The "mysticism"of engine break in

[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"