I usually use the double nut method. Thread one nut on and then a second nut on top of the first nut. Tighten them against each other and then use a wrench to get the stud out.

 

Nut Buster, PB Blaster & let it soak down in & around the threads like over night or a day & night.
Those studs have been in those cases for quite a few years, unless someone has pulled them out often, so it will take some soaking to get them to release their bond between the aluminum case & the steel stud.

I've let them soak a good while, even to the point all of the PB Blaster had soaked in & still had to end up using a torch to heat the crap out of the case to break the bond.
Neil

 

They can be a 'bear' to remove...as suggested, 'double nut', 'stud removal' tool, lot's of penetrant like PB-Blaster, soak 1-2 days, heat the cases if needed.

Carlos

 

thanks for the tips just a quick picture of how the motor shall turn out

 

I had this problem before and when the double nut didn't work I had to get an extractor. You can pick them up at NAPA. I got a universal extractor that works with a socket wrench. It is a cylinder with an offset hole in it. The socket attaches to a binding mechanism that pinches the stud inside the offset hole. It was about 30 or 40 bucks if I remember correctly and it still took a lot of force, but the last thing you want to do is break off a stud in the case.

 

I bought a stud extractor set from matco tools and it has not failed me yet!