silly question about cams

[PanzerSD]

When references say "cam pointing up" to indicate TDC or for adjusting valves, are they referring up to the earth or the axis of the valve?

And what's with the orange buttons in the message editor?

[bwostosh]

Up is away/opposite from the valve stem axis.
This is a relative position as the base circle is the majority of the cam.

[Tomguy]

The orange is just a CSS change to the board layout!

Up is the tip of the lobe you are measuring at the time should be at or close to 180° away from the valve. From my experience on a 4.5 with manual adjustment, it can be close to 180, as long as it's not like 120° or less, or 240° or more

[PanzerSD]

If one installs new cams, and a new chain at the same time, can all the marks be set at zero? or are offset woodruff keys an absolute?

[Tomguy]

Without the offset keys you won't get to 0° on the dot most likely, even with a new chain. The sprockets wear and this can cause it to be off a few degrees, but it usually isn't an issue. 2-3° of retard or advance won't hurt a thing.