Sportster Oil Pressure and Dynamics

[Hippysmack]

One could, if so desired, put a slack tube tee'd off the inlet hose down low.
I don't have a transducer and I'm not in the position to do any testing at the moment.
All I'm doing in this thread at the moment is bringing this information to light.
Don't get me wrong as I think you already have.
I'm not saying our pumps are cavitating going down the road.
I'd think cavitation would end with some pump damage.
But if I don't bring this out, it'll never come out especially if one simply follows the manuals in a sheeple fashion.
Really didn't know the word cavitation would ruffle any feathers.
It's used frequently on the forum.

What anyone does with the information, again, is out of my control.
But at least I'm not telling people to take a chainsaw to their engines cause it is what everyone else does.
Just things to think about.
And this stuff can be verified pretty easily with a simply internet search.

[bustert]

now that is super funny, mr. hippy
"NOT LAUGHING AT YOU BUT THE CONCEPT"
have you ever worked with HVAC systems??? we are talking like .01 wc and such. the water manometer cannot do it as you cannot see it due to resolution issues.
you will need a magnehelic gauge or a electronic diff'l instrument, just went through this with a friends heater last winter.
your are talking 300+ dollars for a cheap one.
if the air switches are not set right, the ecu will shut down the furnace and with multi-speed and variable speeds, the more complicated as there are more sensors.
as a side note, just because the ecu codes out the pressure switch does not mean it is the switch as it reacts to many things that effects flow like blockage and excess water in the flue.

[Tomcatt]

Originally Posted by bustert

"NOT LAUGHING AT YOU BUT THE CONCEPT"

Don't laugh at our pseudo science expert... He probably spent quite a bit of time doing internet searches finding the big words to use.

[bustert]

mr. tom i do not think mr. hippy like that at all

IF there wasn't people like him, we would NOT be as advanced as we are.
a lot of things we take for granted came from shade trees and not engineers. truth told, engineers often take the info and improve it, but where did it come from???
when i started doing tv work, the course sorta starts at the history of things. true or not, i do not know, BUT, it was said that tv was invented (concept) by an IOWA farm boy with a vivid imagination who wrote a story for class, the teacher said why not and submitted it up line and eventually, walla, the tv was born.
take the ponitac engine, when multiple carbs were installed, there was an issue with stock manifolds. shade tree mechanic cut grooves into the floor to funnel fuel drop out to the out board cyls and help stop middle cyl over rich conditions. it worked and then the factory did the same.
i once tried to 5 port my suzuki engine to be like the yahama, many failures, never got it right, but i did learn a lot.
i build steel guitars and i learn more from my mistakes that anything and gain a great deal of skill correcting them. my father built steels from the 60's and i machined for him in my spare time, but it is WAY diff doing it by my lonesome! being 99 with macular degeneration, is what stopped him, his steels are all over the world.

[Hippysmack]

Hahahaha...
That was kind of a tongue in cheek.
If'n there is no suction on the inlet, no worries using a slack tube.
The actual figures will depend on viscosity and others if you really wanted to get to it.
I don't know the resolution needed. But obviously I can't do that right now.

[Tomcatt]

Originally Posted by bustert

take the ponitac engine, when multiple carbs were installed, there was an issue with stock manifolds. shade tree mechanic cut grooves into the floor to funnel fuel drop out to the out board cyls and help stop middle cyl over rich conditions. it worked and then the factory did the same.
i once tried to 5 port my suzuki engine to be like the yahama, many failures, never got it right, but i did learn a lot.

We learn from our mistakes, or at least some of us do. But we don't go on crusades because we're then instant experts on everything creating new interpretations of physics. Learning from what we've done is one thing. Many things are "work-arounds" to fix a design problem (the Pontiac manifold plenum floor) rather than a great new principle to be applied to everything. "5th ports" worked very well when we converted piston port intakes to reed valves. Scrolling thru the internet looking for bits and pieces to "prove" preconceived positions really isn't a good practice.

[Hippysmack]

xxxx off Tommykins, you are nothing but a wart.

[Tomcatt]

Originally Posted by Hippysmack

xxxx off Tommykins, you are nothing but a wart.

When there's a lack of hands on experience and just repetition of what someone's read this type of response is typical.

[Hippysmack]

Son, my hands have been all over these pumps.
I have a pump of every change model from 1977-present.
What do YOU have?
Wait, get your hands out of your pockets. It's not very becoming....

Priming the Oil Pump per FSMs

Parts lube on assembly:
1977-1985 FSMs say to "lightly" oil all the moving parts in the oil pump on assembly.
1986-up FSMs say to "liberally" coat all moving parts in the oil pump on assembly.

To prime or not to prime:
1959-1978 FSMs make no provisions for priming the gear type oil pump.
1978-1990 FSMs say the oil pump must be primed whenever oil lines have been removed or pump has been disassembled.
1977-1978 oil pumps:
Prime the pump by loosening (not removing) the oil switch off the front of the pump while engine is running and let 3 ounces of oil to be forced out.
1979-1985 oil pumps:
Prime the pump by loosening (not removing) the oil switch off the front of the pump.
(and additionally pull the oil filler cap off the oil tank)
Then fire up the engine and let 2 ounces of oil to be forced out.
1986 (dealer) FSM
Prime the pump by loosening (not removing) the feed hose at the pump and remove the oil tank filler plug.
Start engine and at idle, allow 2 ounces of oil to be forced through the hose connection or until the oil light goes out.
1986-1990 oil pumps:
Prime the pump by loosening the feed hose connection at the pump (but does not mention removing the oil filler cap).
Start engine and at idle, allow 2 ounces of oil to be forced through the hose connection or until the oil light goes out.
1991-up FSMs just say to liberally coat the moving parts (with no mention of priming the oil pump).
What changed? Why no need to prime the pump?
The only thing that changed in the pumps were getting rid of the spring washer between the gerotor divider plates.
Plus reducing that to 1 plate for 91-up pumps.
What did that do? It relaxed the tension on the gerotors and clearances.
1977-1990 pumps are hard to turn by hand due to the spring washer.
The spring washer creates tension against the feed gerotors which creates more heat when first operated after disassembly.
There is an air space in the suction cavity that (as bustert mentioned) will compress the air prolonging the introduction of oil in the cavity.
The longer the gerotors spin without oil, the faster they heat up without oil cooling them down.
Thus the reason to "prime" the pump.
This pulls oil into the suction cavity from the tank hose before full operation of the pump is needed.
Less stress on metal to metal contact, lessens pump damage, lessens heat generated due to the tight feed gerotors.
1991-pumps have no added tension on the gerotors and they spin freely.
Coating the moving parts establishes the hydraulic seal allowing the pump move oil into the suction cavity (as it does with77-90 pumps).
But the free rotating gerotors don't create as much friction from heat before inlet flow is established.
1977-up pumps will prime themselves as long as the hydraulic seal stays intact until they do.
77-90 pumps with the added friction heat can detonate however without priming the suction cavity.
So "priming" 1991-up pumps simply means oiling the moving parts.
Suction handles the rest.

[bustert]

CYA
the fsm must cover themselves hence the addition of priming since they do not know what idiot is owning it.
i say gravity does its job well. i never once primed my pumps on oil change and the 74 got changed every 2k until i added a spin on filter, now 5k. the machine has close to 200k.
not saying it is not a good idea, but i will throw this out.
honda used to have the best filter ever but idiots never cleaned them and honda to protect themselves went to throw away garbage, give me the centrifuge any day!
now on a rebuild, a little petroleum jelly works wonders especially so if the pump has to sit awhile before being used, especially so with lower than pump sump.