Hello

I am quite suddenly getting a lot of white smoke from the exhaust on my 1976 911 Targa 2.7. There is also a little oil dripping from the exhaust. the car is not overfilled with oil but it has been sitting unused for a couple of months. Does anyone have any ideas about what would be causing this?

 

Well, none of this but the first is Porsche specific and it assumes your facts are all correct and the only evidence you have: a) if you get a puff -- even a big puff -- of white smoke upon start up I would not worry about it too much, could be just a little oil settling from sitting too long -- some of them do that. I'd check that it is not overfilled, then drive if for at least one real long drive where you warm it up nicely, then let it sit overnight and start it again and see if you get white smoke. Hopefully no.
b) if you do, and you get white smoke upon start up and when accelerating even a bit when the engine is cold, but it disappears when the engine is warm, it could be worn valve guides: not super serious but an indicator of age. Usually however this problem does not start up suddenly, but starts out barely noticeable and gets worse progressively from there to serious, so this does not match your situation as you described it.
c) but if you get smoke alwhen the engine is warmed up, then:
- if you get more smoke the more you push on the throttle, even when warm, then you very likely have a broken piston ring. This nearly always occurs suddenly: one day the ring is good, the next it isn't and the car smokes, often badly.
- but you could have any number of other issues that allow oil to get into the exhaust. The fact that you find oil in the exhaust tips indicates maybe you have something like this.

You could check the plugs (this much oil must be fouling or trying to foul them) and do a compression test, but I'd recommend taking it to someone who really knows mid 70s 911s and have it diagnosed soon.