PCV System
06-12-2007, 02:59 AM
#2
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Is there more than the hose, pcv valve and grommet (I'm asking honestly, I don't know what all differs on a 95 from mine)? If not, get about 16in of 3/8 fuel line (you won't need all 16in, but good to have more than needed to start), a standard SBC 90º PCV valve, and then run the hose to the plugged off vacuum port on your throttle body. Chances are you won't notice a difference with or without it.
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Down (01-01-2023)
06-12-2007, 03:40 AM
#3
i saw some pics on here where they had the pcv valve hooked to some port on the intake manifold, then I am assuming a line form the TB to the valvecover, and form the looks of it it was jsut a hose into the valvecover nothing more....is this correct?
I was thinking the pcv system was routed different than this....
I was thinking the pcv system was routed different than this....
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Tommys96TA (07-25-2020)
06-12-2007, 01:18 PM
#5
Unless you have nothing in the larger port labeled "PCV" in this pic, you still have most of your system intact:
(Ignore the one labeled "Connect to PCV valve. That's for 92-94 LT1's.) On a 95-up, the valve coming out of this port will be connected to a long metal tube that runs around to the front of the intake manifold and plugs into the port down below the throttle body.
If you don't have anything in the PCV port on the side of the intake, you need to get one. (GM P/N#25095452.)
The job of a PCV system is to provide a way for air pressure inside the crankcase to be purged. Air pressure in the crankcase introduces resistance to the down stroke of the pistons, which can rob horsepower. Notice in the above pic that the PCV valve is connected to a vacuum port on the intake which literally sucks the air out of the crankcase.
Think of the pistons as a plunger inside of a syringe: as the plunger moves, it displaces air on one side with fluid on the other. The PCV valve is like the needle in that syringe. If it is blocked off, the air that is on the other side of the plunger becomes pressurized and is forced to go around it. (Because crankcases are sealed and there's nowhere else for it to go.)
Air from the crankcase that makes it's way around pistons and into the combustion chamber is commonly known as "blowby." If one or more piston rings happen to be worn down enough, it can start bringing oil along with it which can lead to detonation. If your pistons still have a tight enough seal to prevent the air pressure from bleeding off there, the air can actually be forced into the oil itself by way of the crankshaft whipping it up. Ever notice the nice bubbly froth that gets whipped up whenever you mix something inside of a sealed blender? Same thing that happens here. It's called "aeration", which essentially turns your oil into a nice chocolate milk sludge. (And breaks down it's ability to flow and lubricate properly.)
A breather in the valve cover, (which lets fresh air in), won't hurt anything. But you still need a PCV valve of some type to let the air out.
(Ignore the one labeled "Connect to PCV valve. That's for 92-94 LT1's.) On a 95-up, the valve coming out of this port will be connected to a long metal tube that runs around to the front of the intake manifold and plugs into the port down below the throttle body.
If you don't have anything in the PCV port on the side of the intake, you need to get one. (GM P/N#25095452.)
The job of a PCV system is to provide a way for air pressure inside the crankcase to be purged. Air pressure in the crankcase introduces resistance to the down stroke of the pistons, which can rob horsepower. Notice in the above pic that the PCV valve is connected to a vacuum port on the intake which literally sucks the air out of the crankcase.
Think of the pistons as a plunger inside of a syringe: as the plunger moves, it displaces air on one side with fluid on the other. The PCV valve is like the needle in that syringe. If it is blocked off, the air that is on the other side of the plunger becomes pressurized and is forced to go around it. (Because crankcases are sealed and there's nowhere else for it to go.)
Air from the crankcase that makes it's way around pistons and into the combustion chamber is commonly known as "blowby." If one or more piston rings happen to be worn down enough, it can start bringing oil along with it which can lead to detonation. If your pistons still have a tight enough seal to prevent the air pressure from bleeding off there, the air can actually be forced into the oil itself by way of the crankshaft whipping it up. Ever notice the nice bubbly froth that gets whipped up whenever you mix something inside of a sealed blender? Same thing that happens here. It's called "aeration", which essentially turns your oil into a nice chocolate milk sludge. (And breaks down it's ability to flow and lubricate properly.)
A breather in the valve cover, (which lets fresh air in), won't hurt anything. But you still need a PCV valve of some type to let the air out.
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Tommys96TA (07-25-2020)
06-12-2007, 02:20 PM
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Originally Posted by thesoundandthefury
Unless you have nothing in the larger port labeled "PCV" in this pic, you still have most of your system intact:
(Ignore the one labeled "Connect to PCV valve. That's for 92-94 LT1's.) On a 95-up, the valve coming out of this port will be connected to a long metal tube that runs around to the front of the intake manifold and plugs into the port down below the throttle body.
If you don't have anything in the PCV port on the side of the intake, you need to get one. (GM P/N#25095452.)
The job of a PCV system is to provide a way for air pressure inside the crankcase to be purged. Air pressure in the crankcase introduces resistance to the down stroke of the pistons, which can rob horsepower. Notice in the above pic that the PCV valve is connected to a vacuum port on the intake which literally sucks the air out of the crankcase.
Think of the pistons as a plunger inside of a syringe: as the plunger moves, it displaces air on one side with fluid on the other. The PCV valve is like the needle in that syringe. If it is blocked off, the air that is on the other side of the plunger becomes pressurized and is forced to go around it. (Because crankcases are sealed and there's nowhere else for it to go.)
Air from the crankcase that makes it's way around pistons and into the combustion chamber is commonly known as "blowby." If one or more piston rings happen to be worn down enough, it can start bringing oil along with it which can lead to detonation. If your pistons still have a tight enough seal to prevent the air pressure from bleeding off there, the air can actually be forced into the oil itself by way of the crankshaft whipping it up. Ever notice the nice bubbly froth that gets whipped up whenever you mix something inside of a sealed blender? Same thing that happens here. It's called "aeration", which essentially turns your oil into a nice chocolate milk sludge. (And breaks down it's ability to flow and lubricate properly.)
A breather in the valve cover, (which lets fresh air in), won't hurt anything. But you still need a PCV valve of some type to let the air out.
(Ignore the one labeled "Connect to PCV valve. That's for 92-94 LT1's.) On a 95-up, the valve coming out of this port will be connected to a long metal tube that runs around to the front of the intake manifold and plugs into the port down below the throttle body.
If you don't have anything in the PCV port on the side of the intake, you need to get one. (GM P/N#25095452.)
The job of a PCV system is to provide a way for air pressure inside the crankcase to be purged. Air pressure in the crankcase introduces resistance to the down stroke of the pistons, which can rob horsepower. Notice in the above pic that the PCV valve is connected to a vacuum port on the intake which literally sucks the air out of the crankcase.
Think of the pistons as a plunger inside of a syringe: as the plunger moves, it displaces air on one side with fluid on the other. The PCV valve is like the needle in that syringe. If it is blocked off, the air that is on the other side of the plunger becomes pressurized and is forced to go around it. (Because crankcases are sealed and there's nowhere else for it to go.)
Air from the crankcase that makes it's way around pistons and into the combustion chamber is commonly known as "blowby." If one or more piston rings happen to be worn down enough, it can start bringing oil along with it which can lead to detonation. If your pistons still have a tight enough seal to prevent the air pressure from bleeding off there, the air can actually be forced into the oil itself by way of the crankshaft whipping it up. Ever notice the nice bubbly froth that gets whipped up whenever you mix something inside of a sealed blender? Same thing that happens here. It's called "aeration", which essentially turns your oil into a nice chocolate milk sludge. (And breaks down it's ability to flow and lubricate properly.)
A breather in the valve cover, (which lets fresh air in), won't hurt anything. But you still need a PCV valve of some type to let the air out.
LOL So if you know all of this, why the other thread asking about PCV delete?
06-12-2007, 02:25 PM
#7
Originally Posted by Formula350
LOL So if you know all of this, why the other thread asking about PCV delete?
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06-12-2007, 02:32 PM
#9
Originally Posted by Revelation Z28
so on the passenger side VC you cant just get one of thoes little breathers from autozone or whatever and be done with it?
06-12-2007, 07:59 PM
#11
excellent.....so there is no need for me to put that hose into the VC, just a breather tube? I have a pcv valve chilling in it now, as my ignorant *** thought it was where the valve was supposed to go. As for the other portion of the pcv system I will be fixing that asap. I am wondering if this might be my mysterious "fuel leak" that I have been smelling. Anyways thanks for all the info! and very informative. I went through about 100 posts last night and none did as well as this one. thanks again
06-12-2007, 08:37 PM
#12
Originally Posted by solarofthesix
excellent.....so there is no need for me to put that hose into the VC, just a breather tube?
Since you said that you plan on putting a new PCV valve in, you should be okay in this regard, but just for the sake of caution I would keep an eye on the area around the breather for a few miles after you install it. People who have suffered from the infamous "oil in the intake" problem get the oil through that hose that runs from the VC to the TB. Some have put a breather in their VC without knowing that they had this problem, and ended up with oil all over the inside of their engine bay instead of the intake.
Just a heads up.
06-12-2007, 09:34 PM
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Originally Posted by thesoundandthefury
A breather in the VC will allow a small amount of unmetered air into the engine. Small enough that the PCM usually has no trouble compensating for it. You should be fine with it.
Since you said that you plan on putting a new PCV valve in, you should be okay in this regard, but just for the sake of caution I would keep an eye on the area around the breather for a few miles after you install it. People who have suffered from the infamous "oil in the intake" problem get the oil through that hose that runs from the VC to the TB. Some have put a breather in their VC without knowing that they had this problem, and ended up with oil all over the inside of their engine bay instead of the intake.
Just a heads up.
Since you said that you plan on putting a new PCV valve in, you should be okay in this regard, but just for the sake of caution I would keep an eye on the area around the breather for a few miles after you install it. People who have suffered from the infamous "oil in the intake" problem get the oil through that hose that runs from the VC to the TB. Some have put a breather in their VC without knowing that they had this problem, and ended up with oil all over the inside of their engine bay instead of the intake.
Just a heads up.
06-12-2007, 09:49 PM
#14
Originally Posted by Formula350
I fully believe the cause of our intakes being nasty inside is from the PCV. If anyone's had a hot tanked intake and installed it and NEVER ran the PCV, I'd like to see if it's still clean inside.
06-12-2007, 11:19 PM
#15
Originally Posted by thesoundandthefury
A bad PCV valve, yes. If the PCV valve goes bad or becomes clogged with carbon over time, the crank case pressure takes the next path of least resistance which is to start blowing out the valve cover.
06-13-2007, 12:27 AM
#16
Originally Posted by speed_demon24
The path with the least resistance is the fresh air hose.
And if you put a breather filter there, it will suck air in at part throtte
but at full throttle it will be reversed and it will flow out of the air filter relieving the pressure in the crankcase
The pcv valve is a restriction in the line.
Contrary to popular belief, the PCV system on LT1's is actually very efficient. The problem is that it makes no noise, shows no outwardly visible signs, and throws no codes when it goes bad. Combine that with the fact that alot of LT1 owners just simply don't know that this is a serviceable part that needs to be replaced like oil and air filters every so many miles, and it's not hard to imagine why so many people have the oil in the intake problem.
06-13-2007, 08:46 AM
#20
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I'm boosting my LT1 and am planning out my PCV setup.
So far I know I'm putting a breather on my passenger side valve cover, but am wondering what to do about the drivers side intake manifold.
I'd like to completely remove the PCV system, would this be a good setup?
So far I know I'm putting a breather on my passenger side valve cover, but am wondering what to do about the drivers side intake manifold.
I'd like to completely remove the PCV system, would this be a good setup?