Quote:
Originally Posted by MWS
Well, I've learned something today...looks like I've got some googling to do.  |
So, I should start prefacing my comments with "as far as I know", or something like that. I don't mean to be the guy who knows more than everybody about everything. pfft.
So,
as far as I know, the differences are thus:
Expansion-Plug (Also called a freeze-plug)= used to protect larger castings where the stresses that may occur threaten to break the casting. A hole is cast-in to allow for expansion / contraction, and the plug fills that hole. These stresses are (in my experience) usually thermal, and especially about freezing, but they can also be about torsional forces in a stressed-member.
galley plug = These are used as a convenience / access to areas requiring machining, POST-Casting. An example is when an orifice must be drilled at the bottom of a casting, a hole will be cast (or bored) to allow tool-access, and then plugged with the galley-plug. In MANY motors the oil passageways are drilled / bored through the block, and then sealed at the tooling-end with a galley plug.
Casting Plug (Also called a "core-plug") = During the casting process, holes are required as a convenience for removing media after the casting has cooled. They serve no other purpose afterwards, but are an unfortunate limitation of casting methods. These holes are plugged with a casting-plug, or core-plug.
So here's why it matters in respect to the photos: Which type of orifice is being filled with that plug would help to determine potential causes of failure. This is why I noted that I am not the Porsche Expert.
But is this a galley-plug? if so, it shouldn't fail. But I have, on occasion, tapped them for a threaded-plug, to dismiss the possibility.
Is it an expansion plug? Was the motor exposed to some extreme temperatures? Especially freezing?
If it's a casting-plug, then the only likely source of failure is faulty installation.
That's what I know.... as far as I know it. YMMV, I guess.