2007grabberGT
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View attachment 69457 View attachment 69459 Just curious. My oil breathers are vastly different in appearance after 2,800 miles.
Is this unusual, or just the nature of the beast?
Car has 57,000 miles and has had the Paxton on for 2,800 miles. Passenger side oil soaked, driver side clean and dry.
There is a one way valve within the valve cover of the driver's side valve cover. This valve only allows air into the motor, not out. To remove it you need to pull off the valve cover and cut into it.
This.
And the passenger side is a small about 5/16 outlet so all the venting is being done on that side so it will push more oil.
The driver side has much larger outlet about 5/8 but you need to remove the valve inside the cover to take advantage of it. Once both banks are vented properly you will push little to no oil into the breather itself. A oil cap breather helps alot as well as it's a huge opening to vent from.
I run 3 like I just mentioned with pcv valve removed and my breathers drip no oil and rarely need cleaned on a built motor pushing 16-18psi.
I'm confused.
On my Kenne Bell 4.6, the oil catch can is on the DRIVER'S side. It catches a fair amount of blowby. The passenger side is a straight tube that runs right to the air intake and is squeaky clean.
I know it was the opposite on a Coyote. But, why the opposite with the OP's 4.6, i.e. that his oil seems to be coming out the opposite side?
Interesting, i’ve got a 2010 4.6 with KB, breathers on both sides. Driver side is clean as the day i got it, passenger side needs cleaned up from time to time.
Maybe the difference is breather vs. catch can?
The difference is whether the positive crankcase ventilation (PCV) valve in the driver's side valve cover (VC) remains active or not depending on the crankcase ventilation set-up.
If you only have a breather filter on the driver's side, there's no vacuum to open the PCV valve so it always remains closed. This means that the crankcase now has to ventilate on the passenger side, and that's why you either need another breather on the passenger side (which gets dirty more quickly), or a catch can breather like I have (which keeps the filter clean).
If you have a catch can on the driver's side VC that's connected to the intake manifold vacuum port, the PCV valve will open under that vacuum and vent oil vapors from the driver's side. In that situation, you cannot run a breather or a catch can breather on the passenger side as it would effectively cause a large vacuum leak with unmetered air entering the intake manifold. You must run either a regular catch can on the passenger side or a straight pipe from the intake elbow to the passenger side VC.
Kick ass explanation. Thanks. I always thought the driver's side was the only way.
EDIT: From everything I can tell, if you run a catch can on the driver's side, putting a catch can on the passengers side would be a complete waste. At least on mine, zero oil comes out of it.
I highlighted in bold the key feature. It keeps crankcase pressure from building up when theres boost in the manifold. When the line from manifold to driver side valve cover is connected the pcv cant open as boost pressure in the manifold is stronger and keeps it shut. So instead a boosted car is effectively building pressure in the crankcase as the smaller passenger side fitting is not adequate to vent the increased blowby pressure. Then when you let off the throttle and have a transition back to vac in the manifold the pcv opens briefly and you have a big rush out and through your can which tends to push more oil out.