THE PORTAL HUB - Pinzgauers, Haflingers, Volvo 303s and more!

Does anybody know why these vehicles were made with an unvented crankcase? Has anybody tried to install one?

crank case is vented to the air box (from oil filler base).

I saw that hose between the airbox above the carbs and the oiler filler tube. It threw me off a bit when I could not see the inner end of the hose nipple inside the oil tube but I finally figured that out.

I expected to find another house going to the intake manifold with a PCV valve. All my other engines had a way to circulate air through the crank case. Either a draft tube and breather cap or a PCV system. I have always been under the presumption that you needed to circulate air, not just provide a vent, to get the blow-by out of there or you would have trouble with water and fuel in the oil.

My old power wagons (46 to 49) had a tube between the valve cover on the side of the block and the intake manifold with a PCV valve and another tube between the air filter and the oil fill tube. I think most trucks back then had a draft tube but they put this setup on these trucks because it kept dirt and such out of the crank. If the PCV valve would carbon up you would get the white oil-in-water that you get on Pinzgauers.

Hi Jimmy

Years later I am working on an EFI (Jake Raby's) and also wondered where does the air come IN the carterhouse ? There are 2 breather hoses, one from cylinderhead-4 and one from the top of the oil-filler post.
I thought that maybe the one from the cylinderhead-4 was supplying air..., but it seems all sealed off...
I actually need to try and taker the hose off and see if it blows carter gasses out. Not really keen, but no other option, unless you found out more ?

Kind regards,
Jules.

JNijst wrote: ↑Mon May 13, 2024 10:32 am Hi Jimmy

Years later I am working on an EFI (Jake Raby's) and also wondered where does the air come IN the carterhouse ? There are 2 breather hoses, one from cylinderhead-4 and one from the top of the oil-filler post.
I thought that maybe the one from the cylinderhead-4 was supplying air..., but it seems all sealed off...
I actually need to try and taker the hose off and see if it blows carter gasses out. Not really keen, but no other option, unless you found out more ?

Kind regards,
Jules.

From my understanding, this is the same breather tube you are describing.
It starts as you say from the valve cover of cylinder #4.
Then it comes at the base of the oil filler tube.
If you remove the oil filler tube, you will see there is a sleeve around it.
I believe this is to catch the oil mist coming from the valve cover, then that mist falls back into the engine.
The gas that remain exit at the top of the oil filler tube and goes into your air intake.

My breather tube from valve cover to oil filler tube gets clogged rather quickly with this sticky yellow paste.
Remove the tube and blow some air into it, other side in a garbage bag so not to make a mess like i did the first time.
Do the same for the small tube on top, and if you have time, remove and clean up the oil filler tube sleeve.

My tube was so clogged up that once some oil/yellow paste found its way into my air intake and then into the carb, big white smoke at the back.
I clean it twice a year since.

I saw this thread pop up and found out I started years ago! Is there a consensus that the crankcase is vented in only one spot, that there is no circulation to flush out blow by from the crankcase? Do others think that is weird?

Here is a long diatribe about crankcase ventilation. It looks like systems like the Pinz’s are common on lawn mower engines. https://en.wikipedia.org/wiki/Crankcase ... ion_system

Rather that compare the Pinz engine to a lawn mower, I'd say the crankcase ventilation system is comparable to the VW engines of the era in which it was designed.

For years my EFI 710 ran with no Crank ventilation, like a 50's era car vented to the atmosphere.

Couple of years ago after I did a top end rebuild, I decided to be nicer to the environment and
correct that and connect to the vacuum vent side of the throttle body -but- I also decided to
add a Oil catch can in the circuit. Well that turned out to be a good idea. I wasn't sure this
catcher would actually catch much but it does -- the most vile smelly liquid you could imagine.
Lots of Water mixed with Blowby products. I dump this can after every oil change.

Placed on the rear "fire wall" behind the clutch slave.

I also built a oil catch can in the breather tube and then fed it through a pcv valve, just before the throttle body valve, with a ‘smothered’ valve going behind the throttle butterfly valve, to balance the flow across the butterfly valve. Not sure if it is ok, but read on some site, that this was better than just venting it in the throttle valve…
Any ideas how we could circulate fresh air in the Carter and blow it out in the throttle body ?
Regards,
Jules

But isn't the stock oil filler tube acting as a oil catch can? Returning the oil to the oil pan.
I've removed it, it's like one tube into another. The inner tube is where you fill in the oil. The outer tube is like a sleeve around the inner one.
The breather tube coming from the 4th cylinder valve cover comes at the base of this sleeve. Then at the top of the sleeve, there is another short tube connecting to the air intake.
As I understand, gases and potentially oil droplets coming from the crankcase go up into the sleeve, gases can pass through and make it to the air intake but oil droplets are caught into the sleeve going up and fall back into the crankcase.
If you clean these tubes twice a year to avoid clogging, I don't think we need to add another catch can. We already have one. I think.

Hague’s, Ithink you are right, the oil fill tube acts as an oil separator. The problems are (a) any water that condenses out also goes back into the sump, and (b) there is not enough airflow through the crankcase to flush out the water vapor.

I think the big challenge to adding using a PCV system would be keeping the air/fuel ratio correct with what would essentially be a big vacuum leak. I don’t know how to deal with that without a fuel injection system with a feedback loop.

A oil separator with a drain does sound like it might help but it might get too much oil in it.

JimmyC wrote: ↑Sat May 18, 2024 4:40 am Hague’s, Ithink you are right, the oil fill tube acts as an oil separator. The problems are (a) any water that condenses out also goes back into the sump, and (b) there is not enough airflow through the crankcase to flush out the water vapor.

I think the big challenge to adding using a PCV system would be keeping the air/fuel ratio correct with what would essentially be a big vacuum leak. I don’t know how to deal with that without a fuel injection system with a feedback loop.

A oil separator with a drain does sound like it might help but it might get too much oil in it.

Agree.
Someone was proposing here some months ago to open up the oil filler cap after stopping a warm engine, to let the water vapour out before it condenses.
Probably makes sense, but i'm a bit lazy and i forget. Not that it's difficult on the Pinz.....it's just there next to us, no need to pop the hood.
Would need to modify the oil filler cap to add a valve and maybe a little fan to suck the air out for a few minutes when the engine switches off.

So....air/oil separators are common on aircraft (also aircooled), and often the subject of much debate. Some say they're super smart, and others say it's like putting a tube from your mouth to your, well, "backside". Read some arguments here: https://cessnaowner.org/point-counterpo ... separator/

Here's one of the more common brands: https://www.airwolf.com/aw/products/air-oil-separators

I used to run one, and now that I have an engine that's tight, I just let the crankcase breather go overboard.

Some here touched on the big issue: water. Mounting is crucial to ensure the AOS operate above 212F so the water is converted steam.

But beyond this, collected water in the crankcase is why it's critical to not run your engine for short periods of time, and you need to periodically run it long enough that it gets hot enough to boil off the water. Otherwise you're just asking for interior corrosion. My 2c.

Oh, and my Pinz? I run it as the factory built it, and ensure that my trips allow the oil to come up to full temperature.