Firstfives.org

Anticipating engine clean up. Having built an engine on a stand, I'm curious how the main crank nut is removed with the engine in the car.

As it has to be to replace the front cover gaskets, etc. Radiator out,...

I know from 360 some odd foot pounds it's probably an air tool deal, or there's a way to tie an elephant to a breaker bar with a log holding the shifter in first gear.

Airtools are a convenience, not a necessity. Leverage is your friend. As Archimedes once said, give me a lever long enough, a fulcrum to put it against and I'll move the world. In other words with a 3-4' cheater you can generate 500-600 pound of force.

Down to nuts and bolts, I have heard of guys using the starter to break it loose with the breaker wedged up against the frame rail, but you still have to tighten it. If you put it in gear, 1st is the worst, it gives more mechanical advantage to turn the wheels. Still, I think you're better off doing what I did for the wife's E39 when I had to do the front crank seal on it, I made a tool to bolt to the crank hub in 3 or 4 locations. I then put a pipe on it to hold things solid and took my 3' cheater to the bolt. It worked and I didn't break anything. It took a couple of hours to fab it up, but with a slushbox in her car it was the only way to do it.

If you happen to have a spare, sacrificial crank dampener, you could always bolt a plate to it and use it against the frame rail to keep it from moving.

So there are a variety of options.

Bav Auto used to sell the tool that bolts to the front of the crank. Dunno if they're still available. The torque on that is 325 foot pounds I believe.

For this one nut a bought a inexpensive, $65.00, air impact driver from harbor freight. It advertised 450 pounds. It worked. I found it a lot easier than wrenching and eventually cutting off the nut the first time. A new nut runs around $8.00.

I'm doing the homework for when I have to do it. Stripping the car,etc.

I have a compressor and air gun. Compressor 110 psi max. The gun may take more, but that's about the compressor ? So a 450 lb. air impact driver, needs a large compressor, correct ?

In the car, restrained from turning as Mike describes. I've had an engine on a stand, to imagine trying to torque the nut up front to 350 pounds would need flying buttress's.