S!MON

Hi,

a friend of mine had following idea for venting the engine.

Drilling a not so tiny hole in the oil pan on the drivers side.
On this side the motion of the crankshaft should create sucktion, so the oil shouldn't reach the outside.
Then plumbing a hose over it and let it end in a breather or better an overflow tank.

Could this one work or is it ??

If that wouldn't work, where would you locate the breathers when not using a pcv? Only breather will leave some oil marks in the engine compartment...so are there other methods for venting the crankcase?
I couldn't find that much in the search.

Greetings

Simon

sofakingdom

iTrader: (1)

I do not think it will work...

Oil will leak. There is not enough suction generated by the motion of the crankshaft at all times, to keep the oil from splashing out.

Why would someone not use a PCV system?

84z28350

Run a PCV system...

S!MON

I've got these covers from Comp:



I thought, there could be a way without drilling holes.

Can I use every PCV-System from every stock engine?
Greetings,

Simon

84 z28

Sorry to jack this thread but I have a question about pcv vs breather cap. Now I have heard from some people the you strictly have to use a pcv system and not to use a breather cap. If this is the case why does every high performance crate motor come with breather cap if they dont work well and arent good to use ??

S!MON

That's no high jack, because that would be my next question
In combination with an overflow tank there also shouldn't be the mess with oil under the hood...

84z28350

You run a PCV valve on one cover and a breather on the other to allow fresh air to circulate the crankcase. This helps keep contaminates out of the oil to prolong oil and engine life.

On a race motor, oil life and engine life isnt really of big concern, it doesnt have to go for a million miles. Running a breather on both covers allows and pressure in the crankcase to vent, but also makes one hell of a mess of the engine bay!







I dont know how much you like that intake, but what about drilling a hole through the intake and into the lifter valley? that should work...

84 z28

I'm not talking about race motor's I'm talking about regular chevy 350HO and ZZ4 crate motor's. Why does GM send them with breather cap's and not PCV setup?? Do they know something we don't ?

S!MON

The current setup on the engine is a hose on the fuel pump block off plate. works good for venting but pushes up tons of oil. Maybe with a bigger hole and some metal sheets (left-right-left-right) where the oil splashes against...up to an catch tank...that could work!

Apeiron

Or you could stop over-thinking it, and use a conventional PCV system.

84 z28

Not over thinking it just wondering why "GM" would send the new crate motor's with breather's if they would potentically hurt the motor.

sofakingdom

iTrader: (1)

They send the motors out with breathers, because they have to have SOMETHING; and they figure the installer is going to fit whatever facility will work best IN THAT PARTICULAR INSTALLATION.

I agree with Apeiron. Get a hole saw, cut a hole in each valve cover, and put grommets in there; and put a PCV system on it. It will be better for the motor in the long run.

84z28350

Not sure what GM is shipping them with, but the turn key motors (ZZ4 & fast burn 385 ect) are shown with a PCV system.

Only the "race" engines are shown with dual breathers and no PCV

84 z28

Not to start an agrument but thats BS.

http://www.gmperformanceparts.com/Pa...l.jsp?engine=0

Apeiron

All those pictures show PCV valves.

84 z28

No they don't. If you click on the turn key 350HO,ZZ4 350, and the fast burn 385 they all have breather cap.

Actually to correct myself Apeiron you are right they have PCV valve's but they also have a breather cap which is my piont.

Apeiron

That breather is still part of a functional PCV system.

Stekman

And that's a proper PCV system. An air inlet source, and crankcase outlet source.

sofakingdom

iTrader: (1)

What a stupid argument to get into.

The reason they have a breather is because EVERY AIR CLEANER that they might get used with, IS DIFFERENT. They had to put SOMETHING there on the motor, so they put the most generic thing they could. That DOES NOT mean that it's the best way, the "right" way, the "recommended" way, "GM's" way, or any other compelling reason that it should be imitated. It's the "default" (which means, "in the absence of something better") way.

None of which has anything to do with helping this guy out with venting his engine in general, or specifically why punching a hole in the oil pan won't work.

The best all-around solution remains, a PCV valve, and a breather tube that goes to the air intake tract so that crankcase vapors and oil mist don't get all over everywhere.

S!MON

Ok then...

What do I need for a functional PCV system?

Breather
Breather with PCV Valve
1 Hose to the carb (it's a Holley 750 DP with mech. secondaries)
or
to the Intake (it's a Weiand Team G Single Plane)?
Where to connect?


Anything else?

Greetings and thanks for all the answers,

Simon

Sonix

iTrader: (1)

Yea, so get a 1 1/4" hole saw, and punch a hole in each valve cover. Throw on a 1 1/4" grommet on each. The ID of that grommet is usually 1/2" or something smaller. Look for PCV grommets, my #'s are probably off.

- Use a breather, lets say a cheapie mr gasket one, or a nice shiny K&N one. That's the air INTAKE to the block. Push that into one of the grommets. I think passenger side is common.

-On the other valve cover, into that grommet, use a normal, stock replacement PCV valve. What the parts store will find for an '84 Camaro or something. That'll just push into the grommet. On the end of that PCV valve, a piece of 3/8" rubber hose, buy about 2', cut to length. That'll go to the BIG nipple on the base of the carb (if it has one). Or you can probably find a port in the intake manifold if the carb doesn't have one.

This is the second question in a few days about PCV systems, who's got one of those nifty cutaway diagrams showing the flow of air on a PCV system? That's a really good way to help people understand how the flow works.

S!MON

Ok,

if it is that simple, everythin is fine for me.

I prefer nice and smooth but not shiny

like this:

Breather:


Breather with PCV:


Greetings and many thanks again.

Simon

Sonix

iTrader: (1)

That first breather woudl work, but breather with PCV doesn't really make any sense - it shouldn't be doing both functions.

S!MON

I didn't thought to replace the standalone breather with breather-pcv combo. I thought about breather on one side combo on the other.

But if that wouldn't make any sense then I will just take a stock type PCV valve.

Simon

Sonix

iTrader: (1)

I'm not sure how a combo piece would do anything... You really only want it to be sucking air from the motor, and letting it go through the PCV valve to the carb/intake.
If it's a "combo" i'd assume it's also got a breather filter, and it's letting in fresh air and letting it go towards the carb. That wouldn't really accomplish any PCV functionality, but it would drop the amount of vacuum it's showing the crankcase - and decrease the usefulness of the PCV setup.

But I've got to be reading that wrong, it probably works some other way, somehow and i'm just mis-interpreting it.

Stekman

If you flipped a PCV breather over and looked at the bottom, you'd see 2 things. 1.) You'd see a few holes on the "outer ring" - these being where the air enters, the breather portion of the piece. 2.) Inside that "outer ring" would be the PCV valve. The 2 are completely closed off of eachother.

If it were my engine, though, I would much rather have the breather on one side, and a PCV on the other, so it draws through the crankcase, rather than circulating under the valve cover.

5678TA

ok i know jack about PCV systems.. on my motor, i have a breather on the pass side valve cover and a 90* fitting and hose going to the back of my carb.. i blow oil out the pass side breather but nothing seems to happen on the drivers side(no vacuum no pressure)..

what the hell is going on?? and what am i doing wrong?? should i switch them?? some one told me i might have a compression leak..

Sonix

iTrader: (1)

Is that 90* fitting a PCV, or just a fitting? ie, does it rattle when you shake it?
Maybe replace it with a PCV, or if it's plugged, a new PCV valve.
Otherwise, you've got it right on. If you've got a big motor with large ring gaps you might have more blowby then what your PCV can handle. At higher RPM when you'd have more blowby, you have less vacuum to pull out the vapors. I guess that's why some people run crankcase pumps?

Also, oil? Do you have a baffle under the breather valve?
Come to think of it, at higher RPM you should just get a nice puff of black/blue smoke if your PCV can't keep up - oil, as a liquid, should be kept inside because of the baffles. I'd put my half-a**ed semi-edumicated guess on that there.

5678TA

ok the fitting does rattle so i guess it is a valve.. and i dont have baffles under the breather.. i guess i can try find where i keep them.. but will it really help that much?? at any rpm, if you put your hand close to the breather you can feel air pushing out..

1320_Guy

iTrader: (3)

I have been toying with the idea of using the stock smog pump for crankcase ventalation. I was planing on sucking the air from the valvecovers, and then going into an overflow container after the pump. If you did this i dont know where you would pull air from but it is an idea.
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Sounds like a compression leak. You are having to much blowby and the pcv cant releave that much pressure. You could try cutting the botom off of the pcv valve and ritching up the carb so it dosent lean out. This is not the best thing to do but if you dont want to rering it now it will help it run better.

S!MON

Mhh, what is the limit of the PCV valve...what in this case is a big motor?
I'm running an 350 with around 400 horses and 10.5 compression.
Can a PCV handle that?

1320_Guy

iTrader: (3)

Yes, You will only have problems if you are having ALOT of blowby.

sofakingdom

iTrader: (1)

That is NOT a "big" motor.

One of the other cars in my garage, has a 454 in it. Uses the same "size" PCV valve as my 305. The same PCV valve works fine in a larger small block, the 400. I'm sure it will work fine in a small-displacement small block like a 350. After all, there are MILLIONS AND MILLIONS of 350s on the road over here, and plenty of vehicles with MUCH larger motors than that, with perfectly functional PCV valves.

S!MON

That is what I wanted to hear

Ok, everything but that small engine thing, lol.

Believe me, here in Germany with all the compact cars like the Smart or whatever, everything with more than 3 liters displacement is a big engine, muahaha.
Greetings,

Simon

5678TA

we'll see what happens.. i'll keep that in mind.. thanks

Sonix

iTrader: (1)

I would absolutely go smart car tipping... hippies... *cough*

I'm a little concerned about this though;
Sofakingdom, any thoughts on this?

I would check;
-the fitting at the base of the carb that's going to the PCV. Make sure it's got suction at idle, from the carb.
-the bottom of the pcv valve, make sure it's got suction when connected to the carb
- then finally pop off your breather, and put your finger over the hole. You should really feel suction, at least at idle.

You using forged pistons? Remember what your ring gaps are?
I think you'd need CRAZY amounts of blowby to overwork your PCV system. Does it burn a lot of oil?

5678TA

forged pistons=yes
remember ring gaps=no, but they were not enough to feel safe running alot of nitrous..
burn oil=no, the only smoke i got was from running rich, 8 jets too high in front of my 750 mighty

i'll tell the father to check those things you mentioned.. (i would do it myself but its a 2 hour trip to the airport, a 6 hour plane ride and a 20 minute drive home to the car) college=no car

Sonix

iTrader: (1)

Car is in hawaii? And you're not? Better get your head examined while you're at it...

If you don't blow through a lot of oil, then you probably have decent rings, and aren't getting a lot of blowby, hence the PCV should be ok.

5678TA

ya i wanted to bring the car up with me but costs $1000 to ship her and then when i go back home for summer, what will i drive?? the parents said i wouldnt be able to study if the car was up here.. but i think i'm going more crazy every day without the car..