Harmonic balancer

It is a device that absorbs and dampens the vibrations produced by the crankshaft, connecting the crankshaft to the engine’s frame. This helps reduce wear and tear on the engine’s components, as well as reduce noise levels and smooth out engine operation. The harmonic balancer also helps keep the timing belt or chain in sync, as it controls the crankshaft’s speed of rotation. The crankshaft does not ride directly on the cast iron block crankshaft supports, but rides on special bearing material. The connecting rods also have bearings inserted between the crankshaft and the connecting rods. The bearing material is a soft alloy of metals that provides a replaceable wear surface and prevents galling between two similar metals. Each bearing is split into halves to allow assembly of the engine. The crankshaft is drilled with oil passages that allow the engine to feed oil to each of the crankshaft bearings and connection rod bearings and up into the connecting rod itself.

The harmonic balancer itself does not control timing. It’s keyed to the crankshaft and only affects timing if:

• The timing tab or the balancer's timing mark is misaligned (e.g., using an incorrect replacement).
• The timing chain is disturbed (which won’t happen just from balancer removal).

removal

Use a proper harmonic balancer puller to avoid damage. Before removal, check where the TDC timing mark on the balancer lines up on your timing tab (note the position for reference). Inspect or clean the keyway on the crankshaft snout and the key itself.

Harmonic Balancer Puller

The balancer is press-fit onto the crankshaft snout. It’s very tight. A puller removes it evenly and safely by threading into the balancer and pulling from the center.

Without it, you risk:

• Damaging the crankshaft threads or keyway
• Warping or cracking the balancer (even if it’s already bad)

tips for removal

Remove the drive belts and any accessories blocking access (e.g., power steering pump or fan). Use an impact wrench to remove the crankshaft bolt (7/16” fine thread).

Use the longest forcing rod in the kit to reach the deep crankshaft snout. If using a 3-jaw puller ensure the 3-jaw puller grips the balancer’s inner hub securely, avoiding the rubber ring.

Older engines may have corrosion. If the balancer is stuck due to corrosion, apply penetrating oil and gently tap with a mallet to loosen it before using the puller.

Some haramonic balancer removal tools are for a specific design. A GM engine might have 7/16” fine-thread holes so you will want to use a bolt-on puller. Otherwise you may have to use a 3-jaw puller which can have manual adjustments with our without being spring loaded. The bolt-on puller is a better option for engines with 7/16” fine-thread holes and a heavier built puller is more reliable. For bolt-on pullers, use the provided 7/16” bolts and tighten evenly. For jaw pullers, position jaws on the inner hub, avoiding the rubber ring, and secure with manual adjustments or shims if needed.

installation

Installation requires specific tools and considerations to ensure proper alignment, seating, and torque without damaging the crankshaft or balancer. You’ll need a separate harmonic balancer installer tool to press the new balancer onto the crankshaft without damaging it.

When installing the new balancer, make sure it: Matches the old one in diameter and depth. Has the timing mark in the same position relative to the keyway. Is seated fully using a proper installation tool (do not hammer it on). Avoid using the crankshaft bolt alone to install the balancer, as this can damage the crank threads or misalign the balancer, leading to vibration or failure.

After installation: Re-check timing with a timing light once the engine is running, in case the new balancer’s mark is slightly off due to manufacturing differences.