Here I go again....PCV

[TurboJim]

Re: Re: Think about this

Originally posted by opzWE4
I don't know, but you may have hit a nerve there Seems the only time I have this problem, really, is AFTER I have been in the boost. I can start the car cold and let it idle for 3 hrs and it won't pull oil in through the pcv. BUT, after I've been out driving, and get into the boost, (Can't help it ) that's when it starts sucking oil. I can make a run at full boost, and then go let it sit and idle, and after 3 or 4 minutes that's when it starts smoking and the pcv is sucking oil like mad. I let the car Idle at my house the other day for 15 or 20 minutes and continually checked the pcv, and even looked down into the into the grommet for the pcv several times and saw zero oil under it. I varied the rpms several times also, and still no change. With no boost I seemed to not have any problem.

Do you have bronze valve guides? Maybe the problem isnt PCV at all. Maybe after a high rpm run 2 things happen. 1) the guide expands due to the extreme heat, increaseing clearance between stem/guide, and 2) the oil doesnt drain back to the crankcase fast enough and puddles under the spring, leaving some "reserve" to be sucked into the chamber thru the valve guide.

Another thought if its definately PCV is run more than one PCV valve. I dont buy the blocking breathers scenario as this would cause the crankcase to be pressurized and cause OTHER problems. The breathers locations are designed to create a certain "flow". Kinda like putting a straw in a soda cup. To pull soda out, you must replace it with air. Well, to pull vapors out, you gotta replace it with air.

I winder if since were increasing the amount of blowby with more boost, we need to increase the scavenging as well.

Just a couple thoughts....

 

[87LtdT]

Can someone take some data measuring vacuum at PCV hose when idling, revved up, etc?? Would prefer at least a couple with stock setup as I can do the same on my modded when I get my new T+, MAF, etc installed.

If so, please contact me offline to discuss.

Thanks, Bob

 

[Chuck Leeper]

PVC problemz

Originally posted by BMRFIREHAWK
Listen, It stop the oil in my intake 110 percent. You can take that to the bank. I don't know what you are making, but if it is anything like the ones I have seen on LSI, you will continue to have problems and less vacuum. This will stop oil for going through pcv system. Now if you motor has so much blow by because of ring issue, that would be your problem.

I'm sure glad we got that lesson out of the way!! Now I know the problem is really mine....

 

[BMRFIREHAWK]

Re: PVC problemz

Originally posted by Chuck Leeper
I'm sure glad we got that lesson out of the way!! Now I know the problem is really mine....

What do you mean by this comment?

 

[TKGN1]

Hey guys, was doing a little research on the board and thought some might be interested. A few GNs along with many LS1's have purchased this kit and thought it might be worth something to look into for those with similar probs.
http://ls1tech.com/forums/showthread.php?t=152990
http://www.accmachtech.com/pcvcatchcans.htm

 

[Wicked]

Originally posted by stickybones
I think Walt Judy (hoping I'm giving credit where it's due) posted the idea of putting the PCV in the stock passenger side breather thingamabob (the one that used to connect to the turbo). You just cut the nipple end of the PCV and it fits pretty snuggly in that thing. Then you just run a rubber hose to the vacuum block like usual and plug the stock PCV hole in the intake. This way you use the baffle that's in the PS valve cover at the breather hole to help prevent the oil suck problem. I've been hesitant to try this since I'm not sure how the PCV would function way up there in the front of the motor as opposed to the stock location on the intake manifold. But it could be worth a try. Don't know if Walt Judy runs this setup but I think he's one of those guys with a 10 sec TSM car so he probably knows what he's talking about.

I remember reading this in an old PCV post.

That would work very well, I would only do it if you have the larger driver side breather to let air in.

 

[stickybones]

Originally posted by TKGN1
Hey guys, was doing a little research on the board and thought some might be interested. A few GNs along with many LS1's have purchased this kit and thought it might be worth something to look into for those with similar probs.
http://ls1tech.com/forums/showthread.php?t=152990
http://www.accmachtech.com/pcvcatchcans.htm

So who are the GNs running this? Does it work?

 

[TKGN1]

Quite a few were sold down at the the Temple meet two weekends ago here in TX. Two 10 sec. cars each purchased a kit, one of the cars being a featured car in GM Hightech Performance. Thier reason for install is to help protect the wide band O2 from oil fouling. ATEAV8GN, 11-sec. hot air car, installed one a while back to help reduce oil contamination.
Not being a sponsor on the sight, I don't want to create bad vibes trying to push this item, but on my personal
GN and on many other vehicles its been installed on, it works. I know its been a big debate on how to fix the problem all together, but for now I feel its a very good alternative to an ongoing problem.

 

[stickybones]

Good to hear. I've been working on my own solution for this problem, but I don't have enough miles on it yet to make any claims that it works and is reliable. I can say that in about 1500 miles of driving with it, I've collected an ounce or two or oil/other junk. It may not be as nice as the ACC can, but mine is cheaper...for me at least.

How well is the ACC device working? Are you running a clear line from their trap to the intake to see if it's clean? What are they using for a filter media?

I would pay the $80 for one if I was confident it was going to work.

Mike

 

[TKGN1]

I came upon this catch can by trying different solutions and found this one to be superior to anything out there.
I've seen this kit installed on about 25 cars localy and ALL have caught a considerable amount of contaminates. There is a little more involved to the can than just filter media, quite a bit of R&D has gone into this unit.
Contact me offline if you don't mind, don't want to get this thread locked. Thanks tkay@accmachtech.com

 

[soundguy]

If your motor has alot of miles on it, it seems highly possible you have some varnish and build up from the oil over the years inside the oil drainage passages. These buildups effectively make the drain holes smaller thereby lowering the drainage rate. If the oil drains slower than it is pumped up top, there will be a gradual buildup of oil at the top waiting to drain. With nowhere else to go, the oil is gonna drain thru any hole between the valve train and under the intake. If this goes on long enough you now have enough build up to pass the valley pan and eventually you reach the PCV valve. To check if the build up is gradual, put a clear filter like the fuel one mentioned inline with the pcv hose. Do a quick small test drive and check for oil in the filter. If nothing, do another slightly longer and recheck. Keep the rpm range about the same each time so the baseline doesnt change and its not boost pushing it thru. Keep going till you notice oil in the filter. If its not immediate and takes a while of driving seems most likely its a drainage thing as the oil needed the time to build up to being a problem. Possible cheap solotion would be try the Gunk Engine Flush. May not be a cure or it may at least help a little. Try it and add a new clean fuel filter in line and re do the test. See if you get further before any sign of oil if any. If not, may look into widening the drain holes a little. Since this never seems to be a problem on new cars or engines but rather higher mileage ones, a build up issue seems like a high possiblity.

 

[soundguy]

BTW, catch cans...just a rig to get by a problem that will just keep getting worse if it's ignored too long. The cars didnt need them when new and shouldnt need them now.

 

[soundguy]

One other possibility I thought of is to use an electric vacuum pump on the pcv. You can put an adjustable valve in line to pull only say 2-3 instead of the 20 or so the engine pulls. That small amount should be plenty to keep vapors out but not enough to suck up something as heavy as oil.

 

[GDNF2ET]

What if you put a piece of screen material over the pvc inlet before installing it ? Wouldn't that help keep out liquid ? Of course make dang sure it can't fall inside....

 

[jimmy987]

I have been reading all of the posts for the PCV sucking oil. Prior to the purchace of my buick I was into Oldsmobiles. The PCV is inserted into the valve cover, and is shielded from the oil by a baffle. With this baffle in place I never had problems with oil being sucked into the intake. Aftermarket valve covers do not have this baffle and I always had issues. You will see that both valve covers have holes and baffles. One side gets the PVC which has a hose that is connected to the bottom plate of the carburator, and the other side has a breather element.

 

[yullose]

Why not just plug the dang thing and change the oil more often ?

I came to that solution all by myself, and didn't even need to consult the advice of experts.

Some people like to make things overcomplicated.

PCV stands for: Positive Crankcase Ventilation

That's ALL IT DOES.

It keeps the underhood fumes down by sucking out the blowby gasses from the crankcase and burning them in the combustion chamber. The additional benefit to this is it reduces and slows oil contamination.

If you have oil in the upper plenum and don't mind fumes under the hood, then just rid yourself of that pesky PCV system.
I did it months ago, and I'm glad I did. Oil is BAD in the intake when making lots of boost or dumping Nitrous.
I'll bet money that many TR owners are seeing knock issues directly related to PCV/oil problems.

The ONLY downside to eliminating the PCV is the crankcase fumes pushed out of the breathers, and having to change the oil more often. I change the oil in my car every few hundred miles anyway, so nothing has changed in my maintenence routine.

 

[bison]

From my experience with PCV problems the only time i see excess oil going in is when their is a really good ring seal and not enough fresh air entering the crankcase. I had this problem every time i used total seal rings on a block with plate honed cylinders. They just about totally eliminated all blowby and the result was oil going through the pcv. The solution is the use a restrictor orifice in the PCV hose. I usually start around .050in and increase the size of the orifice as the engine gets some higher miles and some WOT passes on it. I could see this happen in an engine with conventional rings to less of an extent. The CFM flow of the PCV needs to be reduced to elminate an excessive low pressure area in the crankcase. If theres a low pressure area anything in the crankcase will be drawn towards it. Only a GM PCV should be employed in series with a positve sealing check valve and a stock style intake valley pan gasket should be used to prevent oil from the cam being flung onto the PCV valve opening. The effects of excessive PCV flow will be most prevalent at low load and higher than idle rpm (like minimal throttle cruising) where vacuum is the highest. These are just my observatons and i didnt read the entire thread, so im sure alot of what i covered has already been mentioned in the previous posts.

 

[Rosewood T-Type]

I'm going to revive this thread because it dosent seem to me like weve gotten to the bottom of this yet.

I have a similar problem crankcase pressure not evacuating and causing oil to be pushed through turbo seal (because its a 4.1 stage I and oil drain goes to oil pan).
I also have aftermarket vc's so no baffles or cc vent to turbo as most guys having this problem. high cc pressure could easily cause this problem by pushing open pcv under boost.

so why not use cc vent kit from jegs where you run a line from vc breathers to dp. this is not a new problem its been around since the beginning of the internal combustion engine.

Just a thought maybe this has something to do with constant leaks theese cars seem to have.

 

[TurboBuickSix]

What I did to stop it was easy.I took the oil filler from a hotair car(had one left from a parts car)that goes into the DS valve cover.Hooked a piece of molded 90 degree 5/8 heater hose onto the breather tube nipple that sticks off the filler and put my delco pcv valve in the end of that.Now I have a taller stock looking filler tube and the pcv does not pull any oil anymore but is able to work at full capacity.I made a catch can out of an old "cool can" because they are big and have a petcock in the bottom to drain the oil and would hold about a quart capacity BUT I never installed it because the first mentioned solution worked so well.Another thing some might want to try is the test where you use the 3" pipe and remove the rocker shafts then pressurize the intake tract with shop air to check for leaks.This would rule out your intake gaskets or maybe draw attention to something you had no idea about.

 

[VadersV6]

About a year ago, I made my own PCV catchcan setup, and it still works great. It traps oil vapor so well that i have to drain it about every 5 days. The capacity is maybe 1/2 pint. I build automation equipment, so I have just about every electronic and pneumatics doohickey you can imagine. I just used an SMC micro mist separator
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All the AM series ones would by far be the best way to go, but I didnt have any of those laying around. I used an AF series. You just pull down on a latch, and the catch rotates and comes off. real easy to drain. Its made for separating tiny water vapor droplets from air lines, but it works just as well for oil vapor. I grabbed a 90 degree elbow PCV valve off the wall at Kragen, that had the right sized valve to fit in the PCV grommet. For what car I dont know, but it works. Then I ran a hose off of that, and into the mist separator. Then I ran a hose out of the separator, to a factory PCV valve (which sits horizontal), and then hooked up to the line on the vacuum tree. The catch is made of polycarbonate, so it shouldnt be able to handle the heat, but Ive found it works just fine. You can get them with a glass resovoir as well if you're worried about it. With my setup, I'm using the factory PCV valve as a check valve, which keeps boost out of the catch, and then the separator, and then the 2nd PCV valve. I wanted to make double sure to keep boost out of the crankcase. It works great. I used to choke from all the blow-by fumes coming out of the valve covers, but I have yet to smell oil fumes since making this. The whole SMC catalog is heaven for anyone who wants to customize anything to do with air lines, fittings, pneumatics, fluids...Its great to keep their home page bookmarked.