1973 Chevrolet Blazer Crankshaft Pulley and Harmonic Balancers

Essential 1973 Chevrolet Blazer Crankshaft Pulley and Harmonic Balancers

Mr. Gasket – Billet Style Aluminum Crankshaft Pulley (Part No.5317)

Billet Style Aluminum Crankshaft Pulley

from

$92.99
Double groove, crankshaft pulley, LWP, 1969-85. The pulley has been heat treated for strength and has an attractive satin finish. It is manufactured from machined aluminum to give your engine a hi-tech look.

Product Features:
  • Machined aluminum
  • Heat treated
  • Attractive satin finish
See More

Dorman – Crankshaft Pulley (Part No.A2080719514DOR)

Crankshaft Pulley

from

$43.01
Durable and sleek, Dorman crankshaft pulleys feature a stress-resistant rubber bond that withstands the damaging effects of heat, salt, ozone and general wear and tear. The ductile steel construction allows for improved tensile and impact strength, safeguarding the engine and maintaining fuel efficiency year after year. Dorman crankshaft pulleys undergo detailed dimensional checks of the full assembly and critical components to ensure the strength and integrity of the part.

Product Features:
  • Includes woodruff key, bolts, and washers for a complete repair (where applicable)
  • Direct replacement to ensure proper fit
  • Ships with protective sleeve over cone and trigger to prevent damage (where applicable)
See More

ACDelco – Original Equipment Crankshaft Pulley (Part No.A2080202265ACD)

Original Equipment Crankshaft Pulley

from

$52.57
The ACDelco Crankshaft Pulley is a direct fit OEM replacement that contains the same high quality craftsmanship as the original equipment manufacturer.

Product Features:
  • Original Equipment Supplier validated by GM Engineering, which assures proper form, fit and function
  • Precision machined belt and seal surfaces
  • Dynamically computer balanced
  • Durable long life performance
See More

Dorman – Harmonic Balancer Assembly (Part No.594-010)

Harmonic Balancer Assembly

from

$83.99
This direct replacement harmonic balancer features a stress-resistant rubber bond to properly absorb engine vibration. Stringent standards help ensure excellent tensile and impact strength for greater durability.

Product Features:
  • Ideal replacement – this harmonic balancer assembly exactly matches the fit and function of the original harmonic balancer for a direct replacement
  • Durable construction – stringent specifications and careful construction help ensure longevity
  • Thoroughly tested – this harmonic balancer has undergone dimensional verification, material validation and functional testing
  • Trustworthy quality – backed by a team of product experts in the United States and more than a century of automotive experience
See More

Dorman – Harmonic Balancer Assembly (Part No.594-012)

Harmonic Balancer Assembly

from

$72.99
This direct replacement harmonic balancer features a stress-resistant rubber bond to properly absorb engine vibration. Stringent standards help ensure excellent tensile and impact strength for greater durability.

Product Features:
  • Ideal replacement – this harmonic balancer assembly exactly matches the fit and function of the original harmonic balancer for a direct replacement
  • Durable construction – stringent specifications and careful construction help ensure longevity
  • Thoroughly tested – this harmonic balancer has undergone dimensional verification, material validation and functional testing
  • Trustworthy quality – backed by a team of product experts in the United States and more than a century of automotive experience
See More

PowerBond – Race Performance Harmonic Balancer; 202.25mm Diameter (Part No.PB1018SS)

Race Performance Harmonic Balancer; 202.25mm Diameter

from

$191.99
For use on the most popular passenger car, light commercial and four-wheel drive applications, Dayco harmonic balancers use special rubber compounds to dampen and remove engine harmonics and add to engine performance. Manufactured using a premium ductile iron casting and injection bonded dampening rubber, Dayco harmonic balancers offer engine builders and technicians the highest quality replacement to standard OEM balancers, which are typically made with press inserted dampening rubber. Dayco balancers utilize both inserted and pressure-bonded rubber to provide superior bonding strength between the inner and outer balancer rings, helping minimize spin and dislocation.

Product Features:
  • Designed as premium OEM replacement balancers for serpentine and V-belt drives
  • Manufactured with ductile iron casting and injection bonded dampening rubber
  • Engineered to offer superior bonding strength between the balancer rings
See More

Dorman – Harmonic Balancer Assembly (Part No.594-014)

Harmonic Balancer Assembly

from

$95.99
This direct replacement harmonic balancer features a stress-resistant rubber bond to properly absorb engine vibration. Stringent standards help ensure excellent tensile and impact strength for greater durability.

Product Features:
  • Ideal replacement – this harmonic balancer assembly exactly matches the fit and function of the original harmonic balancer for a direct replacement
  • Durable construction – stringent specifications and careful construction help ensure longevity
  • Thoroughly tested – this harmonic balancer has undergone dimensional verification, material validation and functional testing
  • Trustworthy quality – backed by a team of product experts in the United States and more than a century of automotive experience
See More

Dorman – Harmonic Balancer Assembly (Part No.594-170)

Harmonic Balancer Assembly

from

$89.99
This direct replacement harmonic balancer features a stress-resistant rubber bond to properly absorb engine vibration. Stringent standards help ensure excellent tensile and impact strength for greater durability.

Product Features:
  • Ideal replacement – this harmonic balancer assembly exactly matches the fit and function of the original harmonic balancer for a direct replacement
  • Durable construction – stringent specifications and careful construction help ensure longevity
  • Thoroughly tested – this harmonic balancer has undergone dimensional verification, material validation and functional testing
  • Trustworthy quality – backed by a team of product experts in the United States and more than a century of automotive experience
See More

PowerBond – Premium OEM Replacement Harmonic Balancer; 171.45mm Diameter (Part No.PB1027N)

Premium OEM Replacement Harmonic Balancer; 171.45mm Diameter

from

$94.99
For use on the most popular passenger car, light commercial and four-wheel drive applications, Dayco harmonic balancers use special rubber compounds to dampen and remove engine harmonics and add to engine performance. Manufactured using a premium ductile iron casting and injection bonded dampening rubber, Dayco harmonic balancers offer engine builders and technicians the highest quality replacement to standard OEM balancers, which are typically made with press inserted dampening rubber. Dayco balancers utilize both inserted and pressure-bonded rubber to provide superior bonding strength between the inner and outer balancer rings, helping minimize spin and dislocation.

Product Features:
  • Designed as premium OEM replacement balancers for serpentine and V-belt drives
  • Manufactured with ductile iron casting and injection bonded dampening rubber
  • Engineered to offer superior bonding strength between the balancer rings
See More

PowerBond – Diesel Performance Race Harmonic Balancer; 202.5mm Diameter (Part No.PB1490DP)

Diesel Performance Race Harmonic Balancer; 202.5mm Diameter

from

$408.99
For use on the most popular passenger car, light commercial and four-wheel drive applications, Dayco harmonic balancers use special rubber compounds to dampen and remove engine harmonics and add to engine performance. Manufactured using a premium ductile iron casting and injection bonded dampening rubber, Dayco harmonic balancers offer engine builders and technicians the highest quality replacement to standard OEM balancers, which are typically made with press inserted dampening rubber. Dayco balancers utilize both inserted and pressure-bonded rubber to provide superior bonding strength between the inner and outer balancer rings, helping minimize spin and dislocation.

Product Features:
  • Designed as premium OEM replacement balancers for serpentine and V-belt drives
  • Manufactured with ductile iron casting and injection bonded dampening rubber
  • Engineered to offer superior bonding strength between the balancer rings
See More

Dorman – Harmonic Balancer Pulley (Part No.594-530)

Harmonic Balancer Pulley

from

$45.99
This engine harmonic balancer pulley is designed to match the fit and function of the original pulley on specified applications. Made of quality materials, it is engineered for reliable performance and durability.

Product Features:
  • Direct replacement – this engine harmonic balancer pulley is designed to match the fit and function of the original pulley on specified applications
  • Restores functionality – reliable replacement for an original pulley that has failed due to vibration
  • Durable construction – this part is made from quality materials to ensure reliable performance and long service life
  • Trustworthy quality – backed by team of product experts in the United States and more than a century of automotive experience
See More

Dorman – Harmonic Balancer Assembly (Part No.594-037)

Harmonic Balancer Assembly

from

$151.99
This direct replacement harmonic balancer features a stress-resistant rubber bond to properly absorb engine vibration. Stringent standards help ensure excellent tensile and impact strength for greater durability.

Product Features:
  • Ideal replacement – this harmonic balancer assembly exactly matches the fit and function of the original harmonic balancer for a direct replacement
  • Durable construction – stringent specifications and careful construction help ensure longevity
  • Thoroughly tested – this harmonic balancer has undergone dimensional verification, material validation and functional testing
  • Trustworthy quality – backed by a team of product experts in the United States and more than a century of automotive experience
See More

PowerBond – Premium OEM Replacement Harmonic Balancer; 155.4mm Diameter (Part No.PB1012N)

Premium OEM Replacement Harmonic Balancer; 155.4mm Diameter

from

$49.99
For use on the most popular passenger car, light commercial and four-wheel drive applications, Dayco harmonic balancers use special rubber compounds to dampen and remove engine harmonics and add to engine performance. Manufactured using a premium ductile iron casting and injection bonded dampening rubber, Dayco harmonic balancers offer engine builders and technicians the highest quality replacement to standard OEM balancers, which are typically made with press inserted dampening rubber. Dayco balancers utilize both inserted and pressure-bonded rubber to provide superior bonding strength between the inner and outer balancer rings, helping minimize spin and dislocation.

Product Features:
  • Designed as premium OEM replacement balancers for serpentine and V-belt drives
  • Manufactured with ductile iron casting and injection bonded dampening rubber
  • Engineered to offer superior bonding strength between the balancer rings
See More

Dorman – Engine Harmonic Bala (Part No.A2210682654DOR)

Engine Harmonic Bala

from

$65.62
Durable and sleek, Dorman Harmonic Balancers feature a stress-resistant rubber bond that withstands the damaging effects of heat, salt, ozone and general wear and tear. The ductile steel construction allows for improved tensile and impact strength, safeguarding the engine and maintaining fuel efficiency year after year. Dorman Harmonic Balancers undergo detailed dimensional checks of the full assembly and critical components to ensure the strength and integrity of the part.

Product Features:
  • Includes woodruff key, bolts, and washers for a complete repair (where applicable)
  • Direct replacement to ensure proper fit
  • Ships with protective sleeve over cone and trigger to prevent damage (where applicable)
See More

Dorman – Harmonic Balancer Assembly (Part No.594-156)

Harmonic Balancer Assembly

from

$64.99
This direct replacement harmonic balancer features a stress-resistant rubber bond to properly absorb engine vibration. Stringent standards help ensure excellent tensile and impact strength for greater durability.

Product Features:
  • Ideal replacement – this harmonic balancer assembly exactly matches the fit and function of the original harmonic balancer for a direct replacement
  • Durable construction – stringent specifications and careful construction help ensure longevity
  • Thoroughly tested – this harmonic balancer has undergone dimensional verification, material validation and functional testing
  • Trustworthy quality – backed by a team of product experts in the United States and more than a century of automotive experience
See More

Dorman – Harmonic Balancer Assembly (Part No.594-713)

Harmonic Balancer Assembly

from

$81.99
This direct replacement harmonic balancer features a stress-resistant rubber bond to properly absorb engine vibration. Stringent standards help ensure excellent tensile and impact strength for greater durability.

Product Features:
  • Ideal replacement – this harmonic balancer assembly exactly matches the fit and function of the original harmonic balancer for a direct replacement
  • Durable construction – stringent specifications and careful construction help ensure longevity
  • Thoroughly tested – this harmonic balancer has undergone dimensional verification, material validation and functional testing
  • Trustworthy quality – backed by a team of product experts in the United States and more than a century of automotive experience
See More

PowerBond – Street Performance Harmonic Balancer; 202mm Diameter (Part No.PB1046ST)

Street Performance Harmonic Balancer; 202mm Diameter

from

$122.99
For use on the most popular passenger car, light commercial and four-wheel drive applications, Dayco harmonic balancers use special rubber compounds to dampen and remove engine harmonics and add to engine performance. Manufactured using a premium ductile iron casting and injection bonded dampening rubber, Dayco harmonic balancers offer engine builders and technicians the highest quality replacement to standard OEM balancers, which are typically made with press inserted dampening rubber. Dayco balancers utilize both inserted and pressure-bonded rubber to provide superior bonding strength between the inner and outer balancer rings, helping minimize spin and dislocation.

Product Features:
  • Designed as premium OEM replacement balancers for serpentine and V-belt drives
  • Manufactured with ductile iron casting and injection bonded dampening rubber
  • Engineered to offer superior bonding strength between the balancer rings
See More

PowerBond – Premium OEM Replacement Harmonic Balancer; 203mm Diameter (Part No.PB1150N)

Premium OEM Replacement Harmonic Balancer; 203mm Diameter

from

$153.99
For use on the most popular passenger car, light commercial and four-wheel drive applications, Dayco harmonic balancers use special rubber compounds to dampen and remove engine harmonics and add to engine performance. Manufactured using a premium ductile iron casting and injection bonded dampening rubber, Dayco harmonic balancers offer engine builders and technicians the highest quality replacement to standard OEM balancers, which are typically made with press inserted dampening rubber. Dayco balancers utilize both inserted and pressure-bonded rubber to provide superior bonding strength between the inner and outer balancer rings, helping minimize spin and dislocation.

Product Features:
  • Designed as premium OEM replacement balancers for serpentine and V-belt drives
  • Manufactured with ductile iron casting and injection bonded dampening rubber
  • Engineered to offer superior bonding strength between the balancer rings
See More

PowerBond – Race Performance Harmonic Balancer; 202mm Diameter (Part No.PB1046SS)

Race Performance Harmonic Balancer; 202mm Diameter

from

$169.99
For use on the most popular passenger car, light commercial and four-wheel drive applications, Dayco harmonic balancers use special rubber compounds to dampen and remove engine harmonics and add to engine performance. Manufactured using a premium ductile iron casting and injection bonded dampening rubber, Dayco harmonic balancers offer engine builders and technicians the highest quality replacement to standard OEM balancers, which are typically made with press inserted dampening rubber. Dayco balancers utilize both inserted and pressure-bonded rubber to provide superior bonding strength between the inner and outer balancer rings, helping minimize spin and dislocation.

Product Features:
  • Designed as premium OEM replacement balancers for serpentine and V-belt drives
  • Manufactured with ductile iron casting and injection bonded dampening rubber
  • Engineered to offer superior bonding strength between the balancer rings
See More

PowerBond – Premium Harmonic Balancer Pulley; Steel, 198 Inch Diameter (Part No.PB1194N)

Premium Harmonic Balancer Pulley; Steel, 198 Inch Diameter

from

$114.99
For use on the most popular passenger car, light commercial and four-wheel drive applications, Dayco harmonic balancers use special rubber compounds to dampen and remove engine harmonics and add to engine performance. Manufactured using a premium ductile iron casting and injection bonded dampening rubber, Dayco harmonic balancers offer engine builders and technicians the highest quality replacement to standard OEM balancers, which are typically made with press inserted dampening rubber. Dayco balancers utilize both inserted and pressure-bonded rubber to provide superior bonding strength between the inner and outer balancer rings, helping minimize spin and dislocation.

Product Features:
  • Designed as premium OEM replacement balancers for serpentine and V-belt drives
  • Manufactured with ductile iron casting and injection bonded dampening rubber
  • Engineered to offer superior bonding strength between the balancer rings
See More

Dorman – Harmonic Balancer Assembly (Part No.594-009)

Harmonic Balancer Assembly

from

$60.99
This direct replacement harmonic balancer features a stress-resistant rubber bond to properly absorb engine vibration. Stringent standards help ensure excellent tensile and impact strength for greater durability.

Product Features:
  • Ideal replacement – this harmonic balancer assembly exactly matches the fit and function of the original harmonic balancer for a direct replacement
  • Durable construction – stringent specifications and careful construction help ensure longevity
  • Thoroughly tested – this harmonic balancer has undergone dimensional verification, material validation and functional testing
  • Trustworthy quality – backed by a team of product experts in the United States and more than a century of automotive experience
See More

PowerBond – Premium OEM Replacement Harmonic Balancer; 169.8mm Diameter (Part No.PB1023N)

Premium OEM Replacement Harmonic Balancer; 169.8mm Diameter

from

$106.99
For use on the most popular passenger car, light commercial and four-wheel drive applications, Dayco harmonic balancers use special rubber compounds to dampen and remove engine harmonics and add to engine performance. Manufactured using a premium ductile iron casting and injection bonded dampening rubber, Dayco harmonic balancers offer engine builders and technicians the highest quality replacement to standard OEM balancers, which are typically made with press inserted dampening rubber. Dayco balancers utilize both inserted and pressure-bonded rubber to provide superior bonding strength between the inner and outer balancer rings, helping minimize spin and dislocation.

Product Features:
  • Designed as premium OEM replacement balancers for serpentine and V-belt drives
  • Manufactured with ductile iron casting and injection bonded dampening rubber
  • Engineered to offer superior bonding strength between the balancer rings
See More

Dorman – Harmonic Balancer Assembly (Part No.594-181)

Harmonic Balancer Assembly

from

$61.99
This direct replacement harmonic balancer features a stress-resistant rubber bond to properly absorb engine vibration. Stringent standards help ensure excellent tensile and impact strength for greater durability.

Product Features:
  • Ideal replacement – this harmonic balancer assembly exactly matches the fit and function of the original harmonic balancer for a direct replacement
  • Durable construction – stringent specifications and careful construction help ensure longevity
  • Thoroughly tested – this harmonic balancer has undergone dimensional verification, material validation and functional testing
  • Trustworthy quality – backed by a team of product experts in the United States and more than a century of automotive experience
See More

PowerBond – Premium OEM Replacement Harmonic Balancer; 203mm Diameter (Part No.PB1046N)

Premium OEM Replacement Harmonic Balancer; 203mm Diameter

from

$49.99
For use on the most popular passenger car, light commercial and four-wheel drive applications, Dayco harmonic balancers use special rubber compounds to dampen and remove engine harmonics and add to engine performance. Manufactured using a premium ductile iron casting and injection bonded dampening rubber, Dayco harmonic balancers offer engine builders and technicians the highest quality replacement to standard OEM balancers, which are typically made with press inserted dampening rubber. Dayco balancers utilize both inserted and pressure-bonded rubber to provide superior bonding strength between the inner and outer balancer rings, helping minimize spin and dislocation.

Product Features:
  • Designed as premium OEM replacement balancers for serpentine and V-belt drives
  • Manufactured with ductile iron casting and injection bonded dampening rubber
  • Engineered to offer superior bonding strength between the balancer rings
See More

PowerBond – Street Performance Harmonic Balancer; 154.5mm Diameter (Part No.PB1012ST)

Street Performance Harmonic Balancer; 154.5mm Diameter

from

$109.99
For use on the most popular passenger car, light commercial and four-wheel drive applications, Dayco harmonic balancers use special rubber compounds to dampen and remove engine harmonics and add to engine performance. Manufactured using a premium ductile iron casting and injection bonded dampening rubber, Dayco harmonic balancers offer engine builders and technicians the highest quality replacement to standard OEM balancers, which are typically made with press inserted dampening rubber. Dayco balancers utilize both inserted and pressure-bonded rubber to provide superior bonding strength between the inner and outer balancer rings, helping minimize spin and dislocation.

Product Features:
  • Designed as premium OEM replacement balancers for serpentine and V-belt drives
  • Manufactured with ductile iron casting and injection bonded dampening rubber
  • Engineered to offer superior bonding strength between the balancer rings
See More

PowerBond – Harmonic Balancer (Part No.PB1449N)

Harmonic Balancer

from

$95.99
Powerbond Premium OEM Replacement Balancers are manufactured using premium ductile iron castings and injection bonded dampening rubber. Unlike typical original equipment balancers that are made with press inserted dampening rubber, the bonded dampening rubber in the Powerbond Premium OEM Replacement Balancer provides superior bonding strength between the inner and outer balancer rings that minimizes spinning and dislocation in high torque and serpentine belt appplications. With a unique combination of high strength castings, bonded dampening rubber, and dynamic balance, the Powerbond Premium OEM Replacement Balancer is the ultimate standard replacement balancer.

Product Features:
  • Designed as a premium OE replacement
  • Dynamically balanced for smooth operation
  • Strong Iron casting for maximum strength
  • OEM equivalent bonded rubber
See More

PowerBond – Premium OEM Replacement Harmonic Balancer; 156mm Diameter (Part No.PB1597N)

Premium OEM Replacement Harmonic Balancer; 156mm Diameter

from

$63.99
For use on the most popular passenger car, light commercial and four-wheel drive applications, Dayco harmonic balancers use special rubber compounds to dampen and remove engine harmonics and add to engine performance. Manufactured using a premium ductile iron casting and injection bonded dampening rubber, Dayco harmonic balancers offer engine builders and technicians the highest quality replacement to standard OEM balancers, which are typically made with press inserted dampening rubber. Dayco balancers utilize both inserted and pressure-bonded rubber to provide superior bonding strength between the inner and outer balancer rings, helping minimize spin and dislocation.

Product Features:
  • Designed as premium OEM replacement balancers for serpentine and V-belt drives
  • Manufactured with ductile iron casting and injection bonded dampening rubber
  • Engineered to offer superior bonding strength between the balancer rings
See More

PowerBond – Street Performance Harmonic Balancer; 202.25mm Diameter (Part No.PB1018ST)

Street Performance Harmonic Balancer; 202.25mm Diameter

from

$118.99
For use on the most popular passenger car, light commercial and four-wheel drive applications, Dayco harmonic balancers use special rubber compounds to dampen and remove engine harmonics and add to engine performance. Manufactured using a premium ductile iron casting and injection bonded dampening rubber, Dayco harmonic balancers offer engine builders and technicians the highest quality replacement to standard OEM balancers, which are typically made with press inserted dampening rubber. Dayco balancers utilize both inserted and pressure-bonded rubber to provide superior bonding strength between the inner and outer balancer rings, helping minimize spin and dislocation.

Product Features:
  • Designed as premium OEM replacement balancers for serpentine and V-belt drives
  • Manufactured with ductile iron casting and injection bonded dampening rubber
  • Engineered to offer superior bonding strength between the balancer rings
See More

1973 Chevrolet Blazer Crankshaft Pulley and Harmonic Balancers

Maybe you’re in the middle of a full rebuild of that 1973 Chevrolet Blazer. Maybe you just need a couple of Crankshaft Pulley and Harmonic Balancers. Either way, Advance Auto Parts has 16 different Crankshaft Pulley and Harmonic Balancers in our inventory ranging from $49.99 to $191.99. That means you can find the exact parts or products you need to keep that 1973 Chevrolet Blazer running smoothly.

Crankshaft Pulley and Harmonic Balancers are only as good as their brand. We stock 3 different brands to make sure you have plenty of trusted parts to choose from for your 1973 Chevrolet Blazer. Dorman, PowerBond, and Mr. Gasket are just some of the brands we stock. Search for brands you know or compare prices and reviews to help you decide!

We know you’ll find the perfect Crankshaft Pulley and Harmonic Balancers for your 1973 Chevrolet Blazer, but don’t take our word for it – read our customer ratings and reviews and buy with confidence.

So if you’re in the market for aftermarket Crankshaft Pulley and Harmonic Balancers to keep your 1973 Chevrolet Blazer rolling for years to come, look no further. Shop online and have your products shipped direct to your door, or pick up at the nearest Advance Auto Parts location today!

Crankshaft Pulley and Harmonic Balancers Brands To Make Your 1973 Chevrolet Blazer Last

Simple repair, complete replacement, or a full rebuild. No matter the job, your 1973 Chevrolet Blazer demands trusted brand parts and products to keep it running. Many trusted brands of Crankshaft Pulley and Harmonic Balancers make up Advance Auto Parts’ inventory, and all are ready to help make your Blazer the best it can be. Be sure to browse some of our top Crankshaft Pulley and Harmonic Balancers brands and parts.

Popular PowerBond Crankshaft Pulley and Harmonic Balancers

We carry PowerBond parts in our stock across Harmonic Balancers categories, plus more. For a 1973 Chevrolet Blazer, our most popular PowerBond Crankshaft Pulley and Harmonic Balancers include:

FAQs for 1973 Chevrolet Blazer Crankshaft Pulley and Harmonic Balancers

What are the most purchased Crankshaft Pulley and Harmonic Balancers for the 1973 Chevrolet Blazer?

Out of 16 Crankshaft Pulley and Harmonic Balancers for the 1973 Chevrolet Blazer, the most popular in our inventory are:
Harmonic Balancer Assembly
from $73.99
(10)
Harmonic Balancer Assembly
Harmonic Balancers
Harmonic Balancer Assembly
from $83.99
This product is not rated
Harmonic Balancer Assembly
Harmonic Balancers
Harmonic Balancer Assembly
from $64.99
This product is not rated
Harmonic Balancer Assembly
Harmonic Balancers