Searched and now confused, ? about breather/pvc system.

[BullittAndy]

I have a rebuilt 306, AFR heads, moderately big cam.

Should I cap the tube on the oil filler neck or connect it to the T/B?

When I cap the oil filler tube and then remove the cap, I get a hissing/sucking sound.

The car still has the stock pvc system and pvs is clear and screen looks clean (new motor).

read all the posts but am still confused.

Thanks for the help!!

 

[vristang]

Andy,
The hose from the TB to the VC is part of the pcv system.

From this hose, fresh air enters the crankcase, picks up contaminants that have boiled off from the oil, then takes those contaminants into the intake manifold (via the pcv) to be burned during combustion.
Fresh/clean air is able to pick up more conataminants.

The air which enters the crankcase has been measured by the MAF meter.
This minimizes the 'vac leak' effect of running clean air through the crankcase, and into the intake manifold.


Hope that helps,
jason

 

[HISSIN50]

Jason is right on.

To be explicit, if you cap the bung on the oil filler, it'll be hard to get air into the crankcase (the PCV valve, if it works properly, can be thought of as a check-valve). There HAS to be a way for air to enter the crankcase.

Good luck.