Another balancer question

minbe

Registered User
On the BHJ I hear differing opinions about balancing the pulley to the balancer. Is this neccessary? I pulled this off another forum:

""""If you look at the current FAQ on this basically the thinking now is that the balance pins are not used to match balance the pulley to the damper...they were placed in there to dynamic balance the entire engine assembly as well as pins in the flywheel or rivets in the flexplate.

So to answe your question...yes you can use the stock pulley. Not much use in balancing the pulley or the damper (damper is already neutal balanced). """"

I lean toward the billet because I've had 2 stock ones break so far. Though I made the mistake of using a used bolt when I did the replacement. It looks like the bolt broke first then without support the balancer twisted apart. I think the billet one would be strong enough to hold for a while even with a broken bolt. If I am incorrect let me know. I want to try the Mustang bolt as I've heard they hold up better(what was that part number...).

Also I understand the BHJ needs to be honed to fit the crank. Is this something I can do with a drill mounted hone? The crank is still in the car and I would have to mic it in place and hope my measurements were correct if I take it to a machinist. Will my timing vanes bolt up OK to the BHJ? Is timing an issue?

Any info would be appreciated.
Thanks
Minbe
 
Minbe, you may get lucky as it is not always necessary to hone a BHJ balancer. It just depends on where your crankshaft snout falls in Ford's tolerance range. I just installed a BHJ on my 90SC and the fit was a perfect .001 interference fit out of the box. Because the stock balancer has an aluminum center hub Ford didn't find it necessary to hold the snout diameter to a perfect dimension. The aluminum hub has the ability to stretch and adapt better than steel without welding itself to the snout by being too tight.
It's my opinion (as well as others) that the balancer bolt doesn't fail causing the HB to fail. It's the other way around, the balancer begins to fail breaking the bolt, then the balancer comes apart.
The stock sensor vane bolts up to the new balancer.
I've heard some say that you can use a small cylinder hone to hone out the new balancer, but personally, I wouldn't do it. I would take your snout measurement then take the balancer to a machine shop and tell them to finish hone it to the exact size you want (.001"- .0015" smaller than snout). They should have a good Sunnen wet hone that will give a perfect and consistent finish end to end. good luck, John
About balancing: the BHJ is neutral balance, so all you need is a neutral balance pulley. I used a underdrive set which has a neutral balanced pulley. I went this way for convenience and also because the aluminum underdrive pulley is much lighter than the stock one. I suppose you could find a machine shop to zero balance the stock pulley, but I couldn't find a shop close to me. I suppose if you take any balancer weights off the stock pulley it should come to near neutral, but not sure if close enough to not cause a vibration.
 
You can "hone it" yourself....

I used a small cylinder hone drill bit made for a lawnmower engine to fit my BHJ. Maybe not the best way to do the job, but it worked fine. I just "honed" a little and check the fit, "honed" a little more and checked again. Just remember that once you remove the metal, you can't put it back. That was about 2-yrs ago and no problems so far. The best way to be sure that the pulley will be "in balance" with the BHJ is to invest in a set of underdrive pulleys. They come "zero balanced" as does the BHJ. The "hall-effect" ring (the thingy with the vanes on it) for the crank sensor will line up with the bolt holes on the BHJ. Just re-use the little bolts that are on the old balancer. I don't know if it is necessary, but I marked the vane that lined up with the key-way on the old balancer so that I could match the relationship to the key-way on the BHJ. It may only fit one way, so it might matter. If you can get a balancer install tool, that will help alot. You want the balancer to be as tight on the crankshaft as possible (and still be able to get it on the shaft).
 
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