufacturer that says not to lap their rings because the finish on the ring is designed to lap into the piston rind land during break in.

[guydoc77]

Owners manual has all you need to know.It is not a mystery..........

The owners manual applies to stock engines that come to the customer completely tuned and are at a performance level that is so restricted that they are almost indestructible, almost.

[guydoc77]

The point about multiple oil changes is a good one.
Heat cycles with "break in oil".
Then drop that oil and put in regular motor oil.
Dyno tune and then change oil at 500-1000 miles.
Then every 3000-5000 after that.
Works for me.

[gordonr]

Dry lapping?

I will take piston rings and run them over a piece of glass and some 400 grit wet or dry to take off the high spots on the top and bottom surfaces before slapping them on a piston.


I do a process similar but if there are high spots and the ring isn't flat I toss it. Using a procedure like that is similar to lapping a valve and seeing that its bent. You toss it.

I know of at least one ring manufacturer that says not to lap their rings because the finish on the ring is designed to lap into the piston rind land during break in.

I agree not to lap at all and I don't recommend it. The purpose of the procedure is a visual inspection only to insure a "flat" ring is what is being installed. As I have mentioned before in old posts, rings that are flat and round are the foundations for 2% and less leak down results on an engine that hasn't been fired.  Flat and round is an assumption most every builder has when they open their product boxes and lay the rings out for prep.

[Don D]

And then there is the "break-in oil". I tell guys to run 30w Rotella or similar. ZDDP is not essential in any large numbers for a new twin cam motor. So that eliminates the need for a dedicated "break-in" oil. I like a straight weight, sans friction modifiers, inexpensive high quality oil. The relatively low viscosity allows more splash and cylinder cleaning at lower rpm. Heat cycles, minimal, should be done at 1500 rpm not a low idle to get the advantage of splash.

[gordonr]

  Rotella diesel high detergent motor oil has been recommended in the past by a chemist at Torco for break-in. The oil is suppose to keep dirt/debris in suspension so the filter can do its job. Iv'e used Rotella for over a decade.

[guydoc77]

Well this thread has gone well I think.

My hope was that we could lay to rest the seemingly perpetuated notion that it takes a magical 1000 miles to break a motor in.

In addition, I was hoping to shed some light on the break in process without a spot on tune. This notion seems to also be perpetuated. And some are quite dogmatic about it.

Given the relative high cost of hot rodding a Twin Cam (compared to a small block Chevy for example) it just frustrates me to hear of or see guys spend their hard earned money on components that theoretically should work well together and make good power only to come up short, in my opinion, because of the first several minutes and hours of engine operation with a poor tune present.

There have been threads before that address this: guys will spends hundreds on pipes, cams, headwork, air cleaners, etc. But when the idea of spending a grand (give or take) on a tuning device and a comprehensive dyno tune, they protest and balk at the cost. And the advice to "go put 1000 miles on it to break it in and then we'll tune it....." only plays right into that.