Crank Bolt Harmonic Balancer nightmare

notsofine89

Registered User
HELP!!!!

I have a 89 SC with less than 100K original. Awhile back it started busting crank bolts.... It took three trips to the the dealer to figure out that they didn't know what the hell was going on. Readers of this forum pointed out the well known problem with the harmonic balancer on this motor. I cut and pasted alot the responses, and emailed them to the service manager (at Serramonte Ford in Colma). I wound up taking BART to Fremont, and buying one of those bomb-proof harmonic aftermarket steel balancers that someone here reccomended (OUCH!! around $400 with tax!). Dropped that off at the ford dealership, and had the car on the road for another grand or so.... But the dealer fixed it under the premise that this was a gamble....there might be someting wrong with the crank or the motor that was causing this. Throwing caution to the wind, I had it done. With 250 miles on the trip odometer, It starts doing the same thing it did when the crank bolt would break, i.e., several miles of violent chugging, after which the engine light would come on and the car would refuse to start.... I popped the hood...felt the recess in the middle of the crank pulley....the crank bolt is still there this time.

I had the thing towed to Big Valley Ford in Stockton, CA. I have to get back to San Francisco soon. Is there anything I should tell this dealer about fixing this car? Does anyone have any idea what unseen pitfall is causing this car to fail again? Any idea where Serramonte Ford might have screwed up? Or is the motor/crank pretty much shot. At Serrmonte, I almost had to give them some help in diagnosing it, and I'm <B>NOT</B> a knowlegeable mechanic....

Question #2: Vehicle in question is a completely stock (except for trick harmonic balancer) 89 SC with about 96K orig, 5 speed, new tires, good body and paint with sevral minor flaws (white) with normal wear and tear, what would be a good starting price for trying to sell this thing as-is if the motor is toast?

I have no resources to deal with a broken car in San Francisco (garage, parking, etc.) And if the engine is toast, I need to sell this thing QUICK to someone who has a garage, and is bit better with a wrench than I am....

Thanks for any advice....I'm headed down to see the service people at Big Valley Ford monday morning.

Mike
a.k.a. notsofine89
 
Due to the small clearance with the crank sensor and the harmonic balancer vanes, it is not uncommon for a broken balancer to take out the crank sensor. It sounds like that may be your problem. As a rule of thumb, its best to replace both whenever you have the balancer replaced.
 
Replace both sensor and balancer if it is a FORD unit.
But you have a BHJ balancer? I don't beleive these are like the factory ones. I THINK reusing it should be fine, just the factory ones are crap and once you pull them you have to replace them. That is probably why everybody spends so much on the aftermarket one is so it can be reused.

Definately take a look at the crank sensor though..that goes your car won't start and if already running will go into limp home mode.
 
This is one of those chicken and egg deals. If the crank sensor goes intermitant then the engine gets violent power spikes as the ignition turns on and off. This causes severe strain on the dampner and bolt. Now it could also be that the dampener is out of balance and casueing the breaking of the bolt and the smacking of the sensor.

Two instances from my personal experience:


My nephews crank bolt while the crank sensor was going out. I had removed and reinstalled dampener after a timing chain and gear replacement three months prior. The night the bolt broke the crank sensor was bad and casusing violent bucking of the engine. I replaced the dampener, bolt , and crank sensor under advise from this board. Upon inspection I could not find any fault with the old balancer and the crank sensor never struck the balancer shutter vanes. I replaced balancer with new FORD unit.


On my car the balancer snout broke off clean. This caused my timing to be retarded about 15 degrees causing very low power. I had replaced the timing chain and gears a year earlier and had reused the balancer, but with a 98 Mustang style bolt. In my case the bolt did not break and the crank sensor is still working fine. I replced balancer with new FORD unit.
 
They replaced the sensor

They replaced the sensor, and it was the BHJ balancer that I shelled out for.

>Did they also replace the crank sensor with the new harmonic >balancer?

>Thomas
 
I think NotsofineSC's question is:

Should he replace the BHJ balancer? I thought these were like indestructable or something, thus the extra $$ over the stock one. I don't have one so we need a BHJ expert to answer...
 
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