Harmonic Balancer 8"

[Greg S.]

I purchased an eight inch finned balancer for my 340 horse 62 to replace a non finned eight inch balancer that was on the engine. I am concerned that the fit of the new balancer is too loose. It feels like I can push the new balancer on until it bottoms on the crank shoulder. When pushed on until it bottoms there is still some wobble or side to side play when rocking the balancer.

I took some measurements of the old and new balancer front and back diameters as well as the crankshaft snout at the front of the timing cover. They are: Crankshaft OD 1.247", Old Balancer Rear 1.2475, Front 1.2145; New Balancer Rear 1.261, Front 1.219.

Questions I have are: Is the crankshaft snout tapered from back to front and how much? Even though the new balancer is noticeably loose will the front bolt hold it on the shaft? If not can I have this balancer machined and sleeved to the proper clearances? What are my options? I do not want this balancer to come off at 6000 RPM!

By the way an old thread mentioned the possibility of the timing mark slipping as the rubber connection gets weaker. I noticed that the timing mark on the old balancer is about a half inch behind the key way in the hub. Shouldn't they line up?

[Bill Clupper]

Re: Harmonic Balancer 8"

Let's start with the slippage of the timing mark, yes, the timing mark should line up with the edge of the keyway. so that is a problem in itself. I can't speak to the bolt's ability to retain a loose damper, but I would think it very questionable.

[Joe L.]

Re: Harmonic Balancer 8"

Greg-----

I was not aware that harmonic balancer crankshaft mounting holes were tapered, but you measurements seem to confirm that they are.

In any event, the harmonic balancer should be an interference (press) fit on the the crankshaft snout. I would NOT USE this balancer. I would return it and get one that has been properly machined. I know of no practical way for this balancer to be repaired.

[Greg S.]

Re: Harmonic Balancer 8"

I was pretty sure of the answer but wanted a second opinion. I bought this balancer out of the Driveline. First time I have had a problem. Thanks for the response.