LS6427

iTrader: (2)

Long, but it might be a winner.

First, as I've said before...I think oil going into an "air" intake is about the dumbest design I've ever seen in the auto industry.

Second, the problem with this whole PCV/oil issue is......I think the strength at which the intake vacuum port sucks air from the crankcase is just way too much to begin with. If you ever had just a hose connected to the lower intake port and you put your finger on it, just at idle, you'll know what I mean, its crazy strong. (and I'm well aware that the job of the PCV valve is to regulate that strength at different throttle levels). Its still just way too much suction even at idle and part throttle. We're not at WOT throttle long, we live in the lower and part throttle ranges 99.99% of the time.

As some of you know, I completely disconnected my PCV valve for 4 weeks and drove around with just a vent to my crankcase through the valley cover. I then changed the oil after that 4 weeks (it had right at 3,000 miles on it, maybe 1,000 of that with no PCV) and it was perfectly normal with not a drop of water in it. As far as acids building up, nothing has enough time to build up, I change my oil every 3,000 miles, at the most. (People who go, 5,6,7000 miles between oil changes, don't know what to tell ya.) Also, my oil consumption issue which is about 1 qrt. every 2 weeks, stopped..... I also have no more black soot building up on my rear bumper, AT ALL. It used to turn black in 3-4 days after cleaning it all off. Looks like the oil going into my intake was causing me to run rich as hell and turning my bumper black. No more. Not running rich anymore also means better gas mileage. Also, longer lasting and better operating 02 sensors.
So a few good things came from it.

The crankcase IMO, just has to NOT build up excessive pressure, so venting is all it really needs. A filter/vent on each valve cover and the oil fill cap is fine, there's no way excessive pressure can build up like that.

Here's what I did for 4 weeks. Filter/vent on my vally cover port only. Both valve covers were capped and the two intake vacuum ports were capped. I've always had a grommet in my drivers side valve cover since my 427ci went in and they put on an LS6 valley cover.



But I thought I'd try something new for the next 4 weeks before Icompletely disconnect the PCV again and run an external air pump on it.
I did this.



Same filter/vent on drivers side valve cover.



First thing I did was took a clear hose to see if the valley cover crankcase port OR the passenger valve cover vent port allowed more oil into the lower intake port under idle suction. The valley cover port was ridiculous (now I know where all my oil was going). The valve cover port was hardly a trace, so I went with the valve cover port to suck from. I hooked the PCV valve hose to the passengers side valve cover like you see in the picture above, started the engine, and felt suction on the valley cover port vent and I reached back and felt light suction on the rear of the drivers side valve cover port. So I know, at idle, the suction is enough to draw fresh air into those two filer/vents. Thats good.
But, like I said earlier, the normal suction is way too much. So before I put that PCV valve hose on, I impeded the air flow by jamming some folded tape into the 3/8" heater hose at the end that connects to the passenger valve cover port. So the final suction strength is about half its normal strength....and I still have fresh air getting sucked into the two filters. Good deal.

Here's how I made the filter/vents. About $3.00 each. $2.00 for the filter and I bought those little rubber packaged pieces for like $1.00 each.





You can see that packaged little hose is tapered down at one end.



I jammed and twisted the bigger end into the filter till it reached those little ridges on the hose. Then I drilled a hole with a 1/4" bit into the grommet, and also rounded it out a little bigger. I then jammed and twisted the tapered end into the grommet hole till it reached those other ridges. The ridges made it seat nice and tight. Using the tapered end for the grommet makes sure it cannot fall into the valve cover. But its friggin tight as hell, very strong when its all togther.



Thats it. Very strong and stiff. No way it can come apart unless you pull it apart by hand.



Here's the PCV valve and hose. Its all I had to work with, just a test so its fine for now. Its just a little 5/8" hose jammed into the end of 3/8" heater hose, then I clamped it to the PCV rubber housing. Its all sealed perfectly and fits great. The heater hose end is where I put the folded tape to reduce the suction strength.



So, we'll see in 4 weeks how much oil I've been using. If my oil consumption has basically stopped, here's a very cheap fix to this decades-long dumbass design. Great crankcase venting, but no more oil in the intake. And no need to buy catch cans, this costs under $10.00.

Another thing I'm going to try after I try this...IF I still have oil burn because of the intake suction from the valve cover port.....I'm going to simply remove that PCV hose and PCV valve, cap off the lower vacuum intake port for good, move the filter/vent thats on my valley cover port to the pass side valve cover port, and add a small (cigarette pack sized) pusher air pump to the valley cover crankcase port to push air into the crankcase and vent it out of the drivers side filter/vent port and passengers side filter/vent port. ......No, I don't care about venting crankcase gasses to the atmosphere.....

We'll see what happens. Hopefully I'll show no oil burn and I can do a Mopar top end clean, and never have oil build up again in my top end. Thats the goal here.

elias_799

iTrader: (8)

i had the same issue before, when i was rebuilding my motor i found some oil in the intake and some coolant also, so i just installed a breather on each valve cover and completely blocked off the pcv.



this is the after picture of about 1000miles on the new motor and the intake is nice and dry. and this is a turbo car btw

LS6427

iTrader: (2)

Yeah, if the crankcase is vented, you're good to go. As long as you don't let the oil go for 6,000+ miles.

My 4 week experiment confirms it does nothing to the oil at all.

How is your oil looking so far?

Any water in it? (I doubt it, just thought I'd ask)

Isn't it nice to have a spotless "air" intake.

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elias_799

iTrader: (8)

i change my my oil every 200miles, i am actually doing a break in on my motor so the oil comes out pretty dirty.

but it makes me feel happy that the only thing my motor is burning is fuel and air. not fuel air and oil like a ******* two stroke

LS6427

iTrader: (2)

You might want to put a little pusher air pump on it to pump fresh air through the crankcase. I'll be testing that in about 4 weeks. What you're doing is just fine for crankcase pressure, it worked great for me just having it vented, but I still would like a fresh air-flow through there all the time.

The air pump will be the ultimate set-up. No oil going into the intake and a fresh air flow all the time.

Hell, for any tree-huggers that might complain about it being vented to the atmoshpere, just a thin metal line running from one of the valve cover vent ports, down and welded to a bung on one of the exhaust pipes would fix that issue. That would be cheap and it wouldn't take more than an hour to install.

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neutron82

iTrader: (26)

i just recently installed dual catch cans and i checked it after about 100 miles after installing it and i had a light film of oil on the back of my throttle plate... granted i'm running the stock ls1 pcv system but i shouldn't have anything getting in with the catch cans there... i have heard people argue back and forth whether you need the pcv or not and i'm fed up with it myself... if i can't figure out why i'm still getting oil in my intake i'm just gonna ditch it and use breathers... i change my oil religiously, no more than 1500 miles between changes, so i'm not at all worried lol

elias_799

iTrader: (8)

all the diesel trucks i work on basically have breather, they have a tube routed from the valve cover that goes down bellow the oil pan, and all the oil and gases that come out just go on the floor. not one has it routed back to the intake.

LS6427

iTrader: (2)

You have no use for a PCV system, especially if you do changes at 1,500 miles.

Do it. Catch cans are BS. OIl is getting in the intake, regardless if they see it or not. When I had the clear hose on my intake port to see how much oil was being sucked out of my valley cover....it was a tiny little stream smaller then a human hair that was winding its way through the hose. Almost impossible to see unless you really try to see it. But that tiny little stream was hauling *** just drinking it up. Sometimes a little tiny tiny bubble or something would get sucked in and it would cover the ~2 foot length of clear hose in 1 second flat. Thats a shitload of oil going through there. Ain't no way a catch can is gonna stop tiny stream of slippery oil


.

LS6427

iTrader: (2)

Yeah, I just think a metal brake line from one fo the valve covers down to one exhaust pipe after one of the cats, would suck air out of the crankcase whenever the engine is running. All you would need is a tube that goes into a bung hole and then turns rearward and points backwards......the passing exhaust flow would draw air from that line constantly and fresh air would enter the crankcase from the filter/vents on the other valve cover and valley cover port on LS6 stuff, also from a oil filler cap filter/vent.

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1 FMF

iTrader: (1)

http://www.aa1car.com/library/pcv.htm
http://en.wikipedia.org/wiki/PCV_valve
http://www.supersixmotorsports.com/pdf/PCVBypass.pdf

here's a couple decent writeups on pcv,
there are millions of cars on the road with pcv systems which are fine, along with many LS1's including mine which do not have a problem. So to me that seems to point to something on your motor. In general, the pcv valve port in the rocker cover has a baffle, this primarily is what prevents liquid oil from being sucked up. And by design it does not let oil into the intake, it lets in vapors or gases.
PCV valves are specific to each engine, and it is the amount of vacuum at a given rpm/load which determines how much air (and oil) get pulled through it. So with having no idea what you have and what you've done with your motor, I would first ask are you using the correct pcv valve, and do you have stock rocker covers? Are you running a different cam than stock, because that will change vacuum at various rpms which the oem pcv valve is designed around?
The strength of the vacuum which the motor sucks on the pcv valve is not a problem, that vacuum just moves the pintle inside the pcv valve all the way up which limits, or controls airflow. and it's the spring strength and size of the pintle which allows how much airflow through the pcv valve. And at idle it should be crazy strong suction, if it wasn't then you have other problems. So you need to size your pcv valve based on manifold pressure, unfortunately i've never come across a listing of pcv valve sizes so i wouldn't know how you could choose a pcv valve (like you can with spark plugs for example).
I would test the pressure/vacuum of the crankcase via the aa1car link above- on the breather side rocker cover, which would have the hose going to the airlid, put a vacuum gauge on it and see how much vacuum the engine is pulling on the crankcase with the pcv connected. Then i would disassemble the pcv from the stock hose it's in, leaving the engine to suck through the pcv but not pulling air from inside the engine, then hook up the vacuum/pressure gauge to the other side of the hose and see how much pressure is in the crankcase at idle, and if possible rig a hose to run inside and monitor cranckase pressure when driving, then systematically troubleshoot from there.
fwiw, i have 49k miles on my 2002 with zero intake/oil related problems, so either you have a mod on yours causing the problem, maybe excessive blowby under load or leaky valve guides or something. something has changed with yours where the stock pcv system is being used outside it's capacity or designed intentions, and you simply have to modify it or get a different pcv valve size so it works, like with spark plugs if you run higher compression or boost and the oem spark plug burns out or doesn't fire, you don't say the spark plug design is bad when what it really is is plug gap is now too long or the heat range is too hot.

CMurph

Awesome write-up LS6427! Very detailed and easy to follow, can't wait for the results and further refinements.

I've been wondering if this has been an issue for me. As it seems that my '01 with 38k miles on it has burned through about a quart of oil in the past 3k miles. So far my short list is to refine the PCV system, replace the O2's with vette O2's, and upgrade the plugs and wires. I'd also like to tune out the rear O2's and get an ORY and high flow cat...but that's not going to happen for a bit.

Eagerly awaiting updates...

LS6427

iTrader: (2)

Thanks.

The way I have it now is only better than totally disconnecting the PCV 100% like I had it before. Before I had a breather so there's no possible way to have a build-up of crankcase pressure. Now, I added the PCV back and just reduced its suction on the crankcase. If this stops my oil burn (1 qrt every 2 weeks) then its total winner. Just partially blocking the suction is the fix, and venting both valve covers.

I'll know in 2-3 weeks if this is a winner set-up. But I have another idea that might work, it will be a free mod basically, and it will allow 100% capping off of both intake vacuum ports, no more oil into the intake AT ALL, forever.


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CMurph

Very cool! I'm guessing it's using the AIR motor to pump fresh air in there?

Just a refresher, with the filter on the valley cover...are you still putting a breather on the oil fill cap, or is it not necessary? I see in the pictures all you have is the fuel filters on the valley covers, plus the line in front that has the PCV valve on it (and partially blocked a bit more). Is that it?

Thanks!

LS6427

iTrader: (2)

I have the PCV valve and a hose hooked right now to the intake vacuum port, but at a reduced flow to suck air from the crankcase via the passengers side valve cover. I'm trying this for one month to see if I have any oil burn. If not,, its a done deal and it works.

The air pump pusher will be the next experiment if any oil is burned in the above described method. The air pump is a 100% elimination of oil going into the intake and just venting the crankcase with a fresh air pump. There's no doubt at all the air pump method will work, it will be a great set-up. But it will be venting to the atmosphere, which I personally can care less about.

No, right now I just have a filter/vent on the drivers side valve cover and that front valley cover port. So 2 intakes for fresh air. I have not done the oil fill cap yet. That would just be as bonus to what I'm doing now.

I think if I do the air pump I'll push air into the valley cover port and only use the two filter/vents on each valve cover. I think if I have a filter/vent on the oil fill cap, too much air would flow that way and maybe not have so much going to the drivers side valve cover. I'm thinking maybe a little back pressure is better so I have venting more equally out both valve covers. But I'll experiement with both set-ups. I'll be able to feel the air getting pushed out of all 3 exits, so we'll see how it flows.

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PAGregSS

iTrader: (10)

So, from what you're saying is that even though I'm running a breather in my valve cover, it's just my imagination that I'm still getting oil in my catch can?

LS6427

iTrader: (2)

Do you still have your PCV hooked up to the intake vacuum port suckeing air out of the crankcase, through the catch can and into the intake?



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good2go

LS6427: You should check your LTFT's with your fresh air breathers open and again capped. That is unmetered air and throw your tune off. If you have reduced the vacuum (and airflow) it might not be enough to set the CEL, but you should check anyway.

LS6427

iTrader: (2)

You know what, I wondered about that. Would all that matter "FOR ME" if my MAF does not work? It hasen't worked for years. Engine runs perfect. I can simply unplug my MAF and the engine runs the same, no difference in an way. It just takes about 1-2 minutes to idle smooth on cold start-up.

I can tell you this....for about the past 6 weeks with totally capping off my intake vacuum port and now partially slowing the flow but having it hooked up to the passenger side valve cover........for the first time in like 4 years my rear bumper doesn't turn black in 3-4 days above each tailpipe. So I think I've always been running rich as hell. Now the bumper is spotless. So something got better as far as richness goes.

brian r

iTrader: (14)

let us know how that works, very interesting

LS6427

iTrader: (2)

I'm a few days shy of 2 weeks. Haven't burned any oil (I mean NONE). Oil looks perfectly clean too, no signs of moisture at all. Rear bumper is spotless, so I'm not running rich anymore.

2 more weeks to be sure, but it looks like its working great. I also put my fingers on the two filter/vents on my valve covers and still feel that slight, constant suction when idling, so the crankcase is seriously being vented.

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