Harmonic balancer

[Jenny5050]

Hello everybody,
I have inherited a 1959 FC special sedan from my grandfather.
It seems in fairly good condition so I decided to get it registered and use it occasionaly.
I took it to a mechanic for roadworthy, and he gave me a list of things I should have fixed before he actually does the inspection.
One of the items was to replace the harmonic balancer, which he claims is missing (fallen off?).
A friend of mine says this is impossible and the car would not run properly without it.
What does the harmonic balancer do, and is someone having me on?
Is it a case of bamboozle the woman and get her money quick?
Please help,
Rhonnda.

[Hobbo]

Hi, maybe someone removed it to get it repaired due to oil leaking? Fan belt would have nothing to fit to either as the harmonic balancer drives the belt to turn water pump,fan and generator. Get others to look at it?

[EffCee]

One of the items was to replace the harmonic balancer, which he claims is missing (fallen off?).
A friend of mine says this is impossible and the car would not run properly without it.
What does the harmonic balancer do, and is someone having me on?
Is it a case of bamboozle the woman and get her money quick?
Please help,
Rhonnda.

Hi Rhonnda

The harmonic balncer helps to even out the power pulses of the engines that is not possible to achieve with balancing engine parts. In a 6 cylinder 4 stroke engine, (as in the holden 6) the engine fires  every 120 degrees, requiring 2 revolutions to complete the sequence on all 6 cylinders. Crankshaft counterweights and flywheel help absorb some of the dynamic vibrations of the engine firing every 120 degrees, but there are little vibrations called "engine harmonics" that continue. In order to reduce these further a harmonic balancer is fitted, usually on a rubber mount to help reduce these further. That is the purpose of a harmonic balancer.

To have one missing completely would result in catastrophic oil loss from the front of the engine, the engine at the front would be very noisy where the hole for the harmonic balancer has been exposed. To have just the outer ring of the harmonic balancer come off then as hobbo said there wuld be nothing that you could mount a fan belt toto driver the generator or water pump. Obviously if the whole balancer was missing than you would not be able to driver either the water pump or generator.

I would be taking it to another mechanic to have a look at, alternatively, if you were to post a picture of the front of the engine on the forum, around the region where the fan belt attaches to the harmonic balancer, which is below the water pump (attached to the fan) then we will be able to confirm that the harmonic balancer is in place.

HTH

Keith

[Jenny5050]

Thanks Hobbo and Keith,
I had another (older) mechanic look at the problem and your messages.
He said there are no oil leaks around the hub, and that the hub and pulley are intact, but the small "flywheel" on the end appeared to be missing, or was never fitted.
He had not seen this sort of harmonic balancer before, even though he had worked on possibly hundreds of these motors.
He said if it had been manufactured this way, he would leave it alone, but if the flywheel had in fact fallen off due to rubber failure or whatever, it should be replaced.
There is no damage or marks to indicate it had come off.
I am at a loss to know what to do, has anybody else seen something like it?
I am sorry I cannot send pictures yet, but hope the description helps.
Thanks,
Rhonnda.

[FCwagon]

Hi Rhonnda,
Yes the flywheel thingy is part of the unit and is the balance weight. It sounds like that and the rubber bushing has gone bye-byes. I had this happen on my old FC years back and if it comes off while running it usually does a fair bit of damage to the fan blades. The engine will run without it but be very harsh and put undue stress on the crankshaft. Replacing it should be done sooner than later.
cheers,  Leigh