mjm4jc

I buy the Pennzoil 2 cycle oil at Advance Auto and mix it 1oz. per 1 gallon. So far so good. I think that 1oz. per gallon might be a little overkill, but better a little more than not enough. I understand why Mazda probably went with the OMP design, but it certainly is the poorest, dumbest thing they installed on a rotary IMO.

RotaryEvolution

iTrader: (30)

just wanted to comment on the 2 stroke oil settling point someone made.

i have let 2 stroke fuel sit in containers for literally years and the oil was still fully dilluted into the mix so i'm not sure what kind of fuel you were running but it certainly wasn't gasoline or possibly not 2 stroke oil.

i have many 2 strokes and some sit for long periods of time between uses so the fuel sits alot, like in my jetski for example.

j9fd3s

iTrader: (3)

nah premixing is lame. it only really works for racing, where you're full throttle all the time and thus need 100:1 ratio all the time.

you don't need that much premix just driving normally.

mjm4jc

So which is it? You're saying two different things under the same breath. Premixing is lame....................you don't need that much premixing just driving normally. So you think that an out-dated OMP system, thus injecting dirty engine oil is better than premixing?

j9fd3s

iTrader: (3)

for "normal" driving the OMP is better. if its a race car, then premix is better.

just IMO, too much premix doesn't really hurt anything, although the PP doesn't burn it and it'll come out liquid...

ray green

iTrader: (14)

So now I'm totally confused so I did an experiment. I added 5 ml Walmart 2 stroke (thanks '73rx3 for the clue) to 500 ml gas (that's a 1/100 dilution, for you environmentally challenged dudes) and gave it a swirl. Looks like the stuff mixes pretty good to me, I'll let it set 24 hours and post another pic.

http://www.youtube.com/watch?v=pdLFVCwQtkM

Box_Man

Castor oil is the ****, it's all I run in my high combustion temp model engines. Some complain that it gums up engines over time, but I've found that with a proper tune it's not an issue.

A while back I did a wear test between two identical 2 stroke model engines (brass con rod bushings, ABC (ringless piston/cylinder), etc. Both engines running a large flywheel instead of a prop, one running popular synthetic oil based fuel, and the other running castor fuel @15% nitromethane. After about 5 minutes the engine running on synthetic got to around 450 degrees fahrenheit and failed in an amazingly catastrophic manner (black smoke everywhere, metal bits out the exhaust, piston/cylinder completely toasted. When I tried the castor oil in the other engine I could not make it fail, it just kept running until it got so hot it started boiling the fuel in the carb and running inconsistent (CHT was around 500 degrees at this point). I took the engine apart only to find a brown glaze all over everything from the castor oil and no noticeable wear anywhere. The glaze came right off with carb cleaner, and the engine still runs.

For the time being, I'm running Protek R at 1oz. per gallon in the 7, but I plan on changing over to a castor based oil at the same ration when I convert to EFI.

PercentSevenC

Besides the internal engine varnish and carbon buildup, I've heard castor oil can also clog fuel filters pretty badly. At cooler temperatures it also has a tendency to separate from gasoline. Very interesting lubricity properties, though.

Hyper4mance2k

iTrader: (40)

Well I cant wait for pix tomorrow. I sure hope I'm wrong, because My car clearly runs different below a 1/4 tank than it does right after I fill up. Then again if i'm wrong there's something else going on. I just went into the garage and looked at the can of gas for my chainsaw. It's pretty hard to see if the oil has settled in that red can. LOL!

ray green

iTrader: (14)

The stuff looks pretty darn stable to me Hyper, here's the mix after sitting 24 hours:



So for daily use, with daily mixing, the premix should be fine. I'm thinking I just might block off the OMP and join the PreMix Club. The WalMart stuff isn't that bad by the gallon, I just need to find a convenient way to measure out 16 oz for each fill up.

PercentSevenC

Some of the single quart containers have marks on the side you can use to measure out 16 oz. That's what I do.

mjm4jc

I think that you have come to a very sensible conclusion. Ever since I went premix, I never looked back. You certainly will be fine with the Wal-Mart 2 cycle. Welcome to the premix world--------clean, clean, and clean!

Stevan

iTrader: (17)

To use 16 oz, you would have to run your tank very close to empty.
I usually let it get anywhere bellow a 1/4 tank and put in 10 gallons with 8 oz Walmart 2 stroke(.8 oz per gal). I use these STP bottles to depress the tab in the gas filler neck. The dry gas(Heet) bottles hold 12 oz if you want to do 12 gallons at your mix ratio.

j9fd3s

iTrader: (3)

thats what i did with the 20B.

i actually found this freezer ice tray that fit perfectly in the spare tire well (or the FC). you'll want a couple of quarts (enough to go a few tanks), a funnel (or other way to fill the tank) and maybe a pair of gloves.

premixing makes a mess too

ray green

iTrader: (14)

I think you've identified the true Achilles Heal of premixing J9 - the mess. I filled up this morning and used a 250 ml beaker to add the 16 oz of 2 cycle - eventually I got most of it in but there needs to be a better way.

Prefilling dry gas bottles and versions of that strategy sounds like a nuisance too, especially on that day you pull over for a fill up and discover you used you last bottle last time.

Still, I like the premix, the exhaust has never been cleaner than it has for these last couple tanks with the 2 cycle oil.

For now I'm going with PercentSeven's suggestion of using 16 oz motor oil containers, at least you get two fill ups per bottle.

But in the long run I'm going to look into adding a 2 cycle reservoir under the hood and converting the OMP to use that.

Thanks to Doc for these links on the OMP mod, I'll be checking out the options:

https://www.rx7club.com/1st-gen-archive-71/oil-12a-mop-mod-illustrated-597431/
https://www.rx7club.com/1st-gen-archive-71/oil-oil-metering-options-550951/
https://www.rx7club.com/1st-gen-archive-71/oil-omg-omp-519139/

Anybody have a favorite method for the conversion? Can you adapt the original OMP somehow to do this?

Sgt Fox

iTrader: (3)

Not without significant gear damage in the front cover.

Lowe Performance makes a rebuild kit for the OMP. Its easy and cheap.
https://www.rx7club.com/showthread.p...&highlight=oil
or
https://www.rx7club.com/showthread.php?t=597431

j9fd3s

iTrader: (3)

yeah i always feel like i'm too old for this when i have to premix....

oh for the P port for a while, i was putting some premix into a 5 gallon gas tank, and then i'd go put gas in that, and then fill up the car.

t_g_farrell

iTrader: (1)

Hmmm, I think I have an extra OMP around somewhere. The RA solution looks nice
but if I can use an existing pump modded, so much the better.

Stevan

iTrader: (17)

Well you have to put it in something, one16 or 32 oz oil bottle and a funnel doesn't sound too efficient (or less messy) to me. As far as discovering you used your last 8 or 12 oz bottle, you could just as easily find your 32 oz bottle empty when you go to fill up.
As far as the "ultimate" under the under hood reservoir, you have to monitor,and FILL that too. I don't see the point unless it holds a half gallon or more.
I'll just stick with the bottles with the built in funnel that hold enough for a fill up. Gas in, oil in (oil first).

Sgt Fox

iTrader: (3)

My oil reservoir is tied into the low oil system. As it starts to get low, it beeps on acceleration from the oil slosh. This lets me know its time to top it up. If it got dangerously low, it would beep and illuminate the low oil light in the dash.

NoPistons!

iTrader: (3)

I have an na but i'm paranoid about my **** so like yourself, i usually run a bit more. Maybe closer to 1.3/1.4 ounce per gallon. Car seems to like it.

RustyRacer

Wow, I daily run 4 gal : 1.5 oz. I was told by an old rotary nut that the stock OMP distributes at about 350:1. 6K mi at that mixture. Plus the cologne is just as strong as the engine pulls. Only problem I'm having is the oil dowel pin leaking.

ray green

iTrader: (14)

This is a point I raised earlier, the stock OMP delivers much less than 1 oz per gallon, probably more like the 350:1 ratio Rusty Racer mentions (but I haven't done the calculation). I don't mind having a bit more oil than is needed, but I don't want to go broke paying for it.

I used to put 8 oz MMO in with every fill up (15 gallons) on top of what the stock OMP was delivering, but I quit this when I realized all that oil was the cause of my recurring yellow stain over the tail pipe (a problem on lighter colored cars). I figured the Mazda engineers must have known what was best when they designed the OMP, as long as it's working right everything should be fine (except mine is not right now - Tim, how much for that spare OMP?)

Maybe just 8 oz of 2 cycle oil premixed per tank full of gas or even less is plenty for routine highway driving without the OMP?

For the long run, I like what you've done Sarge, especially since it has the warning light to let you know if some idiot forgot to fill the reservoir.

PercentSevenC

The OMP delivers a varying amount of oil depending on throttle position. I've read before that it's something like 150:1 at WOT.

j9fd3s

iTrader: (3)

yeah its not 350:1 all the time. additionally the 100:1 ratio mazda gives in the competition prep book is for a high output carbon seal engine, the steel seal engines take less oil.

as you can see by the SAE paper, the oil needed is in relation to the seal temperature