Accufab TB Question - TB to Oil Neck Filler?

[AnthonyR23]

Hey, I am still running EGR and emissions components.. on my new accufab tb there is no vacuum stem that has the hose that runs to the oil filler neck like the original throttle body. One suggestion was that I just put a vacuum stem on my anderson ford power pipe right before the throttle body, and it will do the same thing.. but wanted to know if I don't want to go that route, can I just hook up the oil filler neck vacuum, which I am assuming is to release vapours, to another manifold vacuum source, like from the vacuum tree. Will that be okay? Thanks!

 

[AnthonyR23]

Please if someone could help that would be great!

 

[liljoe07]

That line is not a vacuum line. Its a fresh air intake line for the PCV. If you install it to a manifold vacuum, you will have a mess of oil in the intake.

Drill a hole in the Air intake tube, between the Mass Air sensor, and the Throttle body. Thats the correct way to do it, and you were told correctly.

 

[$uperstang]

my accufab TB has the provision? You sure it just does not have an npt fitting in it?

 

[AnthonyR23]

Is there any other option, like leaving it open to fresh air, or putting a breather cap on.

 

[RatStang]

You would then be pulling unmetered air into your induction system any time you pull vac. It would be the equivalent to leaving a vac line open.

Is your Anderson pipe ceramic coated? If so, just drill the hole and install a rubber grommet and PCV. If not, you might consider having a bung welded in so you can cap it if you have the need.

 

[AnthonyR23]

okay so if I drill a hole in the side of my anderson pipe, and have a line running to my oil filler neck, are you saying I should have a pcv valve there? Is it supposed to be fresh air from the intake going into the filler neck or other way around, the intake pulling air or vapour from the filler neck, assuming the pcv valve would be like a check valve which allows only air to go one way, so if it is for fresh air from the intake to go to the pcv, wouldn't a breather cap do the same thing, or will this hurt emissions, I am still running with my pcv valve. So I need another pcv valve for the intake to oil filler?

On the original stock tb, the tube that goes to the oil filler neck, is it just an open tube, or does the stock tb actually have a valve built in? and just need to know which way... the arrow on a pcv should point, towards the oil filler neck or other way around.. Thanks

 

[sd331]

if your new tb doesnt have the tube to hook up the hose, it maybe a offroad or race type of tb, no there isnt a pvc in that setup its just a hose that runs between the tb & filler neck. if your going to run the hose from the fillerneck to intake pipe i would install some type of oil separator

 

[liljoe07]

Yes there is a PCV in that setup. Its in the same place as it normally is. And the oil separator goes on the PCV line. Not the line from the filler neck to intake piping.

 

[sd331]

Yes there is a PCV in that setup. Its in the same place as it normally is. And the oil separator goes on the PCV line. Not the line from the filler neck to intake piping.

there is no pvc in the oilfiller to tb hose, that anthonyr23 was asking, theres only 1 in the back of the intake. and why not install a oil separator on the fillerneck to intake piping, its going to be sucking the air from the valvecover

 

[liljoe07]

The line from the oil filler neck is part of the whole system. Its the fresh air intake. Meaning it draws air from the intake tubing, into the crankcase via the PCV valve and manifold vacuum. If oil is getting in the intake tubing or throttle body, then the PCV valve and/or PCV screen is clogged up in most cases. At wide open throttle conditions, manifold vacuum should be very small, and the crankcase pressure is high. When the crankcase pressure is greater than the maniflold pressure, the crankcase pressure still vents through the PCV valve and into the manifold. So unless something is totally screwed up, there should be no point in which oil is being pushed into the intake tubing or throttle body. So the oil separator should be on the PCV valve vacuum line. In all the years I have ever ran a PCV system on a 5.0 SEFI engine, I have never had the first hint of oil get into the oil to filler neck line and into the throttle body. So if a guy needs to have an oil separator on the oil filler neck line, then he needs re-evaluate his PCV setup.

 

[sd331]

The line from the oil filler neck is part of the whole system. Its the fresh air intake. Meaning it draws air from the intake tubing, into the crankcase via the PCV valve and manifold vacuum. If oil is getting in the intake tubing or throttle body, then the PCV valve and/or PCV screen is clogged up in most cases. At wide open throttle conditions, manifold vacuum should be very small, and the crankcase pressure is high. When the crankcase pressure is greater than the maniflold pressure, the crankcase pressure still vents through the PCV valve and into the manifold. So unless something is totally screwed up, there should be no point in which oil is being pushed into the intake tubing or throttle body. So the oil separator should be on the PCV valve vacuum line. In all the years I have ever ran a PCV system on a 5.0 SEFI engine, I have never had the first hint of oil get into the oil to filler neck line and into the throttle body. So if a guy needs to have an oil separator on the oil filler neck line, then he needs re-evaluate his PCV setup.

so your saying the hose thats attached to the oilfiller neck draws air into the valve cover? how is that possible when that hose being connected to the tb or the intake tube (depending on the setup ) is always under a vacuum (air being drawn to tb or intake tube)?

 

[liljoe07]

Its called manifold vacuum. The manifold draws through the crankcase, and through that Oil filler line. If you cap the oil filler line off, it puts a vacuum on the crank case, and sucks major oil into the intake. With the oil filler line hooked up, it allows the crankcase pressure to flow through. No different than a vacuum line. One side sucks, other side draws. And the intake tubing vacuum is almost always less than the manifold vacuum. There is a pressure delta between the two, with the manifold being the lower.