PCV placement

**Mr. Luos** · 05-23-2010, 08:47 AM

After spending about an hour reading up on this....

I am curious. I have a cheapo EGay catch can. The PCV hose behind the intake decided to crap out on me, so I replaced with basic 3/8" fuel line as it is $5 instead of the $130 GM wanted for that stock hose.
Anyways...
I am running stock style with a catch can.

Is it possible to put the PCV valve AFTER the can but right before it goes into the intake?
Or do even those cheap ass cans have a PCV valve on them??
This is the can....
EGay link

Or do I rid of the valve all together since I have the can?
Or does the valve need to go before the can?

TIA!!!

**pajeff02** · 05-23-2010, 08:51 AM

That's not a bad looking unit. I don't see why you can't install the valve after the can -- all the PCV valve does is meter the vacuum and contain a check ball. I think it was the later style valves that had the metered hole.

**tatertot91** · 05-23-2010, 09:26 AM

Sure you probably heard of this, but if i were you i'd go with an LS6 style valley cover. Its saves having to use all those hoses, it cleans up the engine bay, and it is much more efficient as far as oil consumption goes.

**Mr. Luos** · 05-23-2010, 03:06 PM

Originally Posted by tatertot91

Sure you probably heard of this, but if i were you i'd go with an LS6 style valley cover. Its saves having to use all those hoses, it cleans up the engine bay, and it is much more efficient as far as oil consumption goes.

I know. Don't have the $120 or whatever it is right now.
Eventually though.

**tatertot91** · 05-23-2010, 03:28 PM

Originally Posted by Mr. Luos

I know. Don't have the $120 or whatever it is right now.
Eventually though.

I gotcha, just checking.

**Mr. Luos** · 05-23-2010, 03:29 PM

Hmmm...

So do I even need the valve with the catch can? I would think yes. Placement shouldn't matter too much though.

**tatertot91** · 05-23-2010, 03:32 PM

Originally Posted by Mr. Luos

Hmmm...

So do I even need the valve with the catch can? I would think yes. Placement shouldn't matter too much though.

I'm pretty sure you still need it
I think the best place for it is in between the PCV valve and the intake

**Cutlass** · 05-23-2010, 05:47 PM

yes you still need the PCV valve to meter the airflow. without it the car will act like it has a big vacuum leak.
You can install it on either side of the catch can. I suggest after the can, near the intake. that way the oil should be filtered out and the valve will say cleaner.

**tatertot91** · 05-23-2010, 05:50 PM

Originally Posted by Cutlass

yes you still need the PCV valve to meter the airflow. without it the car will act like it has a big vacuum leak.
You can install it on either side of the catch can. I suggest after the can, near the intake. that way the oil should be filtered out and the valve will say cleaner.

Great minds think alike

**02Sweet** · 05-24-2010, 03:49 AM

I run mine a little different.
I capped both spots on the passenger side valve covers. Got rid of the inlet for the throttle body
I run a breather on the oil fill cap on the passenger side valve cover.
I use a standard pcv valve coming out of the driver side valve cover.
Hose runs from pcv valve to catch can.
Then from catch can to vacuum on intake.

Works fine for me did the setup for $60ish. Got a sweet deal on a used norris catch can

**shady milkman** · 05-24-2010, 07:06 AM

C the ls6 swap is only 60 bucks roughly by the way

**Mieux97** · 05-24-2010, 11:48 AM

How can I do the LS6 swap AND pass illinois emissions? Is there a write-up for this.

**peterlawl84** · 05-24-2010, 03:45 PM

The new +04 LS6 valley covers have an internal PCV, so you don't need the expensive tube from GM. I wish I had known this last month when I did my swap, as the new VC is less than $10 bucks more than the older style LS6 VC. (p/n listed below).

And there is a write up on LS1howto.com, shouldn't have any issues with emissions as you still have the PCV, just a better system that will cut down on oil consumption.

From another thread:
"What they did was to engineer valley mounted oil separators which uses internal baffling to force the crankcase vapors in a circuitous (think roundabout) flow. This in turn causes the oil to separate and drain back into the engine."

And also there is a fixed orifice set in the valley cover, therefore no need for external PCV valve. The older style does not have the orifice and therefore requires an external PCV valve.

Scoggin-Dickey carries both parts.

Part no for 04 style : 12577927 $74.69

Hose: 12594779 $3.29

**Mr. Luos** · 05-25-2010, 04:13 PM

Looks like I will be ordering the LS6 valley cover soon.
Won't hurt, although everything seems good as is right now.

Not a fan of breathers on street cars. Heard some guys think that our rockers like having a little vacuum on them as well.

**INMY01TA** · 05-28-2010, 05:47 PM

I'd save your money on the LS6 valley. I have one and got just as much oil in the intake as it did before. I now use a catch can with the valve before the can.

**shady milkman** · 05-31-2010, 01:50 PM

Originally Posted by INMY01TA

I'd save your money on the LS6 valley. I have one and got just as much oil in the intake as it did before. I now use a catch can with the valve before the can.

odd...my car's oil eating and my intake both dramatically improved

**INMY01TA** · 05-31-2010, 01:53 PM

Originally Posted by shady milkman

odd...my car's oil eating and my intake both dramatically improved

That's good. Mine didn't. I've read of others having poor results with it too. Results vary. I will just advise people to go straight to a catch can and save the money cause you may be disappointed.