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| Engine Reliability is #1
!! An engine failure = zero HP Many race tuners make the mistake of sacrificing reliability for more power. The reasoning is that since race engines get rebuilt a lot, a sacrifice of some long term reliability is a fair trade off for increased horsepower. This is a natural conclusion. My philosophy about race engines is completely different. My number one priority has always been that rock solid reliability comes first, while increased power always comes second. Another way of saying this is: anything that will cause a reliability problem or power loss at a later time, is also a reliability problem or power loss right now. It's only a matter of degrees. My goal as an race engine tuner was to help my customers (who didn't have nearly the same financial re$ource$ as the factory teams) win an unusually high percentage of races and especially championships, without any rebuilds. In order to do that, the engines still had to be fast for the last race of the championship !! When my customers won races and championships, an amazing thing happened -- they started to attract sponsors, and their financial resources greatly improved !! But, we still stuck to the original plan, and kept "reliability without rebuilds" as our first priority. While it's true that factory race teams rebuild their engines after every race, during my career as an engine builder, many of my customers noticed that 1/2 way through the season after their engine was originally built, they could still easily pass factory riders on the straightaway. This has happened many times with many different riders and many different brands of motorcycles, and there are reasons for it ... What I did was to study ways to improve reliability over what's considered to be normal engine wear in production vehicles. The result of this research is a great benefit to street riders and car drivers who want better than normal reliability and vehicle longevity. In order to determine how to minimize engine wear, it's important to first study the true causes of it. In racing, this understanding can make the difference between a race win or a zero horsepower failure parked by the side of the track. On the street, it can mean the difference between 100,000 miles / 160,000 km of high maintenance or 200,000 miles+ / 320,000 km+ of trouble free use in a car. (Note: Motorcycle engines usually wear out much sooner, mostly due to an easily avoidable problem which will be explained on this page.) |
|
In this article I'm going to show you something in
an engine which is so fragile, that it can be easily destroyed by
the friction from a wimpy piece of paper towel. |
|
| Note: this issue contains a lot of
photos and graphics. Many of the smaller photos are "clickable" so
that you can view the full sized version. The problems with this is
that if your browser is maxxed out on graphic memory, then all of
the graphics on this page have to re-load again when you use your
back button to return to it. If you know how to clear out your
temporary internet files, that's one solution, otherwise, it's even
easier to just do this: Click on the photo with the right mouse button. When the gray menu box comes up, select "Open in New Window". When you want to return to this page after viewing the photo, just close the large photo's browser window. (This works with most popular browsers ... but there probably are exceptions.) |
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~Damian Hi Damian !! The Ratio of
719 to 1 I bought a new W650 parallel twin Kawasaki three years ago. I had read of an Australian race car tuner who developed a running -in strategy similar to yours. His was to start the brand new motor, warm it enough to be safe, get it into third (or some gear where the load was high but the speed not silly) and then nail it to the red line and allow it to come down to idle before repeating ten more times, making a total of eleven. Taking my heart into my mouth, I did this with my brand new twin. About 1000 miles
later, I ran it on a dyno, and it posted 51 bhp...not too bad for a
street, long stroke 670cc parallel twin. I belong to an enthusiasts
group and typical horse power levels for motors run in by the
manufacturers methods run from 41 to 44
bhp ... I'm glad someone else is prepared to put it on the line! ~
Jon Hi Jon
!! She's Learning Fast
... I am a 21 year old female who has never had any interest in motorcycles. In fact, I even hate driving cars and do so about once a year (or less). However, I decided to buy a motorcycle and to hell with my narrow-mindedness. I’ve been reading motorcycle-related material on the web all day, but I am totally lost. I know nothing, and I mean NOTHING about motorcycles. They all look the same, I have no idea how they work (or any engine for that matter), and it is a wonder how anyone actually manages to drive them. All the abbreviations and codes are a complete mystery to me. Also, some sites contradict each other – adding to my confusion. I read all of your
newsletters because—well--they're fun to read, and after a
while I found that I understand about 35% of the technical stuff.
This is very encouraging. I understand, of
course, that yours is the wrong site for a beginner to learn the
basics, but I was hoping you could help me. Self consciously yours,
|
Investigative Journalism of Journalism
Now we're going to examine how and why the perception of
"expert" status
in the media can so easily fool the general
public ... as well as most engineers, and
even professional
tuners at the top (factory) level of competition !!
 |
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"They couldn't all be saying it if it
wasn't correct."
We have a natural tendency to
automatically trust the "official" media.
Another common
perception is that when a particular bit of info is repeated in
multiple
sources, that fact alone proves that the info is
true.
As many have noted, my conclusions about most tech
topics haven't at all matched up with the information written by
other magazine tech writers. The difference is, Power News goes
beyond
written ideas by comparing those ideas against
actual physical observation and testing.
This is just a basic principle of good
science.
Because of the difference in conclusions, the
info presented here has been heavily debated
and often sharply
criticized on hundreds of motorsports discussion forums !!
I
encourage readers to post the Power News articles on discussion forums and
let everybody
Rip 'em
up & Tear
'em apart ...
... because whether this info
is right or wrong, sooner or later some logic
will begin to surface !!
Isn't that the way
things should be ??
|
Thinking outside of the
box is usually associated with creativity, and doing things in a new
and improved way. (Right side of the
brain.)
It Was Our Perception That Was
Fooled, Not Our Eyes !! This substitute for thinking usually becomes a lifelong habit --
a habit which invites perceptual problems !! Taking mental
short-cuts severely limits our ability for rational thought. (Note: when you click on the links, these articles will open up
in a new window.) The second article is an excerpt which was featured in the Feb.
1991 issue of Motorcyclist magazine and it's entitled "Give It
A Break-In". 2 Important Notes: The Problem With Non-Critical Reading ... This comment was posted on a popular motorsports forum by a degreed mechanical engineer in regards to plain bearings and why they require a long, gentle break in: "The new bearings are shedding their surface layers as they become intimate with the journals." If our "next door neighbor" had written the above comment, someone would have challenged it. Because of this person's expert credentials, the debate process just stopped cold. For another variation of the "expert phenomenon." Here are 2 different comments on 2 different forums about Break-In Secrets VS How Long Do You Have To Baby It : #1: " I ran across an article on the subject by Kevin Cameron. I like his articles because he always seems to know what he is talking about, and because he provides meaningful technical explanations as opposed to just leaving the reader to wonder why this and why that. " #2: " I think Cameron (one of the most respected motorcycle engineers) and Muzzy (one of the most respected motorcycle builders/tuners) take top honors out of everything posted in this entire thread. It's up to you who you want to believe but I'll continue listen to the most educated ones. " Here's a 3rd common variation of the "expert phenomenon", posted about the Break-In Secrets article VS the owner's manual on yet another motorsports forum: "Why haven't you read your owner's manual? Can't you read? Take it easy for at least 500 miles. The engineers who actually designed your bike know best, everything else should be considered snake oil.* * Note: "Snake Oil" is a slang term usually associated with unscientific and unethical marketing. At this point, a good question would be... do the engineers who actually design the vehicles know things that they aren't telling us in the owner's manuals ?? |
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Do Ball
Bearings Require |
|
The Ball Bearing Manufacturers Polish Their
Balls.
Even in this low-resolution photo, you can
easily see the reflection of the camera lens.
.
|
Ball bearings
are among the most closely dimensioned parts in the world of
manufacturing. |
|
Turbochargers
This has particular significance for
turbo cars.
The consequences of an easy break-in for a turbo
vehicle can be
even more serious than in a naturally aspirated
vehicle.
One of the justifications for an easy break-in with
a turbo vehicle is that the ball bearings in the turbo unit need to be
gently broken in. Does anyone know a reason as to why this should be true
?
I'd like to discuss this topic in a future issue.
How Do Plain Bearings Work
??
A main bearing (left)
and rod bearing (right). They just can't wait to get to work !!
Before I took
apart my first engine, I imagined that the bearing itself was some sort of
anti-friction device. This incorrect idea came from the more familiar ball
bearing -- in which the rolling balls
themselves do
function as an anti-friction device.
I had formed the wrong mental picture.
Instead, it helps to think of plain bearings as a sleeve or
an insert.
How Do Plain Bearings Fit, And Stay In Place
?
Bearing "Crush"
...
The outside diameter of the 2 bearing
shells are slightly larger than the housing they fit into. This creates an
interference or press fit, which is known as "bearing crush". When the
assembly is bolted together, the bearings are forced outward to give a
positive contact with the connecting rod, or in the case of main bearings,
the crankcase block.
By using the tab/notch system and crush, the
bearings are
securely locked in place within their
housings.
The Bearing
Surface
The main and rod bearings work in a similar way. One exception is that the main bearings have holes in them, and an oil channel machined down the middle. This is how the oil gets into the plain bearing system which will be explained later on this page. In some engines, some of the main bearings don't have oiling holes. The reasons for this are outside of the scope of this article, but the short answer is that there's just a slightly different oiling path. Even in those engines, the other main bearings have holes in the like the one shown here, and that is how the oil is introduced into the system. In the majority of late model motorcycle engines, all of the main bearings have oiling holes, like the one pictured here. . |
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How Does A Plain Bearing
Reduce Friction ?
In use, the bearing
itself doesn't have any friction reducing characteristics. Rather, the
system uses the unique properties of liquid (oil) as the
anti-friction "device":
|
In this animation, the oil clearances have been
greatly increased to give a clear view of the oil film's dynamically
changing dimensions between the bearing and the crank
journal. |
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|
| |
* In theory, even solids
are compressible, as in Black Holes in outer space. These are forces which
are far beyond the ones we're dealing with in engines. Under laboratory
conditions, liquids are slightly compressible. The pressurized fluid loses
only a micro percentage of its volume
when it is squeezed with
extraordinary pressures.
In real world applications, this has no
measurable effect on hydraulic systems. This is why, although from a
strictly theoretical scientific viewpoint, liquids are considered
compressible --
in engineering applications, liquids are
considered non-compressible.
The Power of Hydraulics
1
I had the opportunity to test
the power of hydraulics by digging gigantic rocks at the
Arctic
Circle Raceway in Norway. I was amazed at how easy it was to learn to
operate this huge machine, and the ease with which I could toss around
mega-ton boulders, as if they were little pebbles.
Of course, the
power to do this comes from an engine, but the reason it's possible to
lift such a heavy load, is that the power is transmitted through the
hydraulic fluid which in turn lifts the shovel.
The shovel would just collapse under the heavy load,
were it not for the non-compressible qualities of
liquids.
Many big name race teams
just put some stickers on the race vehicle and consider that
"promotion".
This is by far the most impressive sponsor promotion
effort I've ever seen:
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The Power of Hydraulics
2
Hydraulic Lock --
this happens when an engine's cylinder is filled with gasoline from a
leaking carburetor float valve. When one attempts to start such an engine,
the non-compressible fluid stops the piston. If the battery is strong
enough, the connecting rod will transform from a useful engine part, into
an interesting "S" shaped sculpture worthy of an abstract art gallery
!!
Liquid makes an incredibly strong
bearing.
The Ingenious Design Concept
of Plain Bearings
Plain bearings are designed with the
idea that, should failure occur, the expensive crankshaft will be
unharmed, with the damage limited to the inexpensive bearing
insert.
In actual practice, this is true to a point, but
if the engine is allowed to continue to run much after the bearing is
damaged, the crank will soon be damaged as well.
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It Really Works ...
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Main
Bearings |
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The Oil Path Within The
Crank
Because they get their oil supply after the main
bearings, this is one reason rod bearings are the weakest link in this
system. If there's a loss of oil pressure, the end of the system is
affected first, so the rod bearings are the first to suffer from oil
starvation.
A second reason is
that the force of the power stroke bears down on just 1 rod bearing, while
the same force is always shared by at least 2 main bearings. In a 4
cylinder engine the load is spread over 5 or 6 main bearings (depending on
whether it's a center cam chain tensioner or end cam chain tensioner
design.) This stress on the rod bearing, combined with being the last to
receive oil,
are 2 problems that the main bearings don't
have.
Rod Bearings Whereas the oil supplying the main bearings went from the cases into the main bearing / journal interface and into the crankshaft -- the rod bearings' oil supply direction is just the opposite. It comes from inside the crank and is forced outward between the rod bearing and journal. The oil delivery is in reverse, but the action of the journal "trying" to squeeze out the excess oil, and meeting an uncompressible pressurized oil film is the same as it is with the main bearings. As you can see, there are no holes in the rod bearings, since the oil is fed from within the crank. The occasional exception to this is some engines which have a very small oil hole going through the bearing and the upper rod where the beam meets the upper bearing housing of the rod. The purpose is to spray a jet of oil up to lubricate the cylinder walls, pistons and rings. .. |
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Where Does The Oil Go Next
?
|
If you've never dug into an engine this "deep", you
may be surprised to find that the connecting rod can
be |
|
|
It does seem "wrong" but, this rod side clearance is
required, because it's the only "escape route" for the
oil |
|
" Break-In Secrets
Part 5 "
Do Plain Bearings Require
Break-In ??
What is Logic ??
You've probably heard people
say "that doesn't seem logical", which is a misuse of what logic actually
is. Logic isn't a feeling; and a statement all by itself is neither
logical or illogical (although it can be true or false). True logic is the
process of drawing a conclusion from premises, and it is set up kind of
like
a math equation. Unless all of the premises are
correct, the conclusion will be flawed.
What is Circular Logic ??
Here's a common
example:
Premise 1: Most mainstream
motorsports magazines warn that you shouldn't run
new
engines hard right away, because that will cause serious
damage.
Premise 2: Power News says
exactly 100% the opposite of that.
Conclusion: Therefore, Power News is snake oil.
The problem with this argument is that it contains an assumed
premise, which is,
that these magazines know the full
story and contain accurate technical information.
In order
for the conclusion of a logical argument to be accurate,
the
premises must be proven to be true first.
One premise is
absolutely true, and that's #2
!!
Let's examine premise #1...
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|
The other 1/2 of the story drastically changes the meaning of the entire story.
Quote from the Give It A Break article:
"... it's likely
that a new bike was run at the factory ..."
This statement is very misleading,
because it really downplays what actually happens.
Power News readers are
learning the other 1/2 of the story ...
the part which has
been kept well hidden for over 20 years:
|
This is like the famous scene in the Wizard of Oz when Dorothy got to see how it all works ... except this is real: | |
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The bikes aren't just
"likely" to be run at the factory, in fact ... |
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|
The magazine tech writers and the factory race team bosses and mechanics quoted in these articles don't know about this aspect of the manufacturing process !!! |
|
It might seem
unfair to say this, since these break-in articles appeared back in 1991
& 1995. But a close look at the new
bike in the photo above confirms that it's an early '80's model !! I'm not
exactly sure when the factories started doing this, but it's safe
to say that this reality predates these 2 articles by a
very long
time (at least 8 to 12 years respectively.)
My estimate is that some factories were doing this as long ago as
the mid 1970's ... can anyone confirm ??
When we examine the
information purely from the basis of mechanical logic, while keeping
in mind
the info that the writers of the numerous easy break-in
articles don't know about ...
... it becomes possible to
understand the real logic (reasons) behind the modern easy break-in
concept.
There are many levels of
logic. Once one level is seen and acknowledged,
only then is
it possible to examine logic on the next level higher.
(Seeing
the bigger picture.)
5 More Reader
Reports:
New Nissan Cars
Fully Blasted:
A number of years ago I was in Japan working
for Nissan Canada and we were invited to visit an assembly plant. You
should see the final road test they submit the cars to on a dyno. The
driver floors the accelerator and takes vital
statistics from dials for about 3 minutes. If
they pass this test they are OK. The Japanese must be
laughing when they read the lines about engine break in.
All of the motor vehicle industry insiders
have been laughing at this situation ... for a long
time.
New
Ford Cars Fully
Blasted:
I once took a tour of the Ford plant. The engines
are all dyno tested and screamed to top RPMs at full throttle. That's when
I knew the easy break-in engine damage warnings weren't true. The funny
thing is that they checked my bag for cameras or video recorders -- that's
not allowed !!
Why all the concern
about video & camera equipment ?? If there's nothing to hide, why is
there an effort to hide it ??
New
Honda Motorcycles Fully
Blasted:
At Honda at Marysville Ohio the new bikes
are strapped to a dyno wheel and run to red line
and at over 100
mph before it is crated up and shipped.
Didn't they read those easy break-in articles ?? After all,
they helped pay for them.
Diesel Blastage @
Ford:
I can only speak for 1.8 Diesel for Ford
as that's what I'm assembly engineer for, but once the engine is built its
conveyered into a cell and then started. After idling for 30 secs (with a
lot of auto checks on oil pressure, coolant temp etc etc) it's then taken
up in 500rpm increments every 10 secs until the grand finale of 10 secs at
max no load speed. I still cringed this afternoon when
I walked past them screaming (as much as a diesel can) away. Of course, every so often half way through this
a con rod will emerge from the side of the block but this is what the test
is for, to show up any manufacturing defects.
Screaming
Diesels !!
New Aprilia
Motorcycles Fully Blasted:
Every bike that leaves the
Aprilia factory (and every other OEM factory)
goes through each gear to the {rev} limiter, no bull,
its part of quality control.
Bikes used to come in without the high
speed indicator reset, quite often the bikes would have 175mph on the dash. I saw a Factory {model type} with
182mph on it, and I know I sure didn't do it.
{Note: the 2 bracketed comments are my additions ~MotoMan}
I wonder how
the guy whose job it is to full throttle redline new Aprilias all day
breaks-in his family car ??
Does he follow the owner's
manual and drive real nice and easy for 600-1,000 miles, to avoid
severe engine damage ??
|
|
"Gee Whiz ... you
can't really violate the logic of the easy break-in articles any
more outrageously than that." |
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. . . |
When you think about it
...
The first running at the
factory really is the hardest running
most engines will
ever receive.
Except
for the small percentage of cars and bikes that are used for
racing,
the vast majority of vehicles on the road will never get the
sustained full throttle,
maximum RPM use that
they experience in their
very first time
running.
Let that
idea soak in for a little while ... it's a real brain twister !
The Denial Mechanism Known
As:
CD
Some in the
motorsports press, have literally "scared people out of their minds" that
engine damage occurs from running a brand new vehicle hard.
Seeing all of this information now may cause the
readers
of those magazines to experience an extreme perceptual
illusion.
No one likes to think that
they've been fooled.
Like an
optical illusion, even the most rational, highly educated
and otherwise intelligent people
will be able to see the
words and pictures, yet still have their perception distorted by
CD.
CD = Cognitive Dissonance. This effect completely blocks disturbing
new information from entering the consciousness.
Just as if it
never existed.
Some will immediately get over it and see the easy
break-in deception for what it is. But, there's no question that others
will come up with a powerful rationalization in order to keep on believing
the myth.
Whatever the rationale is, it would have to also
ignore the concept of cause and effect,
so it won't be a
scientifically sound reason.
Here's one possibility:
|
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The Evil
Hobgoblins |
Newly Revised Easy Break-In
Warning:
Heavy throttle and
high revs in the absence of the magical Dweeb-a-zoids will cause serious engine damage.
The Evil Hobgoblins will make sure of that.
;)
|
To be fully convinced,
people have to really believe in an idea, not just mentally,
but in their heart. | |
|
|
Quote from
the How Long Do You Have To Baby It article: |
It's Crystal Clear that the
manufacturers actions show that they don't agree with
the
destruction statement.
Of course they agree publicly, in an "official" sort
of way ... but Power News isn't about fake "official" stuff.
Many people have asked me:
"Why didn't you just reveal what goes on at the
manufacturers
in the Break-In Secrets article, since
it would have made it much easier to believe ??"
Because this isn't about believing things, it's about
understanding things.
This page is all about a higher
level of thinking ... so in a way, revealing what happens at
the factories
is taking a mental short-cut.
Just knowing what they do, doesn't give us an understanding
as
to why blasting a new engine doesn't cause any
damage whatsoever.
If we fully understand how bearings
work, then we will come to the same conclusions that
the
factory engineers did regarding bearings and break-in, without even
knowing the
other 1/2 of the story or having to personally visit
a factory !!
In other words:
Is it possible to just
"think out" the bearing part of the break-in secret
without the luxury
of knowing this hidden information ??
Yes
!!
I figured out that the manufacturers blast
the new vehicles 12 years before I heard about it from eyewitnesses or had
photographic evidence of it. This is what science is all about -- thinking
things out using logic and observation, without having to be told by
someone
who's widely perceived as an expert.
It's not about me being the perceived expert ... it's
about you being a real expert !!
Quote from the How
Long Do You Have To Baby It article:
" ... bearings spin without
metal-to-metal contact, on full oil films "
(Note: in the article's context, this means "after
the break-in process is complete." )
Oil, like all liquids, is non-compressible !
This quote brings up 3
questions:
1) Do the bearings spin with metal-to-metal
contact in a running engine ??
2) Do they spin on anything
less than full oil films in a running engine ???
3) Come to think about it .... do main & rod bearings even
spin ????
Not to be confused with the term "spun
bearing" which means a ruined bearing.
Do the main
bearings spin (rotate 360 degrees continuously) ??
No, the main bearings don't spin ... they don't move at all
!!
|
. |
|
Do the rod
bearings spin (rotate 360 degrees continuously) ??
No, not all all. In fact a close
examination reveals that for nearly 50% of the time, rod bearings rotate
...
... backwards !!
.
.
.
.
.
..
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Practice making
more complex visual mental images !!
The next (much more
challenging) step is to visualize what an actual engine looks like as the
rod rotates backwards. Make the picture in your mind complete with metal,
oil, and especially the movement of the parts. Eventually you'll find that
it becomes much easier to make mental pictures even to the point of
simultaneously visualizing the incredibly large number of complex events
happening in a running engine !!
People who are
capable of doing this have an immense advantage, but it takes
practice.
This is the secret to your becoming an exceptional engineer /
mechanic !!
Why Is It
Important To Understand The Concept Of
The Rod Bearings' Backward
Motion ??
Because
we can now examine one of the least understood reasons why the rod bearings
are more failure prone than the main
bearings are.
This is a more challenging concept to understand,
because you've really got to study
the still pictures and make a
mental image of 2 moving things at once (Right side of the brain)
while at the same time you have to think
about what's logically happening
(Left side of the brain):
|
As the piston descends from the top to 1/2 its
stroke, the crank is rotating clockwise while the rod bearings are
rotating counterclockwise. The speed differential between the
bearing and the journal is dramatically |
|
|
As the piston descends from 1/2 its stroke to the
bottom, the crank is rotating clockwise while the rod bearings are
now also rotating clockwise. The speed differential between the
bearing and the journal is now dramatically |
|
|
As the piston ascends from the bottom to 1/2 its
stroke, the crank is rotating clockwise while the rod bearings are
also rotating clockwise. The speed differential between the bearing
and the journal is the same as the frame above -- decreased !! |
|
|
As the piston ascends from 1/2 its stroke back to the top, the crank is rotating clockwise while the rod bearings are now rotating counterclockwise. The speed differential between the bearing and the journal is again dramatically increased !! |
|
|
. | |
Why Do Rod Bearings Usually Fail First
??
Now we have 3 reasons why rod bearings are more
stressed than main bearings. If a main bearing and a rod bearing had
identical friction problems, the rod bearing will fail sooner than
the main bearing would.
To summarize:
1)
Rod bearing frictional problems are magnified because of the higher speed
differential during the 2 "backwards acceleration" points shown
above.
2) Oil delivery gets to the rod bearings last. If there's a
loss of oil pressure, or an obstruction in the oil delivery path from the
main to the rod bearings, the rod bearings are the first to suffer from
oil starvation.
3) The force of the power
stroke bears down on just 1 rod bearing, while the same amount of force is
always shared by at least 2 main bearings.
This Next Concept Really Rocks
!!
The 2 times that the bearing's speed in relation to
the journal surface is increased, also happen
to be the 2 most
stressful points in the 4 stroke cycle. These 2 points are the first half
of
the power down stroke, and the last half of the exhaust
upstroke.
It's important to understand
this, because it makes reason #1 above even more
serious.
The forces involved in the power down stroke are
obvious, but can you see why the last half of the exhaust upstroke is such
a highly stressful point in the 4 stroke engine cycle ??
Why ??
The last
part of the exhaust stroke is stressful, because there is nothing
to
"cushion" the G- forces of the weight of the piston and
rod !!
The Solution:
Strange but true... "Oval Bearings" !!
Since metal to metal bearing contact in a running
engine quickly leads to failure, bearings are designed so that even at
maximum RPM, there is never any metal to metal contact.
It
was found that a slightly oval bearing inner diameter is required to
compensate for the high RPM stretch of the bearing housing ...
| . The bearing wall is thinner near the ends of the bearing shell than it is in the center section. This section corresponds with the horizontal split between the full circle formed by the 2 bearing shells, providing extra clearance, so that when the rod bore pinches inwards, there is no contact with the crankshaft journal during the high RPM exhaust upstroke. A ball is required to measure the thickness of a curved surface like a plain bearing. While this won't give the absolute thickness of the bearing, it shows the comparative difference between the 2 measurements. (For the absolute thickness, just measure the ball and subtract the difference.) When using a micrometer, it's important not to get any heat from your fingers into the micrometer, or the part being measured !! The heat will expand the part or the micrometer which will make the measurements inaccurate. ..
Why is it so important to measure (test)
things for yourself ?? Throughout history, most of the
really big innovations and inventions were made by people who
rejected the idea that people should be trained to think a certain
way. The bearing solution was found "back in the old days", but
knowledge of this hasn't fully reached the mainstream. As a result,
the seriously out-dated idea still survives among many tuners and
engineers that new bearings don't have the right running tolerance,
and need to be gently worn in before they fit correctly. | ||||
Quote from the How
Long Do You Have To Baby It article:
" ... firm part-throttle operation for a
period puts a load on bearings and other
parts, forcing their surfaces together so they can polish each other to a fine
fit.
"
Quote from
the Give It A Break article:
" ...a constant
load is not ideal for breaking in the bearing
tolerances."
Bearing Clearance Break-In ?
Limited
observation can "prove" that the above bearing statements are
"true" !!
Why is that ??
For those who
don't work on engines, it has to do with the perceived expert status of
the people saying it. This "expert phenomenon" also influences many
professionals, but another factor becomes involved for them. It has to do
with what I feel is the most common problem in science. The distinctly
unscientific method of not taking
an open minded, objective, thorough and personal observation of the
subject being studied. This has to
do with fear.
There are very few scientists who can be objective
when new ideas threaten their already preconceived ones. This has nothing
to do with how well they memorized scientific "facts" or the amount of
time spent in school. The most important skills of science aren't
currently being taught in school.
It's all about honesty and the courage to have a favorite idea
found to be wrong. Decide to be completely honest with yourself
(objective), and you'll have the potential to be a better observer of
reality than many scientists.
Bearing
Comparison
The rod bearings from left to right
in the photo below are as follows:
1) Brand new, just unwrapped
from the package.
2) Blasted at the factory, and run hard on the street
for approximately 30 miles / 48 KM.
3) Raced for 1 season, constant
high RPMs for about 2,000 miles / 3220 KM.
4) Raced for 2 seasons (inc.
endurance races), constant high RPMs for about 6,000 miles / 9660
KM.
Except for the brand new one, all of these bearings came from
engines which were broken in
according to the Break-In
Secrets article.
.
|
. |
4 Yamaha R6
rod bearings |
What's really
surprising ...
... is that experts in both articles thought that new
engines are assembled with bearing clearances
that are so tight,
that the words "fit" or "tolerance" are applicable.
What do you think would eventually happen if bearings,
(which possess the softest metal
in an engine), are run
with less than the correct oil clearance ??
(Ka-Boom !!)
How much did the most
heavily used bearing's
babbit layer actually wear ??
|
.. |
|
|
. |
And Now
...
It's Time For The "Paper Towel"
Experiment !!
For less than $10, you can learn more than many
engine experts know about bearings ...
.
|
|
. |
Note: "destroying"
the coating doesn't damage the bearing !!
Many race engine builders wipe off the gray
coating with some paper towel before installing them, without any problems
whatsoever. (The coating isn't able to protect the babbit layer.) If
a wimpy piece of paper towel can wear off the coating this easily
...
Why doesn't
the coating immediately wear off, during the full throttle max RPM
blast
at the factory ?? How can any of it possibly survive after
all that racing use ??
The answer to
this will be revealed in a moment. This will illustrate where the easy
break-in concept has been a total misinterpretation of the
evidence. This in turn has resulted in the widespread misunderstanding of
the causes of bearing wear, and engine wear in general.
How can we determine the
babbit layer thickness ??
Call Yamaha ??
Call a
motorcycle shop ??
Watch the Discovery Channel for a really long
time ??
Ask a Factory Race Team tuner ??
Read the easy
break-in articles ??
Experiment #2
Instead of
asking someone who may not know the correct answer ...
Here's How To Find Out For Yourself:
|
. |
|
|
First, measure the bearing with the babbit layer ... |
|
|
Next, measure the bearing with the babbit layer
removed ... |
|
Yikes !!
There's only .0006 of an inch of babbit before
copper is reached !!
(On some bearings, the
babbit layer thickness is even thinner -- .0005 in. / .0127 mm.)
Just How Thin Is .0006 inch / .015mm
??
|
. |
|
Words and numbers are cool,
but it's way cooler
to make a mental picture
!!
In this diagram, I've illustrated the exact
relationship between the 2 sizes as a
percentage represented by
digital pixels:
 |
The softest
metal in an engine, the babbit layer, is
only |
.
.
Ladies and Gentlemen,
The super thin / ultra soft babbit layer can't withstand
any
metal-to-metal contact while the engine is
running.
Remember what the
experts said about
bearings being "broken-in"
??
Well here's the truth ...
If your "bearings are polishing to a fine fit" while you're on the road ...
or
if you're
"breaking in the bearing tolerances" while you're on the road ...
or
if your "bearings are shedding layers to become intimate with the
crank journal"
while you're on the
road ...
You'll soon be getting
"intimate" with your dealership's parts department
!!
Forget what the experts
said.
You're becoming the real
expert now :)
How Do Bearings Wear Then
??
The next series of photos are from a heavily used
race engine. It was correctly assembled by another engine builder, who
didn't remove the coating before the bearings were installed.
While
this engine design may not be exactly like the one in your vehicle, this
will demonstrate how plain bearings wear in any vehicle.
Knowing
that the very top "layer" is really just an easily removable coating, and
while keeping in mind all of the qualities of plain bearings, we can use
the information to determine how and when bearings wear the way a good
detective does.
Unemotional,
deductive (logical) reasoning !!
Let's see if a
pattern develops...
|
.
Why hasn't this
engine failed ?? |
Which force on the crank is greater: the
upward lifting effect of the cam chain
from the tensioner and the
valve springs ...
... or the downforce of the power stroke at
15,000 RPM ??
There's no comparison, the power downforce is a
much stronger force !!
Of course, during the power stroke,
the force is spread across 5 lower bearings, but realistically, if bearing
wear were a matter of the amount of throttle used (force) and RPM, then
the bottom bearings would be wearing much more than the one being damaged
by the upward pull of the cam chain.
|
The Cam Chain
Pull When you use a wrench to turn an engine over with
the spark plugs removed, most of the resistance you're feeling is
coming from the |
|
" Hold On A Minute, MotoMan
...
I once read in a
magazine article that the right side end main bearing wear is caused from
the motorcycle being leaned over on its kickstand. The oil drains away
from this end of the crankshaft, and the bearing is damaged on start-up.
What do you have to say about that ?? "
Yes, I've heard the
same thing, and most mechanics have automatically agreed with that
idea.
The only problem is ... it's not a correct diagnosis of the
problem.
Clue
#2
|
|
The Race
Stand: |
The "kickstand problem" is
an an example of a mis-diagnosis of cause and effect.
Since the cam
chain is on the right side of the bike, this side gets tipped
up
when the bike's on its kickstand which is on the left side
...
... and so the kickstand explanation "seems
logical".
By using scientific thinking and eliminating that
variable,
one will discover that the same problem still
exists.
Coincidentally, the
discontinuation of centerstands coincided with the use of the end cam
chain tensioner design.
Clue #3
Which force is greater, the weight of the crank, or the power
downstroke at 15,000 RPM ??
There's no comparison, the power downforce
is a much stronger force.
|
|
Why are the lower main bearings'
coatings only worn in the center, not at the end section
?? |
Clue #4
|
. |
|
It's True:
Plain bearings, when correctly installed, and with
proper oil clearance and pressure,
don't wear once the engine is
running.
(While the engine is running, the bearings are
floating on an non-compressible oil
film.)
The wear all occurs at the
moment of start-up, after the engine has
sat,
and the residual oil has drained off.
This is the "certain condition"
!!
It's not a
matter of the amount of force, but rather when the force is
being applied:
|
. |
Figure "A" |
Figure "B" |
Analysis
The main bearing
wear occurs when either the downward weight of the crank or
the
upward pull of the cam chain has squeezed out the residual oil while
the engine is at rest.
Except for the cam chain tensioned one,
none of the other upper main bearings are wearing. This is because
they don't have any "oil squeezing" conditions while the engine is
stopped, and they aren't subjected to any serious force on start-up, only
at high RPM.
In the case of the rod
bearings, oil drain off is also responsible for the start up wear. With
the rods, there is another factor worth considering. Whenever the engine
is stopped, the residual oil drains off soonest from the rods that remain
above the middle of the stroke, and so more wear occurs on these rod
bearings. I've seen an equal amount of bearing coating wear on both sets
of rods in every 4 cylinder engine I've ever inspected. I suppose it's
possible that one set could always stop below the
middle of the
stroke every time the engine is stopped ...
... and that would be
like winning the lottery and getting struck by lightning on the same
day.
It's possible, but highly
improbable.
Even at redline RPM,
all of the bearings are protected by a full pressurized oil film. The fact that
none of the 18 bearings'
coatings are worn into the "oval" section is more evidence of
this.
Unbelievable
The
experts in these articles have confused start-up wear with "break-in
wear".
If this page has caused
you to start wondering about the wisdom of automatically believing
experts,
then you're on the "same page" as me. ;)
You can't prevent start-up
wear by breaking-in your engine "easy" ...
The only way you can
prevent it is to never start the engine.
That would kinda take all the fun out of things.
You've probably heard that the majority of engine
wear occurs as the engine is started.
(It's true.)
.
Take The
Bearing Quiz !!
|
Removing the coating makes it difficult to see how
much a bearing has been used. |
. 1 was heavily used (roadraced), 1 came out of a
brand new bike which was only blasted at the factory, and 1 is brand
new and was |
What happens if the bearings are tight
??
Will a hard break-in damage them ??
Absolutely ... Yes !!
But, it's important to understand that
even during an easy break-in, tight or incorrectly installed bearings will
be equally damaged !! A really tight bearing won't last long enough to be "broken-in", and a bearing
with minor tightness will develop into a major problem eventually,
regardless of how the engine is run.
Here's why:
2,000 RPM ...
Even with light throttle at a super-mellow 2,000 rpm,
the tight section will cause permanent damage to the ultra soft, ultra thin babbit layer from the mere
rotation of the crank journal. The
re-distributed metal can't escape, so it spreads over the
bearing creating new tight areas. This smearing
metal process generates a lot of heat, and the heat expansion and thermal distortion tightens the bearing
clearance even more -- and eventually prevents the formation of any oil
film. The amount of time this takes depends on how tight the bearing
is.
A tight bearing problem can only be solved by taking the
engine apart to correct the clearance.
Tight bearings are an extremely rare
occurrence with production machines. I've only seen one example
of this during my entire career as an engine builder ...
|
. |
|
. |
|
More and more people are discovering that a
hard break-in really does result in a lot more power.
(But, there
has still been a feeling that there must be a trade-off of damage &
lower long term reliability.)
Now, more and more people are discovering
why a hard break-in doesn't do
any damage in a correctly set-up
engine.
There is no
trade-off.
What if it turns out that an easy break-in
actually causes long term engine damage ...
the very thing
the easy break-in article readers want to avoid ??
Stay Tuned !
It's
hard to imagine that truth can be so completely reversed.
The widespread presence of the "expert/prestige box" makes truth
reversal super easy to do !!
|
|
. |
What Does The Paper Towel Experiment Tell Us ??
Myths Teach
Others About Engines: Opinions
and Facts Plain Bearings
Are Easily Damaged ...
Plus:
What kind of epoxy are you using for porting
?? |
I traveled to the Netherlands to work with a
Kawasaki Supersport race team with their
ZX6R cylinder head development. In an
upcoming issue of Power News, I'll be featuring this team, plus much
more about the High
Velocity intake and exhaust porting
concepts, as well as new information that I've gathered since I
first wrote the original porting articles. |
If You've Liked This Issue
Of It's Free,
Just Enter Your E Mail Address Here: |
