Ok my dad all his life grew up with piston engines. When I was explaining to him how rotary engines worked he didn't believe me that it also burns oil as part of its design. He said whoever told me that is an idiot and is trying to take advantage of me. Hah. I know. What I am not totally clear on though is this:

Is it the actual engine oil that is injected every combusion cycle that burns, or is it premix in the fuel? I know it sounds dumb but I'm not 100% sure on that. And how exactly is it injected, through nozzles in the "crankshaft"? (I know it has a different name)

Thanks

 

The stock RX7s burn engine oil in the combustion for lubrication - no big deal, it's not much. The oil gets there through a dedicated Oil Metering Pump.

The engine oil doesn't provide optimum lubrication (plus it's not meant to burn along with fuel, creating harmful carbon deposits in the engine) so lots of people disable the OMP and run 2stage premix into their gas for lubrication.

Those are the basics.

 

Crackshaft would the esectric shaft (i cant spell today too tired) and yes. and you only premix if you take off the emissions and its also better for the engine then normal engine oil... Just like Syncro said eagine oil isnt ment to burn so it leaves carbon

 

Ok, So I live in California and we have strict emissions laws, so if I run premix, it wont pass smog?

and the oil metering pump is seperate from the engine oil gauge? I don't have an rx7 yet, I'm in the process of looking so I can't go check.

 

Pre-mixing 2-cycle oil into your gas tank is a largely debated issue and has fallen into a matter of opinion.

The OMP dribbles oil into the combustion chamber so the apex seals that go by hit the oil and spread it around the housing. Off the top of my head, it should use 1qt of oil every 1000 miles.

Seeing as you have an S4 (86-88) your Oil Metering Pump (OMP) is mechanical and probably works fine, however the lines should be checked pending how well the previous owner maintained it. Then again, if you haven't already you should give everything a good once over so you know what you will need to be replacing down the road, and a full 100K tune-up, that comes with owning a 17 year old car.

Pre-mix is a popular option for when an OMP fails, as a new OMP unit can be approx. $200+

However if you are looking to reduce carbon deposits in the engine remember that gasoline causes carbon deposits, ask anyone who has rebuilt a high-mileage piston engine...


Addition:
By engine oil guage do you mean the oil pressure guage or the dip stick on the engine? The OMP uses oil from the oil pan.

 

Like I said above, I do not have an rx7 as a reference. I meant the oil pressure gauge, and was wondering if there were two seperate gauges.

Also, I see you live in Cali as well, will it pass smog if you use premix?

 

You know if your going to explain something to someone for their first time, don't be lazy and say you can't spell today. It's called an eccentric shaft, but for the sake of typing and periodic memory loss, some call it an e-shaft.

Now I don't want to be a dick, but you were in another thread, to a new member.

 

I was able to get my FB to pass smog but I don't know if I pre-mixed it that day, just go in on a fresh tank of gas without any oil in the gas is all.

Also though that car had a fresh catalytic converter.