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Old 02-13-2016, 10:52 PM
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Default Pcv system

When I bought my car, there was no pcv system hooked up. Now i think its blowing oil out the rear and dripping down my block.

I need to get the pcv system hooked up. Im wondering if I can just run fuel line to all 4 vents and run a few T's, then run to the throttlebody without any type of pcv valve.

Can I hook them up with no pcv valve? It has to be better than just leaving them wide open . I just hooked up the front pcv line to the throttle body. Now theres three more to go.
Old 02-14-2016, 10:17 AM
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If you do without the valve you risk sucking a ton of oil most into your motor, which besides gunking up your intake can cause detonation.

Look into a catch can like Mighty Mouse with an integrated PCV. You'll get good vacuum in your motor without any oil getting to the intake.
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Old 02-14-2016, 11:00 PM
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if you don't use a pcv valve, you will need to put some restriction in the line to limit airflow to some small amount so it doesn't act like a huge vacuum leak.
the oem LS1 pcv system connects to the nipple behind throttle body... which is behind the maf sensor. if memory serves the air into the motor comes from behind the air filter so it is clean air but it is pulled before the MAF sensor. so if the intake sucks too much air out of the crankcase it's basically a vacuum leak.

the 8.1L motor in my truck does not use a pcv valve, but it has a pcv system and they do it by having a little 1/2" hole in the throttle body that lets air flow into crankcase to make up for air sucked out for the pcv system. this is behind the MAF so it is measured air into the motor which is used for combustion so unless the dipstick tube or oil fill cap is not sealed there's no other way for air to enter crankcase.
there's no pcv valve, instead the bottom of the intake manifold has a little nipple which is around a 1/8" diameter tube, and it constantly sucks based on pressure difference manifold and crankcase but it's limited based on the restriction.
in your case, you would just want to buy a $5-10 inline pcv valve and hook it up how it was stock, pretty sure that would be the easiest and cheapest way and it would be correct.
Attached Thumbnails Pcv system-a1.jpg   Pcv system-a2.jpg  
Old 02-15-2016, 05:25 AM
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I went to autozone to buy a pcv valve and they only have the kind that go into a grommet into the valve cover. I told him I had 4 vents, so do I need 4 of these valves?

I'm probably going to buy a catchcan anyway.
Old 02-15-2016, 01:49 PM
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You need the PCV valve. But just run one line from the rear port on the drivers side valve cover......over to the passengers side valve cover mid port. The port thats halfway back on the valve cover. Then through a T fitting run it over to the vacuum port on the intake with the PCV valve right there.

You do not need the TB line, delete that.

.
Old 02-16-2016, 02:39 AM
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This is the kind of pcv valve autozone sells for my car. How can you run that inline?

They said it plugs into the valve cover.
Old 02-16-2016, 09:53 AM
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Originally Posted by Fullblast
This is the kind of pcv valve autozone sells for my car. How can you run that inline? They said it plugs into the valve cover.
There's no easy way to answer that. Stock, the lines all teed together and ran to a rubber boot that held the valve. You had a hose from throttle body to passenger side front port. A hose from rear drivers side and rear passenger side teed into the valve, and then from valve to intake manifold. It was terrible and let tons of oil through.

If you had the ls6, you had a port off the valley cover that went straight to the intake, as the valve was built into the valley cover. Still had a line from throttle to front passenger cover port. It was less terrible.

If all that stuff is already missing, block off all but one of your ports, get a catch can with the built in PCV. Vent your oil cap, and you're set.
Old 02-16-2016, 10:32 AM
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Originally Posted by Fullblast


This is the kind of pcv valve autozone sells for my car. How can you run that inline?

They said it plugs into the valve cover.
Thats the one.

Buy 6 feet of 3/8" heater hose. Then buy one "T" fitting. Then go to a junkyard and find that rubber PCV boot......

Then run the lines and cut the lengths to fit.

Also....for awhile I experimented with a "T" fitting that had an allen screw in it that I could loosen or tighten to decrease or increase flow from the pull of vacuum. It worked great. You can do that with or without a PCV valve in the system.

.......You could also do this.
Pull vacuum ONLY from the passengers side valve cover port. all you need is about 18" of 3/8" heater hose, then cut to fit, with a PCV valve. Then simply put a vent on the drivers side valve cover. Fresh air will be pulled in the vent and across the entire crankcase, into the intake.

.....
Now.....I personally think pulling oil mist into an intake is just about the stupidest, most ridiculous design an auto manufacturer could ever come up with.
I bought a mini-puller fan that runs continuously. Its the size of a cigarette pack. I will be mounting it up under the cowl near the brake booster, out of the way of everything. Then wiring it so it comes on when I start the engine. The pull of vacuum is very light...but if I hold a cigerette up to one of the vents, the smoke gets pulled right in. I will then run a 3/8" hose over to the passenger side valve cover port. Then I will have a small fuel filter (vent) on my LS6 valley cover port and a fuel filter (vent) on my drivers side valve cover. Fresh air will be pulled into the two vents and sucked out of the passengers side valve cover.....into the line....through the air puller fan....and exit straight down through a 6" piece of heater hose.
I did this for over 1 year on my 427ci stroker. Never once did I have a drop of moisture in my oil....oil stayed perfectly clean....and at every 3,000 mile oil change I was able to put my old oil back into the 5 empty 1 qrt oil bottles and top them all off. Meaning the other half quart of oil was whatever remains in the engine and oil pan and whatever was burned in 3,000 miles. That equates to.....no oil getting wasted through a PCV system sucking it out.
My current 390ci has a normal PCV set-up....but its going away as soon as I install my turbo kit.

.
Old 02-16-2016, 11:55 AM
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Man you don't need no catch can. IDK know why everyone else is making it so difficult . That PVC valve from auto zone is enough. This is what you need to do very simple and can buy all the parts at the hardware store. I'm attaching the pictures so you can see what i'm talking about.
Attached Thumbnails Pcv system-pcv-parts.jpg   Pcv system-pcv-valve-part-2.jpg   Pcv system-new-pcv-valve-3.jpg   Pcv system-stockpcvsystem.jpg  
Old 02-16-2016, 03:31 PM
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You run the nipples on the valve cover to a T then the hose from the t will need to slip over the edge of the pcv valve. So the pcv valve sits in the hose not the valve cover
Old 02-17-2016, 05:00 AM
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Originally Posted by soloman369
Man you don't need no catch can. IDK know why everyone else is making it so difficult . That PVC valve from auto zone is enough. This is what you need to do very simple and can buy all the parts at the hardware store. I'm attaching the pictures so you can see what i'm talking about.

Yeah that pretty much simplifies it. Thanks. I was wondering how to attach the hose on the bigger side of the pcv back to the line, but it looks like you use a reducer.

I don't have time to go junkyard hunting, probably wont have much luck here anyway.

A catch can would be nice, but I need to spend $100 on other stuff first.
Old 02-24-2016, 10:15 AM
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to save money just shove the pcv valve you buy into the driver rear valve cover, and hook hose from that to intake manifold.

cap the rear passenger v/c port, and connect the forward most to throttle body.

you only need a catch can when you are losing oil through the pcv system. so look for that next
Old 11-30-2016, 07:26 PM
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Originally Posted by MIGHTYMOUSE
to save money just shove the pcv valve you buy into the driver rear valve cover, and hook hose from that to intake manifold.

cap the rear passenger v/c port, and connect the forward most to throttle body.

you only need a catch can when you are losing oil through the pcv system. so look for that next
Why block off the pass rear vc port if the pcv is in the driver vc?
Old 12-01-2016, 08:44 AM
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Originally Posted by pozesd99'
Why block off the pass rear vc port if the pcv is in the driver vc?
i should have clarified. some ls1 covers already have a grommet back here that the pcv valve neatly sits in.

Pcv system-qsauciw.jpg

plus the passenger side cover is the fresh air side. you want the fresh air side and dirty side on opposite sides of the engine so the pcv system can do the most good

(this hose here is the stock fresh air hose on all ls1)


you dont 'need' the passenger rear port for anything, it was dropped in later valve cover models.
Old 12-02-2016, 03:50 PM
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Originally Posted by MIGHTYMOUSE
i should have clarified. some ls1 covers already have a grommet back here that the pcv valve neatly sits in.



plus the passenger side cover is the fresh air side. you want the fresh air side and dirty side on opposite sides of the engine so the pcv system can do the most good

(this hose here is the stock fresh air hose on all ls1)


you dont 'need' the passenger rear port for anything, it was dropped in later valve cover models.
In this picture you are missing the lower hose. Is that an ls6 valley cover? If so you have the tube squashed under the intake, at least that is what it looks like.
Old 12-02-2016, 05:01 PM
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the photos were an example to help the OP. second pic is ls1 no ported valley, the fresh air line between pass v/c front port and fresh air (tb port) is standard on all gen3+ until you get into ls9/a/dry sump
Old 12-02-2016, 06:39 PM
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ah ok sorry bout that chief.
Old 09-15-2017, 04:37 PM
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Um,, why not just stick the pvc in the valley cover at the back, with a old style sbv valve cover grommet, and cap off the valve cover holes with the plugs?


you could even run a catch can at the back of the intake.


instead of spending $90 - $125 for the ls6 style valley cover.
Old 09-15-2017, 04:51 PM
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Just an fyi I've had a 5.3 up to 7psi of boost pressure with no pcv valve/system (atmospheric vent) just to see what would happen (looking for oil) and the front port of the valvecover (pictured above, that runs to the throttle body) is wide open to the atmosphere on my engine, so I expected oil to come gushing out there with all the crazy catch can setups I see people buying up like crazy I figured these motors must really sling that crude.


But it hasn't dripped even the smell of oil residue. I think if you see oil coming out of one of these engines you must have a bad pistonring or some kind of cylinder sealing problem, given what I've seen so far from an all OEM engine running a bit of boost.
Old 09-16-2017, 08:34 AM
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Originally Posted by F68
Um,, why not just stick the pvc in the valley cover at the back, with a old style sbv valve cover grommet, and cap off the valve cover holes with the plugs?

you could even run a catch can at the back of the intake.

instead of spending $90 - $125 for the ls6 style valley cover.
the valley plate i have found takes a lot more baffling to get a reasonably clean pcv draw off of. i would still use a catch can here, but i would prefer a v/c location if i had the choice.

Originally Posted by kingtal0n
Just an fyi I've had a 5.3 up to 7psi of boost pressure with no pcv valve/system (atmospheric vent) just to see what would happen (looking for oil) and the front port of the valvecover (pictured above, that runs to the throttle body) is wide open to the atmosphere on my engine, so I expected oil to come gushing out there with all the crazy catch can setups I see people buying up like crazy I figured these motors must really sling that crude.


But it hasn't dripped even the smell of oil residue. I think if you see oil coming out of one of these engines you must have a bad pistonring or some kind of cylinder sealing problem, given what I've seen so far from an all OEM engine running a bit of boost.
with all due respect not all here are on stock bottom ends or only on 7psi. cylinder leakage is not the same across every v8 made and not at every power level. stock ring and piston clearances are much tighter, so the leakage per hp is comparably low to a forged build for high power on pump gas.

once you start making some power the airflow will rise to a cfm where oil will start to come with it.

i have hundreds of stock bottom end customers 5-800hp and no significant crank pressure issues to solve. i can do that modifying the existing pcv system.
i have hundreds of customers street driving full functioning pcv systems between 1000 and 1500hp, and a some past that, myself included, with very manageable crank airflow
and i talk to people every day stuck somewhere in between with backyard 'boost gapped' rings resulting in horrible blowby relative to their power, and need a solution.
these guys need something more than what came from gm, and almost all prefer retaining the fumes control and crankcase filtration a pcv system provides.


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