PCV valve,can I remove?
Thread Starter
Racer
Joined: Dec 2009
Posts: 308
Likes: 2
From: South Italy
PCV valve,can I remove?
Hello,
I'm a newbie,I'm doing some work on my '81 and I want to know if to remove the pvc valve and install a breather is a good think or in this way my carburetor dont such theoil vapor and I will have a blowbye.
The car is without all emission control,no EGR,no air pump and the other stuff.The carburator is an Edelbrock 600.
Sorry for my english.
Thank you.
I'm a newbie,I'm doing some work on my '81 and I want to know if to remove the pvc valve and install a breather is a good think or in this way my carburetor dont such theoil vapor and I will have a blowbye.
The car is without all emission control,no EGR,no air pump and the other stuff.The carburator is an Edelbrock 600.
Sorry for my english.
Thank you.
Racer
Joined: Aug 2005
Posts: 308
Likes: 0
From: Salem MA
its a '81 motor, it has low compression and isn't exactly 'high performance.' the PCV gasses wont hurt anything.
Those gasses are really gross and really bad for the enviroment.
if the motor was boosted to the ragged edge, then yes the PCV may be bad thing because rumor has it that the gasses lower the octane of the combustion mixture.
so my vote is to leave the PCV as-is,
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Thread Starter
Racer
Joined: Dec 2009
Posts: 308
Likes: 2
From: South Italy
Ok,I'm going to replace it.
The engine is mild modificated,cam,(I don't know the tipe),heathers,true dual exaust with X pipes,edelbrock intake and carburator and msd distributor.
I drive it only for the cruise.
If I understand well the best think is live it where is it.
You are wery helpfull !!!
The engine is mild modificated,cam,(I don't know the tipe),heathers,true dual exaust with X pipes,edelbrock intake and carburator and msd distributor.
I drive it only for the cruise.
If I understand well the best think is live it where is it.
You are wery helpfull !!!
Racer
Joined: Aug 2005
Posts: 308
Likes: 0
From: Salem MA
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,116
From: Crossville TN
Keep the PCV valve, but make sure that you have a way for the engine to get fresh air into it (internally). Usually, there is a tube coming from the air cleaner housing to the opposite valve cover. That supplies air to the engine so that it can replace the gases released by the PCV valve to the carb [for burning with the air/fuel mixture]. You could put a breather on that other valve cover to allow air inlet...if your tube from the air cleaner is missing. But the original design approach prevents any oil vapors from being released into the air and allows for a cleaner engine compartment.
Thread Starter
Racer
Joined: Dec 2009
Posts: 308
Likes: 2
From: South Italy
I have installed the breather on the other valve cover(passenger side).I have used it for a very few time with pvc valve in place and the breather in the opposite side and I don't have see any oil somewhere.
For this reasons I just asking if is better or worse remove the valve.
In many forum I have seen more chevy engine picture with 2 breather,but of course I can't know if they have some spot of oil in the engne bay.
For this reasons I just asking if is better or worse remove the valve.
In many forum I have seen more chevy engine picture with 2 breather,but of course I can't know if they have some spot of oil in the engne bay.
Thread Starter
Racer
Joined: Dec 2009
Posts: 308
Likes: 2
From: South Italy
too if you are going to do some work is a good think to wait the heathers become cold,they burn like a hell.
Pro
Joined: May 2003
Posts: 593
Likes: 0
From: London England
I have two main issues with PCV.
An engine is designed to run on clean air and petrol, not dirty old oil fumes. Suck in enough oil fumes on over-run and your next acceleration may stumble as the plugs and cylinders clear themselves of all that rubbish you've just sucked in.
Also, PCV relies on a 1¢ spring, if this becomes weak or the valve slightly clogged up, your emissions device has just become a major intake leak.
If you believe all the climate change rubbish we're fed every day and want to feel good about yourself then keep it. Personally I delete it from every vehicle I own.
An engine is designed to run on clean air and petrol, not dirty old oil fumes. Suck in enough oil fumes on over-run and your next acceleration may stumble as the plugs and cylinders clear themselves of all that rubbish you've just sucked in.
Also, PCV relies on a 1¢ spring, if this becomes weak or the valve slightly clogged up, your emissions device has just become a major intake leak.
If you believe all the climate change rubbish we're fed every day and want to feel good about yourself then keep it. Personally I delete it from every vehicle I own.
Race Director
Joined: Mar 2006
Posts: 14,112
Likes: 28
From: Florida
I have two main issues with PCV.
An engine is designed to run on clean air and petrol, not dirty old oil fumes. Suck in enough oil fumes on over-run and your next acceleration may stumble as the plugs and cylinders clear themselves of all that rubbish you've just sucked in.
Also, PCV relies on a 1¢ spring, if this becomes weak or the valve slightly clogged up, your emissions device has just become a major intake leak.
If you believe all the climate change rubbish we're fed every day and want to feel good about yourself then keep it. Personally I delete it from every vehicle I own.
An engine is designed to run on clean air and petrol, not dirty old oil fumes. Suck in enough oil fumes on over-run and your next acceleration may stumble as the plugs and cylinders clear themselves of all that rubbish you've just sucked in.
Also, PCV relies on a 1¢ spring, if this becomes weak or the valve slightly clogged up, your emissions device has just become a major intake leak.
If you believe all the climate change rubbish we're fed every day and want to feel good about yourself then keep it. Personally I delete it from every vehicle I own.
Burning Brakes
Joined: Aug 2005
Posts: 1,164
Likes: 1
From: Europe, France
Even if I removed mine and replaced it with breathers, I would recommend to keep yours.
PCV system doesn't hurt performance, but buy a new PCV valve.
It will also keep your engine bay clean.
And it's good for the planet, too...
PCV system doesn't hurt performance, but buy a new PCV valve.
It will also keep your engine bay clean.
And it's good for the planet, too...
Pro
Joined: May 2003
Posts: 593
Likes: 0
From: London England
To start with if you have any reasonable blow-by you've got a ring problem. The gas in the cylinder is supposed to go out the exhaust, not into the crankcase.
Crankcase ventilation is there mainly to allow for pressure changes due to heat and expansion, not exhaust gas. Most of what comes out of the breather is oil vapour, some unburned fuel (from shutdown and start up) and condensation.
It is very simple to run an open line to a catch can/tank.
Crankcase ventilation is there mainly to allow for pressure changes due to heat and expansion, not exhaust gas. Most of what comes out of the breather is oil vapour, some unburned fuel (from shutdown and start up) and condensation.
It is very simple to run an open line to a catch can/tank.
Race Director
Joined: May 2003
Posts: 10,956
Likes: 409
From: California
To start with if you have any reasonable blow-by you've got a ring problem. The gas in the cylinder is supposed to go out the exhaust, not into the crankcase.
Crankcase ventilation is there mainly to allow for pressure changes due to heat and expansion, not exhaust gas. Most of what comes out of the breather is oil vapour, some unburned fuel (from shutdown and start up) and condensation.
It is very simple to run an open line to a catch can/tank.
Crankcase ventilation is there mainly to allow for pressure changes due to heat and expansion, not exhaust gas. Most of what comes out of the breather is oil vapour, some unburned fuel (from shutdown and start up) and condensation.
It is very simple to run an open line to a catch can/tank.
This weekend I changed all my valve springs out to Beehive, and while all apart I did a leak down test. I was way below 10% on all cylinders..
And I have blow-by.....
PCV baby!!! p:-)