'78 EFI burning oil - oil breather issue

[D52E]

[SGKent]

let us know when you figure it out. Once someone can make that adapter and buy a box of spare valves the world will beat a path to their door a few a year. I threw away three of those later valves about 6 or 7 years ago because no one wanted them even for free if they had to pay $6 postage. Now that the bus model is almost unobtanium it will be interesting to see what people do.
_________________
Canned Water - the new California approved parts cleaner (except in a drought in which case rub it with sand).

George Carlin:
"Most people don't know what they're doing, and a lot of them are really good at it."

Skills@EuroCarsPlus:
"never time to do it right but always time to do it twice"

[bummerbus]

Baumer99 that is rad and basically the one I am waiting for in the mail, Great job!

Cheers,
Pat
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‘75 FI-1800cc.

[baumer99]

[bummerbus]

So unfortunately no matter which way I suck on it, fully closed, fully open, big hole, or small hole, it won’t close. I am going to dig through my crap and see if I have a mityvac still And try to test it more formally
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‘75 FI-1800cc.

[SGKent]

you would have already sucked in a gasket. Most likely somewhere into the case you have an air leak. The air flowing thru the case was flowing into the engine. The mixture is now richer than it was before because that air is opening the flap further.
_________________
Canned Water - the new California approved parts cleaner (except in a drought in which case rub it with sand).

George Carlin:
"Most people don't know what they're doing, and a lot of them are really good at it."

Skills@EuroCarsPlus:
"never time to do it right but always time to do it twice"

[smitty1976bus]

Loving the 3d printed stuff bummerbus

I mounted the VW golf PCV, and from the part description I find online, it should operate the same way as the VW PCV: "This valve is responsible for venting crankcase vapor into the intake manifold so the engine can burn it"

Placed the unit in line from the original PCV and the S-Boot:

Unfortunately, I didn't have time to drive around tonight to test the oil levels, but the bus did idle much much better. I actually had to screw out the idle speed screw. The real test will be is if the PCV actually vents the crank pressure into the plenum... Any signs to look out for if it isn't venting properly? Is this when I suck in a valve cover gasket?

We'll have to see what happens. bummerbus, you mentioned something about needing measurements, i have an extra oil breather and PCV laying around if you need me to break it open for measurements or anything

SS

[SGKent]

you can't close it just by sucking thru it. To close it the vacuum thru it has to be slightly less than atmospheric pressure. Cover it with a piece of paper with a tiny hole in it and suck on it. As soon as you get a little vacuum on the paper side it will close. As soon as that vacuum is released a little it will open again. You can also see how much vacuum it takes to close it with a vacuum pump like a mighty vac on the small hole. Apply vacuum. Measure when it closes and compare that to a known good original.

Personally I think you have it but don't know it.
_________________
Canned Water - the new California approved parts cleaner (except in a drought in which case rub it with sand).

George Carlin:
"Most people don't know what they're doing, and a lot of them are really good at it."

Skills@EuroCarsPlus:
"never time to do it right but always time to do it twice"

[bummerbus]

[SGKent]

[SGKent]

Ray said:

[Wildthings]

[bummerbus]

Here are a couple pictures of the 3D printed body, this one was specifically made for a plate instead of the diaphragm so it does not have the seat around the opening for a diaphragm, but I do have a model for that ready to go.

I also mocked up an "adapter" plate style block off for the baffle/breather box, in hopes to drill out an opening and try a couple more traditional PCV valves that mount with grommets. Just got a shipping notification for that and it should be here Saturday. will post some pics and maybe start looking for suitable options soon.

SGkent- unfortunately being a broke grad student, and school got in the way of me investigating those options, in person. I did email a seller from ebay at some point about getting a measurements, as I think they are a bit larger, but I got no response.

Cheers,
Pat
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‘75 FI-1800cc.

[raygreenwood]

[raygreenwood]

[SGKent]

it will work. Basically it allows the plenum to draw a vacuum. When that vacuum hits ambient air pressure the valve closes so there isn't a vacuum inside the engine. If there are any air leaks into the case, that air otherwise would be drawn with oil into the plenum and engine where it would be burned. That vacuum can also suck valve cover gaskets in. What you may notice however is that your mixture changes because with that air not being pulled thru the engine into the plenum, that air will now go thru the AFM, which will open the flap more and enrichen the mixture.
_________________
Canned Water - the new California approved parts cleaner (except in a drought in which case rub it with sand).

George Carlin:
"Most people don't know what they're doing, and a lot of them are really good at it."

Skills@EuroCarsPlus:
"never time to do it right but always time to do it twice"

[smitty1976bus]

[SGKent]

[bummerbus]

So I mocked up a model of a breather and had it 3d printed (I will try to post some pictures up later today) but I wasn’t able to find a replacement for the diaphragm. I tried using a solid plate as had been suggested but it doesn’t seal or it gets wedged in stopping travel. Haven’t had much time to polish it off and play with it since I just finished getting my masters.

That being said I have cut open the Audi/rabbit breather in the past (of course I can’t find it now) and the diameter is the same/will fit, but it is designed differently and seems to be made of a more rigid material. The major difference in design is the interior sealing surface is a solid ring (no cross vents), there is a metal cup that creates the sealing surface and the spring is a larger diameter.
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‘75 FI-1800cc.

[SGKent]

the plastic valve is ultrasonically welded. The top can be carefully taken off, and someone here on the forum 3d printed a new diaphragm. There aren't enough bus owners to justify making new valves. It is like the EGR thing. We've been working on it now for 10 years. I still don't have anyone who can make a true replacement diaphragm for less than about $2K for the first one. Ray said he could but he destroyed a really good part trying, and in the end we had neither a new one or the rare old one. A commercial shop has been promising me for a year they can do it but they keep flaming out. I suspect the PCV diaphragm would be the same so that guy here who 3d printed one is the best bet.
_________________
Canned Water - the new California approved parts cleaner (except in a drought in which case rub it with sand).

George Carlin:
"Most people don't know what they're doing, and a lot of them are really good at it."

Skills@EuroCarsPlus:
"never time to do it right but always time to do it twice"