hitmanws6

iTrader: (20)

so put a breather on the valve cover, oil cap and in the hose going to the vaccum port?

LS6427

iTrader: (2)

Put something in the hose that connects to the vacuum port so the suction is slowed down. Folded plastic, folded tape, a piece of wood....whatever it takes to clog up the hose and slow the flow. Do that BEFORE the PCV valve so whatever it is i nthe hose can't get by if it breaks free so it doesn't go into the engine.

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hitmanws6

iTrader: (20)

i was thinking of removing the valve altogether and replacing it with a breather, and then butting a breather on the vaccum port of the intake.

LS6427

iTrader: (2)

I think might make things worse. If you don't have that PCV valve in there you will pull too much crankcase gases out of there. There's kind of a mist inside the crankcase that forms from the vrankshaft splashing in the oil pan and that mist helps to lubricate everything. At partial throttle, all the way up to WOT you will suck all that out of there.

I don't think thats good. The more throttle you give it the more the PCV valve closes off and causes it to pull less gases out of the crankcase, then at idle and low rpms it's fully open.

Put a breather on the vacuum port of the intake if you want but keep the PCV valve.

Put a breather on each valve cover. But keep the suction going....just slow the suction down.

The suction is the problem, period. Its too damn strong. All the crankcase needs is 2 things:

venting so pressure does not build up.
Fresh air flow through it.


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add|ct

You're right I wasn't thinking straight, but it was just weird that putting in oil got it to finally crank, but it was just a coincidence because the car didn't start anymore even after that. We think his distributor or distributor shaft, more likely, is bad. The same thing happened on their older Suburban. So, if that is preventing the spark from reaching the plugs there's the problem right there. Battery is good.

SKINNY69

You honestly think it's a good to allow unmetered air into your engine? That's basically the only thing the breathers are doing on the valve covers. Placing a breather filter on the vacuum port on the intake is another big no no. You wouldn't see any ill effects with an SD tune but if you're running a MAF you'll just create a lean issue by doing that.

Run a catch can if you're having issues with oil running through your intake. Keeping the crank case under vacuum is always a good thing.

LS6427

iTrader: (2)

Any crankcase air/gases that go into the intake via the PCV system...is unmetered.

I think if that flow is SLOWED down by at least half and is just pulling a little bit out of the crankcase constantly....I think it will do absolutley nothing to the tune. But I'm not tuning expert either.

Its all unmetered when going through the PCV lines into the intake.

Is it not?

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Scoggin Dickey

iTrader: (34)

No, it's not. You have a clean air side and a dirty air side, it is metered. If you run it in a way that lets in unmetered air it will lean you out. Seems it did it for you since you said it's not running as rich as it was

It's not designed to make an engine fail or even in a way that contributes to engine failure in a stock application, it's designed to 1) vent the crankcase and 2) meet emissions requirements by not venting it to the atmosphere. That second part is where the problems can come into play, although it doesn't generally happen on a stock engine. The system is made to work on a stock engine and as noted even by your experience it does that very well. The problems come with going further and further into aftermarket parts and greater HP. You can't really complain that the factory system is designed that poorly just because it doesn't work once subjected to circumstances it is not subjected to in a stock application. It works great in both aspects of it's design under factory stock conditions.

BTW, GM has actually revised the system more than once on the LS series of engines, making it more efficient and clean each time.

LS6427

iTrader: (2)

I'm talking about metered as in going by the MAF. How does any air that DOES NOT go by the MAF get metered?

I think I was running rich because such an amazing amount of oil was shooting through my PCV line and my 02 sensors were making me rich....???? I'm talking 1 qrt every 2 weeks...now zero oil use.

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Scoggin Dickey

iTrader: (34)

There isn't any air that doesn't go by the MAF with the stock system. It's a completely closed system. The air going into and out of the crankcase is all closed and metered. Hence the reference to clean air and dirty air sides. Clean air is the supply into the crankcase and dirty air is what comes out to be consumed by the engine.

LS6427

iTrader: (2)

The air entering the intake through the lower and upper vacuum ports on the LS6 intake enter and go into the cylinders behind the MAF. That air never goes through the MAF.

Even with a stock LS1 from 1998, the air that gets sucked into the intake vacuum ports through the PCV system are behind the MAF.......NO????

I have to see a diagram or some pics. All mine ever had was a lid connected directly to the MAF, which was connected directly to the TB. Crankcase gasses all entered the intake through the intake vacuum port on the intake and the one on top of the TB.

Show me how the MAF can meter air that enters the intake through the PCV line.

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jclz28

The PCV system is meant to be sealed and closed loop. Blowby into the crankcase and comes up thru the oil drainbacks in the head to the inside of the valvecovers in the head. The PCV line connects this to the intake manifold behind the throttle body, with either a fixed orifice valve (the new PCV valve design) of a check valve that is only supposed to work when intake vacuum is high. So yes, it is 'reburning' unmetered blowby gases that have not passed thru the MAF a second time.

The problem with GMs PCV design is really simple. There is not a good oil separator in the PCV lines. You really need the get that oil mist out of the crankcase gases to prevent three things: 1. Massive oil consumption 2. Soaking the interior of the intake with oil 3. Loading your combustion chambers with carbon, causing detonation and pinging.

So heres the kicker, that you may not agree with, but its just chemistry. Burning gasoline produces lots of water. LOTS of water. For the most part, its blown out your tailpipes as superheated steam and partially condenses in your exhaust system giving that early morning startup visible exhaust. But also going on is that even idling, your car has blowby, so about 4% of this steamy exhaust blows past the rings into the crankcase, again as a mist. As soon as it hits something below 212 F, it condenses. At startup, everything , crank, oil, valvecovers, valvesprings, etc. internal to the engine is not yet up to temp, so you really do get a huge puddle of water inside your motor. How much depends solely on your blowby and how fast your motor warms up. This water is also not nice, clean, Poland springs stuff either. Because along with the water produced by burning gas, you also get 'unburned' hydrocarbons and sulfur compounds. This just is a lot of different combinations of hydrogen and carbon that have reached the magical 'fully burned' H2O (water) and CO2 (carbon dioxide). One of the things you do create is OOPS, Sulfuric Acid, and some amounts of Hydrochloric acids. So your crankcase and exhaust is filled with really nasty crap as the car is warming up.

So now you modify your motor, and come up with a way to fix your oil consumption. It works. Its also typical of 50's and early 60's cars that didnt give a crap about pollution. Oh, and by the way, without vacuum or a vacuum pump to evacuate the crankcase (the positive of PCV) your motor had better reach full operating temp everytime you start it. Otherwise, all this unburned water and crap in your crankcase will turn to acid and tar. Cars of the 50s that were daily drivers for short trips that repeatably didnt warm up built up scarey amounts of sludge. Ask someone (a car guy) who worked cars of this era.

So how do you fix all this stuff? Well, if its a race car, venting the crankcase and no PCV into the intake is a viable solution. Make sure the engine reaches operating temp each time its run. Vent the valvecovers as much as possible, and make sure the vents allow the misting oil to collect and drain back into the heads.
On a street car, you need to keep the pcv, but drastically improve the oil separation of the misting crank air. Catch cans work, but they accumulate the oil and water mist together, and create a nice milkshake that you dont want back in your motor. You still have the lowering of your oil level with mileage, but you are not burning the oil and water in the catch can. You really want to put oil separators at the valvecovers, so the oil mist stays in the motor as oil. The steam and water mist can continue thru the PCV valve and be reburned. The moisture content will actually help keep the heads free of carbon, and allow full timing.

OK, Ive said all I am going to say. You may disagree with what I have written, thats fine. Ive been screwing with cars over 40 years. Ive been a mechanical engineer over 30. Play nice, keep looking for new ideas, and make more power...DONE.

LS6427

iTrader: (2)

Damn dude, I wish you would have joined in earlier. That was kickass insite into this wonderful PCV mess.

So do you agree that if I change the oil every 3,000 miles....and I had a small, constant running, air pump, blowing air into the valley cover port......then that fresh air is vented out of both valve cover ports..........I would be just fine?

****I understand the problem with not getting the temps up to operating range each time you drive the car...I have no problem with that. Of course every now and then there are short trips, but for me thats rare. My car doesn't even leave the driveway till it warms up for at least 2 minutes anyway.

OR....this method....
Leave the PCV valve hooked up to the intake vacuum port and drawing crankcasr air from the passenger side valve cover vent port.....I just obstructed the flow of that vacuum line. It now flows at less than half the strength. So it stopped my oil burning problem AND I can feel a constant pull of air on my drivers side valve cover filter port and on my valley cover filter port. So I know fresh air is constantly being drawn into the crankcase and into the intake vacuum port.


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Scoggin Dickey

iTrader: (34)

The PCV system is closed loop. The PCV system supplies fresh clean air from after the MAF into the crankcase as well as drawing out the dirty air, so it offsets itself, hence "metered". There is not an unlimited supply of outside fresh unmetered air like your method. It DOES make a car run leaner to do it your way, which means there is unmetered air being let in, period. You don't have to like my wording, but it's fact. I'm not going to get into an argument over it, I was simply trying to help you understand the system better and the downfall of that setup.

The only unmetered air is from blowby, which should be minimal and is a problem in and of itself if you have enough to be a problem. The rest is being supplied to the crankcase after the MAF by the clean air side of the PCV and as such, it is metered air from the closed system.

LS6427

iTrader: (2)

Well, in this case it has helped my rich condition.

My rear bumper would get black above each tailpipe in a matter of a week. I would have to clean it off every week. As soon as I did this, that black soot from running rich has 100% stopped. I a haven't cleaned my bumper in almost 2 months.

So, I can only assume that the massive amounts of oil that was going through my intake via my PCV system...was causing me to run very rich. 02 sensors sensed it and made me run richer......
What do you think.....???

Something changed. I have considerably better gas mileage and no more black bumper and it seems to be running smoother throughout the rpm range. I realize it might not be the proper method for a PCV, but its working great.

This past weekend I drove 115 miles to Ft. Myers, the car sat for 3 days and drove home 115 miles. My oil is still full and I did that with right at 3/4 tank of gas. Not bad for an old as dirt 427ci. That's about 24mpg too.

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Scoggin Dickey

iTrader: (34)

Tons of people run it your way and feel that it does not cause problems simply because it stops oil intake and they can't SEE any negatives. Most builders who tear the engine down later will disagree. I personally don't prefer it either. It the most simple solution to oil consumption, but it is not the best solution overall. You can't see the negatives with your own eyes, but they are there building up internally. The best solution is to keep the P of the PCV by keeping it hooked to the intake, but with a setup to separate the oil and water from the air. A quality catch can is the best way to do this. Not a cheap catch can that is nothing but a can with an in nipple and and out nipple, but an actual air/water seperator style catch can from a few vendors here. I do not sell catch cans and have nothing to gain by recommending that BTW.

Scoggin Dickey

iTrader: (34)

Oh, I forgot to mention this: everyone keeps mentioning swapping to the fixed orifice PCV that is now used. It's almost the same thing as you restricting your line, so that should answer that question for you :

LS6427

iTrader: (2)

Yeah, I was gonna put one of those fixed ones in there too. My whole thought was really just to simply slow that damn suction down....its unbelievable how powerful it is.

We'll see in about 4 months what the inside of my engine looks like, as my new engine will be done or will be getting done soon. I'm quite curious to see what it looks like in there. But man....as good as it runs, smooth, quiet, strong as hell....I dont see what bad stuff my builder will find other than normal wear.

Those Cola crankshafts are supposed to last forever.

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LS6427

iTrader: (2)

I was thinking......the first experiment I did with my PCV system was to drive around for a month with both vacuum ports on my intake completely capped off. And just have the crankcase vented.

My black bumper from running rich 100% stopped then too. So what made me run leaner in that situation. I cut off the intake vacuum PCV air, so my engine was getting less air. Only air going in was through the MAF.

?????

Only thing I can think of is the massive amounts of oil that were going through the PCV line into my intake was making me run very rich. NO?????


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Scoggin Dickey

iTrader: (34)

Burning oil obviously affects your a/f. It is not the only part of the equation no matter how many times your throw it in to be a smartalec to me. While using your back bumper as a diagnosis tool, you may want to consider the byproducts that come from burning "massive" amounts of oil. It's not known to be the most clean burning substance. You also might take into account how much of the gas in your cylinder is not burning because of that oil presence and is going out of the tailpipe raw. Not from actually running rich in a/f, but from what oil does to the combustion process that prevents that fuel from being burnt.

I'm not going to argue anything further as it seems to get us nowhere and I don't like the thought of burning bridges. I simply though I might help you out with information based on our own experience with what you are working with. I respectfully leave you with your experiments, and I respect the desire and a quest for finding your own answers. Good luck with your endeavors.