RX-7 GT

muhahaha... i know the **** will hit the fan soon. and since ted is on at least i'll get one answer. is it really that much of a pain to run pre-mix? i noticed ted you run valvoline multi-use premix i think thats what its called. how much of an expense is it a month and is it worth it?

what did you use to block off your omp pump? and what did you do about the oil injectors? leave em on and cap the little nozzles? trying to see if i should do this on my new setup. getting a jspec in a few weeks

RX-7 GT

hwo, reted i know you are running pre-mix..throw some more info over thats over my head

RETed

I run Valvoline "Multi-Use" pre-mix or 2-cycle oil.&nbsp These are in dark blue plastic bottles easily found at any Kragen/Schucks/Checkers.

Per quart bottle, it's priced @ $2.29 each.&nbsp Per gallon, it's $7.99 each (which makes it about $2/quart).&nbsp Every few months, the gallon bottles go on sale via the Sunday insert for $6.99.&nbsp This pre-mix actually used to say "for use in...rotary engines" in the back label, but they have changed this now.

Now, I pre-mix at approximately one ounce per gallon, or 16 ounces per full tank.&nbsp It's actually a little bit richer at around 100:1, since a full tank for me is around 13-14 gallons; I pour half a quart, or 16 ounces into the gas tank before filling up at the gas station.&nbsp Conversion factor:&nbsp 1 gallon = 128 ounces.&nbsp Factor in the 13-14 gallons, the premix ratio comes out to about 105:1 - 115:1.

Depending on your mileage, I fill up gas every couple of weeks.&nbsp So I go through a quart of pre-mix every 3 weeks or so.&nbsp Buying in gallon bottles (then pouring into the old quart containers) makes it pretty easy to store and dispense at the gas station.&nbsp The bottles comes with a transluscent side with graduated levels marked off at every 8 ounces.

As for yanking out the stock OMP, I used 10mmx1.0 bolts with some thread sealant and plugged up the existing holes after removing the stock oil injectors. &nbsp After yanking the stock oil metering pump, I actually went through the trouble of yanking the geared pump from the inside (not that necessary) and covering the exisitng hole with a block-off plate.&nbsp This takes care of anything leaking.

I find it worth it.&nbsp The car runs a little "cleaner", even though I don't have any cats or emissions.&nbsp I've torn down the engine after 20k miles, and it's a LOT cleaner!&nbsp Not as much carbon build-up as with normal motor oil injection.&nbsp I find the theory behind pre-mix superior than the stock oil metering that Mazda uses.

Did all of that make any sense?



-Ted

Scott 89t2

you need to get out more! I was going through a tank every 5-7 days when I was driving it about 15mpg

RX-7 GT

i'm not sure let me read it again.....

ok. i understand the removing of the oil injectors. plug each of the 4 holes with 4 10mm x 1.0 bolts. got that part down. and im confused about the actualy part where the lines connect down on the front cover. just make a custom block off plate and i'll be fine? and thats it?

RETed

Damn, I don't drive as fast as some of you young 'uns!&nbsp I typically get around 18-20mpg nowadays.



-Ted

RETed

Yep, remove the oil metering pump - block this off with a custom plate.&nbsp Remove the oil metering lines.&nbsp Remove the oil injectors and use 10mmx1.0 bolts to replace.&nbsp Yank all the vacuum hoses and 4-1 splitter, and plug the hole in the back of the upper intake manifold (at least for the turbo engine).



-Ted

RX-7 GT

awesome! i just love removing parts to make it simpler

i think i'll post again in another thread about solenoids now!

BBW

Hello RETed,

I have a few questions:

How many miles have you been running on the pre-mix with your current engine?

What would happen if I use pre-mix without taking out the omp?

According to one of my rotary engine books, the inability to put in the correct amount of 2 cycle oil consistantly in the engine was one of the main reason that Mazda abandoned the pre-mix technique. That book was published in the late 60s. I don't know if this information is still applicable today.

Any information you have on long term durability with using the pre-mix is greatly appreciated.

BBW

RETed

My engine has over 30k miles on pre-mix so far.

Worst case scenario, it would smoke out the exhaust.&nbsp Best case, nothing you wouldn't notice out of the ordinary.&nbsp I would bet you would never notice, especially if you stick to the recommended ratio of 400:1 pre-mix to gas when still having the stock OMP functional.

I was always told that Mazda was worried about consumers remembering to add pre-mix to the gas tanks on gas fill-ups.&nbsp The OMP with motor oil was a compromise in design with the least inconvenience to potential owners.&nbsp There is no way to remind you that you forgot the pre-mix, but we all know how loud trhe buzzer is when the oil level is low.


-Ted

llneal

I just picked up a 87,00 mile 87 TII that demonstates another hazard of the OMP and it's old lines. The previous owner had a oil line break dumping oil on the exhaust causing a small fire. On initial observation it looks like the oil and vacuum lines took the brunt of the damage. The price that the dealer quoted him to fix it was outrages so he sold it to me cheap. I had been pricing parts to repair but what I get from here it looks like I might be better off just removing the toast and running premix.

Scott 89t2

it's for ease of use. do you think most owners would want to carry around an extra bottle of oil, and have to put it in everytime? or have to explain the system everytime you let someone else borrow/drive the car? hell most people can't even get their oil changed without waiting a year. they aren't going to be dumbing pre mix in every tank.
I could just see people trying to explain at full serice gas pumps, telling the gas guy to add some chainsaw oil to the tank the gas pumper would probably start laughing his head off.

HWO

i removed the gear drive for the OMP when i had the frotn cover off to replace the oil pressure O ring, i just made a block off plate outta some 1.5mm thick aluminium i had lying about, put some silicone gunge on it and bolted it into place. found some bolts the same thread as the oil injectors, coated them in silicone gunge and threaded them into the holes and did them up tight.

Turblown

iTrader: (12)

Doesn't the OMP deliver all of the oil to the car? Cuz putting in premix would only get the apex seal right? What about the eccentric shaft and inside the rotors? And doesn't it do like 40% of the cooling too? If you all ready removed your omp couldn't you get rid of your oil cooler, pan and all that ****? Im a little confused

Scott 89t2

the car still has the main oil pump, you could never get rid of that!. the OMP is just a little one on the side that only pumps oil into the engine to lube the seals.

tesla042

this may help.. he essentially deleted parts #7, #8, and #9 from the below pic. The rest of the oil system is ESSENTIAL, of course..



-Tesla

turboren

I have heard before that removing the pump and running premix was a good way to keep the internals cleaner. Good to see that in writing from someone with personal experience. I had long thought that the reason for the OMP was for convenience of consumers.

Is there a reason that two-cycle oil is specified? Any reason not to use regular engine oil? Also, and this may sound dumb, but, could you run ATF instead of oil?

Ren

Ever

I have been using premix for a while now, and i dont even think twice about it. 1 bottle with a little spout thingy so i can pour it in easy. when your done put it in you case thing behind the seat then pump up. and your lazy if you cant pump your own gas, it takes 5 seconds to put the knozzel in and push the lever down and wait.

Shamrock1054

How about in a daily driver? Is the oil/fuel ratio so critical as to preclude "guesstimating" with partial tank refills?

mazdaspeed7

Shamrock, the recommended ratio for premix without an OMP is 1 oz per gallon. So if you put 4 gallons in, use 4 oz of oil. With the OMP still functional, you would want to half that, or 1 oz oil per 2 gallons of gas.

Turboren, 2 stroke oil is used because it was designed to burn without fouling out the engine. You will foul the plugs really quick using anything else.

A word of warning. S5 engines with the electric OMP CANNOT just block the lines, unplug or anything else. There is a very specific way you must disable it. I spent a month figuring this out, and had one OMP lock up on me.

First, remove the drive gear from the eccentric shaft and/or all the internals from the OMP itself. Either one will accomplish the same goal, but the OMP casing MUST be left inplace AND plugged in. If not, your engine will go into "limp-home" mode every 7 min without fail. Believe me, I spent a month trying to fix this. The stepping motor MUST be functional, the actuator it pushes must move freely, and the sensor must be calibrated correctly(it comes calibrated, so as long as you dont mess with the shims, you will be fine). Both Plugs must stay plugged into the harness. Then you can block the lines off at the OMP with bolts. The thread size/pitch is listed earlier in this thread. You cannot just block the lines, or the OMP will lock up(ask me how I know). Once the pump itself is disabled by gutting it or removing the gear on the eccentric shaft, then you can block off the lines without worrying.

All of the mechanical OMP's, S4 included can just be removed/blocked off/whatever. Its only the electric ones on the S5 that are a real PITA.

Node

iTrader: (1)

could you make a custom OMP (uses same injectors, just diff timing and seperate oil source) and use pre-mix and a higher ratio?

Or must the oil be diluted in the fuel first.

mazdaspeed7

Ive seen an adapter that makes the OMP take 2 stroke oil from a reservoir instead of the engine oil. I dont have the link though.

Turblown

iTrader: (12)

that makes sense. I thought #9 went inside the rotors. So running premix won't clog the fuel pump, filters or injectors I presume, or hurt the plugs or o2 sensor. Would regular oil clog these things?

j9fd3s

iTrader: (3)

my 65 nsu wankel spider had a metering pump

mike

FC3sRacingSD

I have a highly modded TII and have been running premix for 2 years since I have no choice...88 with a 90 engine...and I have had no problems. Plus....doing my research....2 cycle oil burns much cleaner than conventional oil....that means a cleaner....longer lasting engine.