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There’s not a single 4” stroke engine GM sold with a traditional PCV. Only drysump.
my 402 stroker had years of oil consumption to the point of me being able to see blue smoke out the exhaust when hanging high rpm’s.
I recently deleted the PCV and just put a filtered vent in the VC and couldn’t be happier. No oil blowing out the VC at all, and near zero oil consumption by comparison.
LS engines have an oil burning reputation. The majority is coming from the clean side PCV in my experience.
There's not a single 4" stroke engine sold by GM, EXCEPT for the LS7.
And all use a PCV system of sorts, though instead of a PCV valve, a calibrated orifice is used, with similar results.
ALL pull air from before the TB, but after the MAF, circulate thru the block, then get sucked in after the TB.
What isn't "traditional" about this, functionally?
Your quote Kingtalon...”If the engine is healthy then it should not even need the can in the first place or any pcv to stay clean.”
Yet you state that you’ve torn down all of these import engines, and they were filthy BECAUSE they had no PVC? Your talking out of both sides of your mouth. Please make sure you have some knowledge about what your saying before you post.
A brand new seal, on a brand new engine, will not leak if you immediately take the pcv off when you buy it at 7 miles on the clock.
Then, we apply mileage, 50k, 100k, 200k, 300k
50-70k with the pcv disabled looks pretty beat frequently
200k+ with the factory pcv intact usually looks pretty good high freq
the engines often are removed personally from the vehicle, whole vehicle is scrapped for parts in Japan. The remaining bits are trashed the rest is sent back to USA.
so we know the exact mileage, a small sticker is put on the engine at that moment and mileage recorded.
ALL of the 200k high mileage engines that were spotless still had OEM pcv intact and maintained.
There were not one if any engines without factory PCV which made it so clean to such a high mileage.
It became the strategy for acquiring mostly good engines (only buy pcv intact engines esp if high mileage)
Many have mods and we put alot of them into cars, usually a swap into some foreign chassis. Over time as with anything you learn how to identify a good engine if you are going to start putting them into vehicles, you'd better know which one is good amirite. The cleanest sickest swaps usually start as OEM implants with fully functional PCV. Even somewhat clean engines with modified air filters exhibited turbo-blade pitting and throttle body shaft erosion due to particulate inhale, often accompanied by head/deck pitting. It started to become clear that many 'performance' filter systems are not healthy for engines and that high quality filtration is achievable through OEM-dry or similar paper filters, so we look for those also.
At that moment if you remove the pcv of course it won't instantly go to hell. Thats what I meant when I said "shouldn't need a can" it literally should be able to run without the pcv for a bit and still be ok, because engine is still healthy like a healthy person who just started smoking. Just a minute though, then the pcv needs to go back on it or the symptoms will climb over time. Many remove it and see no ill-effect at first and then 30k later its weeping leaking oil and they think that its just normal so they start a can system.
This is the "big picture" showing all pressure ranges possible and application specific detail
"let us look more closely at OEM pcv applications" Exactly mirrors sentiments from all above posts I have made regarding pressure differences using actual numbers for extremely accurate explanation of what the OEM pcv is trying to achieve for the crankcase system and how to use it to your advantage.
The part you seem to be overlooking is that performance builds often exceed the capability of the stock PCV system and forces vapor/oil out of the fresh air side of the system and this has been well documented on LS based engines. It happens quite often on completely stock engine once they have started to wear considerably. I've seen it happen to low mileage stock engines that have seen sustained high rpm usage (highway pulls). These engines are also sensitive to the type of oil being used to the point that engines might use 2-3 quarts between oil changes suddenly only using a qt because of a brand change.
Have definitely NOT overlooked that aspect. I have addressed several times what the options are when one exceeds oem pcv capability.
Almost every engine will be exceeded once it's oem output is tripled, this is a general assumption, not LS specific and definitely gone over repeatedly in previous posts.
If you have trouble finding them I'll link a bunch, I guess, but try first at least to find at least one
A stock type PCV system does nothing for ring seal...not even a little because it's not a closed system, all it does is pull air from the intake side of the system to the manifold, It does not create a vacuum in the oil pan so it does not help ring seal. Think about what you're implying for a second, You're basically saying that under wide open throttle your manifold has enough vacuum to pull on the oil pan so hard through a small hose that it overcomes the fresh air inlet and the blow by the engine produces to the point that you would have a measurable negative reading at the pan... I'll guarantee you that's not happening.
Hook up a gauge on your oil pan and show me how much vacuum it reads..... If it has reading at all it will be a positive reading because you done blew your **** up lol
I'm not saying anything. I'm hooking a pressure gauge to the crankcase and taking measurements. For many years, on many different engines. And trying to understand how the OEM apply crankcase vacuum situations on various vehicles. And this data is presented, and now arrive to several conclusions. Your statement is wild and confused and has no bearing on anything because you have no data, no numbers, so it's just a bunch of words which to you mean something completely different than what they mean to me.
I've explain this a hundred times on the internet but I'll do it again for you now. If the engine is running and you put your hand over the throttle body to block it completely, what is the pressure inside the intake manifold at that moment? It will be very low. Perhaps 20" and then the engine will die from lack of air molecules. Even if the engine is at WOT.
The OEM take advantage of, and design their orifices with this principle in mind. That is, they create systems which use dry paper filters sized appropriately such that average life-cycle performance creates a pressure drop (a "hand" over the intake tube) of approx 1-2"(sometimes 3") Hg during WOT. Since the pressure at WOT inside the crankcase of such engines is typically 1~psi (healthy) there is quite a difference between them (1psi vs -2psi) and the WOT pcv functions to pull some of that (oily, carbony, tainted flow) out of the crankcase before it can interact with engine oil or attack oil seals.
A PCV system is not vital for performance as it actually hurts instead of helping. Like I've said many times already, You're sucking oil/combustion vapors into the combustion chamber, That brings down the octane rating and can lead to knock....What does the computer do when it see's knock? It pulls timing. Pulling timing does not help performance. The fact is a PCV system is an emission component not a performance component. On a stock engine I leave it fully functional because it does serve a purpose, On a performance engine where I want to make as much power as the combination is capable of then I don't run them, I run a catch can.
You want the best of both worlds you run a vacuum pump where you actually do help ring seal and you can actually pull the vapors from the engine....Yes you can run a vacuum pump on a wet sump system...it's done all the time and you would know this if you had any practical real world experience with high performance engines.
EDIT: Why can't you just admit when you really don't know what you are talking about? You seem semi intelligent but lack common sense, I know you have very little experience with V8 engines and even less when it comes to the LS variety. Sometimes you should learn from people who have first hand experience and quit relying your book smarts because that usually makes you look foolish. I'm not right all the time and will admit when I'm wrong and still learn something every day.
First of all, wrong#1 is watch out. PCV is used to add 100+hp to some engines using vacuum pump. Surely you knew that so you can't actually say "pcv is not vital for performance" when clearly its worth some power in many applications and necessary for any true racing engine "dry sump" is an ultimate form of pcv. I would say pcv is absolutely critical in performance applications. No matter what application there are benefits to sealing up a crankcase and pulling a strong vacuum on it with a pump.
next wrong #2
I am not new to V8 engine. my first twin turbo V8 w/ stand-alone was 2004. I built my first 355 at age 17. they say a holley carb has 144 adjustments
not many people have V8 stand-alone tuning experience since 2004 for V8 and inline 6/4 engines,
I would say that the owner of every engine I ever tuned has more experience than I do, and I'd like to keep it that way
The point of learning how cars and other devices work is so that you don't have to work on them. I don't want to have to stop and spend time doing things to it. I just want to drive it and expect a certain level of performance and economy while doing so. An ice engine is one of the simplest devices on our planet (I dare find another machine so simple as redundant) and I take no particular "obstinate" or "superiority" position just because I happen to consider them as such. I have mentioned several times I am novice and very limited experience. It is highly varied but limited because I work on something and then it runs fine for a very long time so I don't get to do much more to it if ever.
I am new to LSx platform and many other manufacturers still but my expectations are similar for all ice engines because they are all limited similarly and at the mercy of our dark applied fluids
finally, WET sump pcv wrong statement#3:
If we assume you meant In a wet sump pcv system "is not vital for 'performance'" you say.
First, it depends on what you meant by performance. That word alone implies different things to each person. I am sure I have a different idea of what performance is than you do!
For me, performance is more than I can put into words, but I tell you it definitely includes a proper clean high mileage setup.
In your words, I am sure you meant only 'horsepower' when you say performance.
So if we finally correct the statement to read proper;
"you say that in wet sump pcv system, that pcv is not vital for highest output horsepower"
And to this, I completely would agree, for wet sump applications without vacuum pumps: PCV is un-wanted in highest performance (when max HP is needed) output situations because the energy of pressure drop used to drive crankcase pcv action is better spent on ingesting fresh air molecules from the atmosphere.... and I have alluded to this several times.
I never said pcv was vital for max output. I definitely said/wrote we are discussing NON-race car engines. although some race cars value filtration over highest output so even that could be misleading. Its very tenuous on the internet you must be very exact and leave no room for doubt with words, words are almost meaningless without some numbers to supplement.
Talon, have you ever seen an engine come from Japan with a lot of miles on it? I’ve had my hands in the JDM import thing as well. Google Japan Shaken Law. All of those engines coming over are crazy low miles for a reason. Of course they are clean.
Since this has morphed to a PCV argument, on the LS, street driven I guess PCV is ok. It kinda sucks and draws a lot of oil but does its job. At part throttle. Also it depends on a stock or stockish cam. Get some overlap in there, manifold vacuum degrades (shows as map readings increasing from 40-45 up to 65-70). So you end up running more throttle air, which reduces the pull on the pcv nipple, ultimately reducing flow through the block. No additional blowby needed. Stock PCV is less effective
Problem is, at wot, there is no pressure differential between clean side and dirty side of PCV and it is sucking through a rinkydink hose.
All the air movement is through that 3-4 inch opening not the 1/4 inch hose nipple.
VP worth about 15 in my experience, but helps a lot at idle and improves idle quality.
And I’d love to see an engine get 100+ hp from a vacuum pump, as you stated above. Most see 10-20.
i mean, is ur google crippled? or just lazy
One of the first thing we show beginner students in performance application is vacuum pump + blower = 100hp on the right engine
random google1
We now see a 2-4% horsepower gain with vacuum pump systems, and we’ve seen it on everything from a small four cylinders to a 903 cubic inch nitrous Pro Mod motors.
I am sure at 900cid pro mod motor is not without a vacuum pump and that it is worth 100hp+
It's relative to size of engine and how much boost pressure. On any machine if there is a way to adjust a pressure (sigh... differential) with a dial (vacuum pump strategy and boost control strategy) this is an enormous benefit to the control and operation is often greatly influenced.
One pressure can be very low (crankcase) and one can be very high (intake manifold). Think about being on the intake stroke just as the intake valve opens and the piston begins to descend, what sort of pressure would you prefer just below the piston as it descends? Wouldn't it be nice if there was a very strong vacuum, not only will piston be willing to descend faster it could promote faster rate of incoming fresh air intake charge (the pressure between first and second ring is low because molecules normally found there are taken up by the crankcase pcv). This is a great opportunity for vacuum pump to add power by improving ring character for what is already a very high output engine.
You won't get 100hp from a 150hp 4-cylinder by pulling a vacuum. ~500cid+ forced induction engines using 32psi+ of boost pressure it must be worth 100hp or around that.
The engines get sealed up really well and dyno tested if the builder is doing it right
vacuum pumps come in all shapes and sizes right
From google search2 "Does a vacuum pump add horsepower?"
On high-rpm race engines, enough positive pressure can build up in the crankcase during the piston's downward travel to adversely affect cylinder wall ring sealing. Overcoming positive crankcase pressure also wastes horsepower and blows oil out of every crack and crevice of the engine.
sounds right to me
On a 631ci engine we measured 50 cbhp increase with -10 in/hg
For naturally aspirated and Forced induction engines, vacuum functions as an oil containment feature of the crankcase.
Because vacuum helps keep oil in the crankcase like I've been saying since the start.
The question isn't do I want a low pressure in the crankcase or not... because we already established 100 times that you DO DEFINITELY want that.
simply venting is NOT enough. It isn't even "average" or "good" its just "temporarily, barely adequate".
Our GOAL is to provide the vacuum some way. any way we can. Because the benefits...
I'm not an expert But I am a fan. You want a clean charge. Crank spins easier through less windage. Rings seal a little better. All a benifit in my book.
wow these guys really go all out with the stringy details
Pulling vacuum with a dedicated pump has been the preferred method for well over two decades now and the technology has steadily advanced with important performance benefits that include:
Improved ring seal by relieving crankcase pressure below the rings
Reduced friction by allowing lighter tension rings
Reduced windage around the rotating assembly
Improved oil scavenging
Reduced parasitic pumping losses
Minimized cavitation (in wet sump applications)
Reduced lubricant contamination
Improved bay to bay breathing in Y-block configurations
Improved power via reduced mixture contamination
Reduced gas port contamination
As I was saying, the benefits are worth the effort, you try to achieve and measure this pressure as a critical 'performance'(cleanliness) component. If you show me a racing engine immediately I am looking for crankcase pressure sensor and investigate pcv effort. It tells much about the person in charge of the engine. A catch can or vent is the sign of an id10t overlooking and negating all of those benefits due to laziness or lack of understanding. Be ashamed for allowing this awful practice perpetuate
Only with crankcase pressure log/data can you manage complete engine control, it is an absolutely critical components of controlling an engine in a 'performance' application.
More important than boost pressure and almost as important as oil pressure IMO
One of the first thing we show beginner students in performance application is vacuum pump + blower = 100hp on the right engine
random google1
I am sure at 900cid pro mod motor is not without a vacuum pump and that it is worth 100hp+
It's relative to size of engine and how much boost pressure. On any machine if there is a way to adjust a pressure (sigh... differential) with a dial (vacuum pump strategy and boost control strategy) this is an enormous benefit to the control and operation is often greatly influenced.
One pressure can be very low (crankcase) and one can be very high (intake manifold). Think about being on the intake stroke just as the intake valve opens and the piston begins to descend, what sort of pressure would you prefer just below the piston as it descends? Wouldn't it be nice if there was a very strong vacuum, not only will piston be willing to descend faster it could promote faster rate of incoming fresh air intake charge (the pressure between first and second ring is low because molecules normally found there are taken up by the crankcase pcv). This is a great opportunity for vacuum pump to add power by improving ring character for what is already a very high output engine.
You won't get 100hp from a 150hp 4-cylinder by pulling a vacuum. ~500cid+ forced induction engines using 32psi+ of boost pressure it must be worth 100hp or around that.
The engines get sealed up really well and dyno tested if the builder is doing it right
vacuum pumps come in all shapes and sizes right
From google search2 "Does a vacuum pump add horsepower?"
For naturally aspirated and Forced induction engines, vacuum functions as an oil containment feature of the crankcase.
Because vacuum helps keep oil in the crankcase like I've been saying since the start.
The question isn't do I want a low pressure in the crankcase or not... because we already established 100 times that you DO DEFINITELY want that.
simply venting is NOT enough. It isn't even "average" or "good" its just "temporarily, barely adequate".
Our GOAL is to provide the vacuum some way. any way we can. Because the benefits...
wow these guys really go all out with the stringy details
As I was saying, the benefits are worth the effort, you try to achieve and measure this pressure as a critical 'performance'(cleanliness) component. If you show me a racing engine immediately I am looking for crankcase pressure sensor and investigate pcv effort. It tells much about the person in charge of the engine. A catch can or vent is the sign of an id10t overlooking and negating all of those benefits due to laziness or lack of understanding. Be ashamed for allowing this awful practice perpetuate
Only with crankcase pressure log/data can you manage complete engine control, it is an absolutely critical components of controlling an engine in a 'performance' application.
More important than boost pressure and almost as important as oil pressure IMO
Talon, I was referring to an LS engine. This is LS1Tech after all. Save that other crap for YB. So your a teacher huh? Where are you teaching students performance engines at? Your profile says that your a student.
I appreciate your lecture on vacuum pumps. I’m sure we all just learned a bunch here...
Talon, I was referring to an LS engine. This is LS1Tech after all. Save that other crap for YB. So your a teacher huh? Where are you teaching students performance engines at? Your profile says that your a student.
I appreciate your lecture on vacuum pumps. I’m sure we all just learned a bunch here...
Yeah I remember explaining to Kingtalon about the use of vacuum pumps and those who use them for the record don't put the blowby back into the engine via the intake manifold either. Ahh forget about it!
I looked at all their documentation and installation instructions for "high tech" catch can and it's all done exactly as I've been suggesting/teaching.
So if you don't take my word for it, take theirs? How many places need to show you proper pcv before it sinks in that in 2019 we have X different ways to pull a vacuum:
electric pump
mechanical pump
scavenge exhaust
intake pressure
Which adds performance to the engine of this nature:
Improved ring seal by relieving crankcase pressure below the rings
Reduced friction by allowing lighter tension rings
Reduced windage around the rotating assembly
Improved oil scavenging
Reduced parasitic pumping losses
Minimized cavitation (in wet sump applications)
Reduced lubricant contamination
Improved bay to bay breathing in Y-block configurations
Improved power via reduced mixture contamination
Reduced gas port contamination
And instead LLosing it can't come up with a single method for adding this level of professional performance to the engine, and his solution is to put a breather on it and call it done? Mods are deleting posts because they don't understand how engines work?
Just throw away all the benefits because? too lazy?
thats what this is all about. LLosing it saying breather is fine, and PCV has nothing to do with oil control.
Then I prove it does have everything about oil control.
Talon, I was referring to an LS engine. This is LS1Tech after all. Save that other crap for YB. So your a teacher huh? Where are you teaching students performance engines at? Your profile says that your a student.
I appreciate your lecture on vacuum pumps. I’m sure we all just learned a bunch here...
LS engine aren't special or unique. All ice engines work the same way. If a principle can be applied to one of them, it can be applied to all of them.
I am always a student no matter what happens, think you can learn in 100 years everything there is to know about something, and then call yourself that thing?
knowledge > lifespan
you think because we get a degree in chemistry, biology, engineering, that it makes you an engineer, or a biologist, or a whatever
I don't believe that sorry, 'experts' are just as likely to make mistakes as novices, perhaps in some ways even more likely.
different kinds of mistakes.
The PCV (Positive Crankcase Ventilation) system is designed to regulate and remove fumes from the engine crankcase, and to alleviate crankcase pressure which could cause oil leaks or seal damage.
I agree strongly with that
next,
The Clean-side solution addresses that small amount of oil vapor that enters the intake air charge upstream of the throttle body during WOT operation when the intake manifold vacuum is not present.
Very professionally done solution there. Instead of simply using a breather, and a can to vent, they are doing it right the way, addressing the oil ingestion issue directly and maintaining the pcv system as OEM function intended to help control oil and keep oil inside the engine and pressure off the seals.
Imagine you are a teacher, phd professor. and your area of specialty is bridges.
You've studied bridges all your life. All shapes sizes and kinds. Youare attending conferences and publishing papers about bridges.
One day, somebody approaches you about a bridge in their facility. A special kind of bridge that you have never seen before.
Does this sound about right? That a random bridge might have an issue, and they would seek the experts of bridges of all kinds, even knowing that none of them has seen the bridge in question yet. Hoping that, after seeing and experiencing so many other kinds of bridges, the issue would be immediately apparent to you, the expert of bridges in general.
Thus you may test your knowledge and capability by finding 'new never before seen bridges' and then having a high success rate with them, learning while minimizing down time and mistakes through general knowledge as opposed to specifically memorizing what the people on the internet said this engine in particular wanted or whatever "what was good enough"
example: you telling people that a vent is fine and there would be no oil control improvement through the use of PCV. That was wrong, bad information to pass on to the general public and I don't need to be an LS expert to identify that!
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