Breather Concepts, ...taking one from Jake Options

[yeahmag]

I'm considering blocking off my head vents and running a -10 or -12 breather solely from the oil filler/breather to a Morosso breather tank (or the like). The idea here is to keep the crankcase at a lower pressure than the heads so the oil tends to move from high pressure to low (aka from the heads to the case).

Anyone else doing this yet? If so any comments or pictures?

Thanks!

[VaccaRabite]

I am doing this. Not sure I can tell a difference but it is less places to leak.

[HAM Inc]

BTDT. A single -12 line from the chimney is all we ran on our F-Prod car. The oil will return more quickly from the heads to the crankcase with no head vents.

This was a hot topic here on World a year or so ago. I was amazed at how many people got down-right hostile at the suggestion that head vents were not only unnecessary but counterproductive.

The drain back slots on a type 4 are restrictive. If the heads are vented the crankcase pressure interferes with the oil draining back from the heads. Close off the head vents and the pressure differential between the rocker chambers and the crankcase goes away allowing the oil to flow through the narrow slots without interference from crankcase pressure.

[Krieger]

My 75 2.0 did not have head vents. Maybe the factory decided this was not necesary.

[yeahmag]

Len,

Do you have a picture of that? I was thinking of just drilling out the stock location (PCV valve) to a -12/-10. I'm only running 6200RPM *max*. But I'd like to see what others have running. No need to re-invent the wheel...

[ChrisFoley]

...
The drain back slots on a type 4 are restrictive. If the heads are vented the crankcase pressure interferes with the oil draining back from the heads. Close off the head vents and the pressure differential between the rocker chambers and the crankcase goes away allowing the oil to flow through the narrow slots without interference from crankcase pressure.

The drainback slots on a type 4 crankcase aren't narrow, nor are they restrictive.
Their cross-section is at least as large as the cross-section inside a pushrod tube,
and they're shaped in a manner that ensures adequate flow without any likelihood of becoming hydro-locked.

Crankcase pressures are unlikely to ever be above 1.01 atm., vented or unvented.
It doesn't take much of an opening to bleed off that pressure. The diameter of the opening affects velocity of flow far more than volume.
Those very low pressures have little to do with preventing oil from draining back from the heads.

A venting system ensures equal pressure in the 3 chambers of the engine when they're all connected to a central cannister that's open to the atmosphere.
No differential will exist.
On the other hand, when only the crankcase is vented, there will certainly be a pressure differential due to the constant supply of oil into the rocker boxes.

Anecdotal evidence to the contrary (factory design changes, etc.) notwithstanding, there's no proof that unvented heads are beneficial to oil control in comparison to a well designed breather system on a carbureted T4 engine.

BTW, the cross-section of three -8 hoses is greater than the cross-section of one -12 hose.

[7275914911]

Hey Aaron,

Breather/Drain Back Discusions

Here is a link to a topic a while back...there is a link in this thread that leads to the 'heated' discussion Len mentions. That thread lead me to vent to the filler neck only. Len answered on pg 6 that venting back to my stack should be fine. If you don't mind a little bullshit (well maybe more than that?) there is a lot of good info in that thread.

Keep pushing on the envelope (IMG:style_emoticons/default/beer.gif)

[HAM Inc]

Len,

Do you have a picture of that? I was thinking of just drilling out the stock location (PCV valve) to a -12/-10. I'm only running 6200RPM *max*. But I'd like to see what others have running. No need to re-invent the wheel...

Aaron, I welded a -12bung to an aluminum plate that bolted to a cross bar that mounted in the chimney. It would be tough to do that with the engine in the car.

The drainback slots on a type 4 crankcase aren't narrow, nor are they restrictive.

I don't think my 1300sq.ft. home is too small either, but some would disagree.

Anecdotal evidence to the contrary (factory design changes, etc.) notwithstanding, there's no proof that unvented heads are beneficial to oil control in comparison to a well designed breather system on a carbureted T4 engine.

Anecdotal? I'll bet that we did far more testing of oil systems and breather systems than you have. And we approached it with an open mind, something that is essential to progress. Several breathing systems were employed and observed in action on Jakes chassis dyno. We then went out and beat holy hell out of the engine on the track. Two full seasons of competition and one cup of oil in the overflow can total for the entire season!

Ask yourselves this. If you have a breather in the heads and the oil line comes loose from the breather can, why does it puke oil out of the line from the head? Think about that for a moment.

Personally I don't care if folks vent their heads or don't. I'm not selling breather cans and I have no vested interested in how people deal with this. I do advise all of my customers not to vent their heads. So far everyone has been positive about having less oil lines and leak potential.

I've been through this topic before (and was genuinely flummoxed by some of the defenses of vented heads) and I have now said all I have to say about it.

[dstar]

---------------------------
Personally I don't care if folks vent their heads or don't. I'm not selling breather cans and I have no vested interested in how people deal with this.
----------------------

But Chris DOES! SURELY he isn't up to allowing folks to find out that
they don't need an VERY expensive catch can from him......

T4 heads don't need venting, PROVEN FACT.

Don

[dstar]

WOW! Just checked your site...can with T and 2 fittings is $209.95?
No wonder you are adamant about convincing everyone that venting IS necessary!
(IMG:style_emoticons/default/sad.gif)

The economy is bad enough, our politicians rape us enough....find some other 'Snake Oil" to sell us please!

Don

[DBCooper]

The economy is bad enough, our politicians rape us enough....find some other 'Snake Oil" to sell us please!

Don

This type of shit stirring is unhelpful, unproductive, and NOT welcome. Grow up. Or if you can't do that then at least PRETEND to act like an adult.

[FlatIV]

What is the worst thing that could happen from not venting the heads?

[VaccaRabite]

FlatIV, it depends on who you listen to.

I have head vents, and they are currently capped. I've seen no adverse effects and take the car to redline every time I drive it (which has not been often this summer (IMG:style_emoticons/default/sad.gif) ). I have not seen much of a difference from when I had my vents running to a breather box.

I do have the case vented, and don't plan on changing that any time soon.

Zach

[dstar]

The economy is bad enough, our politicians rape us enough....find some other 'Snake Oil" to sell us please!

Don

This type of shit stirring unhelpful, unproductive, and NOT welcome. Grow up. Or if you can't do that then at least PRETEND to act like an adult.

Touch a nerve? I don't need to grow up, I need to NOT get screwed unnecessarily!

Let it go.....you don't have a dog here.

Don

[HAM Inc]

This weekend I wrote an article that covers the testing that Jake and I did on this subject and posted it to my website. Our methods, why we did the tests in the first place, our observations and our explanations of what we observed are all in there.

Folks can (and likely will) debate this subject as long as these engines exist, but this should at least put to rest the notion that we made up our position on the subject just to be provacative.

http://www.hamincgroup.com/type4-test.php

[dstar]

This weekend I wrote an article that covers the testing that Jake and I did on this subject and posted it to my website. Our methods, why we did the tests in the first place, our observations and our explanations of what we observed are all in there.

Folks can (and likely will) debate this subject as long as these engines exist, but this should at least put to rest the notion that we made up our position on the subject just to be provacative.

http://www.hamincgroup.com/type4-test.php

Thanks Len, great writeup! Next time you see Rick and your Dad, tell them
I said Hello and I'll be sure to stop by and see them ASA I hit the States again!

Don

[r_towle]

On this specific subject I find it very interesting that the factory changed its mind more than once...on all the air cooled motors.

Rich

[turnaround89]

The only thing i can add is that if your motor is vented, make sure you either use the vents with a breather, or block them off whichever you fancy. If you don't do anything you will be spraying oil everywhere and that oil will collect in the engine bay. Take a corner quick enough and that oil ends up on the street. (IMG:style_emoticons/default/dry.gif)

[7275914911]

Let it go.....you don't have a dog here.

You don't either, Don.....Just saying?
Hope ya make it back home safe??

It's all to plain that's it's a personal thing between you and Chris..You can keep that shit private or take it to the Sandbox. Your hijacking of threads here get's old and I'm sure other's agree.....Maybe I shouldn't be baiting you be repling to this but your are one Classic Piece of SHIT....

Sorry to stay OT, Aaron....

It's Ken, Don....It seems you misread two things above? You making it back safe was very sarcastic on my part....Humm, still is!!

[Rand]

Touch a nerve? I don't need to grow up, I need to NOT get screwed unnecessarily!

I have noticed you seem to only come here when you want to stir up shit when there are specific dogs in the fight. It just makes you look like an ass.
Instead, why don't you hang around and contribute more often? Maybe even something constructive?