signofinfinity

hi,
so i cnc ed an alumium block off plate, and managed to find a mechanical OMP for my fd.. fitted really slick... now i 'Y' the top two feeder from the pump to the front rotor, and the bottom two to the rear rotor. the fd has only two oil injectors.

now anyone did this on an fd? i can set up a way for throttleing. i held open the lever....but its dumping too much oil... like 200ml for every 35kms!!!!

so the leaver i gather is not just an on off leaver, but a flow regulator!right?

any set up on the fd and any ideas how you made you throttle body control the omp?

thanks

Merry xmas

George

patman

iTrader: (3)

yes, it is a flow control lever. on the fc it is just attached to the end of the throttle shaft with a long rod. im sure you could do something similar with the fd, but i'd have to have one in front of me to tell you how.

Zachmac

I ran across this when I was considering this mod and what resevoir to use. it would seem a brake fluid resevoir would stand up fine to the oil AND it has an integral low warning switch AND can be had at the junk yard for less than $10.

http://www.jag-lovers.org/xj-s/book/...ervoirFix.html

TonyD89

iTrader: (10)

Can I use the sub-zero start tank? Will it hold up? Is it large enough?

Aviator 902S

Large enough, yes. Will it hold up? No. It's made from the same plastic (and is about the same thickness) as the washer fluid reservior. The power steering fluid reservior idea is a good bet since they are designed to hold mineral-oil-based substances to begin with.

sevensheaven

iTrader: (1)

I used a radiator tank for mine and it has been working well. It holds around a quart and three tanks of gas takes it down to about half full.

https://www.rx7club.com/3rd-generation-specific-1993-2002-16/location-ra-adapter-2-cycle-oil-resevoir-show-me-pics-583688/

Marcel Burkett

[QUOTE=signofinfinity]hi,
so i cnc ed an alumium block off plate, and managed to find a mechanical OMP for my fd.. fitted really slick... now i 'Y' the top two feeder from the pump to the front rotor, and the bottom two to the rear rotor. the fd has only two oil injectors.

This is what I think I want to do , put a mechanical OMP on my FD since my ECU cannot control the stock one , and I see that an adapter is now available for this ,..........I still have some questions for u guys thiugh .

1. How about an independant aftermarket controller for the OMP , is anything like this available ?
2 . Anyone thought of using an actuator from an internal wastegate to "open" the pump up progressively under boost ?, of course it will be set to an appropriate position to allow proper oiling in vacuum .
3 . Anyone tried using boost pressure to pressurize the 2 stroke reservoir for increased flow under boost ?

patman

iTrader: (3)

1. there isnt anything available, but it would be a fairly easy thing to design if you wanted.

2 and 3. the injectors already take care of this. thats what the vacuum lines on them do.

from what i understand, the late model MOP is just a stepper motor. stepper motor controllers are easy to find or make, but why not just use the mechanical pump, that seems even easier still...?

pat

Marcel Burkett

So are saying that the vacuum lines attached to the oil injectors "suck" oil through the injectors when in low load conditions and push it through them when in boost ?
I have since decided to go with the adapter from RA and put on a mechanical pump , and forget the stepper motor , but a problem arises since I use an aftermarket Holley Style big bore throttle body that doesnt have any type of attachment for the rod , and I really dont want that thing hanging on there .Mounting and setting up a mechanical pump is easy , but getting it to change the flow will take a bit of work , the easiest thing I can come up with is attaching an actuator to the OMP's lever and allow boost pressure to move the actuator which will in turn move the lever .

patman

iTrader: (3)

yeah that should work, just might be a bit of a PITA to get set up.

i havent ever cut one of the injectors apart, but i believe they work similarly to a diaphragm type fuel pump, the vacuum or boost variation causes it to pump and spray the oil. i guess thats not quite what you were asking about, sorry.

RXBeetle

replied to the wrong post... nothing to see here

RXBeetle

The injection pump is actually a positive variable displacement pump. I took mine apart the other day and it is really a neat setup and took a few minutes to really figure out how it functioned.
The tube lookin thing (matte gray finish) is the cylinder of the pump and the holes in it are the intake and outlet ports. It rotates with the worm drive off the motor and that rotation causes it to also reciprocate back and fourth due to the little cam at the linkage end of the gear shaft. Yes the cylinder reciprocates and the piston (the little ~1/8" rod inside with the spring on it) is stationary. The rotation and reciprocation cause the inlet port to be opened as the cylinder goes back toward the linkage end and closes the inlet / opens the outlets as the cylinder moves toward the spring end. The rotation of the linkage determines the stroke of the cylinder by limiting how far the cam at the gear end can retract.

13BT_RX3

Wonder if this can be used to control the electronic OMP?


Oil injection module for a Mercury Outboard Engine Pt # 41470A27.

Photo take from:
http://cgi.ebay.com/ebaymotors/OIL-I...QQcmdZViewItem

Isphius

Ok, sorry for the newbness, but i am new to the rexs. Im guessing the MOP injects oil into the intake? like manifold oil pooper or something? And what does it do by blocking it and using 2 stroke oil? or are you modifying it to use 2 stroke oil instead of crankcase oil? thanks for patience lol.

sevensheaven

iTrader: (1)

This is how it works, It uses vacuum controlled injectors that mount on the rotor housings. Oil is directly injected to lube the apex and side seals. It not intended to aid combustion or anything else. Motor oil is not meant to be in the combustion chamber and that’s why some of us like to change the system and the oil it uses. As for what the vacuum really does I am not positive. There have been many ideas. The injectors only feel vacuum and not boost so under low vacuum situations I think the flow through the injectors is limited / metered differently, I assume low vacuum less oil is allowed in. I bought new ones for my rebuild so maybe I should cut one open to see how it works!

Terry7

Isphius

Yup, kinda figured the apex lube thing. And I would think 2 stroke oil would be a natural choice, its supposed to be burned with a spark plug and gas. Plus it looks pretty cool when you rev it up. I used to use 2 stroke oil at 100:1 premix in my racing karts (briggs powered) to keep the valves and top end happy/cool, because they are air cooled. If i get a rex, this is something i would do too.

Marcel Burkett

Really ?, I can remember the vacuum hose that was connected to the oil injectors were also connected to the LIM , and that would mean that they would see boost , what I know for sure is that the oil injectors are one way valves too .

NewbernD

iTrader: (1)

It ultimately connects to the intake tract, pre-turbo. The LIM has 4 "pass-through" vacuum passages and this uses one of them. That's probably why you remember it connecting to the LIM.

Some have argued that where the pickup is located (pre-turbo) it doesn't even really see much vacuum and this is just a source of filtered air.

Marcel Burkett

OK , I just looked at it in the vacuum diagram and you're both correct , the oil injectors don't see boost through the vacuum hose attachment, they only see boost pressure momentarily at the injection end when the pressure in the intake tract increases under boost , as I said before I know for sure that the oil injectors are "one way" so pressure is prevented from getting into the OMP lines if OPM pressure is lost , I would expect , however that the oil pressure would ALWAYS be higher than the boost pressure , so reversion should not be an issue , but little or no forward flow can be an issue . This is what I think the vacuum attachment to the oil injectors are for , to create a greater pressure differential between the OPM and the oil injector in low load (low RPM) situations , since there can be instances where the intake tract is at atmospheric pressure or very low boost (.5-2 psi) and the RPM's are still low resulting in "low" oil pressure since oil pressure is directly related to engine RPM . The turbos suction would ALWAYS be in vacuum no matter what the motor is doing (once the BOV if functioning properly) so it would make sense to connect there and always have a pressure differeential at the nozzle causing the oil to be "sucked" forward .
Also could the vacuum connection also be intended to keep the holes in the injectors clear ?

DamonB

The vacuum lines to the OMP injectors are plumbed to a filtered air source that does not see boost pressure. This means they plumb between the air filter and the compressor inlet as this is the only area that is filtered and sees vacuum 100% of the time.

Why do these vacuum lines exist? The OMP pumps oil into the motor via the injectors which really are just simple nozzles. When the manifold pressure is negative (vacuum) the engine is literally sucking on everything connected to the intake tract, this includes the oil injectors. The vacuum line provides a leak path to the oil injector so that when the engine is under vacuum and "sucks" on the injector it doesn't suck all the oil from the metering tubes. Instead the engine "sucks" filtered air through the leak path created by the vac lines and the OMP oil lines are not placed under excessive vacuum which would quickly empty them. If this happened the OMP would not be in complete control of the amount of oil ingested as whatever oil the OMP admitted into the tubes would be immediately sucked out rather than metered in small "doses". Without the leak path at the injectors the engine would merely suck as much oil through the tubes as it could get anytime the engine was under vacuum.

When positive manifold pressure is present the one way valves in front of the vacuum lines inside the oil injectors close. If there were no one way valves present inside the injectors manifold pressure would leak into the OMP system and pressurize the sump. Not only would you have a boost leak, you'd be pressurizing the sump. Both bad. When positive manifold pressure is present the OMP has to overcome the boost pressure inside the engine in order to deliver oil inside the motor but that's not very difficult since the diameter of the injector nozzles is so small.

An analogy of this would be you sucking soda through a straw. Imagine built into your straw was a pump that was supposed to control the amount of soda passing to your mouth as well as deciding how often to deliver a sip of soda to your mouth (this is what the OMP does. It decides when you get a sip and how big that sip is). If the pump were merely built inside the straw there are only two openings present; one in your mouth and the other in the drink. If you were to suck hard enough you could suck as much soda through the straw as you wished because you could suck it right through the pump, even if the pump were attempting to deliver a smaller amount of soda. If we inserted a tee into the straw between your mouth and the pump whenever you suck on the straw you'd merely suck air through the tee, allowing the pump to be in complete control of how much soda is delivered to your mouth no matter what you do at your end of the straw. We'd also install a one way valve in that tee so that when the pump is delivering soda to your mouth none of the soda goes out the tee, it all goes into your mouth.

As many have done you could eliminate the vacuum lines all together and leave the vac nipples on the oil injectors bare but that's not a good idea. This allows the engine to ingest unfiltered air anytime the engine is under vacuum. Everyone claims the OMP system works fine without the vac lines attached and they're right. The OMP system will work fine but your engine is ingesting dirty air everytime it's under vacuum. Poor choice.

My posts in this thread have further description on how the OMP works:

https://www.rx7club.com/3rd-generation-specific-1993-2002-16/omp-how-works-modification-amecu-discussion-regarding-premix-60867/

13BT_RX3

Nice OMP function discussion.

I would imagine that pressure in the chamber gets pretty close to maniflod pressure. Even if the check valve closed there is more than atmospheric pressure in the chamber to fight the OMP lines. I think the check valves are there to allow air in at low speed operation to spray the oil around a bit when the engine isn't moving fast to do it for itself.

sevensheaven

iTrader: (1)

I have mentioned this several times before and no one has wanted to discuss it. The rotor housings themselves have extreamly small jets under the injectors mounted in the rotor housings themselves. I could bearly see light through them in the dark and could not even find anything small enoff to push through the jet. I was able during my rebuild to feel compressed air through them on both my rotor housings making me comfortable they were not blocked. A warning to those that leave oil injectors open, it wouldn't take much to plug the path for oil through the rotor housings to the apex seals. Not one thread I have read on this forum has ever mentioned rotor jets that I can recall. It may be that some plain worn out low compression motors have fallen to this oversite. New rotor housings have a little different set up, but still have them (jets). If you have looked at a new full gasket kit it will come with two small brass spacers. There is a difference in distance between those jets and the old rotor housing jets and thats where these spacers come in to play. It has been noted in other threads that the new injectors have smaller holes than the old ones, but based on the jets inside the housings that wouldn't make any difference in the amount of oil to the apex seals. With this all aside not much air could ever pass through the oil injection system, at least not going in. Under boost I would agree that air / fuel could be pushed back through the system and that is prevented by the check valve as stated above. Its funny to note that old jets appeared to be removeable because they were sloted. Perhaps Mazda used different sizes over the years and that is the reason. Its seems now that with new housings they are pressed in and more permenant. I would like to try and remove a set If I had a chance sometime. However I couldn't get mine to budge and didn't want to possible ruin a housing trying to remove one. I do have an old used housing but I have no idea what year it is and haven't remembered to look closely at it to see that set up.

Terry7

micah

Okay, digging this thread up AGAIN..

I just changed my oil and tranny fluid... Its like... 20F degrees outside. The consistancy was like honey.

How will the thickness of 2cycle at low temperatures affect the injection process? I can imagine this isn't that much of a problem on a normally OMP'd or premixed engine because the engine either heats up the oil, OR the premix is thinned by the gas.. so...

any thoughts?

Aviator 902S

2-cycle oil is less viscous than the 4-cycle stuff, but unlike synthetics it does thicken up when cold. But then again, so do the 4-cycle multigrade dinosaur oils. Yet the system still functions in the cold even with this stuff.

So, since the 4-cycle dinosaur oil thickens up more than the 2-cycle stuff does, your 2-cycle system will work fine.

micah

Thanks for the reassurance.

EDIT: That wasn't sarcasm FYI. I just re-read it... and it totally sounded sarcastic. Hehe.