Hey All,
Last year I ended up selling the Blue boxster as a roller to a friend nearby who needed a donor car for his race car. After he took off everything he needed he gave the engine back to me so I had a chance to take a better look inside. I took a couple pictures before I scrapped most of the engine, here they are, just fyi.
Head off:
This is where the thick white smoke was coming from:
The other 5 cylinders looked totally fine.
The top of piston #1 broke off:
I don`t know how could I miss this completely during the rebuild, but one bank had been resleeved.
Here`s what the other bank looks like from the bottom:
I`ve read somewhere that some early bore scored blocks were sent back to Porsche in warranty and got resleeved. Later these engines had a tendency to fail. Perhaps mine was one of them?
When this engine blew up, it was a hot day and I was stuck in traffic, and the coolant temperature was higher than ever before. I had been going to clean the radiators and check the fans because I suspected they are not blowing at the highest speed. I never got around doing it. Nevertheless, now that I think about it, probably the engine got overheated. Another suspect is the aftermarket rings which perhaps didn`t like the Lokasil bore too much. Anyway, my theory now is that somehow the piston got seized for a moment and pulled the sleeve down, then in the next cycle the rings got stuck in the shoulder of the sleeve and that broke off the top of the piston. Also possible that that the rings broke first, hard to tell at this point. Just thought I share.