My catch can routing ok?
I have an LS3 in a F-body. Mine is valley cover > Norris catch can inlet > catch can outlet > tube containing stock-type PCV valve > manifold. Would it be okay to remove the external PCV valve in the tube so I can run generic tubing between the can and manifold?
You'll still want something you can either insert inside the 3/8" ID hose to snuggly to use as a fixed orifice restrictor, or fixed orifice pcv valve with a 3/8" hose end on both sides. If you buy one at your autoparts store, or make one make sure the hole in it is no bigger(preferably smaller) than 1/8" . That way so you can drill the hole to a larger size if needed. The restrictor type gm uses now have about a 1/8" hole so that should be a good starting point.
Last edited by 99Bluz28; Oct 24, 2015 at 06:16 PM.
Russ Kemp
Not if done correctly with the proper system. IM vacuum can be the primary evacuation suction source and the area just in front of the throttle body will still have measurable suction at WOT when the IM vacuum drops to zero due to reversion pulses. You have to get above 8,000 RPM or so before the reversion pulses from a LS engine reach past the TB. And if you deal with the celanside properly, then you should never have pressure build. You wont be able to maintain vacuum like with a belt driven vacuum pump with a adjustable vacuum relief valve, but still can avoid any pressure unlike a system that vents to the atmosphere after pressure already builds enough to crack the vent valve. You can, even with a turbo or centri SC applications accomplish evacuation pull on the crankcase at all times AND retain a closed EPA compliant system.
I was curious about doing something like this because having my engine just vented open wasn't enough for my engine at an open track day the other weekend which caused oil to blow past my dipstick tube all over the engine bay after my first lap on the track (much better than losing the main seal) I've since made it the closed system with my Rev Xtreme per the LS1 layouts shown earlier in this thread, and I've found that if I add a second "1 way valve" on the hose from the pass valve cover to the TB it makes a vacuum in the crankcase area immediately (air whooshes in the dipstick tube when I open it). I get why it does this...
I was wondering if I could add this 1 way valve and run my car like this on track days for the added vacuum and remove it for normal street driving. Thoughts?
I'm just concerned about crankcase pressure causing more damage...
Engine is as follows:
383 stroker NA LS1 pump gas
553hp
ported LS6 heads/ matched cam
redline 6800
Rev Xtreme catch can
Melling 10296 high volume oil pump (oil psi is around 80 with 20w 50 oil)
2300 miles on engine
Reading this makes me sad.... I always cap my intake off and vent my valve covers on all my cars. I'm doing a motor swap right now after 263k miles and the motor still ran fine. I just can't see putting hot crankcase air in my intake that I want cold air going into. Not to mention the oil vapor. I'm just gonna be happy with not knowing what you guys are talking about. No dip stick issues, no leaking seals, and normal oil changes....
Reading this makes me sad.... I always cap my intake off and vent my valve covers on all my cars. I'm doing a motor swap right now after 263k miles and the motor still ran fine. I just can't see putting hot crankcase air in my intake that I want cold air going into. Not to mention the oil vapor. I'm just gonna be happy with not knowing what you guys are talking about. No dip stick issues, no leaking seals, and normal oil changes....
well ignorance is bliss, i guess you are also going back to carburetion with that outlook?
TECH Senior Member
Joined: Apr 2002
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From: So.Cal.
That is the whole purpose of the correctly designed/plumbed baffled catchcan (to pull oil/vapor out so it won't be sucked into intake);
it has been shown by the car makers that a light negative pressure in the crankcase does keep the external seals from leaking, and that it pulls moisture from the oil.
it has been shown by the car makers that a light negative pressure in the crankcase does keep the external seals from leaking, and that it pulls moisture from the oil.
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Verdad Gallardo Nah, it's a cam only LS7, but I do have a carbed 5.3 in my Sonoma. I'm sorry, I'm 41 and I've never had any of those issues. I would like to know how not running it back into the intake makes your oil dirty. I have heard plenty of theory, but I just never see the issues in reality.
any gas byproducts (if not drawn off) will settle into the oil, to name a few
-carbon monoxide
-sulfur dioxide
-formaldehyde
any vapors (if not drawn off) will condense and drain into the oil
-fuel
-water
any heavy particulate waste 'soot' (if not drawn off) will mix into the oil
-carbons of several types
you would have to be a chemist to evaluate it vs 'see' it but the soot build up is normally visible by 2000 miles if you were to compare apples to apples.
-carbon monoxide
-sulfur dioxide
-formaldehyde
any vapors (if not drawn off) will condense and drain into the oil
-fuel
-water
any heavy particulate waste 'soot' (if not drawn off) will mix into the oil
-carbons of several types
you would have to be a chemist to evaluate it vs 'see' it but the soot build up is normally visible by 2000 miles if you were to compare apples to apples.
I did AOAP samples in the army so I am familiar with contaminated oil samples. The very mild vacuum isn't enough to draw off those things any better than the crankcase pressure will blow it out on its own in my opinion and even if it did create a slight advantage in that area passing it though a catch can isn't going to contain much more than oil vapor and then you are burning things that could be taking the place of fuel and oxygen, not to mention creating build-up on the top end of your motor that you can't get out by simply changing the oil (supposing there is actually contamination). Look, you guys are obviously way smarter than I am so I'll let you have it from here. I don't have anything to sell so I'll just keep doing it the old backwoods way....
Ok good luck to you.
I don't sell PCV; It already comes stock on all gas automobiles (the theory is for no reason I heard).
I sell answers to problems to help people enjoy their hobby.
I don't sell PCV; It already comes stock on all gas automobiles (the theory is for no reason I heard).
I sell answers to problems to help people enjoy their hobby.
Had the RX can on for awhile with the check valve breather on the oil cap (TB tube capped off). Noticed im getting blow by up the dirty side of the cc tube going into the intake. Removed the stock PCV valve since the RX can has one built in, maybe I should put that back in?
This is how mine is routed with the exception of the TB fresh air tube:
This is how mine is routed with the exception of the TB fresh air tube:
Last edited by BrntWS6; Nov 15, 2016 at 08:37 PM.
Had the RX can on for awhile with the check valve breather on the oil cap (TB tube capped off). Noticed im getting blow by up the dirty side of the cc tube going into the intake. Removed the stock PCV valve since the RX can has one built in, maybe I should put that back in?
This is how mine is routed with the exception of the TB fresh air tube:
This is how mine is routed with the exception of the TB fresh air tube:
^^ I have a check valve as well on the valve cover for when I was getting oil through the TB hose. It solved that problem but now oil is coming through the catch can hose side that is attached to the intake manifold.