3.4L mark 2 saloon

Started By: on 2015-06-19 00:00:00

I have recently restarted my mark 2 and heard a bad engine noise. Upon investigation i discovered a broken valve head on #2 piston and a hole in my piston. I am trying to determine the cause. The engine head was overhauled 9 years ago with new valve guides and seats. When I started the car is was at approx 2500 rpm then i accelerated to 3000 rpm then decelerated then my problem happened. are these cars known for valve float at high rpms? I am tearing the engine down and noticed that the broken valve had a spring which was 3% shorter in free height than spec. Could this have caused my problem? comments welcome