Harmonic Balancer

I have a problem with a recently purchased 90 SC with 46,000 miles. It was purchased at the police auction so I don't have any background on the vehicle, but it is in overall excellent condition.

The problem is that two of the four bolts on the bottom pulley are sheared off. A semi-pro mechanic said that Ford used "soft" bolts and that all I need to do, is remove the pieces and reattach the pulley using better bolts.

I'm not sure that I like the "soft" bolt theory and am wondering what you guys think. Doesn't the bottom pulley attach to the Harmonic Balancer? Could it be the real problem?

TW

The harmonic balancers are a problem in these cars. I would suggest a new balancer/pulley assembly from Ford (~$200). The balancer that you have has obviously seen some kind of shock to shear off those two bolts and may be weakened.

A BHJ balancer would be a great move if you are going to mod the car but it's an expensive option ($400 balancer + $150 pullies)


Aaron

I agree.

Ford never uses an un-heat treated bolt in such an application. That theory is rediculous and I'd look into possibly moving to another, more astute mechanic.

The balancers are a combo of aluminum and rubber. The rubber over the last twelve years is getting brittle and may fail soon. Anyone with an older SC should consider this procedure as a "maintenance" item soon to ward off a failure at an inopportune time. The Ford balancer/pulley combo will be fine for any application up to 325 (+/- a fudge factor) Horsepower. After that, consider the BHJ unit.

From what I've heard, the common problem with these balancer assemblies is that the compound bonding the outer ring to the hub gets weak resulting in a serious unbalance problem, sometimes leading to the crank bolt (the large one in the center of the hub, or the whole snout of the crankshaft breaking. I have yet to hear of a case where the failure of the balancer resulted in the smaller bolts breaking off that mount the crankshaft pulley to the balancer.

Is it possible that someone has had that crankshaft pulley off before, and perhaps they snapped of the bolts? If so, and so long as they put the pulley back on properly, you may just need to remove the broken off bolts (including the parts buried in the hub) and replace them.

If you can afford a new balancer and pulley assembly from Ford at approx. $200 USD, then I agree fully with Pastera. Further, if you can afford the $400 USD part from BHJ, then go for it. I helped Bill McNeil install his BHJ balancer, and it truly is a quality piece! Ford should have used a similar design, instead of the weak set up that they did use.

Good luck!

Cheers,

Sean

I have the BHJ balancer and it's MUCH better than the stock unit.
The problem is for most people it's 3X the cost with a set of UD pullies.

I believe the bolts on the pulley are metric grade 10.9 , just buy them from ford if you want to keep the old balancer.

Aaron