Krank Vent Plus, anyone use one?

[JEEPRUSTY]

Could no one here hook up a vacuum gauge to the hose exiting the top of the valve train cover?

There will be a pulse but I wonder if its very much due to the inherently balanced nature of the I4.

The circuit that wends its way across the top of the valve train cover cover seems to exist to allow oil vapour to precipitate back into the sump.

It seems to be a tuned affair with two really small holes in a gasket and a maze that the gasses have to pass through to exit into the the clean side of the air-filter via a hose connecting the air-box to the outlet.

I imagine the pressures in race engines are far greater and that blow-by is also greater. It may be so great as to significantly impede the reciprocation of the pistons. They may even bunch up to the point where gaskets would fail.

On one of our bikes I would bet the difference in pressure would be small and steady.

[mighty13d]

Doesn't the venting into the air box cause a slight vacuum on the vent line too? It should since there is negative pressure in there.

[rich001]

Ray,
Can you give us some names of proprietary pumps that are used by people like you

Racers, I mean of course.
Thanks
Richard

[gearheadE30]

Doesn't the venting into the air box cause a slight vacuum on the vent line too? It should since there is negative pressure in there.

yes, and it's a fairly significant effect at WOT and high revs. The snorkel to the airbox is a bit of a bottleneck, thus resulting in the vacuum. That's also why the side covers of the airbox have those big rubber gaskets-if you ride in the rain with much throttle, you can actually get a pretty good amount of water in the airbox. When I bought my GS I rode it home in a torrential downpour. The PO had left those seals out somewhere along the way (they were in a box of parts) and when I got home I gave the bike a once-over as it was running a little funny. Pulled a cover off and got a flood of water in my lap.

[Spyder]

What about an actual PVC valve from say a small 4 cylinder car. Like maybe a Geo or small Honda? Same function?

[gearheadE30]

Automotive PCV valves are usually just like the GS-they use intake vacuum to draw a slight vacuum through the engine. Rarely is there actually a valve. It's typically a bunch of passages designed to separate oil, followed by a tube to the intake. That being said, now that I'm typing this I kind of think that there is a valve like this on early saturn twincam cars...

[Spyder]

So, what would be the ideal crankcase vacuum for a 16v GS engine?
I'm merely curious at this point. Might even get to be mildly experimental...

[Steve]

Automotive PCV valves are usually just like the GS-they use intake vacuum to draw a slight vacuum through the engine. Rarely is there actually a valve. ...

Sorry, but I will respectfully disagree here.

The PCV device is a valve. There is a ball inside that blocks the passage, but is held open with a light spring. The valve is connected to engine vacuum, not airbox vacuum. Engine vacuum is much higher, and is too much ventilation at lower engine speeds, when the vacuum would be highest. At lower engine speeds (smaller throttle opening), the high vacuum level will overcome the spring and pull the ball into the closed position. When the throttle is opened and vacuum is lower, the spring is able to open the ball open the passage to ventilate the crankcase.

Our GS engines only rely on the modest vacuum in the airbox to help draw some of the excess fumes out of the crankcase, so don't need any complex valves. It will just ventilate any time the engine is running.

.

[gearheadE30]

Sorry, but I will respectfully disagree here.

The PCV device is a valve. There is a ball inside that blocks the passage, but is held open with a light spring. The valve is connected to engine vacuum, not airbox vacuum. Engine vacuum is much higher, and is too much ventilation at lower engine speeds, when the vacuum would be highest. At lower engine speeds (smaller throttle opening), the high vacuum level will overcome the spring and pull the ball into the closed position. When the throttle is opened and vacuum is lower, the spring is able to open the ball open the passage to ventilate the crankcase.

Our GS engines only rely on the modest vacuum in the airbox to help draw some of the excess fumes out of the crankcase, so don't need any complex valves. It will just ventilate any time the engine is running.

.

Good to know; the ones I've had apart are just a set of baffles, but my experience is all in early '90's and earlier BMW engines. Simple old stuff.

[surviverguy]

food for thought- vacuum venting crankcase

I like the simplicity and general idea of the "road draft ventilation". On earlier (pre-70's) vehicles a steel vertical pipe with a cut at a 45 degrees at the bottom so that the longest end faced forward. Moving through the air (going down the road) the pipe naturally creates some vacuum. Connect breather tubing to this vertical "road draft ventilator" and voila. Of course vacuum increases with road speed ...
If more vacuum were desired- a horizontal pipe with a wider end facing forward would create lots of vacuum..attach breather vertically to this horizontal vacuum pipe. If enough vacuum were created I suppose it could pull lots of oil out the engine. Stop and refill. Oil changed without pulling drain plug if no lockup occurs...

[Steve]

I like the simplicity and general idea of the "road draft ventilation". On earlier (pre-70's) vehicles a steel vertical pipe with a cut at a 45 degrees at the bottom so that the longest end faced forward. ...

That is what I have done on my son's 650L that has pods. I just have a section of breather hose long enough to go down below the swingarm pivot.

If enough vacuum were created I suppose it could pull lots of oil out the engine.

I don't think that is ever going to happen. The only way oil is going to get sucked out of the engine is if it ever rises to the level of the breather at the top. There is no other vent to the atmosphere, so any gasses inside the crankcase must be what has come past the rings. The breather is merely providing someplace for them to go without building any pressure. And, ... I don't think there will ever be enough vacuum generated by a "road pipe" to suck oil out of the pan, even if there were a direct tube that went down that far.

.

[Spyder]

Good to know; the ones I've had apart are just a set of baffles, but my experience is all in early '90's and earlier BMW engines. Simple old stuff.

That is a crankcase vent that connects to the air filter. A PCV (positive crank ventilation) Valve is an "in line" check valve connected to engine vacuum. when you are deeper in the throttle the valve closes to allow the engine to maintain the vacuum it has accumulated during lower rpms.
That is the best way I can explain it, without reciting the technical definition.

[AJ]

Funny to run across this thread. Oldvet66 and I have been talking about installing his Hayden valve on my 1100 to try some comparison testing. I was also thinking about inserting a vacuum gauge with a T fitting to see if any vacuum is pulled, as music man and jeeprusty mentioned. Probably need to add a large vacuum reservoir to filter out the pulses, but that shouldn't be hard to rig for an easy test.

Been thinking about the PCV vs, this Hayden valve. They're both check valves of a sort, but my suspicion is that the PCV check ball may not react quickly enough to work well with a motorcycle engine, whereas the umbrella valve in the Hayden part should react much faster, if being more expensive to manufacture and more prone to failing from contamination.

Musicman, suggest you contact oldvet66 directly about placing the valve. He replaced the rubber part (replaced by hayden) and moved the valve further from the engine.

I'm still a bit skeptical about all this for the reasons Steve pointed out, but am willing to try a test. OV66 is certainly happy with his installation.

[musicman]

My valve is on the way to Hayden to get rebuilt free of charge, so not sure if it had the defective stamped valve or not, didn't hear about it soon enough. And my valve was sitting inside the now hollow air box, so had lots of separation. Can't wait to get it back though and do some testing, I swear it made a difference when it was working, as short a time period as it was.