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  #311  
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Now move everything into a walk-in freezer using 60 wt

Curious what the pressure would go to.....

Helluva job there, thanks!
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  #312  
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Hahahah...No, I like my drill press too much.
I've had that plexiglass for a couple years now with this project in mind.
The reason I haven't done anything with it til now is due to motor and speeds.
I have many small gears for changing speeds but I need a metal lathe to pile all that together into something useable.
I have a wood lathe motor that I was going to repurpose but the build just never came together.
Tomcatt mentioned the drill press, and I figured it be fine just for flow rates.
Then of course, curiosity bit me again hunting pressures.
So I'm doing what I can with the drill press right now.
The oil is a cross between 10W-30, predominate 10W-40 now mixed with I think 1/2 quart of 50W Rotella.
The pressure figures will change based on ambient temp and viscosity plus restrictions I have as opposed to restrictions in the motor.
So my results should be seen as percentages between the feed and return and not as much the actual figures themselves.

I didn't realize the feed vacuum would go higher than the return vacuum.
I know now that negative pressure is predominate in the feed line to the pump.
The pump is capable of pulling vacuum in the return passage from the sump to the return inlet.
But with the return being bigger than the feed, it pulls air also.
When the return pulls air, vacuum is either very low to none.
So don't take the vacuum readings on the return as gospel.
I can pull the vacuum line from the gauge, cup the end with a finger, then let jist a little air come thru by lessoning pressure over the end.
Then I can watch air bubbles galore enter the return just like when the gasket surface was distorted.
I can also raise the return line end in the jug with the vacuum gauge attached and watch the vacuum go to zero.
See this video: http://www.sportsterpedia.com/lib/ex...hippysmack.mp4
So when there is air in the return passage, vacuum is low to nil.
What that means is vacuum is NOT as helpful on the return line as the test results show in real time.
THAT's the need for positive pressure of downstroke to help the pump's vacuum when it's receiving air instead of oil.
Cause it's not pulling a steady stream of vacuum.
It won't keep vacuum in the line whilst pulling up air.
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Last edited by Hippysmack; 5 Days Ago at 23:52..
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  #313  
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The oil to the crank is restricted on both ironheads and evos.

Sidenote from chevelle http://xlforum.net/forums/showthread...=561553&page=3 :
Stock 76 and earlier pinion shaft hole is .1875" (3/16") the shaft has a reverse thread cut in it.


The threading in the shaft end alone is a restriction as well as friction and it's fed just like evos from the pinion bushing bore.
So they are all restricted, just a little more on Evos.

If you take a straight piece of 6" pipe, cap and tap the ends with the holes left open;
Then roll it down hill. As long as it stays horizontal, water splashes from both ends but there is no suction due to it rolling.
And the majority of water will stay inside the pipe.

Same same on the pinion shaft itself.
If it's just spinning, centrifugal force pushes the oil against the pinion shaft walls.
There is no force in that instance to make it move out to the crankpin.
The force that makes it move to the crankpin of course is oil pressure upstream (not just the presence of oil).
Let's forget about how much pressure for now.
Now oil (flow pressure) is carrying oil into the right wheel and out into the crankpin.
So now you have oil in the crankpin, good. But what happens next?

The motion of the wheels and the position of the crankpin as opposed to the hole position in the crankpin is important.
The crankpin is not spinning. It's locked into the wheels.
Wheel rotation throws oil in the crankpin against it's walls.
Every rotation, oil is pushed against the portion of wall away from the outlet hole then spins around where it pushes oil toward the hole and into the low end bearings.

Newtons law?, I believe, states that a body in motion will stay in a straight line until a force acts on it to change direction.
The oil wants to go out the hole but can't cause the crankpin is now in opposite rotation from the hole, then back into rotation direction the oil is traveling.
So if there were no bearings on the crankpin OD and with a window to the crankcase, you'd see oil would do the same as it does coming back to the tank.
Spurt out when rotation permits.
Now add the oil pressure back.
Oil flow pressure works in conjunction with centrifugal force.
Oil flow pressure will push oil out even though centrifugal force is in the opposite direction of the crankpin hole.
When the hole lines up with centrifugal force, that force is added to oil pressure as it is pushed out the hole.
Strictly nonsensical figures but, if you had 1/2 ounce of oil being pushed out by oil pressure alone when centrifugal force was out of rotation with the hole;
You might be looking at 1 ounce of oil being pushed out when centrifugal force is in rotation with the outlet hole.
If there were too much oil backing up into the crankpin, it would get slung out with more fervor by the time centrifugal force lined up with the hole.
Now we've got oil leaving the crankpin into the low end bearings. What happens next?

The wheels and crankpin spin twice the speed of the oil pump.
So there is plenty of time and speed to lower the static oil pressure in the pinion shaft before it gets to the crankpin.
When the wheels rotate and deplete the main body of oil of pressure in the crankpin, the only force we think of is oil pressure to replenish that.
But for every action, there is a reaction.
When the crankpin throws out oil, it leaves a lower pressure inside the crankpin (lower than incoming oil pressure).
Basically, it lessons the pressure in the crankpin and the oil pressure upstream doesn't have as much pressure to fight against to get into the crankpin.
So centrifugal force of the wheels/crankpin act to assist oil pressure.
The size of the crankpin hole was enlarged at one point and some have 2 holes instead of one.
So there has been some engineering done on that as well.

The restrictor in the pinion shaft on Evos was obviously not to lesson the amount of oil to the crankpin.
It was done to keep more static oil pressure at the lifter bores.
Ironheads feed the rocker boxes off oil pump (flow pressure).
They don't need a residual amount of oil, just constant flow.
So there is no need to build any oil pressure to keep up top.
Evos do not flow feed pressured oil to the rocker boxes. Oil from lifter action is the all they get.
Oil pressure to the rocker boxes stops at the lifter bores.
Since you're not keeping a constant flow up there, you have to keep a constant oil reserve to the lifter bores.
Then when the lifters come down, they can pick up some of that "reserve" oil and send it to the boxes.
The stored oil up top for evos is called static oil pressure (oil that is resistant to flow).
This oil "reserve" just hovers there awaiting to be carried by the lifters.
In the meantime, oil is passing around there going to the piston squirters on 04-up models.
So there is slow moving oil up top that is fluent (still moving) and the reason it can do that is because of the restrictor in the pinion shaft.
Without the restrictor, more oil would go out the pinion shaft INSTEAD of hovering up top around the lifter bores.

From previous posts, I don't think I did that good at distinguishing between static and flow pressure.
But friction in the pinion shaft will slow oil down (deplete incoming pressure needed to push up to the crankpin).
As flow increases, so does friction,
Friction is the roughness of the passage walls (be it rubber hoses or drilled passages).
The more pressure you have, the higher the friction.
I had drawings and the whole thing on friction I lost with the power spike.
So this is more off the cuff than I had planned.
Due to friction, some of the passing oil basically sticks to the walls and the center of flow speeds up as the sides of the flow slows.
So if you can visualize a clear hose of oil with the sides flowing slowly and the center faster;
You'll see that what actually is able to flow does so in a smaller diameter thru the middle of flow, pressure drops like a restriction in the pipe.
As static pressure rises, so does the affects from friction.
So the lowered pressure in the crankpin from the affects of centrifugal force aide in lowering the affects of friction on the incoming oil.
Speeding up oil flow, lowering heat (higher the friction, higher the heat).
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  #314  
Old 1 Week Ago
Tomcatt Tomcatt is offline
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Another trip down the rabbit hole... Alice will be installing a toll booth.
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  #315  
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Back up and running.
I added 3/8"x 1/4" tees inline for the vacuum gauge. It's easier to swap from return to feed that way.
I just plug the one I'm not using with a drill bit end.
I noticed an air pocket at the outlet side of the return tee, thought it was an air leak but it's not.
When I shut off the drill, the air pocket walks up to the high point in the hose (to the right of tee).
I then fire up the drill an the air pocket flows into the pump and back to the bucket.
No more air at the tee.
The line was full of air due to me working on the fittings before firing up to see this.
The end of the fitting is being sucked on by the pump.
This is an example of what happens to the flow coming from a restricted space (smaller tee ID) to a more open space (bigger hose ID).
Tee ID is (.210"), vacuum is 14cmHg (app -2.71 psi), speed is 657.4 RPM.
And the air pocket stays stagnant as does the oil directly around the air pocket.
Also an example of oil moving in the center but not on the sides.
You can see the vena contracta and recirculation pockets.
If the air hadn't got locked up in the recirculation zone, I wouldn't have seen it.
But this proves that it does exist even though.
edit:
Here is the video showing the recirculation zone around the tee.
That area is a source of turbulence and heat generation as are other areas in the oil path that have the same qualities.
http://www.sportsterpedia.com/lib/ex...hippysmack.mp4



edit:
Remember all those irrevelent drawings I did that don't apply to the Sportster engine?


Last edited by Hippysmack; 5 Days Ago at 23:47..
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  #316  
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I added a video to post 315 showing the recirculation at the tee.
I also added a video to post 312 simulating vacuum in the return line.

I added a plastic universal tee to both the feed and return lines on the new setup.
I left the 5-16" nubs on the tee and slipped 3/8" hose over them to the 3/8" nubs.
I then tested the vacuum on the return hose.
It was at 20 cmHg with the 5/16" nubs (app 0.160 ID).
Then I cut the 5/16" nubs to find a .210" ID thru the 3/8" nubs.
Tested again and found the vacuum lowered with the bigger tee ID.
I first cut the left (sump) side of the tee and retested (vacuum at 14 cmHg).
I then cut the pump side of the tee (vacuum stayed at 14 cmHg).



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  #317  
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Now why I am concerned on what happens when you change fitting ID sizes on the sump to pump side when in reality we can't really that?
Well, that's what the MoCo did.
The inlet hole in the oil pump below the duck bill was enlarged twice over time.

1977-1990 return inlet hole ID = 0.250“
1991-1997 return inlet hole ID = 0.280”
1998-Present return inlet hole ID = 0.350“

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  #318  
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You guys ain't gonna like this.
Those inlet holes inside the duck bill on the return side (post 317) were not sized to add more volume, they were sized to reduce the possibility of cavitation.
I squeezed down the hose (restricted it) at different vacuum points.
All the way to 50 cmHg, the volume sucked out of the bucket was about the same.
So the pump will suck the same volume of oil from the sump (as long as oil is available) no matter how hard it has to work to get it.
But the harder it has to work, the more vacuum it creates in the return passage to the pump.
I had the fan on with noise when I did the return volume testing.
Later I left the fan off and found noise and vibration starting anywhere from about 45-50 cmHg.
Noise is the first sign of cavitation followed by vibration, then detonation.
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  #319  
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In the first video below, the inlet hose from jug to pump was squeezed down (restricted it) at different vacuum points.
All the way to 50 cmHg, the volume sucked out of the bucket was about the same per each 10 cmHg increment (more or less) but nothing significant.
edit:
Each mark on the jug is 16 ounces. Restrictions from 1-5 all danced around 17-19 seconds of removal time for 16 ounces.
So the pump will suck app. the same volume of oil from the sump (as long as oil is available) no matter how hard it has to work to get it.
But the harder it has to work, the more vacuum it creates in the return passage to the pump.
The more vacuum that is created, the easier it is to pick up bubbles from the oil leading to cavitation of the pump in some form.
The greater the heat, the easier it is to pick up oil vapors leading to destructive cavitation. Oil temp during this testing was 88°F.
Noise is the first sign of cavitation followed by vibration, then detonation.

The video shows that increasing or decreasing the inlet hole size would not amount to any significant volume change from the pump.
However, the gains from increasing the hole size does reduce the amount of vacuum exerted along the return path from the sump to the pump.
If that 50+ cmHg holds in real world experience in the motor, then any more vacuum than that can begin to cavitate the return side of the pump.
Video: http://www.sportsterpedia.com/lib/ex..._aac_audio.mp4

In the second video below, testing was done at different RPMs and restrictions to find some evidence of cavitation.
The pump experienced sizzling noises from low RPM-high vacuum, vibration from higher RPM-high vacuum and grinding gravel noise from higher RPM-high vacuum.
It seems that 50-55 cmHg of vacuum was the point at which problems began throughout the RPM range.
The drilled return passages from the sump to the pump in the motor are smaller than what was tested on the bench.
Smaller hose ID (matching the actual return passage ID) will result in increased vacuum. Longer hose length will also increase vacuum.

Air bubbles started to be pulled out of the oil around 50 cmHg and higher (-9.67 PSI).
It is assumed that the horizontal drilled passage to the pump was enlarged to match the pump inlet hole ID.
However, the vertical drilled passage leaving the sump would remain the same size as before the pump inlet was enlarged.
This is due to the need for the 1/8”x27 plug on the bottom of the case. That hole can only be enlarged to the pre-drill size the plug.
Video: http://www.sportsterpedia.com/lib/ex...k_use_this.mp4
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