How To Break In An Engine

How to break in a New engine..

One of the most asked questions is how do I break in my new motor? The
short answer is that no break-in is necessary. The only thing that is
necessary is to seat the rings. All clearances and fitments should be
perfect after blueprinting and precision assembly. So how many miles do
you have to drive it to seat the rings? The cylinders are round, the
rings are round, the bore is freshly honed and therefore your engine
should be ready for tuning immediately. They will continue to seat
better over a short period of time but you should be ready to go tune
right away.
Do I need to drive it 500 miles before I tune it? Absolutely not. How
about 50 miles? No. Perhaps the best thing to do is to drive it all the
way to your trailer and tow it to a competent tuner. In second position
on the “things NOT to do list” is trying to break in an un-tuned engine
by driving it. Too lean an air/fuel will begin to heat and distort
parts, too rich will wash the oil off the cylinders causing premature
wear. What is in first place on the “things NOT to do list”? Boost on
an un-tuned motor. Within 2 to 3 seconds the pistons and cylinders can
be ruined.
Well I did put in a new base map or I’m just running off the stock
Honda computer. Can’t I drive it like that for a few miles? I’m not
even boosting. Well what is the base map? Just someone’s idea of what
numbers will start your car. Just an educated guess by someone who does
not have a clue what components you are running in your set-up. It’s
not intended to drive on for any extended period of time. The same with
that stock Honda computer. It could be ok but it could also be
dangerously wrong.

So what exactly do I do at the first engine start-up? Pull the spark
plugs and crank the motor with your starter for a maximum of 30 seconds
or until you see the oil pressure gauge begin to register. Re-install
the plugs and wires and fire up that candle. While keeping one eye on
the oil pressure gauge, use your other eye to scan for fuel leaks. If
there are no fuel leaks, look under the motor for any major oil or
coolant leaks. If that is ok, run the engine for 5 to 10 minutes while
keeping an eye on the temperature and pressure gauges. Keep the rpm’s
between 1000-3000. Shut the engine down and double-check everything.
You are now ready for tuning.

But my engine was already tuned from my previous set-up. Well, what
happened to your previous set-up? Did you melt a stock piston or crack
a cylinder? No problem because now you have forged pistons and sleeves?
Wrong. Although you now have stronger components that will take more
abuse, you are still not right on your air fuel mixture. Get that thing
tuned properly ASAP.

OK, I did it my way instead of yours and now I’m burning a lot of oil.
What happened? Well basically you scarred up the skirt of the piston,
messed up the surface of the cylinder wall and maybe even egg shaped
the cylinder. New pistons are tapered smaller on the top to larger at
the bottom of the skirt. Your piston to wall clearance is measured at
the bottom of the skirt. As the engine warms up to operating
temperature, the upper portion of the piston begins to expand slightly.
The bottom of the skirt does not expand much. When you boost in a lean
condition, the upper part of the piston expands quickly. Since the ring
land area is cut smaller than the tapered skirt below it, the first
part of the piston that pushes into the cylinder wall is just below the
oil ring. Thus you will see the worst scarring on your piston right
under the ring lands where the excess heat is the highest
The more heat that is generated, the harder the piston pushes into the
cylinder wall. The uninformed would blame the piston damage on bad
piston to wall clearance. Untrue. If that were the problem, the damage
would show up at the very bottom of the skirt. What has happened is
that you have expanded your piston to the point that it has just ground
itself into the cylinder wall. Keep expanding the piston by super
heating it and it will push your cylinder egg shaped and maybe even
balloon out the cylinder slightly. At the same time this is happening,
your ring lands will begin to distort to where they will never seal
properly again. Sometimes after doing this, the engine will still run
but it will be a smoker. This all happens in a few seconds of high
boost with a lean air fuel ratio. Also it can happen from 500 freeway
miles of driving where the tune up is off enough to build excess heat
at a slower rate, thus doing the same damage over a longer period of
time…but the end results are the same. Death to your pistons and
cylinder walls.

OK, I’m just going to turn the fuel pressure way up and run extra fat,
that way I won’t hurt anything. If you run too rich, you will “wash
out” the rings. First, excess fuel will run down the cylinders taking
the lubricating oil with it. This promotes direct metal-to-metal
contact between the rings and the cylinder wall. This contact does
several things. The upper ring begins to wear quickly. The middle ring
is actually designed as a tapered oil scraper (it is not used for
compression control at all) and the taper will begin to wear down to
where it becomes flat rather than angled. When that happens, it can no
longer control oil away from the combustion chamber. The last thing
that happens is that pretty cross hatch design begins to wear off of
the cylinder wall. While most people think that the cross hatch is
there to help seat the rings, it also has a secondary purpose. That is
to hold microscopic amounts of oil in the grooves to help lubricate
ring to cylinder walls. With the walls smooth and no oil control help
from the middle ring and a tired upper ring, oil will begin to mix with
fuel in the combustion chamber. When this happens, your 93 octane fuel
probably hits a value of about 80. Then detonation comes into play and
begins to beat holes in the pistons, among other things.

So whom can I blame for this mess? The blind machinist that honed my
piston to wall clearance? That poor quality Brand X piston
manufacturer? The idiot pro engine builder that assembled my block? My
ex-friend that helped me put this all together? Those ignorant
engineers that gave me a bad base map with my engine management system?
The guy on the internet message board whose buddy knows that it takes
at least 1000 miles of break in before you can tune an engine properly?
All of the above? Probably none of the above. Go look in a mirror and
ask…who started this engine and had no idea what the air fuel ratio
was? Who just wanted to jump on it one time to see if it would haul?
Who didn’t know that their injectors were at 100% duty cycle at 4000
rpm but they wanted to see how it would run at 6000 rpm? Why it was
you. Get that thing tuned right away. You will notice that the more you
drive a tuned motor, the stronger it will feel. This is just the rings
seating in their final 5-10% as they thank you for tuning first.

compliments....k202.org

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Silverado Performance Parts

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