Lost crankshaft nut

[DFoley]

A few days ago I noticed a strange sound which sounded like it was coming from the crankshaft. I look under the hood and noticed the crankshaft nut had come loose and the twin groove pulley had slid forward a bit and was wobbling and making the noise. So I simply slid the twin groove pulley back and tightened the crankshaft nut and everything seemed normal again. A few days later, the same thing happened, I check the crankshaft nut, and this time it was gone, it had completely unthreaded itself. OK…so I have two questions 1) the ORD does not indicate that there is any sort of pin used to prevent this crankshaft nut from unthreading, so how do you keep the nut on tight enough while the crankshaft is spinning at pretty high RPM’s. 2) Where can I get another crankshaft nut? The ORD indicates it is simply a 1-1/16 steel hexagonal nut, can I simply get this from any hardware/auto parts store, or is it something special?

Thanks,
Dan

[MODIFIED]

check with Brent Mullins in College Station, TX, I'm quite sure he has NOS in stock. the crankshaft nut has a raised surface that provides more surface contact to your pulley. there is no hole provided for a cotter pin.
check your threads and pulley surface where the nut "rides". Also make sure you did not loose the woodruff key on the shaft either. When you get the Nut, put some blue lock-tite and torque to spec. If you dont find a nut with Brent ....give me a pm, may have a spare for ya.

[sonny]

I damaged mine trying to get it off and bought a new one from Midwest Military - Sonny

[DFoley]

Thanks, I'll give Brent a call. I lived in College Station for too many years while getting two degrees from Texas A&M...Whooop!