Letting it breath
#1
Letting it breath
What's the best setup for crankcase ventilation? I know the stock setup uses the PCV valve, is it just on one side or both sides? I think both valve covers vent into the air cleaner?
I see some folks using the open vents that plug into the valve cover holes and just vent to the engine compartment...does this lead to oil misting and build up in the engine compartment?
I'm using a pair of GMPP tall cast aluminum valve covers on my 455. Edelbrock Performer intake, Quickfuel carb and around 10.1:1 compression (approx as engine isn't assembled yet). Street engine, won't be spinning to high RPM very often. My machine shop will be opening up a hole in each cover to facilitate venting and installing baffles inside the holes, but at this point I don't know what air cleaner I'll be using and how much room there will be for fittings going into it.
So basically I'm looking for suggestions on the best approach to ensuring adequate venting that isn't going to leave a mess.
I see some folks using the open vents that plug into the valve cover holes and just vent to the engine compartment...does this lead to oil misting and build up in the engine compartment?
I'm using a pair of GMPP tall cast aluminum valve covers on my 455. Edelbrock Performer intake, Quickfuel carb and around 10.1:1 compression (approx as engine isn't assembled yet). Street engine, won't be spinning to high RPM very often. My machine shop will be opening up a hole in each cover to facilitate venting and installing baffles inside the holes, but at this point I don't know what air cleaner I'll be using and how much room there will be for fittings going into it.
So basically I'm looking for suggestions on the best approach to ensuring adequate venting that isn't going to leave a mess.
#3
I agree, venting to the engine bay leads to exhaust gases getting into the passenger compartment. I did that once while troubleshooting issues and it was smelly.
The factory setup for most engines is a breather in one valve cover and a PCV valve in the other valve cover. This allows fresh air to be drawn in via the breather, move through the crankcase to the opposite valve cover, then be drawn into the intake along with all the blowby gases and be burned in the cylinders. The connection from the valve cover breather to the air cleaner is to provide filtered air into the system. The blowby gases do not enter the air cleaner, they go into the intake manifold.
You can also use a breather in each valve cover and a PCV valve tapped into the base of the intake manifold where it's open to the lifter valley. This method pulls fresh air into both valve covers, through the crankcase, then into the intake.
The factory setup for most engines is a breather in one valve cover and a PCV valve in the other valve cover. This allows fresh air to be drawn in via the breather, move through the crankcase to the opposite valve cover, then be drawn into the intake along with all the blowby gases and be burned in the cylinders. The connection from the valve cover breather to the air cleaner is to provide filtered air into the system. The blowby gases do not enter the air cleaner, they go into the intake manifold.
You can also use a breather in each valve cover and a PCV valve tapped into the base of the intake manifold where it's open to the lifter valley. This method pulls fresh air into both valve covers, through the crankcase, then into the intake.
#4
#5
I purchased one of these for a BBC project but haven't started the engine yet.
http://mewagner.com/?p=444
http://mewagner.com/?p=444
#6
I purchased one of these for a BBC project but haven't started the engine yet.
http://mewagner.com/?p=444
http://mewagner.com/?p=444
#7
#8
So I think I'll put the PCV valve towards the back on the passenger side, and the carb has a 3/8" PCV valve vacuum port on the back. Then a breather (probably the same as Powerm01 used...just a black Summit breather with a SS2 center cap decal on it) towards the front on the driver side. Should be plenty, no need to overthink?
#9
I agree, venting to the engine bay leads to exhaust gases getting into the passenger compartment. I did that once while troubleshooting issues and it was smelly.
The factory setup for most engines is a breather in one valve cover and a PCV valve in the other valve cover. This allows fresh air to be drawn in via the breather, move through the crankcase to the opposite valve cover, then be drawn into the intake along with all the blowby gases and be burned in the cylinders. The connection from the valve cover breather to the air cleaner is to provide filtered air into the system. The blowby gases do not enter the air cleaner, they go into the intake manifold.
You can also use a breather in each valve cover and a PCV valve tapped into the base of the intake manifold where it's open to the lifter valley. This method pulls fresh air into both valve covers, through the crankcase, then into the intake.
The factory setup for most engines is a breather in one valve cover and a PCV valve in the other valve cover. This allows fresh air to be drawn in via the breather, move through the crankcase to the opposite valve cover, then be drawn into the intake along with all the blowby gases and be burned in the cylinders. The connection from the valve cover breather to the air cleaner is to provide filtered air into the system. The blowby gases do not enter the air cleaner, they go into the intake manifold.
You can also use a breather in each valve cover and a PCV valve tapped into the base of the intake manifold where it's open to the lifter valley. This method pulls fresh air into both valve covers, through the crankcase, then into the intake.
Not that it makes any difference, but I'm swapping my tired 350 to a 455 that's built up a little... Aluminum heads, hotter cam and such that I got from Olds Rocket parts.
#10
Good question. Are there integrated options that don't involve installing a baffle to the valve cover?
I came across this setup in one of the facebook groups. Leaning towards this implementation now to avoid machining/cluttering the outboard face of the valve covers. Breather on the passenger side, PCV valve on the right.
I came across this setup in one of the facebook groups. Leaning towards this implementation now to avoid machining/cluttering the outboard face of the valve covers. Breather on the passenger side, PCV valve on the right.
#11
I saw the same FB post. I asked the guy for details but he didn't know, as his mechanic came up with this... are both sides PCV or is one a mini breather, don't know. I'm leaning towards the outside mounted side breathers, they look cool and old school at the same time and I'd put the PCV in the manifold.
#12
I saw the same FB post. I asked the guy for details but he didn't know, as his mechanic came up with this... are both sides PCV or is one a mini breather, don't know. I'm leaning towards the outside mounted side breathers, they look cool and old school at the same time and I'd put the PCV in the manifold.
The PCV valve looks something like this one: https://www.summitracing.com/parts/sum-440308-blk
And the breather filter: https://www.summitracing.com/parts/spe-3991
#13
I see that now, the breather is on that elbow a bit hidden. I just went into the barn to check my manifold and it appears as though they've already prepped it for a PCV, there's predrilled holes with knockouts in front and in back. The engine in the photo sure looks clean with that setup, still undecided.
#14
Good question. Are there integrated options that don't involve installing a baffle to the valve cover?
I came across this setup in one of the facebook groups. Leaning towards this implementation now to avoid machining/cluttering the outboard face of the valve covers. Breather on the passenger side, PCV valve on the right.
I came across this setup in one of the facebook groups. Leaning towards this implementation now to avoid machining/cluttering the outboard face of the valve covers. Breather on the passenger side, PCV valve on the right.
#16
I agree, venting to the engine bay leads to exhaust gases getting into the passenger compartment. I did that once while troubleshooting issues and it was smelly.
The factory setup for most engines is a breather in one valve cover and a PCV valve in the other valve cover. This allows fresh air to be drawn in via the breather, move through the crankcase to the opposite valve cover, then be drawn into the intake along with all the blowby gases and be burned in the cylinders. The connection from the valve cover breather to the air cleaner is to provide filtered air into the system. The blowby gases do not enter the air cleaner, they go into the intake manifold.
You can also use a breather in each valve cover and a PCV valve tapped into the base of the intake manifold where it's open to the lifter valley. This method pulls fresh air into both valve covers, through the crankcase, then into the intake.
The factory setup for most engines is a breather in one valve cover and a PCV valve in the other valve cover. This allows fresh air to be drawn in via the breather, move through the crankcase to the opposite valve cover, then be drawn into the intake along with all the blowby gases and be burned in the cylinders. The connection from the valve cover breather to the air cleaner is to provide filtered air into the system. The blowby gases do not enter the air cleaner, they go into the intake manifold.
You can also use a breather in each valve cover and a PCV valve tapped into the base of the intake manifold where it's open to the lifter valley. This method pulls fresh air into both valve covers, through the crankcase, then into the intake.
Last edited by covers1972; January 26th, 2023 at 09:19 PM. Reason: added information
#18
https://www.summitracing.com/parts/m...CABEgIMO_D_BwE
#19
Yup, kind of cool. I have Moroso but Mr. Gasket makes it too. I might be off base, but I assume wouldn't have to worry about regular baffles on valve covers.
https://www.summitracing.com/parts/m...CABEgIMO_D_BwE
https://www.summitracing.com/parts/m...CABEgIMO_D_BwE
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