pcv really need 2 vacuum lines?

ronstang94

Member

May 10, 2007

204

1

18

Phx, AZ

Jun 17, 2010

#1

• Jun 17, 2010

• #1

i searched and found some talk about it, but i didnt find a good answer

So, does the pcv really need two vacuum lines?

Im trying to use as few vacuum lines as possible.
and as short of vacuum lines as possible.
so there is only as little clutter as possible.

it seems like maybe there are 2 lines (one located on the bottom) to allow blow-by (oil) to drain back down into the block but I dont know.

Thank you

 

HISSIN50

"How long does it take to get help in here?

15 Year Member

Nov 29, 1999

31,179

34

129

Jun 17, 2010

#2

• Jun 17, 2010

• #2

PCV flow is bi-directional. The PCV valve only allows air to flow one way, so the other hose completes the circuit. It's needed.

 

nmcgrawj

Advanced Member

Sep 28, 2003

3,651

4

68

Indianapolis, IN

Jun 17, 2010

#3

• Jun 17, 2010

• #3

I thought the PCV valve sits in the lower intake in a stock type setup? Did you or the previous owner change that?



I could have sworn that the pcv only has 1 line on top of it...the bottom of it is in the lower intake. But i could be wrong...its been a couple months since i had my motor apart.

 

ronstang94

Member

May 10, 2007

204

1

18

Phx, AZ

Jun 17, 2010

#4

• Jun 17, 2010

• #4

Hissin, I trust that you are right

but i dont get it.

arent both of the vacuum lines going to the intake from the pcv doing the same thing? sucking air through the pcv into the intake? or is one doing something different?

thanks

 

nmcgrawj

Advanced Member

Sep 28, 2003

3,651

4

68

Indianapolis, IN

Jun 18, 2010

#5

• Jun 18, 2010

• #5

the air goes from the crank case/lower intake to the upper....you dont need 2 lines to allow this. Is your valve not sitting in the lower intake?

 

ronstang94

Member

May 10, 2007

204

1

18

Phx, AZ

Jun 18, 2010

#6

• Jun 18, 2010

• #6

nmcgrawj said:

the air goes from the crank case/lower intake to the upper....you dont need 2 lines to allow this. Is your valve not sitting in the lower intake?

Click to expand...

sorry, i think you are confused about what im saying. it comes out of the crankcase at the lower intake manifold into one vacuum line. it then T's off to 2 vacuum lines, both of which connect to the upper intake manifold.

Im installing a performance intake and am trying to simplify all of the vacuum lines.

thanks

 

nmcgrawj

Advanced Member

Sep 28, 2003

3,651

4

68

Indianapolis, IN

Jun 18, 2010

#7

• Jun 18, 2010

• #7

No I fully understand....although my late night posts may not make it seem that way

all lines see the same vacuum...so you only need 1 line going to it. This by no way affects how the valve works.

 

HISSIN50

"How long does it take to get help in here?

15 Year Member

Nov 29, 1999

31,179

34

129

Jun 18, 2010

#8

• Jun 18, 2010

• #8

And I misunderstood too. I thought you wanted to eliminate the line from the oil filler to the air-inlet.

In terms of just dealing with the PCV valve hose, I can't think of why you couldn't just have one line instead of two (regarding at the rear of the engine where it splits into two lines to the plenum).

 

cjrpony

Member

Jan 23, 2010

439

0

17

West Michigan

Jun 18, 2010

#9

• Jun 18, 2010

• #9

I am running the Edelbrock RPM II intake and only have the one line hooked up. I haven't had any issues yet.

 

revhead347

Apparently my ex-husband made that mistake.

20+ Year Stangneter

Jun 14, 2004

9,302

1,645

214

Acworth, GA

Jun 18, 2010

#10

• Jun 18, 2010

• #10

PCV valve is just one line to the intake. If you buy one from the autoparts store, it comes with a rubber T on the top for use with different applications. Someone must have not known to pull that T off for Mustangs.

Kurt

 

Beasty306GT

Active Member

Dec 19, 2002

671

4

28

Oxford,Mass

Jun 18, 2010

#11

• Jun 18, 2010

• #11

does it matter which vacuum line..meaning there both different sizes on the pcv valve....should it be on the larger one or the smaller one..reason i ask when i installed my new motor i used the smaller one and i got a slight oil leak from the rear main arean..wondering if it should be the larger one

 

revhead347

Apparently my ex-husband made that mistake.

20+ Year Stangneter

Jun 14, 2004

9,302

1,645

214

Acworth, GA

Jun 18, 2010

#12

• Jun 18, 2010

• #12

The T is suposed to be pulled off completely, and you use the single 3/8" hook up that remains on the PCV valve itself.

Kurt

 

HISSIN50

"How long does it take to get help in here?

15 Year Member

Nov 29, 1999

31,179

34

129

Jun 18, 2010

#13

• Jun 18, 2010

• #13

We're talking about the Tee on the driver's side of the intake (where the PCV valve line splits and goes to the underside of the plenum and to the driver's side of the plenum), not the two nipples on the PCV valve itself.

 

ronstang94

Member

May 10, 2007

204

1

18

Phx, AZ

Jun 19, 2010

#14

• Jun 19, 2010

• #14

Thanks for all of the responses. Nice to have a definitive answer.

got all of the vac lines figured out, intake manifold installed, and then ran into some problems

EGR tube too short and broken fuel line
but thats another thread, lol

 

Beasty306GT

Active Member

Dec 19, 2002

671

4

28

Oxford,Mass

Jun 19, 2010

#15

• Jun 19, 2010

• #15

on mine i got the pcv valve going to the bottm of the intake...i got a trick flow upper and lower..should i install a tee right off where it come off the firewall manifold that goes to the upper intake

 

W

wytstang

Mustang Master

Mar 14, 2004

4,988

4

78

Summerville,SC missing South Fl. weather :(

Jun 19, 2010

#16

• Jun 19, 2010

• #16

HISSIN50 said:

We're talking about the Tee on the driver's side of the intake (where the PCV valve line splits and goes to the underside of the plenum and to the driver's side of the plenum), not the two nipples on the PCV valve itself.

Click to expand...

Here's a picture reference of what JT is talking about (for future references/searches)

 

nmcgrawj

Advanced Member

Sep 28, 2003

3,651

4

68

Indianapolis, IN

Jun 20, 2010

#17

• Jun 20, 2010

• #17

Bingo. ^