Cylinder head studs.

[toglhot]

Tried to get the. Cylinder head studs out of an old case this morning, no luck. Soaked them in WD40, then two nuts, then three nuts, then three pairs of vice grips, then a bloody big vice. I did get one out, but the remainder refuse to budge.

Looks like heat is the only thing left to try, but I'm not pulling the bottom end apart at this stage.
I wanted to remove them and slot them, so in future I wouldn't have to pull the motor to work on the top end. No dice. So It'll have to wait, one day I may have to strip the bottom end, then I can try heat.

Ridiculously tight, The. Japanese sure didn't want these studs to come loose.

 

[Raymond]

They probably fitted em tight at the factory, but then you've got forty plus years of electrolytic reaction between steel and alloy. Sorry, cannot think of a better suggestion for shifting them than what you're already doing. Except maybe try penetrating oil instead of WD40?

 

[toglhot]

Oddly, the threads of the one I managed to get out were squeeky clean as was the aluminium threading in the case. It is a very long thread though, so they've obviously taken advantage of that to make them super tight.

Oh well, one day I may get bored enough to rip the motor apart again. Easy, peasy getting the engine out of the frame now.