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First question. Regarding dirty/clean sides on the valve covers. What actually makes the driver side "dirty" and the passenger side "clean". Is it the valve cover vent location being in the rear of the engine for dirty? or something particular to that head that is different. I'm guessing my clean valve cover is now on the dirty side.
With the LS6 valley with two catch can's, I've read different things. Plug dirty side vent, join to clean side, join to valley etc. I thought vacuum in crankcase was improved by keeping the valve covers separated in terms of catch can's. or basically that it worked more effectively. I don't care about easiest, I care about best so should the dirty side valve cover (whichever side that is) be combined with the valleycover vent on one catch can OR should the dirty side valve cover be plugged and only run the valley to the can?
is the baffling on the valve covers specific to their locations on the side of the engine/head? In other words should I move them back because the clean side cover is going to be getting splashed with oil and i'ts not baffled appropriately there? This just means all the lines from the front of the engine (valley cover & clean side) will run around the engine to the throttle body.
Is there benefit to opening up the size of any particular opening/tubing? If all other hoses/barb fittings remain the same, is it better to run a bigger clean air line off the oil cap?
"Clean" = clean air from the outside goes into the engine.
"Dirty" = air mixed with oil mist and blow-by exhaust coming out of the engine.
I'm pretty sure the valve covers themselves are identical, and clean-side / dirty-side convention just came from the way the air flows in the factory setup. But which is which, for any given engine, really just depends on which way the air is flowing.
On my car there was definitely a big advantage to restricting the valley cover when I was using that as the dirty-air exit. Without a restriction, intake vacuum was sucking a lot of oil mist out of the valley cover vent. With a restriction it's fine. The guy from Mighty Mouse said that the camshaft slings a lot of oil around in there.
As the clean-side air path gets less restrictive, the crankcase vacuum goes down. Vacuum is negligible without a restriction on the air coming in. So that might actually be an argument for a smaller, more restrictive path for the intake (clean-side) air.
I ran my Subaru without clean-side plumbing for years. All three PCV lines just fed crankcase gases into the intake manifold.
I have to get myself an F-body. I miss the days of having a real engine bay with plenty of elbow room. Back on point, your install looks pretty clean to me provided you’re getting the proper flow. 👍
I have to get myself an F-body. I miss the days of having a real engine bay with plenty of elbow room. Back on point, your install looks pretty clean to me provided you’re getting the proper flow. 👍
What engine bay are you referring to with less elbow room than the F-body?
I always felt that there wasn't much room in the engine bay of the F-body until you relocate/remove a bunch of things.
If you like the creature comforts such as air conditioning you will not like the 6 & 8 plug change and since half the engine is under the windhield cowl it's not the most joyable of times working up top pulling heads and intake.
Can anyone please tell me at what point is there any benefit to using a clean air side catch can as well as the dirty side one? I have a pretty much stock 5.3 but am getting some oil in the intake, on the valves and the pistons. I currently have a can on the clean and a can on the dirty sides.
Also, does it matter which of the rocker cover connections I use for the clean side?
Is there any reason not to remove the outlet hose from the catch can on the dirty side (that goes to the intake) and put a filter on it instead so any air from the can doesn't go into the intake?
Can anyone please tell me at what point is there any benefit to using a clean air side catch can as well as the dirty side one? I have a pretty much stock 5.3 but am getting some oil in the intake, on the valves and the pistons. I currently have a can on the clean and a can on the dirty sides.
Also, does it matter which of the rocker cover connections I use for the clean side?
Is there any reason not to remove the outlet hose from the catch can on the dirty side (that goes to the intake) and put a filter on it instead so any air from the can doesn't go into the intake?
most catch cans with a single in and single out are restrictive, because that restriction is supposed to stop oil
-on the clean air side of the system restriction is your enemy, this is the vent on the engine and any restriction will increase crankcase pressure and is generally detrimental
so the keys are to only modify that side when necessary, and then when it is, a comprehensive approach that does not reduce flow capability, and hopefully increases it.
it absolutely matters on almost every catch can made you cannot reverse the configuration, for sure not on truck covers or valley plate cars with integral pcv control.
the pcv system is a filtration cycle of clean air into the crankcase and dirty air out, if you stop either one of those you have stopped pcv and its benefits.
most catch cans with a single in and single out are restrictive, because that restriction is supposed to stop oil
-on the clean air side of the system restriction is your enemy, this is the vent on the engine and any restriction will increase crankcase pressure and is generally detrimental
so the keys are to only modify that side when necessary, and then when it is, a comprehensive approach that does not reduce flow capability, and hopefully increases it.
it absolutely matters on almost every catch can made you cannot reverse the configuration, for sure not on truck covers or valley plate cars with integral pcv control.
the pcv system is a filtration cycle of clean air into the crankcase and dirty air out, if you stop either one of those you have stopped pcv and its benefits.
Thanks for the reply.
Can you please answer in simple terms, should I remove the clean side catch can and just replace it with a hose to aid flow into the crankcase?
I do not have an external PCV but instead have the later LS6 Valley cover with the outlet in the corner.
Ideally I would like to prevent any oil mist going into the intake. Is this actually possible to do with a catch can or do I need to vent to atmosphere and if so, how is this best done?
Can anyone please tell me at what point is there any benefit to using a clean air side catch can as well as the dirty side one?
The clean side can helps when you have reversion. This can should stay pretty clean for a street car. It's much more critical for cars used on a road course.
Originally Posted by TableLeg
I have a pretty much stock 5.3 but am getting some oil in the intake, on the valves and the pistons. I currently have a can on the clean and a can on the dirty sides.
Do you have a picture of the current engine compartment?
Originally Posted by TableLeg
Also, does it matter which of the rocker cover connections I use for the clean side?
No
Originally Posted by TableLeg
Is there any reason not to remove the outlet hose from the catch can on the dirty side (that goes to the intake) and put a filter on it instead so any air from the can doesn't go into the intake?
Doing this disables the PCV system by venting to atmosphere. Under good conditions, the PCV system will pull a slight vacuum on the crankcase causing a slight pressure drop. This is what makes the PCV system work by pulling clean air in and recycling the dirty air back into the intake.
if the clean side can is remotely more difficult to blow through then the hose, remove it
if the clean side can never has any accumulation, remove it
unless it is our parts i cannot suggest how effective or at what power level it can support
for sure there is never a time when you have to disable the pcv system
You need an external PCV valve with the LS6 valley cover. The LS6 valley cover does NOT have an built-in PCV valve.
I want to avoid sending the oily mist back into the intake and instead vent it to atmosphere. I think I'll remove my clean side can as it doesn't seem to be doing anything (is dry inside). As I don't have an external PCV only the late version LS6 valley cover how should I plumb this?
I want to avoid sending the oily mist back into the intake and instead vent it to atmosphere. I think I'll remove my clean side can as it doesn't seem to be doing anything (is dry inside). As I don't have an external PCV only the late version LS6 valley cover how should I plumb this?
You can use the LS6 PCV valve and rubber boot to add an inline valve. Adding a PCV valve and venting the catch can to atmosphere disables PCV system functionality. There is nothing on the dirty side to provide a pressure drop and pull air through the system.
This is what I think you are asking for.
Here is a great article showing real world testing of different PCV valves and systems. https://mewagner.com/?p=1130
Last edited by 405HP_Z06; Sep 17, 2022 at 02:11 PM.
Reason: Added content.
You can use the LS6 PCV valve and rubber boot to add an inline valve. Adding a PCV valve and venting the catch can to atmosphere disables PCV system functionality. There is nothing on the dirty side to provide a pressure drop and pull air through the system
So does that mean it's not possible to vent to atmosphere with the LS6 valley cover?
removing pcv and venting to atmosphere is almost always undesirable for a street style application unless there is no other way to control the oil (there almost always is)
given that you have no oil control issue on that side, you are only hurting your fumes control and crankcase filtration by tampering with it
So does that mean it's not possible to vent to atmosphere with the LS6 valley cover?
You can do it as its just a choice. The choice becomes a functional PCV system or non-functional PCV system. If you choose to vent to atmosphere this results in a non-functional PCV system. If you choose not to vent to atmosphere then your PCV system functions as designed.
Another benefit of a functioning PCV system is ring seal. The vacuum introduced to the crankcase aids in ring seal.
Think of the motor as a system. Everything works together for a purpose. When you upset the balance, negative affects ensue.
So can you both guarantee that if I have a correctly setup PCV system I won't get any oil going into the intake?
If so, do I need a specific kind of oil catch can and if so, can you recommend any? I currently have a Mishimoto compact oil catch can (https://www.mishimoto.co.uk/compact-...port-html.html).
Given I have the LS6 valley cover should my system be setup as per this drawing?
1, I therefore need a PCV in the system ( between the LS6 valley cover and the catch can)
2, Do I blank off the other rocker cover (as it is now) or should I connect both? And the above image shows the clean side connected to the throttle however I have mine on the intake pipe before the throttle body and after the air filter. Is this wrong?
Last edited by TableLeg; Sep 18, 2022 at 11:43 AM.
Thanks to both of you.
So can you both guarantee that if I have a correctly setup PCV system I won't get any oil going into the intake?
I cannot guarantee you will never get ANY oil in your intake. The best PCV system and configuration cannot overcome a mechanical problem.
Originally Posted by TableLeg
If so, do I need a specific kind of oil catch can and if so, can you recommend any? I currently have a Mishimoto compact oil catch can (https://www.mishimoto.co.uk/compact-...port-html.html).
Given I have the LS6 valley cover should my system be setup as per this drawing?
I have not used or tested the Mishimoto you reference so I have no opinion on it. I would at the very least fill the reservoir with some stainless wire mesh to help increase surface area within the can to help coalesce oil vapor from the air.
Originally Posted by TableLeg
1, I therefore need a PCV in the system ( between the LS6 valley cover and the catch can)
2, Do I blank off the other rocker cover (as it is now) or should I connect both? And the above image shows the clean side connected to the throttle however I have mine on the intake pipe before the throttle body and after the air filter. Is this wrong?
Yes, you need to introduce a PCV valve into the configuration. I don't know the current configuration or intended use of your motor; however, I would encourage a look at the ME Wagner adjustable PCV valve. It is light years better than any OEM PCV valve and allows for flow adjustment.
Here is what I think you are asking for as it relates to routing and configuration on your engine.
I should have noticed that we discussed this via email. Here is the single version diagram from the email conversation.
Last edited by 405HP_Z06; Sep 18, 2022 at 08:48 PM.
I would at the very least fill the reservoir with some stainless wire mesh to help increase surface area within the can to help coalesce oil vapor from the air.
Thanks Aaron I'll try that too.
Originally Posted by 405HP_Z06
Yes, you need to introduce a PCV valve into the configuration. I don't know the current configuration or intended use of your motor; however, I would encourage a look at the ME Wagner adjustable PCV valve. It is light years better than any OEM PCV valve and allows for flow adjustment.
.
My intended use is street and track day driving. I look the look of the ME Wagner PCV but it is quite pricey. I think I might try a standard PCV first. Do you happen to have any part numbers for an LS6 one? I see in an earlier post you mentioned to somebody about removing the orifice in the LS6 valley cover. Is this to create more flow?
Originally Posted by 405HP_Z06
I should have noticed that we discussed this via email. Here is the single version diagram from the email conversation.
Just wanted to check I'm not completely misunderstanding the above, shouldn't the flow go from the inlet pipe to the rocker cover (green line)?
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