How to break in my new 370Z Nismo?

Zsteve

Just something I have found in mototuneusa.



What's The Best Way To Break-In A New Engine ??
The Short Answer: Run it Hard !

Why ??
Nowadays, the piston ring seal is really what the break in process is all about. Contrary to popular belief, piston rings don't seal the combustion pressure by spring tension. Ring tension is necessary only to "scrape" the oil to prevent it from entering the combustion chamber.

If you think about it, the ring exerts maybe 5-10 lbs of spring tension against the cylinder wall ...
How can such a small amount of spring tension seal against thousands of
PSI (Pounds Per Square Inch) of combustion pressure ??
Of course it can't.

How Do Rings Seal Against Tremendous Combustion Pressure ??

From the actual gas pressure itself !! It passes over the top of the ring, and gets behind it to force it outward against the cylinder wall. The problem is that new rings are far from perfect and they must be worn in quite a bit in order to completely seal all the way around the bore. If the gas pressure is strong enough during the engine's first miles of operation (open that throttle !!!), then the entire ring will wear into
the cylinder surface, to seal the combustion pressure as well as possible.


The Problem With "Easy Break In" ...
The honed crosshatch pattern in the cylinder bore acts like a file to allow the rings to wear. The rings quickly wear down the "peaks" of this roughness, regardless of how hard the engine is run.

There's a very small window of opportunity to get the rings to seal really well ... the first 20 miles !!

If the rings aren't forced against the walls soon enough, they'll use up the roughness before they fully seat. Once that happens there is no solution but to re hone the cylinders, install new rings and start over again.

Fortunately, most new sportbike owners can't resist the urge to "open it up" once or twice,
which is why more engines don't have this problem !!

An additional factor that you may not have realized, is that the person at the dealership who set up your bike probably blasted your brand new bike pretty hard on the "test run". So, without realizing it, that adrenaline crazed set - up mechanic actually did you a huge favor !!

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Here's How To Do It:
There are 3 ways you can break in an engine:

1) on a dyno
2) on the street, or off road (Motocross or Snowmobile.)
3) on the racetrack


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On a Dyno:
Warm the engine up
completely !!

Then, using 4th gear:

Do Three 1/2 Throttle dyno runs from
40% - 60% of your engine's max rpm
Let it Cool Down For About 15 Minutes

Do Three 3/4 Throttle dyno runs from
40% - 80% of your engine's max rpm
Let it Cool Down For About 15 Minutes

Do Three Full Throttle dyno runs from
30% - 100% of your engine's max rpm
Let it Cool Down For About 15 Minutes
Go For It !!
Frequently asked Question:

What's a dyno ??

A dyno is a machine in which the bike is strapped on and power is measured.

It can also be used to break in an engine.


NOTE: If you use a dyno with a brake, it's critical during break - in that you allow the engine to decelerate fully on it's own. (Don't use the dyno brake.) The engine vacuum created during closed throttle deceleration sucks the excess oil and metal off the cylinder walls.

The point of this is to remove the very small (micro) particles of ring and cylinder material which are part of the normal wear during this process. During deceleration, the particles suspended in the oil blow out the exhaust, rather than accumulating in the ring grooves between
the piston and rings. This keeps the rings from wearing too much.

You'll notice that at first the engine "smokes" on decel, this is normal, as the rings haven't sealed yet. When you're doing it right, you'll notice that the smoke goes away after about 7-8 runs.

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2010 LS3 C6 Silver coupe corvette