OMP nozzles??
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OMP nozzles??
I am in the process of the re-assembly of the omp setup and I have installed the pump and lines. I have gone with the non sequential setup and I have done away with all the vacum solenoids. My question is do I hook vacum lines to the nozzles that secure the omp tubes to the housings? I have looked through the pile of excess, and I cannot find any vacum lines that I may have pulled off of the nozzles. I can probably post some pics if it would help explain what I am trying to accomplish. Also should I run a premix with the first tank of fuel for the break in?
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I connected a line to one and used a vacum pump... it held vacum.. Then I blew. I was able to blow air into housing.. So I connected them directly to the intake manifold. I am assuming that when it is not boosting the OMP has enough pressure to pump oil in the housings and under boost the nozzles probably spray the oil in. I hope its right... but it seems like the only logical explination as to why the vacum/boost lines are needed.
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I just converted to a single turbo and after much laborious forum searching, I believe the general consensus over this debated topic is to vent (with a filter) the vacuum lines from the OMP to the atmosphere. Read this thread: https://www.rx7club.com/showthread.p...ht=vacuum+vent
The purple lines are the ones in question.
The purple lines are the ones in question.
Last edited by RXJJang; 10-04-04 at 06:57 PM.
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Originally Posted by xb2002
I connected a line to one and used a vacum pump... it held vacum.. Then I blew. I was able to blow air into housing.. So I connected them directly to the intake manifold. I am assuming that when it is not boosting the OMP has enough pressure to pump oil in the housings and under boost the nozzles probably spray the oil in. I hope its right... but it seems like the only logical explination as to why the vacum/boost lines are needed.
the nozzles have 1 way check valves in them. You should not be able to blow through it both ways.
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Originally Posted by RXJJang
I just converted to a single turbo and after much laborious forum searching, I believe the general consensus over this debated topic is to vent (with a filter) the vacuum lines from the OMP to the atmosphere. Read this thread: https://www.rx7club.com/showthread.p...ht=vacuum+vent
The purple lines are the ones in question.
The purple lines are the ones in question.
Well I read that tread and I cant figure it out!
This is what I know(tested):
1... I can blow through the nipple into the housing (with it installed)
2... I can NOT suck any air from the nipple (check valve)
This is what I think:
3... vacum would do NOTHING when connected
4... boost would spray the oil into the housing with a siphoning effect??
5....There has to be some purpose of the nipples on the nozzles otherwise there would just be a banjo bolt there instead.
Can someone please post their comments/advice?
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#8
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Originally Posted by xb2002
\
Well I read that tread and I cant figure it out!
This is what I know(tested):
1... I can blow through the nipple into the housing (with it installed)
2... I can NOT suck any air from the nipple (check valve)
Well I read that tread and I cant figure it out!
This is what I know(tested):
1... I can blow through the nipple into the housing (with it installed)
2... I can NOT suck any air from the nipple (check valve)
Here's a post from this thread:
The injectors are above the OMP and once the engine (and therefore OMP) is switched off the oil will siphon back down the OMP lines and into the pump. Then at the next engine start the OMP would have to prime the lines again before ever getting oil into the engine, thus starving it of OMP oil at startup.
That valve in the injector is like putting your finger over the tip of a straw. If you dip a straw into a glass of water the straw fills with water but runs out as soon as you lift it from the glass. If you put the straw into the water and then put your finger over the end you can then pull the straw out and hold the water in. That's exactly what the little valve on top of the OMP injector does; once vac is gone the diaphram closes across the top and holds the oil in the OMP lines so it can't drain back.
The OMP injectors would still function normally with the engine running without vac present on the valve, but the oil would siphon after shutdown. This means at startup the engine seals get no lubrication as the OMP has to prime the lines again.
#9
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https://www.rx7club.com/showthread.p...4&page=2&pp=15
That valve in the injector is like putting your finger over the tip of a straw. If you dip a straw into a glass of water the straw fills with water but runs out as soon as you lift it from the glass. If you put the straw into the water and then put your finger over the end you can then pull the straw out and hold the water in. That's exactly what the little valve on top of the OMP injector does; once vac is gone the diaphram closes across the top and holds the oil in the OMP lines so it can't drain back.
Hey Damon, I don’t understand the statements that you are making that the OMP injector receives enough vacuum to open the diaphragm from the turbo inlet. From what I understand vacuum would hold the diaphragm closed and not open as you said.
I also don’t see if that were true, how would the diaphragm stop the OMP nozzle from siphoning back under that configuration unless you were to apply vacuum even when the car is off to avoid siphoning if it is an issue.
Here is wargasm’s video showing that the diaphragm is on the back side of the injector assembly, and would be held closed under vacuum from the top of the OMP injector to the turbo until suction from inside the engine exceeded the vacuum created by the turbo inlet.
http://www.zeroglabs.com/rx7/howoilmeteringworks.htm
Originally Posted by DamonB
Just for the hell of it I attached my boost gauge to the primary intake elbow. The guage isn't capable of measuring the small vac reading There's certainly plenty of vac available as I noticed when I cupped my hand in front of the primary intake a couple weeks ago (airbox was out), but the amount is not near as great as what's behind the throttle plates since they choke off the intake tract.
There's still plenty of suction present to be useful though. You guys go suck on the ends of your boost gauges and tell me what kind of reading you can get You may be able to make the needle move but it won't be much. More than enough to open the little diaphram in the OMP nozzles though.
There's still plenty of suction present to be useful though. You guys go suck on the ends of your boost gauges and tell me what kind of reading you can get You may be able to make the needle move but it won't be much. More than enough to open the little diaphram in the OMP nozzles though.
Originally Posted by DamonB
That valve in the injector is like putting your finger over the tip of a straw. If you dip a straw into a glass of water the straw fills with water but runs out as soon as you lift it from the glass. If you put the straw into the water and then put your finger over the end you can then pull the straw out and hold the water in. That's exactly what the little valve on top of the OMP injector does; once vac is gone the diaphram closes across the top and holds the oil in the OMP lines so it can't drain back.
Hey Damon, I don’t understand the statements that you are making that the OMP injector receives enough vacuum to open the diaphragm from the turbo inlet. From what I understand vacuum would hold the diaphragm closed and not open as you said.
I also don’t see if that were true, how would the diaphragm stop the OMP nozzle from siphoning back under that configuration unless you were to apply vacuum even when the car is off to avoid siphoning if it is an issue.
Here is wargasm’s video showing that the diaphragm is on the back side of the injector assembly, and would be held closed under vacuum from the top of the OMP injector to the turbo until suction from inside the engine exceeded the vacuum created by the turbo inlet.
http://www.zeroglabs.com/rx7/howoilmeteringworks.htm
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Originally Posted by rotarypower101
https://www.rx7club.com/showthread.p...4&page=2&pp=15
vacuum even when the car is off to avoid siphoning if it is an issue.
vacuum even when the car is off to avoid siphoning if it is an issue.
I feel that the check valve is there to prevent internal pressure from blowing out and to allow the oil to be injected (with assist under boost)
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Originally Posted by xb2002
Thats what I'm thinking! I still feel that it needs boost to assist the spray at lets say 7000 rpm! Any more takers?
I can't view the vid. Guess I need to download something...
Last edited by DamonB; 10-05-04 at 01:55 PM.
#12
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This is interesting. I can see both sides. But the vacuum diagram in the FSM shows that the nozzles are hooked up to the inlet side (always vacuum) of the turbos. I just redid mine. Apparently most people/builders feel that it should be hooked to boost pressure. Although this is wrong. Mine was hooked up like this for a while now and I suppose I was lucky I was using Proteck fuel lubricant.
Now another question: If you have had your OMP nozzles hooked up to boost pressure, could you have damaged the OMP system in any way?
Is there a way to test the OMP system?
Thanks
Now another question: If you have had your OMP nozzles hooked up to boost pressure, could you have damaged the OMP system in any way?
Is there a way to test the OMP system?
Thanks
#13
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Originally Posted by DamonB
I can't view the vid. Guess I need to download something...
I have read about the oil metering nozzles to no end I know, but it seems no one can really make sense of what it should really be doing in terms of the diaphragm. It is very conflicting as to what the purpose of the valve was really supposed to do if infact the OMP pump does release x amount of oil perhaps the vacuum of the engine does suck the oil that is in the banjo into the chamber distributing and helping vaporize the oil.
There is one thing that is undeniably true though, and that is that mazda engineers hooked it up to the front of the turbo inlet and it is either for the vacuum or simply clean air . Whether or not the vacuum is simply there to help hold the valve closed when the chambers are pressurized and open when the engine is under higher vacuum than the turbo intake I don’t know but that seems to make the most sense.
Though then the idea of applying boost to the injector doesn’t sound like such a terrible idea.
I personally just took 2 ratsnest solenoid air filters and glued them to the top nipples, because I was told it simply needs clean air.
Has anyone confirmed that the OMP lines drain back into the pump? That seems like a odd thing to happen or for mazda engineers to overlook? Any feedback or experience with this?
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Originally Posted by rotarypower101
There is one thing that is undeniably true though, and that is that mazda engineers hooked it up to the front of the turbo inlet and it is either for the vacuum or simply clean air .
If they were hooked up to turbo inlet stock... then thats where they are going.
Last edited by DamonB; 10-05-04 at 04:40 PM.
#15
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Originally Posted by rotarypower101
in fact the OMP pump does release x amount of oil perhaps the vacuum of the engine does suck the oil that is in the banjo into the chamber distributing and helping vaporize the oil.
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Originally Posted by xb2002
Thats what I'm thinking! I still feel that it needs boost to assist the spray at lets say 7000 rpm! Any more takers?
I feel that the check valve is there to prevent internal pressure from blowing out and to allow the oil to be injected (with assist under boost)
I feel that the check valve is there to prevent internal pressure from blowing out and to allow the oil to be injected (with assist under boost)
#17
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Originally Posted by mjw
No your oil pressure takes care of that, watch your oil pressure gauge as you raise the revs..it rises, or at least it should. If you apply boost pressure to the nozzle you will be reducing the effectiveness of the oil pressure in my mind, say 50psi oil pressure that is fighting against 10psi of air pressure in the nozzle ..now you have a lubrication problem unless you premix.
#18
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Originally Posted by DamonB
Boost= manifold pressure. The chamber inside the engine where the OMP injector is located is not under vacuum when there is boost in the manifold. The oil is forced through the injector and into the engine by oil pressure and the OMP pump, it is not "sucked" into the engine.
Have you been able to view that video yet? It shows pretty clearly the way the OMP nozzle has to work (I know we have beat this issue to death but…)
“Negative pressure created in the rotor chamber would cause all the oil within the nozzle to be sucked out.”
http://www.rx7.net.nz/newrx7.htm
from this paragraph about 11 paragraphs up from the bottom “Apex seal lubrication has become a critical issue. In a race engine, oil supply to the rotor housing by means of injection was precisely monitored and controlled, whereas in the production unit, a larger amount is supplied, just to be on the safe side. Some of the lubricant is fed into the trochoid chamber through a metering nozzle. The previous nozzle's oil passage was 2.0 mm (0.08 in.) in diameter. Negative pressure created in the rotor chamber would cause all the oil within the nozzle to be sucked out.”
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Originally Posted by rotarypower101
Just found this while brousing the page again, and thought of this thread.
Have you been able to view that video yet? It shows pretty clearly the way the OMP nozzle has to work (I know we have beat this issue to death but…)
Have you been able to view that video yet? It shows pretty clearly the way the OMP nozzle has to work (I know we have beat this issue to death but…)
#20
sdrawkcab
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Damon, do you have the correct codec installed to play divx files?
Here is a link to a divx codec I installed on a computer here at school with just windows media that wouldn’t play divx files, until I installed the divx codec.
http://www.filemirrors.com/search.sr...vX412Codec.exe
You really need to see this video, I think it will change your view on how they work. I don’t think the OMP nozzles stop the oil from siphoning back down the line the way you describe, and the diaphragm is on the other side of the air line porting inside of the nozzle from how I think you describe it.
And it still seems like the oil is literally being sucked into the chamber, meaning that if boost is applied to the top nipple that it doesn’t restrict the oil flow, but maybe it could disperse it better(assuming the pump is not pressure sensitive, and releases the same amount of oil for each cycle regardless of the pressure in the line)
Not that I am running it this way, just stillwondering about it.
I think the purpose of the top of the OMP nozzle connecting to the intake elbow is, to keep just enough vacuum on the diaphragm to keep it closed and tight when oil is being pumped into the nozzle and avoid leakage through the top nipple(as it gets old or distorts looses some of its plasticity), while still retaining the ability to pull the oil charge into the chamber unabated.
Here is a link to a divx codec I installed on a computer here at school with just windows media that wouldn’t play divx files, until I installed the divx codec.
http://www.filemirrors.com/search.sr...vX412Codec.exe
You really need to see this video, I think it will change your view on how they work. I don’t think the OMP nozzles stop the oil from siphoning back down the line the way you describe, and the diaphragm is on the other side of the air line porting inside of the nozzle from how I think you describe it.
And it still seems like the oil is literally being sucked into the chamber, meaning that if boost is applied to the top nipple that it doesn’t restrict the oil flow, but maybe it could disperse it better(assuming the pump is not pressure sensitive, and releases the same amount of oil for each cycle regardless of the pressure in the line)
Not that I am running it this way, just stillwondering about it.
I think the purpose of the top of the OMP nozzle connecting to the intake elbow is, to keep just enough vacuum on the diaphragm to keep it closed and tight when oil is being pumped into the nozzle and avoid leakage through the top nipple(as it gets old or distorts looses some of its plasticity), while still retaining the ability to pull the oil charge into the chamber unabated.
Last edited by rotarypower101; 12-01-04 at 04:57 PM.
#21
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And I agree with you it dosnt make alot of sense if you think about port timing and where the OMP nozzle is located, that the chamber would be under vacuum. But I have never seen anything stating what the pressure will be inside the chamber for a certain crank angle degree by degree. Maybe the internal volume increases fast enough to overcome the intake charge, though that would seem inefficient and odd.
#22
My take on the video is that this is not an anti-siphoning mechanism. Rather it is simply a way to manage variations in combustion chamber pressure in the oil injector.
Here's my seat-of-the-pants analysis...
I assume oil is injected during intake. And (again) I assume during intake, the combustion chamber could be under positive or negative pressure, depending on boost etc... But the metered oil needs to be injected regardless.
So, the first scenario is negative combustion chamber pressure. The metered oil dose is delivered and greedily devoured, but there is still a draw on the injector. The injector's valve lets some air in so that the oil line is not sucked dry.
Second scenario is positive pressure. Oil can be pushed into the chamber anyway (because it is still at significantly higher pressure), and the injector flap seals so that the oil and valuable boost pressure cannot be blown out the top of the injector.
So... the vacuum lines run to a point before the turbos so that they always see *light* vacuum - enough to keep the valves sealed unless air is needed by the injectors, at which time the light vacuum is easily overcome and air is drawn in.
If you run the vacuum lines to the intake manifold, I would imagine you would see much lower pressure differential (none?) across the valve which would just leave it "flapping" and could result in it some oil leakage up the vacuum line.
Venting the nipple would likely result in an oil leak, as there is not a draw to seal the injector adequately.
Here's my seat-of-the-pants analysis...
I assume oil is injected during intake. And (again) I assume during intake, the combustion chamber could be under positive or negative pressure, depending on boost etc... But the metered oil needs to be injected regardless.
So, the first scenario is negative combustion chamber pressure. The metered oil dose is delivered and greedily devoured, but there is still a draw on the injector. The injector's valve lets some air in so that the oil line is not sucked dry.
Second scenario is positive pressure. Oil can be pushed into the chamber anyway (because it is still at significantly higher pressure), and the injector flap seals so that the oil and valuable boost pressure cannot be blown out the top of the injector.
So... the vacuum lines run to a point before the turbos so that they always see *light* vacuum - enough to keep the valves sealed unless air is needed by the injectors, at which time the light vacuum is easily overcome and air is drawn in.
If you run the vacuum lines to the intake manifold, I would imagine you would see much lower pressure differential (none?) across the valve which would just leave it "flapping" and could result in it some oil leakage up the vacuum line.
Venting the nipple would likely result in an oil leak, as there is not a draw to seal the injector adequately.