Apex Seals Question?

[pr3d]

Because the location of the apex seals, they can only be lubricated by oil that will eventually be lost to the combustion chamber. Does this
guarantees that some oil will be consumed?


i was just curious , i'm trying to argue the fact that the rotary doesnt consume oil but i read this somewhere and just wanted to know if this was true?

 

[atticus1398]

yes, i drove a fc for a long time. i checked my oil every 2 weeks or every time i filled up w/ gas. some people ditch that system and run a premixed gas/oil mixture. but yeah, very important to check oil often.

 

[ZoomZoomH]

stock mazda rotary engines all have a built in oil injection system that injects some oil into the combustion chamber to lubricate the apex seals.

so yes, the mazda rotary engine is designed to consume a small amount of motor oil during normal operation.

 

[rgonza]

yes it comsume a small amount of oil It have a metering oil that's uses oil from the engine oil pan that's you have to check the engine every mounth if youre is new or after the long trip. (thumb)

 

[Signal 2]

Just to confirm what the others said...yes the rotary engine actually burns oil by design. But, in addition to providing some lubrication to the apex seals, it also aids in sealing and increases compression.
This is by design from the factory but in some race applications, guys will remove the oil metering pump (OMP) and just add oil to the gas tank.....IIRC about 4 to 6 oz. per tank in race application, which I think is alot more than the stock OMP would deliver. Still it gives you an idea of how little oil it takes.

 

[KYLiquid]

The old motor in the rx8 burned about 1qt of oil per oil change, that was about ~3000 miles. This new motor seems to burn about 1/4 of a qt PER WEEK, and that is about 3qt per oil change.

 

[peepsalot]

ouch

 

[Signal 2]

The old motor in the rx8 burned about 1qt of oil per oil change, that was about ~3000 miles. This new motor seems to burn about 1/4 of a qt PER WEEK, and that is about 3qt per oil change.

I'm not up on the Renesis that much, but compared to my FD, both figures seem pretty excessive. I change oil about every 2.5k miles and, at MOST, maybe 6 oz. down btwn changes. Maybe the 8 burns a bit more?

 

[ZoomZoomH]

how much oil is used is HIGHLY dependent on how high he revs the engine on a regular basis

i average about 1/3 qt per 3000 miles during normal driving, last time i was driving on track i used a quart in 200 miles

 

[neit_jnf]

The Renesis was designed to burn less oil than any previous rotary under normal conditions but it varies with rpm. If you're constantly in the high rpm band you'll use more oil. It seems like real-world experience for the Renesis is that it burns the same amount as previous 13B's but I think it is great given the higher rpm range.

 

[KYMP5]

Mine burns roughly 3/4qt every 1000-1200 miles if i drive it pretty hard. If i take it easy it does a little better, but then its just no fun to drive

 

[dDuB]

On the older 13b engines, about 1qt per 3000 miles is a good estimate. The 13b renesis, rx8 engine, will use a bit more, though. The renesis has 3 oil injection holes PER rotor housing, whereas the older style 13b's only had 1 per housing. But my rx8 really doesn't burn much oil, I check it every so often and top it off if needed, but it's not something I get too worried over...

My 2nd gen rx7 I never had to check. I did an oil change ever 2-3k miles, and that's all that was needed.

 

[KYLiquid]

The Renesis was designed to burn less oil than any previous rotary under normal conditions but it varies with rpm. If you're constantly in the high rpm band you'll use more oil. It seems like real-world experience for the Renesis is that it burns the same amount as previous 13B's but I think it is great given the higher rpm range.

since i posted the above, my consumption has slowed down, its back to about 1qt per oil change.

Anyway, i read the opposite of what you said, the renesis injects MORE oil than any other rotary as mazda felt that previous rotarys might not have been getting as much lubrication to the seals as they thought it should. In turn the OMP (oil metering pump) in the RX8 injects MORE oil and FLOWS more oil than any previous OMP. Also the RX8 varies the OMP much more than any other rotary car based on RPM AND LOAD. That along with the Higher redline (9600 RPM Fuel CUT) the car uses more oil when driven hard, but less when at idle.

Either way, I dont mind filling up the oil everytime I get gas, it takes what, 60 secs of my time.

 

[Captain KRM P5]

my first gen has very little oil consumption, maybe 1/2 a quart every change

 

[neit_jnf]

I've read (and keep in my pc) lots of information and diagrams about the Renesis' design, engineering highlights, etc.

Due to not having a peripheral exhaust port, the apex seals stay lubricated longer. Also, there are 2 oil injectors pointed to the sides instead of older 13B's one in the center; this allows more even spread of oil film. Since the oil film spread is better it allows to use less oil compared to a center injector which required more oil to evenly reach the apex seal's corners.

The OMP is the best design yet, as you said, varying by rpm and load and having higher flow. The higher flow is required because of 4 injectors instead of 2 and significantly higher rpm limit (my FD fuel cuts just shy of 8000 rpm).

Also, less oil is needed just because it's N/A, which creates less stress on the engine. Note that Racing Beat recommends a modification of the OMP to increase flow if you are using forced induction.

Now, I'm talking about what it was designed for, it doesn't necesarily mean that it actually works that way in real life conditions. Remember there have been numerous PCM calibration flashes, and they may have increased the flow. Just as an example, the Renesis was first designed to output 280 ps (276hp) at near 10k rpm with dual throttles (RX-Evolv) then it was lowered to 247hp (still true in Japan) and finally, taking into consideration the new SAE standards it is sold as having 232 hp.

The same could hava happened to oil injection, it may have been designed to use less but it could have been recalibrated for more after been out in the streets and Mazda gathered more data, etc etc...

since i posted the above, my consumption has slowed down, its back to about 1qt per oil change.

Anyway, i read the opposite of what you said, the renesis injects MORE oil than any other rotary as mazda felt that previous rotarys might not have been getting as much lubrication to the seals as they thought it should. In turn the OMP (oil metering pump) in the RX8 injects MORE oil and FLOWS more oil than any previous OMP. Also the RX8 varies the OMP much more than any other rotary car based on RPM AND LOAD. That along with the Higher redline (9600 RPM Fuel CUT) the car uses more oil when driven hard, but less when at idle.

Either way, I dont mind filling up the oil everytime I get gas, it takes what, 60 secs of my time.

 

[Lt. Dan]

I burn about 1qt every 1,000 miles... but I also have my OMP set pretty high....

 

[showtege]

I change my oil in my FD every 1000 miles and never noticed any oil loss in that short of amount of time. I know that sounds exsesive but i race the s*** out of my car every week end. I do have to add some coollent but thats caused by a bad o ring.

My new motor i am putting in this sommer is by Pettit racing and i will be switching to pre mix.

 

[86Fc3s]

i say you take off your omp and run premix. my motor is a rebuilt s4 motor with a large street port, and its striped of all the crap i dont need. even if you dont take off your omp, you should still run a little premix. you dont have to, but it will lube your motor better. just my 2 cents