TheSamba.com :: View topic - Type 4 Oil Breather Pressure Regulating Valve 022 115 303 A

Tue May 11, 2010 3:17 pm

Wildthings wrote: I am not sure why VW dropped the standard PCV valve they started with. They have tried a halve dozen breather designs over the years and nothing really seems to really shine. I can understand that with D-jet there may have been a problem with the standard valve's pulsing, but virtually everyone else managed to use them with carbs.

I like having some fresh air entering the crankcase to drop the humidity and help flush out contaminants. My 411 with L-jet runs the standard 411/412 PCV valve and vented rocker without problems that I am aware of, and my Bay has its case slightly pressurized by the cooling fan and then vents into the air cleaner, this also seems to work well.

I'm not quite sure if L-jet will have the same problem as D-jet would....with refrence to the valve failing. But the failure mode of the factory PCV valve on 411/412 and 914 with D-jet...was worse onb those that drove lots of high rpm highway miles. What it consists of is a constant high speed rattle due to a combination of crankcase pressure and manifold vacuum (it is both and not just either that cause this PCV valve to open).
This high speed rattle wears away and cracks the thin plastic disc under the spring. It usually wears away the edge first.....making tghe sealing disc small er in diameter....causing bypass and centering issues.
This causes uncontrolled leakage.
The problem with this valve in D-jet...is that its dump location in the plenum disturbs the MPS. The better and tighter your D-jet is tuned...the more you will notice the problem.
It is not a good design of PCV. For D-jet...a fixed orifice works far better and can be permanently tuned around.

For L-jet....hmmmm....a fixed orifice would only be able to be used if it was plumbed into the plenum at a more remote location so as not to disturb the vacuum signature for fuel pressure.

The D-jet style of factory PCV alone will not work on L-jet because it would not open. Since it would have to be plumbed into teh S-boot and not the vacuum side of the manifold...there would not be enough pressure to open it....as it uses a combination of vacuum pressure and crank-case pressure. Neither alone is quite enough to open it. Ray

Wed Oct 06, 2010 6:28 am

I just picked up a clean valve from a junker, it clearly does NOT have the hole refered to as a "drain" or meter (it does have the hole in the cover). It looks good inside and seems to function.

I took the one off my bus and it is really gunked up with oily sludge and it does have that hole. The box that it sits on is also very gunked up. I'm inclined to put on the salvaged one but the lack of the hole is interesting.

Any more developments on this front?

Wed Oct 06, 2010 9:53 am

I was unable to find the hole in one of mine, so I just drilled one.

Wed Oct 06, 2010 11:17 am

But what makes us so sure that those holes are factory? The one I have clearly has no hole, one earlier poster concurred. Could the ones with holes have been drilled by prior mechanics?

Wed Oct 06, 2010 11:44 am

Could be those pesky breather valve weevils.... :lol: Ray

Wed Oct 06, 2010 11:45 am

This was all voodoo engineering to placate the emissions police. I think we may want to insure a proper ventilation from the crankcase to the atmosphere to eliminate the possibility of any irregular pressure or vacuum in the crankcase regardless of the source. Adjust your airflow to provide for proper idling and fuel mixture.

Wed Oct 06, 2010 1:05 pm

Ed Ruth wrote: This was all voodoo engineering to placate the emissions police. I think we may want to insure a proper ventilation from the crankcase to the atmosphere to eliminate the possibility of any irregular pressure or vacuum in the crankcase regardless of the source. Adjust your airflow to provide for proper idling and fuel mixture.

There are few things ever done to a gasoline engine that have prolonged its life as well as a good crankcase ventilation system. Engine life increase markedly when PCV systems were added in the mid sixties. The roads are far safer today without an oil slick down the middle of each lane as well.

Wed Oct 06, 2010 1:17 pm

My 1962 Chevy had a ventilation system that was a simple vent from the crankcase to the air under the hood. It never left oil on the road and had 125,000 miles on it when the transmission failed catastrophically just after passing Capital Hill. I don't believe very much crankcase ventilation occurs by way of the system placed on the VW Bus design in question. My testing of ventilation (I drilled a 3/8 inch hole in a oil cap and stuck a gas hose in it. The crankcase puffed air back and forth as crankcase pressure fluctuated) has convinced me that not much happens here by way of the installed PVC system. I will buy the argument that a more aggressive system may be of some use in helping to vent condensation but the system as designed and, certainly, as presently exists encourages my skepticism.

Wed Oct 06, 2010 1:40 pm

The stock ventilation system on FI buses is designed to maintain some pressure in the crankcase. It will always be above ambient pressure, so when you drill your hole you should get air blowing out of it.

I will agree that the VW system is quite poor as ventilation systems go as there is no fresh air induction. Finding condensation in the rocker boxes and under the oil filler cap is not that unusual. That is one of the reasons I have chosen to modify the system on my bus to force some fresh air into the crankcase from the fan, while on my 411 I run the early stock system that uses a PCV valve and has vented rockers. I have been running synthetic oil and only changing it once every year or two for the last 15 or so years. I would never be able to get away with doing that if I had a crankcase moisture problem.

Wed Oct 06, 2010 2:08 pm

Why was the engine designed to maintain positive pressure? Also, I don't really know how to vent the crankcase except by opening one hole in the case to the air on one side and running a hose to the plenum from another.

Wed Oct 06, 2010 3:32 pm

Wildthings wrote: Ed Ruth wrote: This was all voodoo engineering to placate the emissions police. I think we may want to insure a proper ventilation from the crankcase to the atmosphere to eliminate the possibility of any irregular pressure or vacuum in the crankcase regardless of the source. Adjust your airflow to provide for proper idling and fuel mixture.

There are few things ever done to a gasoline engine that have prolonged its life as well as a good crankcase ventilation system. Engine life increase markedly when PCV systems were added in the mid sixties. The roads are far safer today without an oil slick down the middle of each lane as well.

X2
I can tell you for 100% sure that the flow through ventilation system on teh ijected D-jet enegines keep the inside of the engine case and rocker box...spotless. Looks just like it was bead blasted at 100k miles. And it prevents leaks. Ray

Wed Oct 06, 2010 3:44 pm

Ed Ruth wrote: Why was the engine designed to maintain positive pressure? Also, I don't really know how to vent the crankcase except by opening one hole in the case to the air on one side and running a hose to the plenum from another.

You need to take a close look at what was done by the factory. The type 4 engine in the bus...uses a variation of the system that was used in the 411 and 412.....where the type 4 engine came from in the first place.

The type 4 engine was not designed for the bus. It was designed for the type 4 car....and later a variation of it was used in the bus and 914.

In the original D-jet injected version of the type 4 enegine in the 411 and 412.....the PCV system is one of the most effective that I have seen.

It pulls CLEAN air from the air cleaner...through a flame trap......where it splits to two 12mm hoses...one to each rocker box. This pulls fresh cool air into the rocker boxes...sweeping combustion gasses that come past the valve guides....and excess oil....through thepushrod tubes....into the crankcase....where it is sucked.....along with any piston blowby....out of the cast-in Z baffel of the case....and through the oil separater baffel ....through the PCV valve....and back into the manifold.
It runs very clean...and noticably cooler when its hooked up and operating properly. It was a closed loop system under manifold vacuum.

The problem with this system in a bus...is that you cannot draw the suction needed to run it from the manifold without upsetting the fuel pressure regulator and bypassing air past the MAF.
So to get around that...they settled for a system that draws the gasses out of the top of the crankcase......and is governed by a differential pressure valve.....which is the part we are speaking of.

This is less efective than the one with D-jet....but adequate. If you could supply the suction by another means...such as an exhaust venturi, you could run the fresh air loop just like D-jet and seimply vent it to air.

PCV is NOT simply designed to vent pressure tha may blow seals. That is 1960's tech.
Modern PCV is designed to alleviate pressure AND take out excess moisture delivered by blowby and keep hot combustion gasses from contaminating oil. Ray

Wed Oct 06, 2010 3:48 pm

Ed Ruth wrote: Why was the engine designed to maintain positive pressure? Also, I don't really know how to vent the crankcase except by opening one hole in the case to the air on one side and running a hose to the plenum from another.

Can't say exactly why VW did this, maybe it keeps the valve cover gaskets from being sucked in, who knows.

Ray Greenwood has idea on how to build an improved ventilation system for engines running D-jet, the same principles will probably work on L-jet.

Thu Oct 07, 2010 3:54 am

No one still has said why they think the "drain hole" is original. Logic tells me if there are parts without the hole those would be the originals and that the holes were added by mechanics, maybe a shop bulletin? Or 411 experience?

Thu Oct 07, 2010 3:59 am

From looking at how this differential pressure valve works.....I would think it should have some small amount of pressuer in teh crankcase for the valve to meter itself properly ....because of the painfully small vacuum that L-jet produces at the intake boot.

Yes....I would think that a fixed orifice could be made to work in some fashion. Feed straight to the center plenum like D-jet and then adjust away the excessive lean factor because it will be constnat now not variable. Ray

Thu Oct 07, 2010 6:48 am

I bought two new breathers from Europe and collected about 10 good and bad ones. I also collected three or four similar models for other VW A/C engines. The round breather valve on top of the metal box holds the engine near ambient room pressure. As soon as there is positive pressure the valve opens and the engine pulls the vacuum down to room. As soon as it hits room pressure then the valve closes. When they are working right they cycle hundreds of times a minute. You can feel the small pulses coming out the pin hole on the top which allows the main diaphragm to sense room pressure.

The valve prevents the engine case from becoming a huge vacuum can. It also prevents excessive gasses being sucked through the rings and guides.

When they fail then the engine will see negative pressures which causes rings and guides to wear faster. It also causes excessive oil being sucked into the intake.

The porsche 914 system used bleed jets and cross ventilation to control the pressure instead of a valve.

When they fail you will have trouble tuning your engine properly. The only source I know now for them is used since some people here drove Bobby away. He is the one who found and delivered the two new ones even though it took him several months and three or four hours of calls to VW dealers in Europe to find these two.

You can take them apart although they were not designed for it. You can have a new silicone rubber valve cast for about $1500 for the mold and 100 pieces. If you can find 100 people who need them then the math would work. I tried to find 100 people before Bobby helped me and finally I gave up as only about 5 people ever responded about having working valves.

Thu Oct 07, 2010 12:52 pm

There must be someone out there who has been running a Type IV for years without a cap on their oil filler. In gleeful indifference, their engine releases oil vapor and water vapor from condensation to the atmosphere. Perhaps this has added years to their engine's life unwittingly. I detect no difference at all in my FI system's performance with or without the cap. Admittedly, it may be running leaner but then it may have been too rich to begin with. Bottom line is that the system, however ill conceived or ill performing, was designed to comply with pollution requirements without redesigning the engine or costing too much to accomplish. Its kind of like those diapers you see on horses in the city. You can't redesign the horse and the streets aren't made of mud, like the good old days, so they came up with something however odd it may look.

Thu Oct 07, 2010 2:55 pm

SGKent wrote: I bought two new breathers from Europe and collected about 10 good and bad ones. I also collected three or four similar models for other VW A/C engines. The round breather valve on top of the metal box holds the engine near ambient room pressure. As soon as there is positive pressure the valve opens and the engine pulls the vacuum down to room. As soon as it hits room pressure then the valve closes. When they are working right they cycle hundreds of times a minute. You can feel the small pulses coming out the pin hole on the top which allows the main diaphragm to sense room pressure.

The valve prevents the engine case from becoming a huge vacuum can. It also prevents excessive gasses being sucked through the rings and guides.

When they fail then the engine will see negative pressures which causes rings and guides to wear faster. It also causes excessive oil being sucked into the intake.

The porsche 914 system used bleed jets and cross ventilation to control the pressure instead of a valve.

When they fail you will have trouble tuning your engine properly. The only source I know now for them is used since some people here drove Bobby away. He is the one who found and delivered the two new ones even though it took him several months and three or four hours of calls to VW dealers in Europe to find these two.

You can take them apart although they were not designed for it. You can have a new silicone rubber valve cast for about $1500 for the mold and 100 pieces. If you can find 100 people who need them then the math would work. I tried to find 100 people before Bobby helped me and finally I gave up as only about 5 people ever responded about having working valves.

You mean on the Porsche 914 1.8L right? Because excessive ring and gudie wear has never been an issue with the 1.7L system.

The D-jet system keeps the case under vacuum...and it has
no extra wear on the rings and guides....and they do not burn a drop of oil. This is is (a) because the volume going through the case in CFM is relatively high. It keeps the oil and case internals very clean and the heads slightly cooler (b) the type 4 engine in general has a cast in Z-baffel which is the first line of oil vapor stripping.
Just like the 180* turn of the oil and air in an oil bath air cleaner, air rounding the curves of the Z baffel drops most of the heavier oil droplets.

The next line of oil baffel is the oil baffel box under the oil funnel itself which is very effective. The vaccum is applied at this oil baffel directly to the plenum with a PCV valve.
I have never had an issue with this system putting oil into the intake. I used to think it did at one time...but after swithcing to the round 412 D-jet paper filter...I suddenly realized the oil in the MPS...was from the oil bath air cleaner. It goes away when you get rid of that filter.

The vacuum on the D-jet type 4 case is not high ....maybe 5-10". I think I have seen 10" tops.

I do not see where this would be any issue with the guides or rings because the intake air to feed the vacuum is pulled through the pushrod tubes 100%.

Now...if the case were under vacuum with no air inlet at all...I could see this happening. Ray

Thu Oct 07, 2010 3:03 pm

Ed Ruth wrote: There must be someone out there who has been running a Type IV for years without a cap on their oil filler. In gleeful indifference, their engine releases oil vapor and water vapor from condensation to the atmosphere. Perhaps this has added years to their engine's life unwittingly. I detect no difference at all in my FI system's performance with or without the cap. Admittedly, it may be running leaner but then it may have been too rich to begin with. Bottom line is that the system, however ill conceived or ill performing, was designed to comply with pollution requirements without redesigning the engine or costing too much to accomplish. Its kind of like those diapers you see on horses in the city. You can't redesign the horse and the streets aren't made of mud, like the good old days, so they came up with something however odd it may look.

Actually no. The type 4 engine came with PCV (flow through) from day 1 in the type 4 cars.....1968 and on. The PCV valve system was simply redesigned for a new injection system. Comepletely redesigned.
It actually works well for L-jet because it allowed the syetm to comply with increasingly more stringent idle emmisions.
The L-jet PCV system works adequately....not spectacularly...but adequately.

Its just different. It works for venting pressure...without letting any of teh vapors escape to the atmosphere.

Virtually every 412 or bus I have found that ran without an oil cap was a hot running, greasy monster with hardly a part left usable in it when torn down for a rebuild. So yes...there were zillions of VW owners that happily ran around without an oil cap. that does not mean that it helped the engine at all. Condensation happens AFTER the engine cools down.
Running without the cap just guarantees that as the engine cools and the air in the case contracts...it will pull in more air with moisture in it.

With the cap in place, the hoses on and the PCV valve intact.....moisture cannot renter the case at will after shut down. Ray

Thu Oct 07, 2010 3:48 pm

Ed Ruth wrote: There must be someone out there who has been running a Type IV for years without a cap on their oil filler. In gleeful indifference, their engine releases oil vapor and water vapor from condensation to the atmosphere. Perhaps this has added years to their engine's life unwittingly. I detect no difference at all in my FI system's performance with or without the cap. Admittedly, it may be running leaner but then it may have been too rich to begin with. Bottom line is that the system, however ill conceived or ill performing, was designed to comply with pollution requirements without redesigning the engine or costing too much to accomplish. Its kind of like those diapers you see on horses in the city. You can't redesign the horse and the streets aren't made of mud, like the good old days, so they came up with something however odd it may look.

I worked at one place where the old school mechanic who had been there before me had removed all the PCV system in favor of draft tubes on their standby engines and most of their road vehicles. On the standby engines in particular which were seldom ever run long enough to get fully warm they ended up changing the oil every couple of weeks because of the water build up in the oil. Just normal old school mechanicing. When I started there, I reinstalled the PCV systems on each and every engine and instituted a few other changes like never starting one of the standby engines unless it was run long enough to bring it fully to operating temperature and started changing the oil once a year. Many if not most of the things added to early low emission engines actually improved the operation of the engine. I have added intake air preheats to all my older engines while most other owners of older vehicle choose to live with engines that spit, sputter, and stall until they get to operating temperature. I also like the better gas mileage running intake air preheats, on top of the faster warm up.