oil change, spring on oil plug Options

[vintage914racer]

So I decided to change the oil on my racecar myself, after usually having my mechanic do it during check ups, and was surprised with a spring behind the oil plug. At first I thought nothing of it, until I let all the oil out and tried to put the plug back in. To make a long story short it took a lot of time, cursing and effort to get the thing back in. What I am wondering if is this something on all 6 cylinders, or is it something special? I've changed oil in plenty of other cars, but have never seen anything like it. I remember my mechanic talking about some kind of oil pressure thingy down there, but right now my memory fails me.

[ArtechnikA]

the drain plug is supposed to be a 19mm plug in the middle of the circular plate.

maybe someone has 'updated' your oil pump to one that uses the drain-plug-less cover. or maybe someone just updated the cover. no way to know unless and until you get it off and can see what kind of oil pickup you've got in there.

i would suggest picking up a Haynes manual - 2, actually, one for the year 911 that your engine is, and one for the 914, although the 914 Haynes does cover some /6 stuff...

anyway - if you have no drain plug in the cover plate, yes, the correct technique is to loosen the peripheral nuts and let the oil drain out around the plate. if you loosen one side only a little and the other side more, you can pretty much direct which way the oil will go. then remove the plate, and the strainer or whatever you've got in there. if you have the newer oil pump we'll need someone with more time on those than me for specifics -- i've never had to deal with one of those (yet) ...

you will still have to drain the oil tank at the coupling in the line - only about half the oil lives in the sump...