Well this 3/4” socket should do the trick.

 

I had an interesting adventure a decade or so ago when a local owner had the same issue. It ended up being a two-person wrestling match, with a bar bolted to the flywheel through the engine stand yoke. Then his floor jack handle through the yoke. Then a socket and my 5 foot long demolition bar on the crank bolt. Lots of twisting and coordinating directions to keep the engine stand from falling over, but we managed it do it.

I have a pretty hefty 3/4-drive impact gun. It requires a full 1/2" hose and fittings to make any more torque than my 1/2"-drive impact, so I've added some connections and a 25' hose directly to a compressor tank fitting just for this duty. It's only been used a couple times, when I needed the "impact" function more than the torque capability when I couldn't counter-hold something adequately by myself.

 

haha, i got a borrowed + 1 m 1" torque wrench today …. just nothing special to get 300 NM. Easy . Think it was 1/2 ...3/4 turn more than 200 NM , but don't be certain, as i didn't got it probably to 200 NM in the engine stand.

 

Lol they sent me a 37mm socket in a bag marked 27mm. Arrrg

 

If you have immediate local access to a 1 1/16" impact socket, it will do the job just fine. It's about half-a-thousandth (0.000492") of an inch larger than 27mm, well within the manufacturing tolerance of any broached impact socket. The oxide coating on the socket probably makes that up.

 

3/4 socket did the trick.

 

No wonder it was so difficult to remove.

Every crank-bolt I've removed the threads looked brand spanking new.

 

Yes, that looks rather corroded. Gotta wonder how that happened. Maybe somebody put something on that bolt. It's supposed to go in clean and dry. I would scrub the threads inside the crank nose with a toothbrush and some solvent, rinse it, and let it dry. It looks like the finish is gone on that bolt. Consider getting a new one.

 

Yep will have to clean it good and maybe get a new bolt. It’s nasty inside the crank.

 

The starter motor method has worked well for me, but it can be alarming to see the car lift a bit before the bolt breaks free

However I tried it on my other car and no such luck

I ended up holding an electric impact wrench on it for some minutes, and then it came loose

Not so easy to do in a 928 unless you remove the rad, and possibly the aircon condenser as well

 

i would a least check with a thread chaser ( or tap .. or the new bolt ) on the crankshaft.... otherwise you won't have any idea if torque is right with a new bolt. You could end up with the 300 NM and the balancer still "loose" .

 

That inside of the crank nose looks impressively corroded. Baffling.