So I recently got into a heated discussion with an old friend about oil injection on mildly modified 12a's.
His argument being that engine oil offered more lubrication to the seals than a 2 stroke oil could, and that the stock oil injection was more than adequate for a modified mill.

Really..
I think he got dropped on his head as a kid...

Firstly. 2 stroke oil is designed to offer more topend lubrication, without burning off completely. So theoretically it would offer twice the lubrication of a conventional engine oil.
It also burns cleaner, with the option of premixing your fuel to avoid injection problems.. It also means that you can avoid costly engine problems from not keeping a vigilant eye on engine oil levels.
I could go on...

But my question is this.
Has anyone ever used an oil injection setup from a 2 stroke sled (snow mobile) on they're 12a?
I plan to use the RB Holley intake, and the 465cfm carb on my build. So I was looking to do something different.
I would be a bit nervous about premixing with the Holley, and having carb issues. That being said, I do want to use a 2 stoke oil..

Can anyone offer furher feedback on this??

 

I don't have all the pics of my setup, but I used a Rotary Aviation OMP pump that you attach between the factory OMP and engine and allows oil from a tank to be injected.

The tank on the right is a Jegs aluminum tank that hold about 28 oz. I used a pigtail on the top is from a Polaris snowmobile oil tank. It's a sliding sensor and also has a dash mounted light that indicates low oil.

I did have one issue and that was with the location of the OMP lines. The new oil pump pushes the lines closer to the water pump housing. I converted to an S4 aluminum water pump housing and that solved my issue and allowed me to install an after market water temp sensor.

One of the advantages of this system is that it can use regular motor oil but instead of drawing from the pan, it takes clean oil from the tank.

 

I looked at those. I'm still not sure if they are worth $140?
The one I was looking at from an artic cat actually has a small electric pump, with a sweeper that attaches to the throttle.
I had a plan in my head to use a small carb spacer, and plumb the lines in to squirt oil directly into the intake under the carb.
But I don't really think it would be as efficient as premixing?
I would have to wonder how much oil would get hung up in the intake as well? Not to mention how the added plenum volume would affect performance?
It could be paranoia about engine damage. I really want to get the most out of this build. But I also want reliability, without having to worry about constantly cleaning everything, checking plugs, and scoping the intermediate housings for wear.. I really don't know what I should do?
Spend the money, and keep the factory OMP. How do you set it up to work on a Holley carb?
My 12a is just a simple street port, it's nothing crazy.

 

Best solution is to modify a 12a OMP to take oil from an external container. The OMP will meter correct based on throttle position. With the snow mobile pump you would need to verify that the volume pumped is good for any throttle position. Thats why doing this or using the aviationone works so well.

 

I like the concept of the of using the aviation OMP, but premixing with gas is just as good. The only advantage with the aviation OMP is that my oil tank holds a lot of dino oil and you can get it almost anywhere in a pinch.

I haven't had my car on the road yet so I can't speak to reliability or effectiveness. I'm going to premix until I'm satisfied with the results. I'm really lazy and procrastinate a lot so this build has been going on 18 years and still not on the road.

 

I totally hear what your saying.
I honestly don't have a problem with premixing my fuel either. But do like the convenience of having oil onboard. Being able to just fuel up, and go..
I've been pissing around for 2 years on my build. I originally was gonna build a 91' b2200 repu. But sold all my truck parts to buy a 78' Datsun 510 wagon.
Now the 12a is a bit small for the wagon, but it's actually lighter than the truck is.
But I'm trying to rethink my whole design setup, as far as dropping it in the Datsun (I really love that car). I was gonna keep the motor fairly stock in the truck, and run the nikki carb.
But now that I'm going to a Holley carb. My thinking has changed completely on pre mixing, and OMP's.
I need to know the best way to make an OMP work with the Holley carb? Or I'll have no choice but to premix.

 

Drill a couple of holes after the choke flaps but before the venturies in the top of the carb (just like on the nikki.


Your friend is right to a point. Motor oil isn't designed to burn, that's a good thing. Two stroke oil breaks down and burns. That's great for a reciprocating piston two smoker that burns and gets a fresh dip of oil and gas with each depression to BDC. A after the rotary makes combustion it doesn't spin backwards for more oil and gas. That's the good thing about motor oil, it keeps lubricating after combustion. That's the argument for motor oil in the omp.

NOW think about two stroke oil and the incomplete combustion of a rotary (FACE IT ROTARIES ARE INEFFICIEANT). Lots of that two stroke oil won't get burned in the combustion chamber and will have the ability to keep lubricating the after combustion area of the housings.


What you should take from this is DON'T pre-mix at the same rate as Mazda's OE oil pump it will leave your housings wanting. I mix in the tank about 50:1 or greater.

 

So I would basically plumb the 2 lines into the choke horn, and down toward the primary venturies. But just close enuf that the vacuum pulls the oil in.. Right??
As far as the oil thing goes. I still feel that a 2 stroke oil would offer more protection over a regular engine oil. But I almost got into a fist fight over it before. So I'll just keep it to myself.. lol
Its a grey area at best.

 

Stock Omp + premix = profit?

 

I'd just stick them strait in just like on a nikki not downward. No need to re-invent the wheel.

 

I'm catching on now.. lol

 

Here's a gas/oil 50:1 reference

http://www.challengers101.com/files/FuelMix.pdf

 

Do you already have the Holley? If not, and the motor is going to be fairly stock, I'd leave the Nikki on and save the headache for the exhaust.


I don't quite follow. First line says motor oil is okay because it doesn't burn so it can lubricate after the combustion stage, and then the second line says 2 stroke oil does the same thing.
The argument has never been that motor oil doesn't burn, rather it doesn't burn cleanly and leaves deposits or adds to the carbon build up.

 

I actually want a bit of a bigger carb. Been thinking of a 650, but don't want the tuning nightmare. The car is gonna be right around 2300lbs, so I want to get as much out of my 12a as I can.
The Holley intake alone offers an improvement over stock. The carb is pre tuned by RB.
What exhaust headache are you taking about to?
I have a pacesetter header, and from my measurements it'll fit the Datsun.

 

Usually with swaps mounting the engine is the easy bit and getting the rest to fit is the hard part.
Doesn't the Nissan L-series exhaust go down the driver's side? Have you figured out the pipes downstream of the header?

 

Yes it does.
But it's not recessed. There's tons of room for the 12a exhaust on the passenger side. Gonna hug the driveshaft, out over the diff, and out in center of the roll pan.
I have a friend who owns his own muffler shop. It's the least of my worries.
I'm also gonna ditch the factory fuel tank. It's pretty rusted, and beat up. Was gonna use a plastic cell from summit racing. It's gonna get recessed into the back of the car. That opens up real estate or the center dump exhaust btw.
It's a build. I don't expect to finish it in a weekend.. lol

 

I'm trying to say that using the same amount of 2 stroke oil as you would motor oil is not a good idea. So if you use 1:100 oil/gas motor oil you should use something along the lines of 1:50 two stroke oil/gas.



EDIT: I have never had an operational OMP, but if I did I'd use it and a few ounces of two stroke oil in the tank. Not in case of failure but just as added protection from wear.

 

I'm not one to tell people what to do but will tell you you DON'T want to go the Holley 4bbl carb route. It is a performance carb for an american V8. In this application it mounts front to rear as it was designed to be. To work with a rotary it is turned 90 degrees(sideways) and while it will "run", all kind of driveability issues ensue from running lean turning the car one way to flooding,hesitating,stalling turning the other way .On its best day,best tune(jetting) it is strictly a straight line performer. Personally i've run 4 bbl carbs NA and Turbo on 12 A engines.Carter AFB & Holleys carbs,tuned and modded to suit the rotary engine. They ran great,the Carter better than the Holley,it didn't have as many driveability problems as the Holley did. The Holley was the worse of the two with constant fiddling to get it to idle,etc. Count on having to overhaul it annually to keep it running best possible-in a straight line. Got the most horsepower out of the engines,but no fuel economy whatsoever.1st gens are meant to handle,power in/out of turns,that ain't happening with this type of carb setup. Having owned a couple 510 sedans,they can be made to handle really well but the 4bbl carb scenario is an unhappy marriage. Do not believe you'll be able to plop that carb out of the box onto your engine and it will run anything close to perfect. Be wary of what RB tells you and do NOT try to adjust jetting or anything else on their carb,you will void their "warranty"and you'll be stuck with it. There are members here who have spent thousands only to find out what i've told you here. Do some research on this site,you will find thread after thread by members here echoing the same sentiments. For much less than you're going to spend on a RB Holley conversion, keep your oe Nikki and manifold,there are members here that will custom modify your carb to make lots of power while retaining all the good reliability/driveability traits of the original carb AND decent fuel economy. Search "HoggedNikki carbs" and do some reading. I just saved you a whole lot of money & bs. You're welcome

 

For the sake of the argument, your buddy is a jack wad.

 

Oh and that pacesetter header will not last long on a rotary. Get a RacingBeat one which will last and last. They sell kits too so you can make your own for applications like you are talking about.

 

I know about the pacesetters, they are junky headers. It came with the motor, and it's almost new. So I was just gonna run it anyway.
Backing up a bit about the carbs. I have been searching info on running Edelbrock carbs.
I'm not totally against the Nikki, but I am an old hotrodder from way back. I can tune a carb, and swap jets, and air bleeds, and throw it threw the garage window with the best of them.. lol
But seriously. The amount of polluion control crap on the Nikki intake, vacuum, electronic crap, and so on.
I'd find it way more simple to run an aftermarket carb.
I'm not a Holley fan either really, and know all about the fuel starvation issues with trans mounting. I have also read some bad reviews about the RB 465. Mostly cause of the vacuum choke, and problems with the vacuum secondaries. So I'm back pedaling.
The Edelbrock AVS 500 would be a better (cheaper) choice if that route was followed. I'm leaning heavy that way right now.

 

I ran an edlebrock for years on my first RX7. Great carb for reliability and A to B work. Sucks in every other department. Cornering is not happening, and fuel econ was beyond bad. Its not a tuning thing.... Its a, not good for this car thing. But all that said I ran the carb for about 2 years DD without a carbureted hitch; fired up every morning to take me wherever. In my defense I had never driven a car with a nikki and when I did I realized what I'd been missing.

Its good to hear that someone did the Carter on a rotary. I always wanted to try a spread bore on one. Seems like the rotary would do well with the super sized secondaries. But I'm not surprised about the results.

The nikki is a super good carb. and all it takes is about 20min with a Philips head to remove the emissions stuff. And you are left with what looks like a tinny square bore version of a Rochester (kind of)

 

I had a pacesetter on my old NA second gen. No problems there.

 

I've been hunting info on Nikki mods.
But at the same time I'm feeling the Edelbrock AVS carbs to.
The AVS has anti slosh technology, and is designed for road racing. I contacted Edelbrock, and they actually have the info to tune a 500 to run on a mild port 12a. From jets, to float adjustments, and a secondary delay mod. I'm gonna bite, and give it a try.
They aren't total garbage. I've run them in the past as well. I had one on my 85' 200sx. The issue is durability. They don't live as long as a ceramic coated, or stainless header.
The Rotary header they offer is a different design than the RB header to.