Breather / PCV System Pipe / Hose / Tube Diameters

[Rusty]

This is for an ABY & ADU, please let me know of any changes for 3B / AAN.

Block Breather - 30mm - 1 1/8" to 1 1/4"
ABY Head Breather - 14mm - ~1/2" but use 5/8" for oil hose
ABY Union Pipe to PCV - 19mm - 3/4"
PCV - 19mm - 3/4"
ABY Inlet Boot - 19mm - 3/4"
ABY HRP to IB - 19mm - 3/4"
ABY Head Return (rear) - 22mm - ~7/8"
ABY IM N80 Inlet - 8mm - 5/16"
N80 Valve - 8mm - 5/16"
1 way valve - 14mm inlet - 13mm outlet - ~1/2"

[dean16v]

There is fitting that threads into the front of an RS2 intake manifold near the freeze plug.

It's 8mm tube I think, but do you know the thread size?

Thank you.

[Rusty]

Sorry, no idea. Can you measure it with some digital callipers and a thread file?