Originally Posted by Danthurs
A VERY important fact you need to keep in mind with once a year oil changes is this. Dirt. Oil not only lubricates, it cleans. It suspends the soot and carbon. Some is captured in the filter, the rest stays suspended. There comes a point when the filter is plugged, and the oil can no longer suspend and more. You need a clean, sludge free engine to do this.
That'* why I buy the whole AMSOIL package. Oil and filter. Even though they say it'll work with a regular filter, there'* is like a $1 or so more.
I got hooked on AMSOIL when a race buddy of mine hooked me up with some. His team is sponsored by them and they run it in their race engines. Told me to run it for 15k, then bring it to his shop. We tore the engine apart and the damn thing looked brand new. Proof enough for me.