Camshaft replacement question

[S54orzo]

Hi All,

I am following the TIS camshaft replacement doc and it says to move the crank 30 degrees against the direction of rotation before removing the camshaft (timing chain is removed at this point) because "No piston must be in the TDC position when the camshaft are removed".

Does anyone know why this is? There's no mention of this in DIYs

[Pklauser]

My guess is just an added layer of safety since the valve springs may make the camshaft spin as you remove it. Don't want that movement to bend a valve. It's fairly common practice to level the pistons and give yourself some wiggle room.

[sapote]

Hi All,

I am following the TIS camshaft replacement doc and it says to move the crank 30 degrees against the direction of rotation before removing the camshaft (timing chain is removed at this point) because "No piston must be in the TDC position when the camshaft are removed".

Does anyone know why this is? There's no mention of this in DIYs

30 deg BTD is a safe position when install/remove head or cams as none of the pistons is at TDC. Don't need to be precise. If the chain was removed, then just slowly turn the crank CCW about 30*