Almost another year has past and everything is working well. I have logged over 5000 miles on this mod so far.

 

Nice. Definitely a to do this over the winter.

Ive seen on my Fd and a few other rotary's the car will sometimes choke up on 2stroke when premixed through the fuel. Or at least that what i believe is happening? Usually happens during a long cruise or a prolonged idle period.

Since the 2stroke is not being injected through the fuel mixture anymore would this solve that?

 

I've heard of two-stroke oil setling out of fuel before, but it is unlikely that would happen while driving the car (That would mean the oil would be picked up in a higher concentration at the pump), still I doubt it. I believe that too much premix is fowling the plugs which is more likely the answer.

 

Still going strong with out issue. I couldn't be happier with the out come to this point. I don't have a milage update, but I have traveled out of state several times and untold gallons of two stroke oil have been combusted. One thing of note, plugs have remained unchanged for this entire modificationl.

Terry7

 

in my list of things to do! have you at least looked at the plugs? how are they?

 

yes, I had them out around a year ago. That is what I ment that they have been in the car since the mod was installed. Plugs have normal deposits.

 

This is a response to a message on this post.

First, the mod is doing well and Mileage is well over 10,000 miles now.
I wouldn't just block off with out drilling, read on to find out why.
To drill or not to drill?
My answer is drill. I don't know what size drill I used. I would drill a smaller hole nest time. My oil pressure is maybe 4 psi lower at idle than stock. Pressure at higher rpms is normal. I believe the slot in the cover has a lubricating purpose for the shaft which drives the omp. How much oil passes through it to lubricate the shaft I don't know the flow rate. At this point I would drill smaller, say 1/16 this will keep your idle pressure up. I think Mazda knew the flow rate through the shaft and case would be low because of tolerances between shaft and case. Pressure at into that area wasn't important, what was important was the oil presence for lubrication. I'm sure the back pressure was almost equal.
I can't see a way to make it more simple. Anytime you modify something you have to take every step to keep the original operation the same. Think of this mod as a dam with a spill way. Oil is needed to this section as part of the design. Your adding a new source of oil, but the new source is separate from the engine source. The new source just replaces the first source at the pump. Never the two shall meet. This is why I did every thing the way I did.
The second thing I would do is put a heat shield over the hose going to the pump. That is if you are running a turbo. They make these to cover hoses.

 

If your oil level is going down it was traveling out of the pump shaft into the shaft reservoir on the case and between the shaft and case into the oil pan.
Why? my guess is because your omp lines were disconnected allowing reverse flow. This is like when you hold your finger over a filled drink straw. The fluid doesn't come out until you remove your finger. This may depend on where the lines are off. Up on the engine or at the pump? If at the pump, I can't say how the pump works internally and why none came out there. If the pump didn't separate input from output it wouldn't work as a pump. With that said, I am sure there could be some leakage through the pump drive shaft into the case around the shaft and into the engine. So consider the condition of all these parts. Wear on the pump and also the shaft/case area. Still I think this would be very very small in amount.
One other thing is how high you placed the oil supply tank. The higher the tank the more pressure from the tank to the pump. Even though this is a gravity feed, remember higher the tank higher the pressure.

I know it has been a long time since this was posted, but I hope it helps others decide on this mod or not.

 

Having to drill and tap for that 1/8" pipe fitting is NOT the way to go. Too difficult and easy to screw up! After I saw one that was done that way and before assembly, there had to be a better way.

A piece of small SS tube, a corresponding size drill, and JB Weld makes a simple, easier, and better looking conversion.

 

^cewrx7r1 did exactly what he is suggesting both to his OMP and my OMP, and both set-ups work perfectly. We have the same mod to the OMP, same diameter line from OMP to tank, same tank, same tank location, and until recently, same oil. After verifying no leaks into the engine, our set-ups, unsurprisingly, use the same amount of 2-stroke. He has more accurately documented his usage (even with different 2-strokes), I will let him chime in on that if he wants.

Not saying the pipe fitting is wrong, but it definitely allows more room for failure.

 

Not to revive but to check in how this mod has been working..

sevensheaven,

I think this solution is truly ingenious. A few questions:

Do you think it is possible that idle oil pressure is dropping because of the relief hole you have drilled? Maybe ever so small ungasketed space between OMP and the housing was enough.

I don't know the exact clearance between protruded OMP assembly and the housing on the motor but they seem pretty tight so that small clearance is enough to push unused oil back to the return through that crack.

While I am gathering parts to do this mod or some variant of it, I am concerned if the gravity fed pressure is enough. One has to agree, stock OMP gets substantially pressurized oil from the oil pump.

I know that OMP dribbles oil into the chamber, other than "I had in my vehicle" evidence, just out of curiosity, has anyone actually checked how it is supposed to work with pressurized oil? I have read most of the articles available/found for past 5 hours including 3 series article on the OMP.

Could that pressurized oil possibly still dribble oil even if the OMP stops pumping ensuring that the motor is getting some oil; protecting the motor in limp mode?
https://www.rx7club.com/3rd-generati.../#post11437970

 

Doesn't Royaryaviation's OMP adapter do just this without all the work? This is only $125 on their website.
Oil Metering Pump Adapters - Rotary Aviation<br />.com
It's been on my "to buy" list.

 

But if you have stock twin, it is not as bolt on as you think without the Mikuni pump. You have to hack your stock OMP to clear the manifold as far as I can tell.

I am trying to understand the process so that I can get my own version machined adapter with different design.

Having said that, RA adapter depends on gravity only.

 

Did you contact RA about this? Their website makes no mention about the adapter working with the Mikuni only. How do you know "hacking the stock OMP" is necessary?

 

Researching and reading for hours.. Yes, it is a known issue at least from the people who has done it on FDs on stock twins.

The difference is not the OMPs mating surfaces, it is the lateral thickness/width of the two different OMPs. The fixes are known and they are to hack the portion of the stock non-Mikuni OMP to fit in between the stock twin and the motor.

 

Wow, thanks for the enlightenment!! I am planning on running stock twins, so I'll have to keep a close eye on your progress with this.

 

You might want to add a Polaris snowmobile oil tank with low level light to compliment the system.

 

Awesome setup, I think I may end up copying your setup or at least the electrode part of tank. How is it hooked up inside? Warning light?

Just gotta find me some space since my CAI in there.

How's your setup holding up? Did you also drill the engine side return? I am starting to wonder if it is necessary.

 

If you are going to drill the loop return, it should only be as big of a hole as the total of the two oil injectors. Otherwise, it is allowing more flow than the OMP would have allowed. This could explain some of the drops in oil pressure.

But the return shouldn't be necessary, as the oil passage to the OMP is just a branch off the oil system, and as long as your plate holds the pressure, it will just dead head there and not affect the rest of the oil lubrication/cooling system.

 

I was thinking something similar.

Now we got that out of the way, do you think OMP needs the pressurized oil supply? Or just need a small pool/pocket of oil in the recession built in the OMP?

 

As long as there is positive head pressure, the pump will be fine. That will keep the reservoir primed.

 

I did not drill a return line... it works that way stock.
As I remember the pressure lubricates the shaft and the overflow fills a cavity on the pump face with it's excess spilling back into the front case.

The warning light is a Radio Shack LED with 12v to it and it finds a ground through the tank float.

If you look closely in the picture you will see the bulb on the top of the steering column...... and the best part... it reflects in the tach face doubling its signal intensity.
This is an old picture. The green bulb is water/meth pressure and now on the other side (not shown) is a red low oil light.

 

Nice mod Jerry. Which 2 cycle oil do you run? What engine oil? How long/miles have you had that setup? How is the tank holding up?

 

This is what 2 stroke oil looks like after about 20k miles. The ashless formula makes a soft carbon that wipes off with your finger.
Many brands of 2 stk oil are good but I use Quicksilver Premium because it meets the requirements for my fishing boat, KTM Enduro bike
and our beloved rotary engine. (about $19 at Academy and Walmart)

The tank was designed for this 2 stk oil... so no problem.
For the engine I can run any oil (synthetic or petroleum) but normally run the recommended 10w30.

 

Does anyone have any pictures of this?