M42 BLOCK OIL CHECK VALVE

[razler]

Hi, Can anyone tell me if the check valve and associated parts are needed in the block of the M42? (fits into thread hole before cylinder head is placed on)
Im nearly 100% that I didn't remove a check valve from the X2 M42's iv stripped but when the correct exploded diagrams are looked at on real oem the bellow is listed..
If the bellow parts are needed whats the FUEL FLOW REDUCER all about?


09 FUEL FLOW REDUCER 1 11111717807 $1.03

09 non-return valve 1 11111734667 $11.15

10 Spacer 1 11111739185 $3.60