realityagent

Hello again folks,
In the process of my LN 4.0 refresh / cracked head repair, I am installing a deep sump kit. When I removed the existing pickup tube bolts, about half the thread came with them on one bolt It almost looks like there are already some kind of insert / helicoil in there already, that has given up.

Curious if anyone has thoughts on options to repair this - I am not sure how thick the walls of the pickup mounts are, if I want to drill out for a timesert. Also, I'm puzzled by what's already in there - is this factory?
This is obviously not a point where failure can be permitted to occur, as it's the main oil pickup. It's also kind of a pain to work on, since I haven't split the case, and drilling is going to include a lot of contamination / impossible to put on a press. I can manage around this if needed, but thoughts welcome, in case anyone else has encountered this. I've never seen entire chunks of thread come out of a casting before...
Truth be told, there are still some threads left and a bolt will catch them (and bottom out without spinning the remaining threads), but I definitely don't feel comfortable leaving it as-is! Sigh. My buddy suggested self tapping screws and we had a good chuckle

Both sides appear to have some kind of insert in them. Here's a longer distance view of both:


And here's a "close-up" of the now-mangled side:

Porschetech3

That's classic aluminum thread gauling, that is what aluminum is famous for...

That close-up looks factory to me, no insert , just a factory countsunk thread...

No problem drilling and putting a thread insert in there, there is plenty of meat around there just watch the depth and don't go any deeper...

realityagent

You rock, sir. Much appreciated!