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July 9th, 2005, 09:26 AM   #31
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Originally Posted by Smorgasbord
So, LINEAWEAVER, it is hard to tell wether your competitors eyes are tearing from the fact that you got ahead of them with your vacuum perked up engine or wether it is because of the oily smoke coming from your exhaust?
No smoke as a true void (vacuum) is created in the small crankcase.
ie no flow = no oil loss through the exhaust.

Kind Regards,
Dale

PS
I simply took an old idea and applied it to the built in fresh air EPA exhaust induction introduced in the early eighties.
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July 11th, 2005, 11:23 AM   #32
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In effect it will be a two stage vacuum pump then, where the reed valve and the piston is the first stage and the exhaust pulse air injection valve the second using the exhaust pulse wake which at best may be a really strong vacuum. LINEAWEAVER, you are indeed a genius!
BTW, how do you connect the exhaust pulse air injection valve to the exhaust?
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July 11th, 2005, 05:49 PM   #33
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If I understand this correctly you gents are suggesting to run the breather pipe/tube from the head to the exhaust pipe with the check valve in between thus creating significant crankcase vacuum. A constant vacuum will lessen pulsing thereby reduce oil spewing and will even eliminate it.
A couple of questions then.

How does this increase horsepower?

It seems that by scavenging oil mist via vacuum greater oil loss would occur.

Would you place the port on the headpipe near the cylinder head or further downstream?

Any photos?

Thanks,

Eric
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July 11th, 2005, 10:37 PM   #34
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Oil loss through valve guides and piston rings would, at least theoretically, be reduced with a vacuum in crankcase and rocker box as the pressure difference to suck the oil in would not be there any longer. The lack of pulsation (no gasses left that can pulse) in breather port might add to oil preservation. Maybe that all of this makes up for the increased boil off of the oil that the vacuum would promote. It could even be an advantage to have the oil degassed to get rid of voilatile components like fuel, water, oxygen and deteroriation products that you would not like to be there? Someone wrote that oil mist lowers octane numbers and if you don't get the oil mist in the combustion chamber you could perhaps increase compression a bit and you'd perhaps gain some power? I have no idea why it would cost so much power to have air in the crankcase. The Formula 1 (if they are still around) engines are supposed to run with vacuum in the crankcase to gain power, no idea how the vacuum is produced on those engines though. It would be very interesting to see a photo of the exhaust pulse air injection valve connection to the exhaust manifold on a Husa-berg.
But would you get cavitation in the oil pump and with that a lower oil pressure/flow?
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July 11th, 2005, 10:48 PM   #35
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Also, how would oil mist in vacuum be possibe? With no gasses left to bear the droplets? They would immediately drop to the bottom as they are created. Thinking of it this way it seems like you are doing the environment much less harm and you gain power...
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July 12th, 2005, 06:54 AM   #36
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How important is vacuum in the crankase? I'm into cars mostly, and I always seal the inlet-crankase hose, and fit filters.. Oil fumes won't be sucked out this way. Is this bad on a Berg?

What happens if I just fit a filter on the head vent?
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July 12th, 2005, 07:27 AM   #37
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But what if you don't get the oil mist in the engine any longer because of excessive vacuum, what will then lubricate the rockers, cams and follower bearings? Is the oil throw-off from the timing chain enough?

Vegard, if your reed valve still works you'll get the proper vacuum in the crankcase. Why don't you just fit that breather filter on the head vent. If you find that it dribbles oil too much then a bit of rubber hose in between would allow most of that oil to settle on the walls of the hose, to run back before it can ascend all the way up to the breather filter. Many engines do not use any vacuum at all in the crankcase and it still works fine. When the pressure is higher in the crankcase the fumes gets sucked out anyway by the lower atmosphere pressure.
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July 12th, 2005, 08:25 AM   #38
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Gentlemen,

Dry crank singles (those already equipped with a reed valve crankcase) benefit from the additional check valve only with regard to oil containment.

Many OEM singles employ a pulse air system which draws from the inlet box. In opposition to deactivating said system (common practice) I often simply replace the air box tap with that of the crankcase spigot.

The majority of OEM multi cylinder street bike engines are also equipped with such a system. I once again take advantage by routing the crankcase vent to the scavenging inlet.

A vacuum in the crankcase reduces pumping losses and improves ring seal. (a result of increased pressure delta above and below the piston and ring assembly)

I would like to take credit, however, such is old school technology and has been around since the sixties.

I am indeed beginning to realize that unlike crankcase scavenging many of you have not been around since the sixties and therefore much of what I have to say comes across as brilliant. Some content is indeed brilliant, however, I cannot take credit for that which is not my own.

Kind Regards,
Dale

Reprint:
Concept: Apply a vacuum to the crankcase. Rather than putting a breather on the valve cover to let pressure out, actually suck the air out to create a vacuum.

Benefits of Crankcase Evacuation:

1) Cleans up installation (prevents oil leaks from crankcase sources)

2) Reduces parasitic losses from pistons pumping air

3) Improves ring seal

4) Increases HP by 4-7% depending on the application

5) Eliminates PCV and possibility of oil being sucked into intake system

Tech / Method:
Basically seal the crankcase and run a line from the crankcase to an air pump (or other source of vacuum) and from the air pump to a breather tank. Additionally, if necessary, use a vacuum relief valve to ensure vacuum does not get too great. If you put more than 12in vacuum on the crankcase, you can suck the oil off the front and rear main bearings. That would be a bad thing. Alternatively, with the crankcase sealed up tight to achieve good vacuum, you don't want your pump failing either which would allow a severe buildup of pressure in the crankcase then.

Typically, crankcase evacuation systems employ either a "race type" belt-driven pump or use exhaust as a source for vacuum. Both of those can have problems for street application. The belt-driven pumps are almost always specified for full race applications and therefore would need rebuilt every few thousand miles. If you use the exhaust as a source for vacuum and you have mufflers, you may end up with a buildup of oil in your exhaust ahead of the mufflers. Electric pumps can be used but our experience was they are problematic and don't produce enough vacuum.
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July 12th, 2005, 11:04 PM   #39
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I'll leave it as it is then
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December 29th, 2005, 08:01 AM   #40
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Re: Crankcase Venting 101

Originally Posted by LINEAWEAVER
Hello friends,
For what it may be worth:

If one can insure a slight crankcase vacuum (in particularly regarding a large displacement single) power shall increase coupled with a reduction in oil spewing. Such technology is certainly not new as it has been used by the drag racing community for many, many years. Simply look to the nineteen sixties era blown altereds with their exhaust scavenged crankcases.

On many a fours cycle engine (including Harley Davidson Big Twins and Rotax Singles) I have placed a high speed one-way check valve in the crankcase vent line. Doing such has proven true to form for some two decades now. (As a matter of fact their are over the counter CNC pieces now available through most HD speed merchants.)

Regarding the Husaberg engine:
Power output did not improve using such a device primarily as a result of the OEM crankcase reed valve. However, If a reduction of oil spewing is your primary objective an auxiliary check valve could be just what the doctor ordered.

An automotive air pump check valve serves the purpose nicely @ a fraction of the HD cost. One may purchase KEM part number 174-176 or cross reference said number to that of your local automotive vendors inventory (Kragen, etc.) .

Hope this helps.

Sincerely,
Dale
Dale,
Is the use of this check valve going to eliminate the oil from running out on the ground in the probable event of being upside down and pinned by the bike?
I ask because on my 01 501 I just had a filter and the hose run up to the steering head and it worked fine but had the disadvantage of loosing oil while bottom side up. I know you are supposed to remain wheels down but I am working on my freestyle tricks and am in the process of doing a jump where I stay upside down for extended periods of time and the only thing holding me back is the loss of oil.
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