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-   -   Sportster Crankcase Pressure / Engine Breathing / Wetsumping and Mods (http://xlforum.net/forums/showthread.php?t=2073932)

Hippysmack 28th July 2019 04:17

Quote:

Originally Posted by Tomcatt (Post 5765759)
???

Does look like their 1250 kitted Sportster had really good ring seal.

Yeah it does.

OK,
Officially, I appreciate the data as presented.
I also appreciate the charted results.
But we need more. More importantly, we need to be able to repeat it.
My understanding is the balloon was capped and set into a graduated container of water to represent displacement thereof.
There are variables to doing that.
But the balloon test video does support the information in the chart, sort of.

What we don't have is 3500,4000, 4500,5000 etc.
That helps to determine at what degree of blowby at what RPM.... (on that engine).

So I agree, it doesn't tell the whole picture.
But that isn't what there criteria was.
They had 4 parameters; idle, cruise, accel and decell.

The redline figure does accentuate the fact that high RPM will produce higher CC pressure.

Hippysmack 28th July 2019 04:21

Quote:

Originally Posted by 60Gunner (Post 5765762)
I am, and have been, highly advocating both the krankvent and relocation to the cam chest as worthwhile upgrades.


I know and I don't blame you. :)

Hippysmack 28th July 2019 05:09

Quote:

Originally Posted by dieselvette (Post 5765761)
Are you also aware there's a wall inside to stop the oil.
Above this weirs, there is probably a 1/16" gap. The oil would have to fill almost the whole plastic housing (this being after having gone through foam + umbrella) before it would come out the vent.

Yes, and it's actually an intricate little unit.
Even more restriction.
(now I have to re-label this picture) :doh.. done
http://sportsterpedia.com/lib/exe/fe...hippysmack.jpg

If the oil AND condensate caught up in the shelf couldn't drain, that would be one big splatter of emulsion.
I was kinda holding out saying that waiting on your picture. :o

Quote:

Originally Posted by dieselvette (Post 5765761)
How is it picked up, more so than under regular conditions? Due to denser air, more turbulence?

I believe it's picked up on upstroke and moved on downstroke.
But the affects of upstroke and downstroke are more equalized the faster the engine runs.
That is until that moment when the rings are banging back and forth against the top and bottom of the ringlands and positive pressure gets between the ring and ringland.
This allows more blowby to escape into the crankcase.
Thus pressure in the bottom goes up due to RPM.
That RPM moment is exclusive to each individual engine conditions.

dieselvette 28th July 2019 05:21

Quote:

Originally Posted by Hippysmack (Post 5765579)
The charted results (notice the results across the board on the Sportster):
DK Customs Products Breather Report (from different throttle / riding conditions) :
Bike tested CFM (idle) - CFM (cruise) - CFM (hard acceleration) - CFM
(deceleration)
Air Cooled Twin Cam (103) /.2172 / .08 /.1952/ .2504
Twin Cooled Twin Cam (103) /.2548 /.0972/ .2231 /.2874
M8 Air Cooled (107) /.1211 /.06 /.1059 /.1127
Sportster (1250 with high compression) / .0125 /.0125 /.0125 /.0125
(At redline (6200 RPM) with no load (.3326 CFM) )
Sportster (1200) /.0626 /.0626 /.0626 /.0626

I just can't wrap my head around it, that the net out-flow is exactly the same at all different conditions. There's got to be something wrong with the test. Or - the outflow is limited to X no matter what (by restriction in the breathing) while the CC pressure is going crazy, net result the outflow is a running average.
(BT breathers maybe are more open)

dieselvette 28th July 2019 05:25

Quote:

Originally Posted by Hippysmack (Post 5765768)
If the oil AND condensate caught up in the shelf couldn't drain, that would be one big splatter of emulsion.

It is possible that oil drain hole to become plugged with mayonnaise, and then you would get it out the breather. Probably more likely on bikes that make short runs and don't get warmed up to purge out moisture.

Edit: You *could* get oil out the breather, but first the oil would have to make it past the foam thingy without running back down.

dieselvette 28th July 2019 05:39

Overall, I like the stock breather design (but don't vent into air cleaner!) No oily mess or catch can to deal with. Cheap too.

If the oil drain hole were to clog, you could easily back-purge it with compressed air to flush the oil drain hole. No disassembly required.

So if you have stock breathers and you get crap puking out, my first advice is to use an air hose (or even mouth pressure) and blow gently backwards through it.

I'm tempted to just route the breathers out the back of the S/E air cleaner (I saw pics of that somewhere) and end it there. Easy mod, not visible, and no filter or other paraphernalia to deal with or see. (Could also be done with stock AC.)

Drawbacks as 60Gunner has pointed out: it's in a hot environment, and it's difficult to service, compared to external.

Hippysmack 28th July 2019 05:48

That link you gave me to Aaron's breather dyno test.
In his observations:
I was surprised at how little air movement there was at the end of the hose.
When a motor is started with nothing screwed into the timing plug, there's a massive inhalation and exhalation evident.
But apparently, necking it down to a 3/8” hole and connecting 2 feet of hose adds a pretty significant restriction.
Air flow was nowhere near what I expected.
Unfortunately, getting a 7/16“ or 1/2” hose into that area would be problematic, space is tight.
Plus, a fitting with the correct thread and a 7/16“ or 1/2” hole may not be available.
Another surprise was just how easy it was to plug the hose with my finger, and how it felt when I did.
The pressure was not great.


I'll have to go back to the video but as I remember, you could see the balloon breath...just slightly.
The balance I keep talking about.
In that engine, the balance is pretty damn good.
The balloon inhales and exhales very slightly.
The balance of positive and negative is pretty even.
It inhales a slight amount and apparently exhales about the same slight amount...pretty even balance.
There is a small amount of blowby in that video.

Air induced (brought into) the engine changes that balance whether from excess blowby or the breathers allowing it.
That's when the balance is tilted and the balloon will get bigger.

Hippysmack 28th July 2019 05:58

Quote:

Originally Posted by dieselvette (Post 5765771)
It is possible that oil drain hole to become plugged with mayonnaise, and then you would get it out the breather. Probably more likely on bikes that make short runs and don't get warmed up to purge out moisture.

Edit: You *could* get oil out the breather, but first the oil would have to make it past the foam thingy without running back down.

I wouldn't think so do to air movement.
The air inside the engine will flow into the inlet and out the tiny hole or vice versa.
The stale condition in a vent line where oil and moisture are allowed to live together without drainage / separation is when the mayonnaise forms.
But I suppose dirty oil with debris bigger than the hole could stop it up and cause problems.

Quote:

Originally Posted by dieselvette (Post 5765774)
Overall, I like the stock breather design (but don't vent into air cleaner!) No oily mess or catch can to deal with. Cheap too.

If the oil drain hole were to clog, you could easily back-purge it with compressed air to flush the oil drain hole. No disassembly required.

So if you have stock breathers and you get crap puking out, my first advice is to use an air hose (or even mouth pressure) and blow gently backwards through it.

I'm tempted to just route the breathers out the back of the S/E air cleaner (I saw pics of that somewhere) and end it there. Easy mod, not visible, and no filter or other paraphernalia to deal with or see. (Could also be done with stock AC.)

Drawbacks as 60Gunner has pointed out: it's in a hot environment, and it's difficult to service, compared to external.

Like these?
http://sportsterpedia.com/doku.php/t...ref:engmech05b

dieselvette 28th July 2019 06:12

YES!
I like the cookie man one actually, with those filters you would never even get a drip. And it's away from the intake so as to not cause turbulence there.

Funny how the MoCo included those bosses which just happen to fit perfectly with the angled hose thingys.

Highly-Dangerous 28th July 2019 08:11

I just have to ask.... seen it several times and still not sure what it means.... What MoCo stands for??

Found these:
MoCo Montgomery County
MoCo Modern & Contemporary (Arts)
MoCo Mozilla Corporation (Mozilla Foundation)
MoCo Motion Compensation
MoCo Mondo Corretto (Italian: World Fair; photography resource)
MoCo Monitoring Committee for Euro-Mediterranean Cooperation in RTD (EU)
MoCo Modern Cornish (linguistics)

I am thinking: Motorcycle Corporation?

:doh


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