A major part of the overall performance of
an engine is the internal balance achieved
between all the moving parts. The forces generated
by an engine at high RPM are truly awesome.
When you start to exceed the designed rev
limit or designed power characteristics these
forces will ultimately threaten the integrity
of the engine itself. Also, there are significant
benefits to be gained from reducing unnecessary
mass. This will reduce avoidable power losses
and make the engine more responsive and free
revving. An engine which is balanced properly
will be more efficient, reliable and will
tolerate much higher RPM.
We've made a big commitment in this area
because it is fundamental to the performance
and race winning sucess of our engines.
We focus on 2 areas
of engine balance.
The first is matching
the amount of power released by combustion in
each cylinder. A dominant factor here is the flow
through the cylinder head. Our gas flowed cylinder
heads flow identically across the cylinders. Compression
ratio of cylinders and camshaft wear is also a
major factor here. Matched fuel injectors/carbs
also dictate balanced power across the engine.
These factors together with inlet and exhaust
manifold design ensures that combustion between
cylinders is correctly matched.
The second area of balance is
mechanical. Here, we look closely at the major
moving parts of the engine (flywheel, piston and
rings, con rods, pins and crankshaft). The piston
rod assemblies are blue printed and mass balanced.
We also employ race quality heavy duty or coated
bearings to match the predicted loads. However,
with the crankshaft we have a number of options.
Custom made crankshafts
If we have reason to believe
that the standard or existing crank in an engine
will have problems handling the power we are aiming
at, we can manufacture a custom made crankshaft.
Likewise if we wish to alter the stroke of the engine
we can also design a crank with the desired stroke
length.
Again, this is achieved with the help of simulation
software. A machined crankshaft made from billet
will be stronger than a cast or forged crank as
it is not subject to the heat cycles and pressure
associated with those manufacture techniques. A
custom made crank can also be lightened substantially
to reduce its rotational mass and then fitted with
custom counterweights to help balance the rotation
of the shaft.
Crankshaft Balancing
The other option we have is to balance the existing
crankshaft, flywheel a piston/rod assemblies. In
this process we are looking for accuracy with very
low tolerances. We match the crank to the rod/piston/bearing
assemblies.
To do this we have invested in state of the art
CNC machinery. Our new CWT Multi-Bal 5000HD heavy
duty balancing machine gives us total control over
the balancing process. A process which we previously
found difficult using 3rd party balancing firms.
CNC Crankshaft Balancing
CWT Multi-Bal 5000 Balancer is the best
balancing machine available today giving "Third
Plane Analysis", ìHMVî Heavy Metal Analysis
and ìPDQî Precision Drill Qualifying combined
with touch screen controls, High Resolution Electronics
and the heaviest base in the industry. It gives
a more accurate and timely method of processing
the balancing jobs.
Features Overview:
Left: A screen-view of the control software's
main screen:
Software also offers unlimited data
storage for bob-weight information, part numbers,
and part description:
The analysing
electronics built into the balancer are state-of-the-art,
which allows our machine to give extremely fast
and accurate analysis of a crankshaft or rotating
part.
This allows "real time" updating of
the correction requirements before you cut the
first chip. This single feature will allow us
to quickly and accurately correct the unbalanced
crankshaft.
The machine itself weighs 4090 pounds. The base,
filled with a special resin material, eliminates
any residual vibration. The entire casting is
encapsulated with steel to give it a long and
durable life. Each bed is cured for six weeks
and all mounting registers are machined in our
CNC machining center. This construction insures
perfect mounting of our stanchions and optional
drill platform.
Using this fantastic tool, we are able to deliver
the accuracy and consistency we need to build great
race engines.
Check out how the crankshaft balancer
works in this video from the manufacturer. It'll
take about an hour to get through but it is an interesting
insight in to the process and how accurate the results
are.
Click on the video screen to go to youtube and
see the playlist. There are 6 videos in the series.
