88 SE

First, they make fuel injection 2 stroke oil

Second, on non turbos, lower octane is better. Not that 100:1 ratio of premix lowers the octane enough to even make a difference.

Third: The problem isnt that it injects TOO much oil, the problem is it injects dirty crankcase oil that not only doesnt burn right but also leaves large deposits behind.

88 SE

Yea, it does get sucked in at a decent rate, the problem is it doesnt distrubute very well. You can see on used rotors that the oil kind of just stays in the middle of the housing, which is yet another advantage to premix, it actually coats the entire seal

88 SE

From reteds premix FAQ page: http://fc3s-pro.com/TECH/FAQ/premix.htm

"One draw-back about the pre-mix system is that the stock ECU shuts off the fuel injectors on decel or anytime you lift off the gas pedal and RPM's are dropping to idle speeds. This can be of a concern, as the stock OMP systems are constantly injecting oil all the time, but the pre-mix through the fuel injectors is not. This is where the before-mentioned pre-mix combustion by-product lubrication comes in - with lubrication already laid down from previous combustion cycles (especially under a heavy WOT run at high RPM's), there's very little worry about proper combustion lubrication.
"

jacobcartmill

iTrader: (6)

i have been pre-mixing with marvelmysteryoil every three tanks or so just to freshen things up a bit. i have the stock OMP and 150k miles and perfect compression on my s5 NA.
am i wasting my time premixing the MMO or does it help as well as the tcw3 stuff?

Amur_

Personally, I don't think of using MMO as premixing. To my mind, it's a fuel injector cleaner that some people have reported does a nice job at also reducing carbon in the motor (on the rotors and in the housings.) MMO is pretty much just kerosene with some other **** mixed in. Kerosene is NOT premix.

Premix doesn't clean anything. It only lubricates.

Aviator 902S

Tracy Crook ran his 13B-powered RV4 airplane on a pre-mix of MMO for the first 800 hrs (equivalent to about 50-75K miles on a car). A borescope inspection at this time (thru the exhaust port) showed a practically new rotor and seals with no build-up of carbon. He then switched to TCW3 2-stroke oil and sez it works just as well or (theoretically) better. Sounds like you can't go wrong with either.
As for OMP vs pre-mix, There's no question that as long as oil is being supplied from the oil pan (4-stroke oil) you're going to have carbon build-up and all of the problems associated with it, including oil-injector failure.
You can't go wrong with pre-mixing (unless you add way too much oil for the amount of fuel in the tank), but there is another option that's been mentioned on this forum before. That option of course, is an OMP adapter that acts as a block-off plate (blocking off oil flow from the oil pan) while allowing 2-cycle oil from a separate reservior to enter the pump and be metered to the intakes. I'm using one on my carburated 12A, which of course allows the oil to pre-mix in the float bowls of the carb before entering the engine.
On your fuel-injected 13B, you don't have the luxury of the fuel pre-mixing in the bowls prior to entering the engine, since the 13B uses injectors for this purpose. But it remains to be seen if the oil injectors will last longer if metering 2-cycle oil rather than the crud from the oil pan, and it also remains to be seen if there will be any difference in wear characteristics between an engine that uses pre-mix and one that had 2-cycle oil metered into it via the oil injectors. (Although in theory, the pre-mix would be more evenly distributed in a fuel-injected 13B) One thing's for certain: you won't have any more carbon build-up.
As for the myth of these adapters allowing the oil to syphon into the engine while the car is parked and shut off, it appears that it's just that--- a myth. Otherwise my car would have a HUGE cloud of blue smoke on start-up. It doesn't. The oil in my 2-cycle oil reservior is slowly dropping at a rate of about one liter per 1000 miles, as it should.
These adapters cost around $78-$88 U.S.D. and take about 1/2 hr to install. Call PCV Technologies at (850)834-4905 or e-mail at unicorn@gdsys.net for more info.

Aviator 902S

OH YEAH, ALMOST FORGOT: the above-described metering pump adapter set-up would also negate the problem of having the ECU on your S5 going into limp mode. Something else to consider...

allforjesus06

Hey, Im rebuilding my 88 13b, and I have looked over a few premixing forums and premix write ups about the mod, and I have 1 question that I haven't found an answer to. Doing this mod, will I still
a) need my regular engine oil,
b) if needed, will it need to be replaced and new oil filter every 2500-3000 miles

Please dont flame, because I've searched and tried to find this answer, and I understand the concept of blocking the oil injector holes with bolts and plugging up the line that goes to the spider. Your help would be much appreciated.
-Chris

Amur_

Absolutely you will still need to use regular engine oil. Continue to use it as you normally would.

Icemark

Yes, you will need regular engine oil in the engine to work. Premix is only mixed in with the gas, and does not provide lubrication or cooling for anything other than the apex seals.

On a Non turbo 3k to 5k miles (or after anytime the engine is flooded) is fine for oil changes.

For Turbo motors, oil changes of every 3K miles (or again after anytime the engine is flooded.

andrew lohaus

it is quite easy to get an s5 car to run on premix. simply pull off the omp, pull out the worm gear that sticks into the engine block, then bolt it back up with a block-off plate inbetween. the omp will keep spining away, thinking that it is injecting and fool the ecu, even though it no longer is actualy injecting oil.

ERAUMAZDA

LOL....You guys are funny.

1. Carbon build up is largerly created from the fuel being burned in the combustion chamber.

2. Oil is not just a lubricate, but it seals and cools the engine down. Premix is mainly benefical to the turbo engine since at high boost and high rpm oil is not injected into the engine anymore.

3. The rotary engine is young, but I fail to believe that the mazda engineers will agree that premix will improve the life of an engine.

4. So you opened your engine and found everything shiney. LOL....So because something is nice an clean its working. Of course if engine oil is not injected into the chamber its going to be nice and clean. I wonder how a bearing looks when it has no oil between the bearing and bearing surface.

I can just imagine a cold engine in the morning with out any oil in the chamber must look like and I don't what to imagine the guys who try to unflood there cars and no oil is being injected into the chamber. I can image the guys who have a ground problem on there rx-7 and keep cranking the engine bitching that they have no fuel getting to the chamber. Oh crap no oil either. I believe if you go premix is should be a combination of premix and injectors or half injectors and premix.

oregano

iTrader: (1)

"On a Non turbo 3k to 5k miles (or after anytime the engine is flooded) is fine for oil changes.

For Turbo motors, oil changes of every 3K miles (or again after anytime the engine is flooded."

why duz flooding the engine require an oil change???

ERAUMAZDA

One more thing. Many people put the improper oil in there engines as well. The engine is suppose to burn oil. (A LOT) use cheap oil in there rx-7's or put in syntheic sp* thats not ashless.

Carbon build up is mostly from gasoline. I pull apart aircraft engines that run on 100ll and the carbon build up contains lots of lead content which is from the gasoline. The carbon build is actually found in the crank. This goes to show how far it will travel.

scathcart

Premixed gas/fuel has nearly the same consistency as gasoline. Premix does not add any deposits to fuel injectors; in fact, it helps them to run slightly cooler.

Premixing gasoline to standard TCW-3 2 stroke oil lowers the total gas/oil mixture by less than 0.1 of an octane (at 91 octane and a 128:1 premix ratio). There is more descrepency between gas station tanks than there is with an octane loss associated with premix.

The stock MOP system is a compromise for stupid owners. Mazda would never have been able to ask people to premix every gas tank, or deal with the repercussions when they forgot, so they designed the stock MOP. Engine oil was never meant to be burnt in the combustion chamber; 2 stroke oil was.

Lastly, anyone without direct experience in evaluating engines running premix vs engines running the stock MOP over a series of time can keep their opinions to themselves. Several of the builders on here have reported next to zero carbon deposits when running premix (including myself, after analysing an 87,000 km engine on premix its entire life); how can this fact be ignored?
Also, if premix is not helping with lubrication of the combustion chamber, then why does vacuum at idle increase when switching to premix? (Turbo/FD guys note this a lot.)

scathcart

Gasoline seeps past the engine seals, getting into the oiling system and diluting the gas.
I do my oil changes every 2000 miles, turbo or N/A. Haven't you ever noticed how the gasoline always smells of gasoline when you change your oil?

RoToReX7

so EVERY time you guys fill up a tank at the local gas station, you put in premix?

scathcart

Flooding is sacused mostly when fuel washes away engine oil from the cumbustion chamber walls, and decreases engine sealing. Adding oil to gasoline would help with sealing, and make flooding less of a problem; the exact OPPOsITE of what you said.

When there is no oil between bearing surfaces, they overheat and weld together. If they can come apart, they look scratched, gouged, and burnt black from overheating; not shiny. Again, you were completely wrong.

The R26B premixed. Is this not enough proof to you that mazda engineers thought it was better?
The engineers were taken into account that the general public are idiots when it comes to car maintenance. There is no way they could justify a seperate reserve canister that ahd to be filled with "special oil", or forcing owners to add a bottle of opil to every tank. People would forget, and engines would blow. THIS is the reason for the MOP, not because it is the most efficient lubrication system.

While the incompltete combustion of iso-octane does have carbon as a product, the primary cause of build-up in a rotary is due to the combustion of 4 stroke oil. This will be hard to understand unless you have a lot of experience with tearing down and building rotaries.

1987RX7guy

iTrader: (3)

Sing it brotha!

RETed

You have been resurrected!
Hallejuyah!

Don't you just love all the negative comments from people who do not pre-mix?

I just had my car "resurrected" from sitting around for 2 years in the hot/cold Vegas desert.  Before I started the car, I spun the engine with the trans in neutral, and it spun so easily I thought it had blown/stuck all it's apex seals.  The engine had been rebuilt and pure pre-mix for the previous 3 years.  It started up on the first try after changing out the bad battery and alternator.  There's no way it would've done this without the pre-mixing.

There are always going to be detractors, no matter how hard your argument it.  It's like all the synth oil and pulsation damper/banjo bolt debates...

*sigh*


-Ted

MPM

I relied on the MOP/OMP and my engine died at 108,000 miles. I did my oil changes every 2000-2500 miles for 54,000 miles(when I bought the car) and it still died. The only usable parts in the engine were the front and intermediate plates and E-shaft. The OMP had died and there was no way for me to know. My new engine is premix only even though I may put the OMP back on I'm not going to rely on it. My racecar is also premix only. If I pay this much for an engine I'm going to spend the extra $2 when I fill the car up to assure my engine will last.

Icemark

When the engine is flooded, gas seeps past all the seals much easier. This leads to contamination of the oil.

Any contamination of the oil requires replacement, or the oil will not do what it is supposed to.

Icemark

That happens more often if the seals are starting to get old, or the mixture is too rich (or you have flooded the motor of course)

Icemark

Yeah, that is how I have gone.

When I put the S5 intake on, I put an additional guide pin hole and adjusted the MOP linkage, so that it is injecting less oil (about 2.5cc at 2k RPM@5 minutes, instead of the normal 5-6cc) and I am using premix.

Best of both. Increased seal lubrication at higher RPM (which premix doesn't do), and constant internal lubrication of the seals (which some would have you believe that the stock MOP doesn't do).

Drawbacks of only having to add premix to the tank at fill up or moving the retaining pin. If I don't have premix available, I simply remove the cotter pin on the linkage, and raise it up to the OEM flow specifications.

projekt

actually it happens always and will always happen no matter what!