Crank Pully Bolt Installation

[sasksupra]

I found the following item while researching replacement of the timing belt for my '84 MKII Supra:

"It is imperative that the front crank pulley bolt be properly torqued with an air impact wrench. Many club members have done back yard cam belt installs and later found that their front crank harmonic dampener pulley had come loose damaging the crankshaft keyway, harmonic dampener and cam belt drive cog."

Is it really neccesary to use an air impact gun to torque the crank pully bolt? I have a good torque wrench. If it's torqed to the proper setting does it mater whether an air impact gun was used?

Thanks

[Jeeves]

I've always tightened 'em with a torque wrench, but the author is correct that the torque wrench doesn't have nearly the same effect. My buddy who's done the same as me has had his come loose before.

If you have access to air tools, do it. If not, keep tabs on it. That's a high motion/important piece.

[sasksupra]

I wish the guy before me had used an impact gun. Went to take everything apart today and the crankshaft pully came off too easy. I knew I was in trouble. The keyway is in pretty bad shape but the pully and cam belt cog are OK. Has anyone tried the bandaid repair and welded a new key into the crankshaft? Thought I might try it. The crankshaft is done anyway. I will get me on the road while I look for a replacement engine. I thinking rebuilding this one would be expensive considering it would need a new crank to fix my problem.

Thoughts?

[mrnickleye]

The main reason an impact gun is used is because it is difficult to hold the crank from turning when using a torque wrench.

Also, use some locktite (thread locker).