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A few months back I was chasing vibration in the FB. The harmonic balancer (a red-motor type aftermarket job) showed quite a bit of wobble, so I chose to replace it. I struggled to get a replacement from Rares due to a supplier issue with Dayco (this may have since been resolved). I ended up buying a Tuffbond balancer from Ross. The balancer (part number 116543) is one of their Metal Jacket jobs, and beautifully made. The main drama I had is that the balancer clashes with the standard grey motor fan, and I ended up notching the fan blades to suit.

One thing I noticed during the installation is that the interference fit between the crank and the Ross balancer is a lot tighter than the normal replacement balancer. I followed normal practice for oiling, and checking for burrs and rough spots on both the crank and balancer – all good. The instructions for the Ross balancer are quite specific that they should be installed with an “installation tool”, not smacked on with a BFH and lump of wood. The BFH method is pretty standard grey motor practice (either with a lump of wood or the fancy service tool that screws into an original balancer).

I know a lot of other vehicle cranks are fitted with drilled crank snout centres. This allows a bolt to be installed, and the “installation tool” to gently squeeze the harmonic balancer onto the crank. This removes the BFH, and has got to be a good thing for the thrust bearings. I’m guessing that it would be possible to drill and tap the standard grey motor crank snout to accept a bolt. I could then make an “installation tool” that uses the bolt to drive on the Ross balancer.

Has anyone drilled and tapped the grey motor crank snout for this? Are there any other (gentle) ways of installing the harmonic balancer on a grey that doesn't load up the thrust bearings?

Cheers,
Harv

Hi Harv,

While I have not done this to a crank and harmonic balancer, I have done exactly that when fitting new timing gear to the cam. It seems reasonable to do it I would have thought.

I was always told before hitting the balancer on to always ensure that the end float has already been taken up before hitting it on. By doing this it minimises the chances of damaging the thrust bearings.

Cheers

Rod

Harv if the engine is out, stand the engine the engine on its flywheel (vertical) with the snout up then belt the balancer on. This will remove the problem of effecting the thrusts. I'm assuming the recommendation to not belt the Ross balancer would also be about not dislodging or damaging the outer ring from its rubber due to the shock impaired on the inner hub. If you manage to thread the crank I would use a long stud and hollow type porta-power ram to pull it on.

Not a bad idea. A bit of rigging to spin the motor 90º, but not impossible with a simple pair of endless chain blocks. With a bit of care, I could damn near get the spun motor into a shop press and press the balancer on.

I've got to get a crank sorted by Duncan Foster in the next few months... might get them to drill and tap the snout while they are there.

Cheers,
Harv

Hi,
I changed a balancer over a few years ago that seemed to have a job wanting to go on. I ended up putting the shaft of the balancer in boiling water and kept it simmering for a few minutes. That provided a little more clearance and then went on no worries using a BFH.

Regards
Stephen

Gday Harv,

Hey did you end up drill and tapping the crank snout for a bolt hole to help install the Ross balancer?

I have the same balancer and I’m curious to know how you went installing it.

Crank is currently on the bench so I’ll drill and tap it in the lathe if you could advise which thread / pitch you used.

Cheers Drew

The one in the FB did not get drilled, but the motor that is out at Duncan Foster being machined did. It's drilled to 7/16-20 UNF to suit this type of installer:

https://www.summitracing.com/parts/mor-61740

If you want to get handy and make your own installer, you can thread it any way you like. I like the thrust bearings in the Moroso ones, but that's just me.

While the crank is out, measure both the Ross balancer and the crank snout. While the crank is on the lathe, you might want to lighten up the interference fit on the crank.

Cheers,
Harv

Cheers Harv, 7/16 UNF is a good starting point and yes I’ll sort the clearance issue for the balancer out