Then tell my y not leave the system stock huh.

Stock hoses stock valve in the intake

 

The lack of respect to posters. The lack of common sense in face of the simple facts laid out here all this tells me that some posters should reconsider posting on here please take the high road. The by products of combustion include carbon gasoline and oil among other things to suggest that blow by gases does not include oil is really silly. Every person here with even a bone stock LSJ and an LNf has seen oil in the intake tube pre tb post MAF At least three people have indicated that they run on vacuum at highway speeds. Because it's self evident. Thank you for responding politely. Jackass comments will hopefully be purged

 

So you really think that every single pcv system is identical from the factory, a web article describing that NA applications can e used to fight your case, and that the check valve sees magical pressure at cruise?
Come on.

 

Have you paid attention to any of the information provided?
The stock system is sub par. It is easy to improve, and even easier to destroy.

 

No i havnt. Cuz y. The stock system works fine. If the engine is healthy the amount of blow by will be minimal thus there's no need to change it.

 

Come on Alan i deal with this stuff on a daily bases with engine meny times the size an alot more HP. We still only use a -16 line on a CAT 3406 (20L engine)

 

Dial in your fuel trims and set PE at a higher pressure, then introduce a large vac leak into your PCV system, then observe trims throughout the vac and low positive pressure ranges. It is interesting.

 

Where did I ever say a single word about bigger lines?
That's a John idea.

What you do at work may pertain to general pcv operation, ad I mean very general (diesels are COMPLETELY different) like the vague article mrB posted, but is little to no help in describing the downfalls of the lsj system specifically.

If you want to leave yours stock, that's perfectly fine. Have at it.

The reason the stock system is less than ideal is largely because it uses the restricted FAI as a blowby relief.

If your system is bone stock and had no signs of oil in the head side of the IM or on the throttle body, you simply hadn't ran it long enough to leave a visible amount, or the fuel sude of the n2o was washing it away.

The oil vapor created inside the crankcase, through normal operation, has ABSOLUTELY NOTHING to do with how "good" or "healthy" your engine is.
It's simply what naturally happens when you have oil covered objects spinning several thousand rpm.

 

diesel engines are different. The seperator I use however, is popularly used on diesel engines. check out the 3406. Does it have an oil seperator in the postive crankcase ventilation system?

 

Nope just a -16 fitting on the valve cover

 

Idk how they could be different. Just on a huge scale.
Anyways the way i see it and the way i was tought in school is that if Ur producing enough blow by to carry oil out. U have a problem may not be a big problem.
Now on extremely high HP builds Im talking 700+ or so Ur more than likely collapsing the rings slightly during the xcombustion cycle. I know there isn't Much of a way around it cuz the amount of room between the pin a top of the piston Dosnt allow for huge rings to completely handle the massive cylinder pressure.

 

wow. compression /ignition engines are different. But as you are a caterpillar fan, you should read this
"BLOW BY
Crankcase emissions result from
combustion byproducts and/or
exhaust fumes escaping around the
piston rings and into the crankcase.
These escaping fumes are commonly
called blow-by. If not controlled,
the blow-by can contaminate the
lubricating oil and pressurize the
crankcase, possibly leading to an
oil leak.
The overall volume of blow-by
varies due to cylinder pressure,
piston ring pressure and component
wear.
Venting the emissions to the
atmosphere is a simple solution to
release the pressure and trapped
fumes. Managing the emissions,
however, adds complexity to
crankcase ventilation systems.
Elements found in blow-by can
include wear particles, oil, fuel, gas
and air. The specific composition of
the elements varies due to fuel type,
engine type, engine speed, load and
maintenance history. Typically,
blow-by is made up of hydrocarbons
(HC), carbon monoxide (CO), carbon
dioxide (CO2), nitrogen oxides (NOX),
water vapor and traces of sulfates
and aldehydes.
Crankcase hydrocarbon emissions
are normally 3% of the total exhaust
emissions tested at the mid-life of
the engines. However, due to
piston ring tolerances, crankcase
hydrocarbon emissions can increase
to 20% of the total hydrocarbon
emissions.
The amount of NOX present in the
blow-by decreases depending on the
air/fuel ratio of the engine. As the
air/fuel mixture becomes leaner,
less NOX should be present.
The sulfates and aldehydes will
change depending on the fuel. An
engine running on diesel fuel, landfill
gas or digester gas will have more
sulfides present in the blow-by than
an engine running on natural gas.
As emission laws become more
stringent, it is inevitable that
crankcase emissions will be included
in total system emission values.
Certain parts of Europe and
California are already counting
blow-by in the emission numbers.
In the future, ventilating crankcase
emissions to the atmosphere will
be discouraged or prohibited. "

The source for this information? TJolley, you should read it, it shows the oil seperator with drain back installation on a Caterpiller diesel engiine.
http://pdf.cat.com/cda/files/3375381...EBW4958-02.pdf

Yup its a CAT. I ran Cats for years in my race transporters.

 

Subd

 

Trevor, how many throttle bodies do those big cats have?

Oh, and where does that -16 line run to/from?

 

Amazing Wat u find on the internet.
I should have Been more specific i deal with off highway engines were there's not much restriction on emmission's for the older ones.
The new engine tear 3-4 Proly will have some type of PCV systems. Customer brings in a engine and says i need X amount of power. I say ok this is Wat it will cost bla bla bla.
And i do Wat it takes to make the engine perform and survive.

 

Most diesel engines to my knowledge do not use a butter fly valve. They control fuel flow. Im still not 100% how the system works. The calibration software (tuner)i use is based off fuel flow and manifold pressure.
Basikly i have control over fuel at set RPM high idle low idle bla bla bla.
Ill tell u this diesel engines love fuel. The richer u Go the more power its Gona make to a point.

 

Can you please explain the difference between gauge pressure and absolute pressure?

Or explain why a 3bar map sensor sees ~ 29psi of boost when 3bar is ~44psi of pressure?

I can tell you why and explain the difference. What you are defining as vacuum is actually a condition where the pressure inside the manifold is less than atmospheric pressure. By having a condition of pressure lower in the manifold than it is on the other side of the throttle body or for the sake of this argument the crankcase, then it will draw air into the intake manifold. Now as pressure increases (the amount of pressure inside the manifold draws closer to atmospheric pressure) those conditions will begin to change.

gauge pressure is your pressure below atmospheric (what your calling vacuum) vs pressure above atmospheric (what your calling boost)
absolute pressure is any and all pressure

So with that said, any pressure above absolute 0 pressure, is pressure and will close the valve.

 

that was my point. they don't use airflow control, so therfore have no manifold vac. which makes whatever pcv system there is COMPLETELY different than what we're dealing with here.

gauge pressure (psig) is equal to absolute pressure (psia) minus barometric pressure
correct
still correct
right on
again, gauge pressure is absolute-atmospheric... nothing more nothing less
youre exactly right i just think you worded it in a confusing way for some
i'm hoping for your sake this was a typo and you meant gauge or atmospheric, not absolute. because the rest of your post was spot on.

the only other thing you have to add in here is the force of the spring in the check valve (2-3kpa nominal).
the valve will close when your vac level in the manifold drops below this, which is just so slightly before 0psig

 

My point is if Ur creating enough crank case pressure to start pushing Alot of oil vaper out Ur loosing cylinder pressure past the rings. By eather a worn out engine or a collapsing ring under massive cylinder pressure. Blow by given in any internal constable engine gas or diesel. How Much is key. An engine built like my 2.0 with a 0.005 ring gap on top and second ring maintains cylinder pressure with little blow by but at the same time u sacrifice other things engine longevity possibly head sealing issues premature bearing wear.
U more than lickly have to pick Ur poison.

My 2.0 made 195-205 psi in each cylinder dry/wet
And leaked 5-8% on a wet leakdown test. It would show 15-20% on a dry leak down test.
I don't know Wat exactly caused the HG failure this time im suspecting i could have damaged something Wen i snapped the water pump drive chain and over heated the engine. But that was 20k miles ago. So idk at this point.

 

I think this should be a sticky icky icky

 

i find this thread very interesting but since there are 3-4 main opinions being pushed its hard to dissect what is truth

in the end id say filter out the bullshit and add the straight dope to the o.p.

tjolleys last big post made the most sense to me so far

 

Im going with a EVAC setup for my new engine cuz i know that ill have a good amount of blow by due to thr small ring set i had to use. And i don't want that **** back in the engine.

 

Maybe if there was a new one.
There's to much bitching back and forth.

 

so now that everything is settled down, we have confirmed that in fact oil can and does get into the intake. Byproducts of combustion, actually nicely broken down in the Caterpillar quote.

That in fact the PCV system works in a vacuum most of the time, off boost, and those who care, have confirmed that their boost gauges show they cruise in vacuum on the highway.

For my part, on a 75 km run to various suppliers this afternoon, a wet blustery November day, I was in boost for about 60 seconds total over 75 km. Turbo 2.3l ecopower.


what remains is folks to embrace and understand what GM intended with the LNF which has a superior PCV system to the LSJ, and for folks like Armclure who is dedicated to improving the performance and power of his LSJ with an enhanced PCV upgrade.

We developed and sell the PCV upgrade, and with the help of our customers are expanding its use into more than a way to help LNF turbo engines to combat DI gasoline engine valve coking.

thanks to all our customers.

 

so is the point of this whole thing to keep the cam cover/manifold from experiencing pressure either inward or outward?