View Single Post
Old 11-27-2018, 04:44 AM   #38
Misfire
Registered User
 
Join Date: Nov 2018
Location: Carolina
Posts: 6
I am new to the site and new to Porsche.

If I understand this event, the vehicle spun and the engine may have turned backwards.

Image one of the cylinders just fired the plug and all the valves are closed while combustion is taking place. There is pressure on the piston to push it down, however the weight of the vehicle (going backwards) does not allow the piston to go down.

The piston is forced up against combustion pressure and as the crankshaft begins to rotate a few degrees backwards, the intake valve opens,(motor is turning the wrong way). The cylinder is above max combustion pressure and this pressure is released into the intake manifold. The throttle valve is shut. The pressure takes the path of least resistance, travels past the AOS into the crankcase. The pressure expands, inside the crankcase, just enough to blow out one cam plug and unseat the others.

Any takers on this "small bang" theory?

Last edited by Misfire; 11-27-2018 at 05:21 AM.
Misfire is offline   Reply With Quote