1967 Toronado Harmonic Balancer Counterweight

[69OldsSpeed]

Hello Everyone,

I have purchased a Professional Products PowerForce Harmonic Dampers 80022 to replace my failing harmonic balancer on my 1967 Toronado. The old one has spun the outer ring (rendering the timing mark useless) and the rubber is cracked and rather wavy. The new harmonic balancer is linked below.

https://www.summitracing.com/parts/pfs- ... +Ad+Groups

The counterweight that comes with this new harmonic balancer (measured as ~516 g) is larger than the counterweight that was cast into the original harmonic balancer. See the two balancers in the picture below.

Harmonic_Balancer.jpeg (537.72 KiB) Viewed 13123 times

Does anyone have any experience or issues running this larger weight on their 425? Does anyone have a target weight for the counterweight in this application? Have you cut the weight down?

I ask because all olds harmonic balancers I've found state that they need to be "rebalanced" for the application to early 425s. I understand that I will need to make clearance due to the front wheel drive application (i.e. the mount takes up some of the clearance behind the harmonic balancer.)

[Otto Skorzeny]

I don't know the answer to your questions but these two companies rebuild harmonic balancers. They vulcanize new rubber to your original parts.



Dale Manufacturing Harmonic balancer rebuilding
3425 Fairhaven Avenue N.E.
Salem, Oregon USA 97301
(503) 364-8685 PST
http://www.hbrepair.com/

Damper Doctor Harmonic balancer rebuilding, drive shaft mounts and motor mounts
1055 Parkview Ave.
Redding, CA 96001
(530) 246-2984
https://damperdoctor.com/

[69OldsSpeed]

Thank you for those contacts.

Unfortunately I have already purchased the harmonic balancer and I'm not quite ready to consider it sunken cost.

Does anyone one have experience, that they can share, in either using the non-425 harmonic balancer as-is or how they modified the counterweight to suite the 425?

[bcroe]

Had that experience of spun timing mark a few time, one came completely off.
My fix was a FLUIDAMPER using liquid silicone inside, no parts that can ever
come loose. There were a couple issues with it.

The first problem was the friction fit onto the crank. 60s stuff just slid on,
Olds started making the damper 1/2 mil undersized late 70s, goes on and off
with a proper tool no problem. But the Fluidamper had an anodized coating,
which inside made it a 1.5 mil undersize fit, just too tight. I put a piece of
metal into the keyway, and used a ball hone to remove the anodizing, now
it was fine.

Other problem, the counterweight bumped the FWD mount on my 79. I
took off the mount and removed a bit of metal, solved the problem. Bruce Roe

[69OldsSpeed]

Thank you for your experience. I will check fitment and let her rip. If I feel vibration I’ll take it off and adjust the weights.

I’ll post my experience.

[Otto Skorzeny]

69OldsSpeed, Did the balancer you bought come with assorted weights to bolt on?

If you get a vibration, how do you know whether to add or subtract weight? And how much?

[69OldsSpeed]

There was only 1 weight provided, 516 g. So, I considered that this new counterbalance weight is designed to fit my 69 Olds Cutlass 350. I measured all three harmonic balancer dimensions, the 1969 350, 1967 425, and the new balancer.

I took the ratio of the counterweight volumes of the 1969 350 harmonic balancer and the 1967 425 harmonic balancer. That ratio was 130:78, by volume, there is no practical way to measure the weights weights. I am taking a leap of faith that the PRO Products weight is accurately sized to match the 1969 350, as it has nearly the same dimensions and the PRO Product technician indicated the proper application of the part. I estimated that the Toronado weight is 325 g, however, it is at a longer effective moment arm than that of the PRO Products weight.

So I split the baby, cut off 0.2 in (~100 g), and hope that it is close enough. If not, I will remove another 50 g. After that 25 g. I have read that +/-28 g counterweight accuracy is the minimum required. At some point, with enough dull hacksaw blades, I’ll hit it right. Or I won’t notice a vibration and I will drive down the road fat, dumb, and happy.

[Otto Skorzeny]

I assume that shiny divot in the new balancer was drilled out by you. Do you just drill a little and weigh the piece, drill a little more and weigh it again, etc. until you remove the amount you want?

How do you decide where to take the metal out?

Sorry for all the questions. I've never done anything like that before.

[bcroe]

I thought the same balancer fit all Olds V8s, weight differences were taken care
of in the crank weights. Bruce Roe

[69OldsSpeed]

I assume that shiny divot in the new balancer was drilled out by you. Do you just drill a little and weigh the piece, drill a little more and weigh it again, etc. until you remove the amount you want?

How do you decide where to take the metal out?

Sorry for all the questions. I've never done anything like that before.

The shiny divot was in place on the new harmonic balancer when I received it. I made no modifications to that. I took the approach to adjust the weight only. If you look at the other PRO Products harmonic balance applications, the weight is the only change between the various engines and years (e.g. Ford 351 Windsor vs. Ford 351 Cleveland.). So I followed the same approach, just change the weight.

Since the weight is almost perfectly symmetrical and in the correct radial location, it was simplest to remove the top surface for more predictable results. Although it is painful, I would rather remove smaller than estimated mass each time so I don’t overshoot and have to buy a new weight.