370z engine blown

Originally Posted by gsxr750

B.S. ! There is no possible way parts from the exhaust can be sucked into the engine thru the exhaust ports.

The engine is a simple pump and the exhaust can only pump pressure out, it can't work as a vacuum and suck particles back into it.

Dirt or foreign objects can only enter thru the intake or other sources, oil, broken internal parts, broken head gasket etc.

Back pressure is only a term used to describe the amount of restriction to exhaust flow caused by a internal muffler, baffle or cat etc. Back pressure does not mean a reverse flow of exhaust gases.

This guys example is a good reason to show why is better to keep the car stock, dealers and manufactures are always looking for reasons to deny a waranty claim if possible.

Just be glad they covered your repair under waranty.

Most likely the ring damage was caused by the rings never really seating properly or a excessivly lean air fuel mixture and even engine timing could do it or bad engine mapping

Originally Posted by Red__Zed

You know the exhaust ports stay open during the intake stroke, right? This is not a terribly uncommon occurrence (when cats go bad, that is)

Originally Posted by gsxr750

exhaust valves are only open after the mixture has been ignited and the gases expelled out the exhaust after combustion, no air is ever sucked into the exhaust ports.

Vacuum is only created in the intake port , not the exhaust port

Originally Posted by Red__Zed

Cat material is fairly regularly sucked into the engine when they go bad. You should try searching these things before posting about them.

I think you misunderstand the way the valves are timed. Overlap is very common.

Originally Posted by Red__Zed

Cat material is fairly regularly sucked into the engine when they go bad. You should try searching these things before posting about them.

I think you misunderstand the way the valves are timed. Overlap is very common.