Engine tech question

Howdy one and all.

Just wonderin' if anyone could tell me what that modification on the engine block is called where the case threads are extended to prevent the #3(?) cylinder stud bolt from backing out? I think this was the remedy VW had come up with when they realized this reliability issue sometime 1972 or later. Did this problem happen in the other variants of the flat-4? Could someone having this problem fix it by counter sinking the case and holding the stud with an iron nut?

Howdy one and all.

Just wonderin' if anyone could tell me what that modification on the engine block is called where the case threads are extended to prevent the #3(?) cylinder stud bolt from backing out? I think this was the remedy VW had come up with when they realized this reliability issue sometime 1972 or later. Did this problem happen in the other variants of the flat-4? Could someone having this problem fix it by counter sinking the case and holding the stud with an iron nut?

They're called "Case-Savers". Do a search on any VW Bug parts place. I believe they must be installed by a machine shop.