When does an inlet valve fully open?Is it BBDC or after?

It opens after the exhaust stroke

Before BDC

I have a timing gear with marks that seem not to be right for my car.My inlet valves are fully open at BDC and taking too long to close.I removed the injectors and the engine is actually compressing into the inlet manifold because the valves are remaining open for too long.I have always wondered my the EGR Valve rattles at idle especially when cold.Later when when hot the idling flactuates by about 50rpm up and down.

Which enbgine do you have?
Do you have any other issues?
How do you know the inlet valves are fully open and when?

It`s a 1.6l.Well the camshaft lobes tell you the valve position.If the toe of the lobe is on the hydraulic tappet or lifter then the valve is fully open.As for the crankshaft I am a sure you very well you get that information from the timing mark on the crankshaft pulley.My issues with the car were lazy take off,EGR valve rattling at idle,Exhaust not burning brownish and remaining blackish a sign for retarded timing.I did a compression test and got 90psi on all 4 cylinders.This was very strange because The engine block was horned and new rings put in.It was losing some compression into the inlet manifold thereby partially compressing the air due to the inlet valves closing very late.Earlier on I asked A QUESTION WHEN DOES AN INLET VALVE FULLY OPEN.You replied with the answer that I know to be right,BBDC.

And then again there's a valve overlap that both are open at the same time

When checking valve and timing belt installation, the valves are not timed when they open fully.


You need to follow the timing marks provided for installing the timing belt.