PCV Delete debate

[kool-aide]

I feel this won't be a short post, so crap a six pack of what ever you like now, .

OK, I thought General Info was a good place to start this thread. I decided to start my own debate thread. I didn't want to side track or hog Sarge's thread over in the GTO section, great thread BTW.

OK, so after reading Sarge's thread about the PCV system. I started following other links posted. I got to thinking. Why are there more opinions on what the right answer is for something I thought should be a just little more cut and dry. And why is it when I think of something fun to do I always find that one post somewhere that scares the crap out of me. Or at least makes me feel like I am going to blow up my engine.

The big debate. I would like to kick it off with someone listing what they feel is the Pros and Cons of running a PCV delete, and at least describe your actual delete.

I have read a post that I felt made the claim the PCV was created to extend the life of your oil and should never be deleted from a street car. So I am paraphrasing here. I have read people kick around Metered air, vacuum, throwing off A/F in the PCM, needing a tune, stinky fumes under the hood, etc.

I thought Sarge's fast explanation of why the PCV exists was pretty simple. So why the heck do some people feel your engine will die if you run your PCV to atmosphere via a breather?

And seriously, does an engine really create sulfuric acid post combustion? Dude I'm not making this crap up, just regurgitating crap I read in other places. Like I said I read other post that make it sound like you just shot your engine with a .45 if you delete you PCV.

So here are my thoughts based on nothing but me =, myself, and I with zero credibility or experience. yeah, pretty much me telling Van Gogh o how to paint, lol...

Is sulfuric acid a by product in the combustion of an engine, hmm, dunno. I would have to pull the molecular structure of the all the stuff, um, read a few fat books, um, look at the chemical reaction, make a few drunk guess, and run a Myth busters style experiment. So my first guess, no, lol.... I hope I'm not wrong, talk about egg on my face.

Does a PCV delete that vents to the world under the hood create smelly fumes you can smell from the next lane on a hot day? Well, I don't know. I would say smelly fumes, maybe, anything more than what you smell out the tail pipes, my guess know. And why does it need to be a hot day? Last time I burned myself on my engine. It still hurt the same in cold as it did in hot weather.

My setup, for now. I am using my existing LS1 PCV tubes. I still have the driver side, the passenger rear side, meeting together where the sun don't shine, up to the front stock location to a 3/8" hose. I run mine under the TB and over into the open area behind my driver headlights. I was trying to avoid hard bends, kinks, or pinches in the line. I run this into a compressor oil/water separator and then to a small breather. Right now I still have the passenger front valve cover line connected to the TB. I plan to remove this in the AM. I have my intake port capped. In the AM I plan to cap the valve cover and TB. I have a gift card for Xmas and I may buy an oil cap breather for fun, because I am crazy that way.

So that's my setup. I have driven all of like 5 miles so far. I am stock, and no tuning.

Personally I don't see the merit of some of the awful stuff I have read about metered air, vacuum leaks, sulfuric acid, short oil life cycles, etc. this is me being ignorant and kicking up a debate to see if we can iron this out before i blow up my engine or loose a fortune in oil changes.

Pros: I don't have combusted by products going back into my air via the intake. Um, is that not the only pro you really need to list.

Cons: Um, no. I personally have no way to back this up, other than me thinking out load, and waiting for Judge Wapner to start. I am waiting to hear the debate as to what the Cons are and why. Oh boy.

Can a PCV delete like mine pull air back into the engine in the opposite direction causing problems? I am using Kindergarten logic 101 for dummies on this one. Wouldn't this be similar to stating I can possibly blow exhaust out of my intake? I mean the current PCV is not a one way valve, so....How can venting to atmosphere be any more dangerous or harmful than the stock PCV?

Is there anything magical about the PCV. I didn't think so. I looked at a couple of different PCVs. I mean, what the heck, some are just pieces of metal with a tiny freakin hole in them. How the heck does that dumb thing fix anything, lol..... And the size of the hole, come on, that is barely venting any thing. If anything I state some of those PCVs are not venting enough. I about wet myself in the store when I took a seriously look at those things. I thought they were some kind of cool device or something. Looks more like a broken whistle to me.

I think one the big debate will be around this idea of metered air, vacuum and contaminated oil. Seriously, I don't see how a PCV delete is contaminating my oil to the point of needing oil changes measured in hundreds of miles vs. thousands.



thanks

kool-aide

[DaddySS]

I don't think it's a debate. The drawback of PCV is oil mist in your intake that is mostly cured by a catch can. The benefits are less oil leakage, cleaner engine compartment, and cleaner engine. So you simply choose which you prefer. To me, if you have a catch can, the benefits far outweigh the drawbacks, to others they may not.

[kool-aide]

I agree, but I have read others that make it sound like the last thing you ever want to do is run a catch can to atmosphere, e.g. delete the PCV.

I'm also curious about this combustion by product. Does an engine really produce sulfuric acid? I haven't done any research yet, but man that would be a real surprise to me.

I had the chance to take my z28 out for a ride yesterday. When I got home I could smell the fumes from the PCV. Now I had to stick my nose right up to the breather though. I'm a little congested. Maybe when I'm not sick I will do the sniff test again and see from how far away I can smell the fumes. I definitely noticed water condensing in the oil/water separator.

the only reason I am venting to atmosphere is because I didn't want any chance of any oil getting sucked back into the intake.

[SSnow]

I agree, but I have read others that make it sound like the last thing you ever want to do is run a catch can to atmosphere, e.g. delete the PCV."

Maybe not the last thing but I do agree it's benefit is real.

"I'm also curious about this combustion by product. Does an engine really produce sulfuric acid? I haven't done any research yet, but man that would be a real surprise to me."

Sulfuric acid is a byproduct of the combustion process. Sulfur in combustion gases (H2S, SO2) mixing with water creates sulfuric acid. But, and this is a big but, sulfur has to be present in lubrication fluids and fuels to begin with.
Not long ago sulfur was only removed in the refining process as deemed necessary (economics). Ever drive behind a car that left the cheap gas station and smell the roses? Regulation in recent years requires that refiners remove it. I've been working in the refining industry involved in upgrading processes that take sulfur from gas and diesel for the last 6 years. There ain't any left in there. So your hearing a carryover of innuendo and hearsay of times past. Anything that might be left can be easily taken care of with regular oil changes.


"I had the chance to take my z28 out for a ride yesterday. When I got home I could smell the fumes from the PCV. Now I had to stick my nose right up to the breather though. I'm a little congested. Maybe when I'm not sick I will do the sniff test again and see from how far away I can smell the fumes. I definitely noticed water condensing in the oil/water separator."


That's right, your open to atmosphere so any condensate/moisture in the air will condense in your system all the way back into your engine.
The PCV concept was initially conceived to keep engine gasses, bypassed into the crankcase from blowing out into the atmosphere. The easiest was to do that is use the vacuum created by the intake system to draw off those gasses. ( hot rodders found there were horsepower gains to be had by employing these systems on their race engines) So they make their way into the intake unless an adequate filter drain system is made. Most find the mess that gets in there objectionable. There are other thoughts on this but that's another discussion.


"Most find the mess that gets the only reason I am venting to atmosphere is because I didn't want any chance of any oil getting sucked back into the intake.

Here are the other thoughts: Back in the day the vacuum used was drawn after the carburetor at the manifold intake so any blow by was right into the manifold and not gunking up the carb. With the advent of fuel injection and throttle bodies perceptions changed because guys were seeing their nice throttle bodies getting gunked up.
Also back in the day lead was outlawed in fuels as an octane booster. Lead had the added benefit of lubrication and sealing valve stems and seats. Now don't you think a little oil blow by into the intake would help here?
Get a good catch can, with a filter if it bothers you, and plug your PCV system back in. Also it really doesn't hurt to be a little green.

[Sarge]

You would better served utilizing a top end lube like TCW3....but I like the way you think

[kool-aide]

Here are the other thoughts: Back in the day the vacuum used was drawn after the carburetor at the manifold intake so any blow by was right into the manifold and not gunking up the carb. With the advent of fuel injection and throttle bodies perceptions changed because guys were seeing their nice throttle bodies getting gunked up.
Also back in the day lead was outlawed in fuels as an octane booster. Lead had the added benefit of lubrication and sealing valve stems and seats. Now don't you think a little oil blow by into the intake would help here?
Get a good catch can, with a filter if it bothers you, and plug your PCV system back in. Also it really doesn't hurt to be a little green.

A little green? When I thought about the PCV post my first thought was the long tube guys and off road Y guys, lol.... I bet I am still more green than them. Of course I think I am like many out there. My f-body barely sees 7k miles a year, and that is a daily driver too. I just don't drive very far.

I don't know. I don't think oil and blow by sucked back into the intake is a good idea. I mean don't you really just want Air and Fuel and nothing else in there? Maybe the blow by may be ok. I guess if it was an unburnt air fuel mix. I just don't know, but I bet someone out there will set me straight.

Maybe I will take a second look under the hood and see if I can find a new mounting location and plug it back in.

Would you still use the PCV valve?

[kool-aide]

You would better served utilizing a top end lube like TCW3....but I like the way you think

yeah, I'm still running the TCW3 stuff. Works out handy too. Just about every two weeks I need about 10-10.2 gallons. Makes the measuring so easy.

What do you think of venting the PCV to atmosphere (plus the catch can) vs. running the catch can out line back into the intake port with no PCV valve?

I'm still thinking vent to atmosphere has nothing but positives, well for the engine. Any downside to plugging my catch can outlet back into the intake? Would the gas separated from the oil still be a downer?

[SSnow]

You would better served utilizing a top end lube like TCW3....but I like the way you think

I read your piece on it a while back and have been doing it in my pick-em-up as that gets heavy use. I drive it upwards of 30k miles a year and change out the synthetic oil when the oil life monitor alerts me and it uses less than a quart of oil every in 7 to 7.5 thousand miles. It's an '03 Silverado 5.3 with 104k on it now.
My Camaro, an occasional toy and lightly modded has only 8.5k on it.
Just to note. Both of my LSX vehicles show little sign of what I think is heavy oil use so I see no need to use a catch can in my case. I know others that have done so and would if I saw a need.

[SSnow]

Would you still use the PCV valve?

Yes negative crankcase pressure is the goal (hint: this was the hot rodders HP trick). The check valve (that is what a PCV is) will keep the crankcase under vacuum should things go toward equalizing. I.E. WOT (wide open throlttle ) will drop intake manifold vacuum.

[kool-aide]

Oh, so it does sound like running the PCV to atmosphere as a downside.

Now I read in another post the LS1 can switch to using the 1009 part number for the PCV. The difference I saw between what you see in the paper look up book and 1009 was the size of the whole and the paper look up one has this sort of spring loaded thing. The 1009 PCV is empty inside.

[SSnow]

Oh, so it does sound like running the PCV to atmosphere as a downside.

Now I read in another post the LS1 can switch to using the 1009 part number for the PCV. The difference I saw between what you see in the paper look up book and 1009 was the size of the whole and the paper look up one has this sort of spring loaded thing. The 1009 PCV is empty inside.

The other part you mention I did not know about but I would wager some one was parts matching to come up with some idea they had in mind. Even though it fits does not mean it works.
The "spring loaded thing" is the check valve I spoke of.

[kool-aide]

The other part you mention I did not know about but I would wager some one was parts matching to come up with some idea they had in mind. Even though it fits does not mean it works.
The "spring loaded thing" is the check valve I spoke of.

yeah. I was trying to surf and find more PCV info. It seems the idea behind the light spring tension is to make sure you don't suck blow by back into the crank. Although i read it is not to be considered one way though, just kind of a check.

i wonder though. wouldn't an oil/water separator behave like a PCV valve? I'm not sure if there is anything in there to prevent the flow from going back against the thing. Personally I haven't tried to blow in mine, and now that it is dirty I don't think I want to.

[SSnow]

i wonder though. wouldn't an oil/water separator behave like a PCV valve? I'm not sure if there is anything in there to prevent the flow from going back against the thing. Personally I haven't tried to blow in mine, and now that it is dirty I don't think I want to.

No, not like a check valve as that will respond to quick changes in pressure. There is a pressure drop across a filter. If clean it is small and as it becomes less effective (dirty, blocked) the differential increases. For all intents and purposes though the container is equalized and gravity will take over and any liquid will collect in the bottom.

[gnomee]

From what I have read, anyone who has TONS of oil in their intake has a faulty PCV check valve. When that valve is operating properly there is no big deal.

Some people are anal and by all means putting a catch can will keep ALL oil from getting in the intake.

That aside, I think its a complete waste of time and effort unless you have a heads/cam setup that is causing increased blow by and therefore leading to extreme amounts of oil in the intake.

I would rank a PCV delete on a stock motor right there with a throttle body coolant bypass. Almost pointless

[kool-aide]

From what I have read, anyone who has TONS of oil in their intake has a faulty PCV check valve. When that valve is operating properly there is no big deal.

Some people are anal and by all means putting a catch can will keep ALL oil from getting in the intake.

That aside, I think its a complete waste of time and effort unless you have a heads/cam setup that is causing increased blow by and therefore leading to extreme amounts of oil in the intake.

I would rank a PCV delete on a stock motor right there with a throttle body coolant bypass. Almost pointless

Something to think about for sure.

But the TB bypass is so easy....lol... being in the hot south that was the first thing i yanked. i saw no point running hot coolant under there.

[kool-aide]

From what I have read, anyone who has TONS of oil in their intake has a faulty PCV check valve. When that valve is operating properly there is no big deal.

Some people are anal and by all means putting a catch can will keep ALL oil from getting in the intake.

That aside, I think its a complete waste of time and effort unless you have a heads/cam setup that is causing increased blow by and therefore leading to extreme amounts of oil in the intake.

I would rank a PCV delete on a stock motor right there with a throttle body coolant bypass. Almost pointless

of course i think this was part of my intention with starting the thread. To really kick around the idea of deleting, not deleting, air out any misconception etc.

[SSnow]

of course i think this was part of my intention with starting the thread. To really kick around the idea of deleting, not deleting, air out any misconception etc.

I believe that is better than just following the pack. Could use more of it around here.

[kool-aide]

I believe that is better than just following the pack. Could use more of it around here.

yep yep.... I don't mind trying stuff, but sooner or later I become interested in the hwys and hows.

[kool-aide]

I'm kind of surprised no one took a stab at the sulfuric acid question. guess it is time for a little searching.

I re-routed my PCV lines so I could send the outlet hose back into the intake port.

I am curious if I really need to use the PCV valve. The whole reason I started this PCV adventure was because that darn factory PCV boot tears apart. I have had two Camaros and they both suffered from the same kind of tears in that darn boot.

[SSnow]

[QUOTE=kool-aide;2186209]I'm kind of surprised no one took a stab at the sulfuric acid question. guess it is time for a little searching.

Read my first reply, it's in the quote of your question.