Jim
-Visible scratches look like what you'd see on any case this old, plus how to explain apparent downward force?

=Frozen water interesting, but will water unconstrained (i.e., surface open to air/environment) cause a pan-like container to crack? Think of an ice cube tray? Could it have been filled to the brim with water which froze? That might do it?

-Your point, plus fact that threaded insert is standard in drain hole, kind of shoots down the oversize plug notion I had.

-I've blown up more 911 engines than I care to remember. After a blow up, if you examine the fiberglass engine cover back over the cylinders, and see cracking or other damage, that's a pretty good indication that a rod bearing failed or a valve dropped, and the cylinder itself was broken, and the connecting rod flailed around or otherwise got loose, and busted the cylinder, and dis some sawing on the case spigot. Could also break the oil pump, and the intermediate shaft splined end broke off, and somehow I even had a cam shaft break in two.

-But none of these attacked the lower part of the case. The pump/IS stuff is in the way, and there are those cross case webs as well. And these assaults have always had at least some external evidence, cracked cylinder at least, even if it didn't burst.

-When a stray nut (like the lock nut on a rocker arm adjuster) gets loose, and travels down the oil return tube, it isn't really much of a worry - it will probably end up in the bottom of the sump, well out of harm's way. Same with stray nuts you drop into a chain housing while doing something in there.

-So some internal force (a spinning crank has plenty of energy to bust a case)sounds like the most reasonable suspect, but what would the force path be?

If the advice to just get a used case is followed (a cost/benefit analysis would be useful - what would Ollies or CE or some equally good shop charge, vs. cost of used case, but worries about welding working seem misplaced)or not, it seems this engine needs to be disassembled. That will reveal the condition of the internal parts, because those are what will need to be transplanted to either a repaired or a replacement case. Visual inspection ought to give some clue to how this happened.
-So if the owner lets us know what he finds, we will all learn something, as this is pretty unusual.

Just pure speculation as this is an interesting and hard to fathom crack of both case halves

We know its a flood damaged car, was transported above the cab of an open transport in April from KY to CA. When transport arrived in CA cab was covered in oil leaked from Porsche.


My guess -
Engine filled with water, oil floating on top. Somewhere on the trip across country the engine froze, water expanded, cracked the case, thawed, water and oil poured all over cab. :eek:

Or

Ever see how the wrecking/impound yards pick up cars with a forklift and toss them around? Would think there would be some evidence of the forks impact though, heat exchangers would get crushed, right?

Unfortunate mystery...

Meh, it's essentially an oil pan down there, not really structural. If I didn't have any plan to sell this engine at some point (which still may or may not happen) I'd be more than ok with welding the case.

Welding the case is $300-$500. A used case half is 2-3x that amount but anyone interested in it would likely vastly prefer a case with zero issues unless it was a sweet deal.

It only looks minor because I cleaned it thoroughly. When it was still grimy it was easier to see.

I'm on it. Slowly taking things apart as I have time! Either way, you'll all know what I decide to do.

Matt, I've thought about it too and the forklift theory is very plausible if it was fine prior to going to the yard. I'll unfortunately never know because I stupidly didn't have the car inspected prior to bidding. Now I know better than to ever do that again.