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LS Engine Venting / Positive Crankcase Ventilation / Fuel Air Trap System

machine the wedge off, get some 1" tube, split it down the middle, weld it to the intake, put a -10 on the end pointing straight up. simple and easy.

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Ported a 5/8" hole in the cover and welded on a -10 fitting.
The short hose is for just for demo. The final hose will follow along the top engine box 4 sides and down and off to a catch can with filter.

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You're still capping both valve covers ?
 
you're greatly over thinking this. even for pirate standards of over thinking

mine is a SBE H&C LS3. each cover has -8 hose 3 sides and down. done. old ly6 was -6 and even that pushed the dipstick during prolonged high rpm use.
 
cdemart2 said:
you're greatly over thinking this. even for pirate standards of over thinking

mine is a SBE H&C LS3. each cover has -8 hose 3 sides and down. done. old ly6 was -6 and even that pushed the dipstick during prolonged high rpm use.
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A long -6 line full of oil can make some back pressure, possibly why the dipstick was pushing with blow by. The larger the line size the lower the velocity and less oil push. Having the lines drain out or back is also important to keep the lines clear.
Valve covers will want to fill up with reving on the side and push oil out.
 
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Coming back to this, Bout to install my LM7 5.3 for street driven wheeler.

If I go 3 sides and down from valve covers and do what Jake Burkey suggest in his video by just drilling a hole and tapping the valley pan in the center (want to retain knock sensors) Do I need to run the orificed PCV inline back to the intake? And do I need to do the center port 3/ sides down then back up to the intake to prevent oil pooling if it ever rolled? Or should I not worry too much as I'm just a rec wheeler and would have time to pull intake and plugs on a roll over. (dont want to ever lol)

Thanks for any advice.
 
Imo. Everything but a dedicated race vehicle should have a pcv, to catch can, to manifold. And a small vent to draw in fresh air. I wouldnt design a system around running upside down, since I dont plan to ever do that. One other thing, gen 3 engines have an oil consumption issue because of poor piston design. The oil rings are small and the pistons are poorly ported to scavenge oil back to the pan. Meaning oil gets trapped and clogs the oil rings. This can be fixed by drilling holes through the piston at the back of the oil ring groove.
 
Oddball said:
Imo. Everything but a dedicated race vehicle should have a pcv, to catch can, to manifold. And a small vent to draw in fresh air. I wouldnt design a system around running upside down, since I dont plan to ever do that. One other thing, gen 3 engines have an oil consumption issue because of poor piston design. The oil rings are small and the pistons are poorly ported to scavenge oil back to the pan. Meaning oil gets trapped and clogs the oil rings. This can be fixed by drilling holes through the piston at the back of the oil ring groove.
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Okay, sounds good. I still plan on running it as a PCV system just with fresh air inlet outside the throttle body as the throttle body was also all gummed up to sucking back through the pass valve cover.


I'm not pulling the pistons just dropping the engine in, I did notice there is oiling issues in there because the intake had a ton of baked in oil build up.

This engine was full of baked on sludge too, got it all cleaned out from heads, valve covers etc. Pistons/ cross hatch still looks great.

It might be easier to stay stock and just run catch cans on both sides.

Funny it's replacing a 43 year old engine that has no offroad issues in stock form with a big ol giant stamped oil pan no windage trays or sump cover. The PCV system on it works good till about 3600k rpm and blow by takes over. (rings are worn out).
 
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Oddball said:
Imo. Everything but a dedicated race vehicle should have a pcv, to catch can, to manifold. And a small vent to draw in fresh air. I wouldnt design a system around running upside down, since I dont plan to ever do that. One other thing, gen 3 engines have an oil consumption issue because of poor piston design. The oil rings are small and the pistons are poorly ported to scavenge oil back to the pan. Meaning oil gets trapped and clogs the oil rings. This can be fixed by drilling holes through the piston at the back of the oil ring groove.
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Air should be pulled from the airbox behind the air filter but before the throttle like vehicles with MAF systems do. Fuck having more filters to keep track of. And if you do wind up upside down the mess is in the intake which usually just means some blue on the next startup vs an actual mess.
 
This is interesting to me, as we've retrofitted several LT4's into other vehicles. GM in their not-right mind put the PCV in the valley to the blower, which causes more issues. It's more of an issue with Direct Injection engines, as you don't have the fuel cleaning the intake

We typically use this, as it blocks the valley port under the blower, it's baffled and returns "clean" side to the throttle body port:

www.mightymousesolutions.com

Mightymouse Catch Can Systems

LSX GM catch cans and complete crankcase ventilation systems for performance, specializing in high power, high flow oil consumption and pressure solutions.
www.mightymousesolutions.com www.mightymousesolutions.com

And drain it back to the oil pan.

They also have Gen3 and 4 systems that we've installed on Connect and Cruise LS3's that work very well.

Now working on Mini's and they have more of an issue, but also DI.
 
arse_sidewards said:
Air should be pulled from the airbox behind the air filter but before the throttle like vehicles with MAF systems do. Fuck having more filters to keep track of. And if you do wind up upside down the mess is in the intake which usually just means some blue on the next startup vs an actual mess.
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I'm more concerned about the valve cover PCV and clean side sucking in oil when accending and descending long steep climbs. A couple small catch cans might be worth it instead. I run one on my Ecoboost but that's direct injection and turbo charged so it would see more benefit.
 
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Make your life much simpler and tap the valley pan with a -8 or -10 hose, go four sides and down and be done with it.
If you want to be less messy add a catch can with filter to the end of the hose and a ball valve for emergency lock off if you roll.
The PCV system was never designed to run off camber while bouncing off the rev limiter, like you morons do. :homer: Depending on the year of the PCV system, it was not even adequate to handle high G's on the track. PCV in its stock engineered form still makes a mess of the intake system which is not good for the health of the engine.
If you have to get smog'd then run PCV. If you want to save the environment their are a lot more important things you can do first.

If you really want to have crank case ventilation without making a mess of the intake. Look into running an exhaust venturi that pulls some negative pressure on the case and sends it out the exhaust.
 
HYDRODYNAMIC said:
Make your life much simpler and tap the valley pan with a -8 or -10 hose, go four sides and down and be done with it.
If you want to be less messy add a catch can with filter to the end of the hose and a ball valve for emergency lock off if you roll.
The PCV system was never designed to run off camber while bouncing off the rev limiter, like you morons do. :homer: Depending on the year of the PCV system, it was not even adequate to handle high G's on the track. PCV in its stock engineered form still makes a mess of the intake system which is not good for the health of the engine.
If you have to get smog'd then run PCV. If you want to save the environment their are a lot more important things you can do first.

If you really want to have crank case ventilation without making a mess of the intake. Look into running an exhaust venturi that pulls some negative pressure on the case and sends it out the exhaust.
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Haha I'm a Crawler hence the 161:1 low low range. I'll likely never hit a rev limiter. Nor go fast. I want simple and reliable.
 
Oddball said:
I'm around a lot of hotrods daily, so I can appreciate a pcv system. It's not about the environment, it's about not having a smokey, stinky car.
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I am running cats for this very reason. Can you confirm that the crank ventilation is the only source or is the blow by that bad? If so It would be worth while to run an exhaust venturi to dump the fumes.
 
chaplinfj60 said:
did you run two lines or one with tees?
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2 lines.
I ended up bumping the hose size to AN10. Completely overkill but I figured it couldn't hurt. And boost is in the future.
 
Bebop said:
2 lines.
I ended up bumping the hose size to AN10. Completely overkill but I figured it couldn't hurt. And boost is in the future.
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No PCV routed to intake? Just both open air?
 
Bebop said:
Gen3 LS here.
3 sides down on both valve covers with 3/8 hose and done.
Works great.
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You are just wrapping around engine on 3 sides and then down on both left & right Valve Cover? And did you add intake to valley also?
 
Here is what I did. Motor is 2001 LM7. The original setup more-or-less mimics the factory routing but with a catch can plumbed into the dirty side. Any severe off-camber or steep climbs and it was about a minute before the catch can was filled and oil was dumping into the manifold. The "solution" was to stick a breather on the catch can and cap off all the other ports. Works fine now. After 3 runs there is only a few drops of oil in the catch can. I don't wheel hard enough to expect landing on the roof very often but yes, if it does happen then some oil can leak out. But none will get sucked into the manifold. Good enough.


pcv.png
 
Eric said:
Here is what I did. Motor is 2001 LM7. The original setup more-or-less mimics the factory routing but with a catch can plumbed into the dirty side. Any severe off-camber or steep climbs and it was about a minute before the catch can was filled and oil was dumping into the manifold. The "solution" was to stick a breather on the catch can and cap off all the other ports. Works fine now. After 3 runs there is only a few drops of oil in the catch can. I don't wheel hard enough to expect landing on the roof very often but yes, if it does happen then some oil can leak out. But none will get sucked into the manifold. Good enough.


pcv.png
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But now you have no clean air going into the engine at all? Air still needs an in and an out.
 
Winchested said:
But now you have no clean air going into the engine at all? Air still needs an in and an out.
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Its just a breather. Air can flow in or out depending on whether pressure inside the valve cover (nominally the "crankcase pressure") is higher or lower than atmospheric pressure. All that's different is that air is not forced through the crankcase by manifold vacuum.
 
Eric said:
Its just a breather. Air can flow in or out depending on whether pressure inside the valve cover (nominally the "crankcase pressure") is higher or lower than atmospheric pressure. All that's different is that air is not forced through the crankcase by manifold vacuum.
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Not super familiar with the internal crank case flow of the LS. No worries about the 3 caps? Pressures could be relieved just fine from said port across the whole engine?

I like this setup a lot.
 
Wuz-A-zuk said:
Not super familiar with the internal crank case flow of the LS. No worries about the 3 caps? Pressures could be relieved just fine from said port across the whole engine?
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I'm not really sure. In the old days, one breather stuck into a valve cover was enough to basically keep the crankcase at atmospheric pressure. At least that's what we believed. Since air is highly compressible there is no doubt that pressure is not truly uniform throughout the crank case. What kind of differences exist is anybody's guess. Side-to-side, front-to-rear, top-to-bottom. Who knows. At some point I will probably run hose from both valve covers into the catch can and then through the breather. But right now, everything is working fine and there are no signs of excessive crankcase pressure.
 
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