GEAROLL Harmonic Balancer Installer for Chevy SBC & BBC — 5/8-16 & 7/16-16 Thread Kit, Thrust Bearing

GEAROLL 66515 is a durable harmonic balancer installation kit designed to safely and accurately press balancers onto SBC and BBC Chevy crankshafts.

This installer tool gives mechanics and home-garage builders a simple, repeatable way to fit harmonic balancers without damaging the crank snout or the balancer itself. Made from quality steel and supplied with threaded rod ends, a nut, washers and a thrust bearing, the kit supports both small block (SBC) and big block (BBC) Chevrolet engines that use 5/8-16 or 7/16-16 crank threads. Its straightforward screw-in design turns the pressing job into a controlled, low-force operation.

How does the GEAROLL installer protect the crank and balancer during fitment?

The installer converts the press fit into a threaded pulling action so the balancer is drawn evenly onto the crankshaft. The included thrust bearing reduces friction, and the washer stack spreads load to prevent marring the balancer face.

• Threaded rod engages crank threads for centered alignment.
• Thrust bearing minimizes torque and wear on parts.
• Washers distribute force to avoid localized damage.
• Nut allows controlled, gradual seating of the balancer.

Which crankshafts and thread sizes does this tool support?

This kit is engineered for Chevrolet small block and big block crankshafts that accept 5/8-16 or 7/16-16 threaded installers. Those two common thread sizes cover the majority of SBC and BBC balancer installations used in classic and modern builds.

• Compatible with SBC (small block Chevy) crankshafts.
• Compatible with BBC (big block Chevy) crankshafts.
• Includes both 5/8-16 and 7/16-16 threaded rod ends to match crank threads.
• Versatile for repairs, rebuilds and performance swaps.

What components are included and how do they simplify the job?

The kit arrives ready to use with all necessary hardware so you avoid sourcing separate parts. With the threaded rod, nut, washers and thrust bearing, assembly is quick and the installer works with standard hand tools.

• 1x threaded rod with both 5/8-16 and 7/16-16 ends for fitment flexibility.
• 1x nut sized to pull the assembly and seat the balancer evenly.
• 1x thrust bearing to cut friction and ease turning effort.
• Multiple washers to protect mating surfaces and adjust spacing.

How easy is it to use this tool in a home garage or professional shop?

Setup is simple: thread the correct end into the crank, position the balancer, stack the washers and thrust bearing, then rotate the nut to draw the balancer on. The tool works with common hand tools, so you don’t need specialized presses for most installations.

• Thread correct rod end into crank and hand-start nut.
• Place balancer over crank snout and align carefully.
• Use the nut to slowly pull the balancer on, monitoring alignment.
• Remove installer hardware after the balancer is fully seated.

Who is this for: The GEAROLL 66515 harmonic balancer installer kit is aimed at DIY engine builders, restoration shops and professional mechanics working on Chevy small block and big block engines. It’s useful for anyone replacing harmonic balancers during rebuilds, performance upgrades or routine maintenance who wants a low-cost, reliable method to seat balancers without risking part damage. Backed by a limited 90-day factory warranty, the kit is a practical addition to toolboxes where accuracy and part protection matter.