- Home »
- Catalog »
- Engine Components- External »
- Harmonic Balancers/Dampers
Harmonic Balancers/Dampers
Pontiac V8 Harmonic Balancers/Dampers
Read It Right, Hold It Together — Harmonic Balancers/Dampers for Pontiac V8s
A harmonic balancer absorbs the torsional twist the crankshaft sees every time a cylinder fires. When the bonded rubber lets go, the inertia ring slips, your timing marks lie to you, and the crank and bearings pay for it. It is also the part your timing light reads, so accuracy matters as much as strength.
Butler stocks stock replacement dampers from Butler AAC and Powerbond, performance street units with 0-40 degree marks, SFI approved balancers from Powerbond and Romac, ATI Super Dampers with 360 degree laser engraved marks, plus crank hubs, spacers and timing tapes.
Browse Harmonic Balancers/Dampers Products
Popular Brands:
More About Harmonic Balancers/Dampers
1. Six Bolt or Four Bolt: Start With the Year
Pontiac changed the balancer and pulley mounting partway through, and that split decides almost everything else you order.
| 1959-67, six bolt | Butler's AAC two-piece performance damper covers the early engines that need a six-bolt, two-piece balancer and hub. The balancer bolts inside your pulley, which is not included, and the kit comes with six grade 8 pulley bolts and a crank key. Its extended hub works with later crankshafts that have longer snouts as well as early short snout cranks. It carries stock timing marks only. |
| 1968-79, four bolt | The four-bolt balancer covers 1968-79 except the 301. Butler offers an AAC stock replacement with stock timing marks that works with A/C pulleys, and Powerbond offers a stock replacement in the same fitment. |
| Timing marks on the early unit | With the two-piece early damper and a 1968 or later timing cover, the first mark clockwise is the 0 mark and you disregard the second. With a 1964-67 cover, the first mark clockwise is 6 and the second is 0. Butler recommends an adjustable timing light either way. |
2. Stock Replacement, Performance Street, or SFI
Three tiers, and the line between them is how hard the car gets used.
| Stock replacement | Powerbond bonds the dampening rubber to the metal under heat and pressure rather than inserting it, which is what stops the inertia ring spinning and separating. Bodies are new high strength nodular iron or 1045 steel, CNC machined and balanced at the factory. Stock timing marks only. |
| Performance street | Powerbond's street balancer for 1968-79 except the 301 adds permanently etched timing marks in 2 degree increments plus 90 degree increments, and 0-40 degree marks. The heat bonding process eliminates slipping and component separation up to 6500 RPM. It is not SFI approved. |
| SFI approved | SFI approved dampers are required for track duty — if the car sees a sanctioned strip or road course, this is not optional. Powerbond's race balancer meets SFI 18.1, is tested and approved to 12,500 RPM, is machined to work with stock A/C pulleys and carries the same 2 degree etched marks. Romac offers SFI approved 1968-79 four bolt balancers with timing marks in an all steel version and a steel and aluminum version in black anodize. |
3. ATI Super Dampers and What Changes With Them
The ATI units are a different design — inner and outer shells holding a steel inertia weight on computer machined O-ring grooves, tuned per application. They exceed SFI 18.1 and carry 360 degree laser engraved timing marks in a black zinc chromate finish. They also move things.
| The sizes | A 6-3/8" three-bolt internal balance unit at 6.325" OD, a 7" three-bolt steel unit at 7.074" OD, and a 7" aluminum unit at the same OD for reduced rotating weight, that one built three-ring for high horsepower and RPM. |
| Thickness | All of them run .0135" thicker than stock. |
| Pulley face | The pulley mounting surface sits .200" further out than stock. You will need a three-bolt V-belt crank pulley and you will have to re-space brackets and accessories to account for that .200" difference. |
| Timing cover | The 7" units may require grinding of the timing marks to clear the balancer. Check it before final assembly. |
| Hubs and spacers | ATI center hubs and a .093" thick crank hub spacer are stocked separately for setting the damper where it needs to sit. |
4. Fitting and Reading It
Two practical notes that come up on nearly every order.
| Hone to fit | Butler flags hone to fit if needed on the Powerbond and Butler AAC units. Romac's balancers run a .002" undersized hub ID and a narrower shell for clearance and may need honing. Do not drive a tight balancer on. |
| Timing tapes | If your balancer only has stock marks, a tape gives you the rest of the curve. Butler's 7" Pontiac tape reads 0-60 degrees and suits 1968-and-up factory balancers and the Powerbond stock replacement. MSD's tapes cover 5.25" to 8" diameters and read 64 BTDC to 14 ATDC. |
Pick by year first, then by how the car is used. A stock rebuild is well served by a bonded stock replacement and a timing tape; anything that sees a track needs an SFI approved unit, and an ATI installation needs the matching pulley and a bracket re-space planned in.
Not sure what your Pontiac needs?
Call our tech team at 866-762-7527. Tell us your engine, heads, car, and power goal, and we will put the parts together as one combination that works.