Is it alright to have unvented valve covers using LS3 valley cover with catchcan?
10-28-2011, 03:09 PM
#1
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Is it alright to have unvented valve covers using LS3 valley cover with catchcan? I have a setup using LSA heads and the valve covers I bought do not have any breathers or lines out whatsoever. Will I be alright to just connect the valley cover to a catchcan than to my intake and just plug the TB port?
i understand why the engine needs to breathe out of the valve covers but will it work to just pull vaccum on the valley port?
If not please somebody tell me what I need to do before i put this engine back in.
Thank you
i understand why the engine needs to breathe out of the valve covers but will it work to just pull vaccum on the valley port?
If not please somebody tell me what I need to do before i put this engine back in.
Thank you
10-28-2011, 03:37 PM
#2
You will need to vent the valve cover. The way it works, is the valley cover is hooked into the vacuum side of the intake manifold (behind the throttle plate) which draws the air out of the valley/motor. The clean air is being drawn from the motor is pulled from the top of the motor, preferably the valve covers. They are hooked into the throttlebody where clean, metered air is drawn. This creates a cycle, by which internal air of the motor is flushed with clean air.
Air enters intake filters, travels through MAF, some gets drawn by the PCV infront of the throttleplate into the valve covers, cycles down into the crankcase, gets sucked into the valley, through the LS3 valley cover, and into the intake, behind the throttleplate (where its sucking like a straw), into the combustion chambers and out of the exhaust.
Without this vacuum circulation you will not effectively clear out the crankcase, nor, will you be able to properly tune with a MAF if it is not in the closed loop like described.
Air enters intake filters, travels through MAF, some gets drawn by the PCV infront of the throttleplate into the valve covers, cycles down into the crankcase, gets sucked into the valley, through the LS3 valley cover, and into the intake, behind the throttleplate (where its sucking like a straw), into the combustion chambers and out of the exhaust.
Without this vacuum circulation you will not effectively clear out the crankcase, nor, will you be able to properly tune with a MAF if it is not in the closed loop like described.
10-28-2011, 08:18 PM
#3
You will need to vent the valve cover. The way it works, is the valley cover is hooked into the vacuum side of the intake manifold (behind the throttle plate) which draws the air out of the valley/motor. The clean air is being drawn from the motor is pulled from the top of the motor, preferably the valve covers. They are hooked into the throttlebody where clean, metered air is drawn. This creates a cycle, by which internal air of the motor is flushed with clean air.
Air enters intake filters, travels through MAF, some gets drawn by the PCV infront of the throttleplate into the valve covers, cycles down into the crankcase, gets sucked into the valley, through the LS3 valley cover, and into the intake, behind the throttleplate (where its sucking like a straw), into the combustion chambers and out of the exhaust.
Without this vacuum circulation you will not effectively clear out the crankcase, nor, will you be able to properly tune with a MAF if it is not in the closed loop like described.
Air enters intake filters, travels through MAF, some gets drawn by the PCV infront of the throttleplate into the valve covers, cycles down into the crankcase, gets sucked into the valley, through the LS3 valley cover, and into the intake, behind the throttleplate (where its sucking like a straw), into the combustion chambers and out of the exhaust.
Without this vacuum circulation you will not effectively clear out the crankcase, nor, will you be able to properly tune with a MAF if it is not in the closed loop like described.
10-30-2011, 05:54 PM
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You will need to vent the valve cover. The way it works, is the valley cover is hooked into the vacuum side of the intake manifold (behind the throttle plate) which draws the air out of the valley/motor. The clean air is being drawn from the motor is pulled from the top of the motor, preferably the valve covers. They are hooked into the throttlebody where clean, metered air is drawn. This creates a cycle, by which internal air of the motor is flushed with clean air.
Air enters intake filters, travels through MAF, some gets drawn by the PCV infront of the throttleplate into the valve covers, cycles down into the crankcase, gets sucked into the valley, through the LS3 valley cover, and into the intake, behind the throttleplate (where its sucking like a straw), into the combustion chambers and out of the exhaust.
Without this vacuum circulation you will not effectively clear out the crankcase, nor, will you be able to properly tune with a MAF if it is not in the closed loop like described.
Air enters intake filters, travels through MAF, some gets drawn by the PCV infront of the throttleplate into the valve covers, cycles down into the crankcase, gets sucked into the valley, through the LS3 valley cover, and into the intake, behind the throttleplate (where its sucking like a straw), into the combustion chambers and out of the exhaust.
Without this vacuum circulation you will not effectively clear out the crankcase, nor, will you be able to properly tune with a MAF if it is not in the closed loop like described.
Very informative post. I'm sure that will help alot of people...
10-31-2011, 08:46 AM
#6
A boosted motor is a little different.
The only difference, is the fresh air line that is hooked up infront of the throttle plate needs to be closed, and the valve-cover vented to air. Per your original suggestion, leaving the valve covers closed will not allow any fresh air to enter the motor, thus, your valve covers need to be vented to open air as opposed to the throttlebody.
The valley cover to intake will remain the same. The PCV valve will shut with backpressure (boosted air from the intake), but at idle, it will still be producing vacuum, opening up the PCV valve, circulating the air, vented from the valve cover.
The only difference, is the fresh air line that is hooked up infront of the throttle plate needs to be closed, and the valve-cover vented to air. Per your original suggestion, leaving the valve covers closed will not allow any fresh air to enter the motor, thus, your valve covers need to be vented to open air as opposed to the throttlebody.
The valley cover to intake will remain the same. The PCV valve will shut with backpressure (boosted air from the intake), but at idle, it will still be producing vacuum, opening up the PCV valve, circulating the air, vented from the valve cover.
