Hayden Krank Vent

[Agemax]

Added note: The crankcase volume in a conventional two-up/two-down inline 4 cylinder engine is pretty constant, since two pistons go up as the other two go down, offsetting the displacement.

You need the engine to create a lot of variation in crankcase volume for something like the Hayden valve to really pull a vacuum. For example, V-twin Harley engines use a single crank pin, so the pistons somewhat rise and fall together (offset in phase by the 70 degree (?) V-angle of the cylinders). When the pistons fall, they push air out the breather. If you have a check valve that prevents air from going back in, then a vacuum is pulled as the pistons rise again. The vacuum reduces drag on the pistons and probably helps keep the oil from foaming so much.

I know that Harley motors "breath" a lot of air out the breather tube. You can really feel it. I don't feel nearly so much out of an inline 4. Perhaps the Yamaha crossplane engine would get more benefit.

i am not trying to cause an argument here i just cant get my head around these allegations. if a vacuum is pulled as the pistons rise then they are experiencing MORE drag, as they are trying to pull away from a vacuum.

also the informative link you posted is interesting but they are talking 30hp gain on a 555ci BBC engine, that is 9000cc (give or take a few). so a 60ci, or 1000cc motor in theory would gain close to 3bhp, but in reality the internal workings of the smaller,lighter bike engine would not create the necessary "reciprocating mass" inside the engine,proportional to the gii ci engine.

i think i am confusing myself now............

[AJ]

i am not trying to cause an argument here i just cant get my head around these allegations. if a vacuum is pulled as the pistons rise then they are experiencing MORE drag, as they are trying to pull away from a vacuum.

also the informative link you posted is interesting but they are talking 30hp gain on a 555ci BBC engine, that is 9000cc (give or take a few). so a 60ci, or 1000cc motor in theory would gain close to 3bhp, but in reality the internal workings of the smaller,lighter bike engine would not create the necessary "reciprocating mass" inside the engine,proportional to the gii ci engine.

i think i am confusing myself now............

Also not trying to cause an argument either, but it is an interesting discussion.

You would not be "causing drag" by having vacuum under a piston, although you are thinking (correctly) that you would have differential pressure that would create an opposing force as the piston rises. But you will also have a higher pressure differential as the piston falls (for both intake and ignition strokes), so maybe it's a wash there.

If you have a vacuum, you won't have turbulence created in the crankcase, which is more than just the pressure differential above/below the piston.

In a vented design, the falling piston has to push air out a complex pathway hitting moving parts (crank with weights), up through a small channel to the head where it vents. It does the reverse as it sucks air back into the crankcase as the piston rises. All that translates to lost WORK. If you block off the flow, you won't do that work. That, together with reduced drag of moving parts in lower air pressure is probably responsible for any potential horsepower realization. You're not making more horsepower, you're just losing less horsepower that can now be applied to the crankshaft as output power.

I think the rest of your rough calculation is correct.
555 cui car engine = 9100 cc
1000 cc Suzuki engine (but spinning twice as fast) ~ 2000 cc equivalent

If you could conceivably pick up 30 HP on the car engine, then maybe you could pick up 2000/9100 x 30 = 6.5 HP. That assumes that it actually works

[Agemax]

Also not trying to cause an argument either, but it is an interesting discussion.

You would not be "causing drag" by having vacuum under a piston, although you are thinking (correctly) that you would have differential pressure that would create an opposing force as the piston rises. But you will also have a higher pressure differential as the piston falls (for both intake and ignition strokes), so maybe it's a wash there.

If you have a vacuum, you won't have turbulence created in the crankcase, which is more than just the pressure differential above/below the piston.

In a vented design, the falling piston has to push air out a complex pathway hitting moving parts (crank with weights), up through a small channel to the head where it vents. It does the reverse as it sucks air back into the crankcase as the piston rises. All that translates to lost WORK. If you block off the flow, you won't do that work. That, together with reduced drag of moving parts in lower air pressure is probably responsible for any potential horsepower realization. You're not making more horsepower, you're just losing less horsepower that can now be applied to the crankshaft as output power.

I think the rest of your rough calculation is correct.
555 cui car engine = 9100 cc
1000 cc Suzuki engine (but spinning twice as fast) ~ 2000 cc equivalent

If you could conceivably pick up 30 HP on the car engine, then maybe you could pick up 2000/9100 x 30 = 6.5 HP. That assumes that it actually works

ok, fair comments. but........ doesn't the internals rely on turbulence to enhance the splash oil feed. and as stated in your link oil feed to small end bearings is compromised. that is no problem on a 1/4 mile drag engine but what about a 100 mile non stop thrashing through the twisties?

also, i have 2 vents in my engine, the oil filler and the stock head cover vent so venting pressure would be less of a complicated passage,

[AJ]

ok, fair comments. but........ doesn't the internals rely on turbulence to enhance the splash oil feed. and as stated in your link oil feed to small end bearings is compromised. that is no problem on a 1/4 mile drag engine but what about a 100 mile non stop thrashing through the twisties?

also, i have 2 vents in my engine, the oil filler and the stock head cover vent so venting pressure would be less of a complicated passage,

Agreed. I'm actually pretty skeptical. Especially about using it on a 2-up/2-down 4 cylinder engine.

Plus, the $100 Hayden valve would pay for more than a few pints for me and my friends! Cheers!

[posplayr]

More reading on Krank Vent

http://www.et-performance.com/faq.html

http://www.jpcycles.com/instructions/pdf/432-271.pdf

http://www.google.com/patents/US5967178

See the description in the patent, it is a type of one way check valve that works best for 1 and 2 cylinder motors. Where the rise and fall of the pistons would create a pressure imbalance in the crankcase.

There should be minimal effect on an GS Inline 4

[AJ]

More reading on Krank Vent

http://www.et-performance.com/faq.html

http://www.jpcycles.com/instructions/pdf/432-271.pdf

http://www.google.com/patents/US5967178

See the description in the patent, it is a type of one way check valve that works best for 1 and 2 cylinder motors. Where the rise and fall of the pistons would create a pressure imbalance in the crankcase.

There should be minimal effect on an GS Inline 4

Your second link says a lot of the same things I wrote earlier. It also says it can show 4 to 7 psi vacuum, which is believable. One thing that bothered me in that dragpost.com link I posted is that the guy was claiming 15 psi, which is a problem given that atmospheric pressure is only 14.7 psi at sea level and that's the highest differential pressure you could achieve on planet earth. Perhaps this thing works better on Jupiter...

[Dj66]

Crankcase vent.

I've used the Spike crankvent on a 93 Sportster and on that engine, there was a noticeable difference.

[posplayr]

Your second link says a lot of the same things I wrote earlier. It also says it can show 4 to 7 psi vacuum, which is believable. One thing that bothered me in that dragpost.com link I posted is that the guy was claiming 15 psi, which is a problem given that atmospheric pressure is only 14.7 psi at sea level and that's the highest differential pressure you could achieve on planet earth. Perhaps this thing works better on Jupiter...

Yes sorry, I quoted the part about 1/2 cylinders in reference to your comments. I still don't understand where this is going to help a GS? Will it at least create enough vacuum on a inline 4 to suck in oil leaks?

[Agemax]

Yes sorry, I quoted the part about 1/2 cylinders in reference to your comments. I still don't understand where this is going to help a GS? Will it at least create enough vacuum on a inline 4 to suck in oil leaks?

are we then talking the potential to starve certain places of oil? if it can "suck in" oil leaks, it could suck oil from delicate places, such as cam journals, or outer gearbox bearings?

[posplayr]

are we then talking the potential to starve certain places of oil? if it can "suck in" oil leaks, it could suck oil from delicate places, such as cam journals, or outer gearbox bearings?

I'm just referring to what I thought I read about the benefits. If there was a small vacuum in the crank case it stands to reason that any standing oil that tried to weep out a gasket would be pushed back into the crankcase by atmospheric pressure. Any high pressure oil would easily over come the vacuum and squirt where it wanted to go

[Agemax]

the more i read about this the more i am believing it. although, from what i have read so far it is only effective and worthwhile in very large CI engines with short running periods. IE drag cars.

the use on small CI engines for street use, cars or bikes, the cons seem to outweigh the pro's.

[posplayr]

the more i read about this the more i am believing it. although, from what i have read so far it is only effective and worthwhile in very large CI engines with short running periods. IE drag cars.

the use on small CI engines for street use, cars or bikes, the cons seem to outweigh the pro's.

It only works when there is a variable crack case volume. An inline 4 does not (appreciably) vary the crank case volume during reciprocation of the pistons. 1-4 cancels out 2-3

The only crank case pressure is from blow by.

[Agemax]

majority of "conversation" about it on t'interweb is aimed at big V8's.

[posplayr]

majority of "conversation" about it on t'interweb is aimed at big V8's.

The inventor stated it was for small 1-2 cylinder engines right in his patent.

[Agemax]

The inventor stated it was for small 1-2 cylinder engines right in his patent.

well the big V8 boys have obviously improved his patent and got it to work well on V8's.....................