underdrive crank pulley?

[stangslayer98]

today while cleaning the engine bay i noticed that my underdrive pulley looked like it was wobbly....but under slight throttle it appears to smooth out. my question is has anyone else done an install using an impact gun and the same old bolt that was on the factory pulley.

[Y2KPewterSS]

You can't re-use the factory bolt. They are torque to yield, so after they have been used once, they are done. Spend $6 and buy a new one at the stealership.

[Hamrhead]

Just get the ARP one and never worry about it again.

[INMY01TA]

How can you tell it's wobbling at idle? The engine is shaking a lil anyway. I think that's what you're observing.

[Hamrhead]

You can't re-use the factory bolt. They are torque to yield, so after they have been used once, they are done. Spend $6 and buy a new one at the stealership.

Be careful with your statement as some people insist that you CAN reuse the bolts and it is just a myth! Ignore manufacturer recommendations, the wobble is your mind playing tricks on ya.

[0rion]

how many psi was your impact wrench? That bolt gets torqued to a phenominal amount of torque. I used the ARP bolt and after reading many conflicting torque numbers I settled on 200 ft lbs I think it was. 200 or 240 or something like that. Basically as much as I could give it. I did get the wrench to click without using a pipe.
I know the stock one is torqued then backed off and torqued again then stretched but I think the final torque numbers are up there even on the stock bolt.