If your Porsche Turbo experiences an unusually large "puff of blue-gray smoke" out the tailpipe on engine startup, chances are this may be caused by residual oil in the turbocharger oil feed system. 

We have devised this solution to end smoking on startup.  The kit simply adds a check valve function which cuts oil flow to the turbocharger feed line when the engine is shut down and residual oil pressure drops in the crankcase.  To install this kit, simply replace the original oil feed line fitting located on the top rear of the engine block. 

Included are the check valve assembly and sealing rings. 
DOES NOT include original 930 M18/M14 concave adapter fitting that threads into the engine case.

Applications:
1976-1992 Porsche 911 Turbo : All models with any brand of turbocharger