Marcel Burkett

I saw a direct tip oiling system on the HURLEY ROTARY site , has any one tried this mod . ? ,I am rebuilding now and i'am concidering going this way .

RETed

It's an interesting idea, but you're still trying to burn engine motor oil inside the cumbustion chamber...

This might cause a problem as carbon will now be concentrated in and around the apex seal and apex seal spring(s).


-Ted

rx7tt95

Yeah I've seen those rotors as well and was wondering...the other solution is the mechanical pump designed for use on rotary-powered airplanes. I do not have the link at the moment, but essentially it replaces your existing OMP with their setup which feeds off of a remote resovoir. Previously, there was extra work required in order to mount it on a 13B. They now apparently have the adapters. One could just run synthetic two-stroke this way and eliminate the stock OMP. Thoughts, potential problems other than forgetting to fill the tank? :-)
Michel

13BAce

I've been pre-mixing since september, and everything seems ok. It only takes me a few minutes to add the oil. I use a long necked funnel to make things easier.

peejay

Here's a solution - always keep a funnel and a supply of 2-cycle oil in the car at all times.

When you fill up, put a bottle of 2-cycle oil in before you put the fuel in.

I do not see how this is incredibly difficult...

13BAce

That's what I do. I've been adding 2 cycle oil to my gas for 4 years, even when the oil metering pump was functional. It takes 2 minutes to add it, and EVERY auto parts store sells it.

Marcel Burkett

This isn't just about the time it takes , although I absolutely hate it (lazy ??) , but on the HURLEY site they also say that 99% of the premix is burnt without lubricating anything , the modification is recomended for modified high performance turbo engines and would cause the seals to seal better and last longer . Would carbon build up be a concern if I use synthetic oil and my water injection system ? , also I owned a TURBO 11 with the mechanical OMP injecting engine oil , I opened the engine after about two years and there was absolutely NO carbon !!, so what gives ?.

RETed

I find this hard to believe.&nbsp The (stock) oil injection was designed to lubricate these areas:&nbsp 1) apex seal to rotor housing contact, 2) the apex seal to apex seal groove, 3) "secondary" seals such as the corner and side seals.&nbsp Pre-mixing would be superior (over Hurley rotor oil jet mod) for #1.&nbsp Hurley oil jet mod would be superior to pre-mixing for #2.&nbsp #3 would be debatable.&nbsp What is undeniable is that pre-mixes burn a lot cleaner than engine motor oil.&nbsp Pre-mixes were designed to burn and leave a slight deposits for lubrication.&nbsp This means all parts of the combustion chamber is affected during combustion.&nbsp How can it not lubricate anything?
http://www.nmma.org/certification/pr...dex.asp?bhcp=1


Synthetic oil?&nbsp Yes.&nbsp I've seen a motor using Amsoil 20W50 which left nasty deposits next to the spark plugs holes.&nbsp These deposits would cause the apex seal to chatter over them (obvious chatter marks).&nbsp This made me cringe - I do not recommend running synthetic oils if you are still running the stock oil injection.


Beats the hell out of me?&nbsp I've seen 30k miles 13BT engines come out with a slight layer of carbon (under 0.5mm) on the rotor faces all the time.

I've got a pre-mix FAQ on my site:
http://fc3s-pro.com/TECH/FAQ/premix.htm


-Ted

fdracer

Quick question about premix. I know its supposed to burn clean, but why do a lot of the 2 stroke vehicles (jetskis, dirtbikes, etc.) look like they have really bad emissions? Also would it be more advantageous to use premix with the OMP at lower proportions so that you have both methods of lubrication, or to just block of the omp and use purely premix at higher concentrations. What are the pros and cons of both using premix w/ omp and using premix exclusively.

Silver7

2 strokes motors have bad emissions because of engine design. It has nothing to do with the 2 stroke oil.

peejay

2-strokes are even worse than peripheral port rotaries in that the intake and exhaust ports open and close at the same time. Also, the oil is premixed at a much richer ratio than a rotary would use. (I think 1:10 instead of 1:100-1:150)

I play with 2-strokes every now and then and every time I work on 'em I come away amazed that the things even run

As for 99% burning instead of lubricating... Yes. That's why we premix as much as we do. Even the oil that the OMP injects will mostly burn off before it lubricates. That is why it is imperative that the lubricating oil be designed to burn cleanly. 2-cycle oil is designed to burn, motor oil is not.

Marcel Burkett

Every thing burns if the temperature is high enough , ih its soo bad then why did MAZDA use tha system instead of a separate two stroke oil injection system? .
HURLEY uses the direct oiling on a 8 second drag bike makind lots of power , so I think something has to be good about the mod!.
What about the piston counterparts ? , dont they employ a splash lubrication system for inside the cylinders ? , so why isnt the burning of oil such a big deal , because I know that some of the oil is consumed and the rest removedby the oil ring.

rx7will

iTrader: (6)

I havent heard of any piston engine designed to inject oil inot the combustion chambers, but i have heard of them squirting oil on the underside of the piston to cool it. Most people would not by a new car that they had to keep a seperate container full of oil. And i'm not sure if 2 cycle oil would pass emissions, when i used it on my car i couldnt smell anything different but my noise is not a smog machine.

Marcel Burkett

I never said anything about a piston engine squirting oil into the combustion chambers , what I said was , the cylinder walls are lubricated by a splash type method caused by the crankshaft and conn. rods moving around cacsind windage and turbulance.

RETed

Sure, but keep in mind that just because your EGT gauge shows you're running 1500&#176F (easily above the flash point of most synthetic engine motor oils right around 700&#176F), it doesn't mean the entire combustion chamber is that temperature.&nbsp The rotary (engine) combustion chamber is a very inefficient design - you get very incomplete burn and the housings would weaken considerable if it sees those peak EGT's at the surface.&nbsp The coolant circulating in the water jacket keeps the rotor housing surface in the combustion chamber easily under the flash point of most synthetic engine motor oils.&nbsp Once these deposits hit the rotor housing surface and stick, nothing short of the apex seal scraping it away is going to get them off.


The consensus seems to be "convenience".&nbsp Mazda projected that to run seperate reserviors and adding one more type of fluid to worry about was not in the best interest of the general consumer population.&nbsp It already had a lot of problems with owners ignoring all the bells and whistles that signaled a LOW OIL condition in early rotary cars - "I didn't know what that buzzer was for, so I just ignored it and kept on driving."


Seems like a popular matra of drag racers - if it goes quick/fast, it must work!


Sure, and the Mazda rotary engine equivalent to that is that the rotors are hollow inside with engine motor oil sloshing in them under normal operation.
http://www.mazdatrix.com/faq/cutaways.htm


Do you know what "normal" oil consumption is for a piston engine?&nbsp Not counting all the recent Chevy "blunders" with the Corvette and Camaros, most piston engines will easily run 50,000 miles before consuming a quart of oil - some will run 100,000 miles (i.e. Honda) due to really tight tolerances of their engines.&nbsp So we're looking at a 10x to 20x difference in oil consumption rates!&nbsp Piston engines were not designed to consume the engine motor oil.&nbsp If they could, the would shoot for "0" oil consumption, as this would imply total sealing and next to nil blowby.&nbsp Blowby contaminates the oil and turns it acidic.&nbsp Next to viscosity break-down (Castrol GTX commercials), it's probably the #1 problems for engine oil engineers.



-Ted

Marcel Burkett

**** !!! you gyys are really agains this mod. , I'll think on it some more and let you know what I decide. By the way anyone with the PCV adaptor. ?.

duboisr

Garfinkle has the adaptor in his FD the omp had to be modified to clear the twins ,he uses amsol 2 cycle oil

peejay

The mod sems like a re-engineered OMP system.

The reason we don't like it is that the basic premise of the OMP is flawed. Sure, it's great for people who are idiots, it's one less thing for them to worry about and that means less problems for Mazda. But let's assume that the average enthusiasts are not idiots. We'd be willing to take the (very minimal) time to pop a bottle of 2-cycle in the tank before every fillup. Heck it takes less time then checking all the tire pressures and topping-up as necessary at the gas station air hose.

Rotaries look REALLY ugly inside after they've had a diet of dirty motor oil instead of nice clean, clean-burning 2-cycle. We're talking scoop the carbon out with a spoon and a chisel kind of ugly.

As for drag engines... It's a drag engine. You can run a drag engine with NO lubrication. I know of 30 year old cars that are only used for drag racing that have under 1000 miles on their original odometers. I've personally driven much more than 1000 miles with no OMP or premixing whatsoever, no ill effects to the engine. I was NOT kind to the car, I drove it with all the enthusiasm of someone who just got his first RX-7. For 2000 miles, God only knows how many miles the PO drove with the a dead OMP.

RETed

We're just playing devil's advocate and giving you another side of the picture.


-Ted

j9fd3s

iTrader: (3)

well i can tell you from experience that piston engines will last about 40-60miles without changing the oil. i have seen several cars that would have had engines under warranty that wern't because the seal on the drain plug had never been touched.

also the metering pump is a direct lineage from nsu. mazda just kept it, beacuse it works for them.

mike
65 nsu wankel spider (sold)
72 r100

3rdGen7

Ted (And Others)

Do you think I should start adding some premix 2 stroke to my tanks on fill up then ..just as an extra help???

My OMP is working fine but I've got a larger than normal streetported motor with non-seq twins and I am in boost pretty much all of the time. I've got a heavy foot.

Should I start adding ...say 1/2 Qt per tank as a started ??

BTW, Can anyone tell me :-

1) What is the Fuel tank capacity on the FD ??

2) What is the cooling system volume on the FD ??

13BAce

Your fuel tank holds about 16 gallons. Adding 4 oz. 2 cycle oil per tank should be plenty. The FD shop manual is on T&R's site: http://www.rx7s.com .