Drain hose from air box - missing check valve?
 

On the front of my my '81 SC engine (930/16), there is a hose that drains any water or oil that might get into the air box. I understand that on pre-SC engines, there is a check valve (duckbill) that keeps dirty air from entering into the air box past the filter while allowing fluids to drain to the ground.
However, there is no such valve on my engine nor can I find it in the PET for the SC motor. What am I missing here?

Thanks, Manfred:confused:

http://forums.pelicanparts.com/uploa...1363972284.jpg

Air box drain tube......
 

Manfred,

This is the same question asked by NoYou Relax (Bill L.) recently. This might help you find the answer to your inquiry.

http://forums.pelicanparts.com/porsche-911-technical-forum/736209-quick-vacuum-line-question.html

Tony

Tony,

thanks for the link to the other thread. It allowed me to find out that the duckbill valve was used up to 1977. The parts are still available from Porsche, so my plan for now is to add it to my engine.

However, the question is still open as to what the original solution is for the SC engines. I cannot imagine that Porsche simply left the hose dangling down and thus allowing dirty air to enter the engine???

- Manfred

Just plugged it......
 

Manfred,

You don't need that drain and keep it close either by plugging it or simply put a duct tape.

Tony

Thanks Tony, understood.

- Manfred