Topic: Harmonic Balancer
in Forum: C3 Engines
Lifetime MemberJimmy B.
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Harmonic Balancers
The Harmonic Balancer, or vibration dampener, is a component connected directly to the front of the engine on the crankshaft. Its sole purpose is to reduce torsional vibrations. These vibrations are generated by the engine as the cylinders fire. The front of the crankshaft will try to twist first as power is applied to it from engine operation. Power is then transferred down the shaft to the rear, causing the front of the crankshaft to unwind and snap back in the opposite direction creating a torsional vibration. Although these vibrations are small, it is necessary to eliminate them using a device called a Harmonic Balancer. The balancer is constructed of two metal pieces connected by rubber plugs, a rubber spacer, spring loaded friction discs, or a combination of two of these.
The balancer’s operation is simple. As power is applied to the front of the crankshaft, it attempts to twist the heavy part of the balancer. Instead, it twists the rubber components connecting the two metal parts of the dampener together. Since the front of the crankshaft can’t speed up as much with the balancer in place, the force is transferred to the rubber which in turn, speeds up the balancer. The resulting action cancels the crankshaft vibrations.
DESIGN DIFFERENCES
There are 3 different design Harmonic Balancers.
• The first design is called a
• The second design is called an
Integrated Design. This balancer is made up of an inner hub and an outer hub separated by a rubber insulator ring.• The third design is called a
Diagnostic Design. This balancer incorporates "windowed vanes for crankshaft position sensor (CKP)FAILURES
All three design balancers are subjected to the same types of failures. The failures are typically a result of:
• Heat stress
• Road salt
• Ozone attacking the rubber components of the balancer
• Stress from integrated drive pulleys
• Loads from other devices (powers steering pump, air conditioning compressor, alternator, air pump, water pump
• Road debris inflicted damage
• Crankshaft failure (broken or cracked)
• Damaged vanes on the balancer causing faulty inputs to the computer
DIAGNOSIS
Unchecked harmonic vibrations can lead to a number of failures or problems. Warning signs of Harmonic Balancer failure include:
• A leaking front engine crankshaft seal
• Excessive engine vibrations (varies with engine speed)
• Elongation of the balancer keyway and/or wear on the crankshaft end
• Loss of the balancer/pulley assembly, resulting in drive belt loss. Without a drive belt, loss of steering assist, alternator, air conditioner, water pump and hydraulic brakes (hydro boost) operation will occur
• Visible deterioration of the rubber insulator between the balancer hub and outer ring
• Slipping, squealing drive belts, accelerated belt wear/failure, or frequent drive belt replacement
• Visible cracks or warps on the balancer
• Wobbling pulleys when the engine is running
• Improperly timed/running engines due to slipped outer ring (contains timing marks)
• Damaged sensors (Crankshaft position sensor)