I have read it on here and the "other" forum that people change oil every 1500 miles, 2000, etc. Why in the hell would you do something like this? I just don't understand it.



And all across the board, I have seen it on daily driven RX-7's, and ones that are heavily modified, i.e. single turbo, etc.



Thanks

Justin



EDIT: did not know where to put this at, if mod feels like moving, whatever.

Stock metering oil injection







I wouldn't be injecting dirty oil to lube up my apex seals, would you? That's the premise behind it. Crack open an old 13B from an FC and look at the scoring on the rotor housing, marks on the rotor itself, just the general condition of the inside considering.



4 stroke oil isn't designed to be burned like that, so an oil change time is outside that of a piston engine (because piston engines don't purposely consume and burn oil).



2 stroke oil is however designed to be burned



But how do you market a car that needs 2 stroke in the gas and if you forget you're car is fucked and isn't warrantied?

Because it ******* needs it. There's nothing wrong with taking more care of the car than it needs.

[quote name='rowtareh' date='Sep 2 2005, 07:11 PM']I have read it on here and the "other" forum that people change oil every 1500 miles, 2000, etc. Why in the hell would you do something like this? I just don't understand it.



And all across the board, I have seen it on daily driven RX-7's, and ones that are heavily modified, i.e. single turbo, etc.



Thanks

Justin



EDIT: did not know where to put this at, if mod feels like moving, whatever.


[/quote]





The owners of rotary powered cars tend to be more interested in the engines than the owners of conventional piston engine powered cars. Its a small club to begin with, and most are **** about maintainance.



The stock rotary engine steals a small amount of sump oil and uses a small pump mounted on the front cover, (oil metering pump, or OMP) injects that oil into the rotor housings to lubricate the housing/apex seal interface.



Although the small amount of injected oil would not endanger the oil level in the sump unless it was never checked, there is more interest in checking oil level in the rotary than in the piston engine. I used to be gifted whole cars with locked up engines because the owner had never checked the oil, and thus lost the engine.



That sounds impossible, but it is true. Americans are the worst on earth at car maintainance.



Since the oil injected into the housings ends up as part of the fuel/air mixture, it is important to keep the sump oil clean and to the extent possible, free of condensate.



To that end, oil changes at less than 2,000 miles are of some value. Not many engines have been lost to the oil being too clean.



Operators that have to make many short trips, where full operating temperature for the oil is seldom seen, should shorten change interevels. Same for areas where daytime and nighttime temps make a big sweep. Same for high humidity areas, dusty and sandy locals, and so on.



Lynn E. Hanover.

impurities the oil retains...

typical rotary temps not excluding turbocharged motors....

id been meaning to run samples of oil during mileage intervals to see at which point does the oil used starts to degrade...

but so many factors and combinations are involved... from environment.. temps.. applications.. oil weight.. synth or non..

Ok, I knew it had something do with the OMP, but I did not that the OMP did that horrible of a job. I have seen the size of the hole where the oil is injected into the housing from an FD and a FC.



My other question is, how reliable is the OMP on a 84 -SE? If it is not that great I am thinking of just running pre-mix on the car.



I am just trying to pick people's brains, and get some really good information.



Thanks Lynn, Colin, and Jio.



-Justin

It doesn't take much of a passage to inject roughly one quart every thousand miles or so, or about 1 part per 250 oil to gasoline, on average. Air/fuel ratios are based on weight, not volume. Based on volume stoichiometric is something like 10,000 or so to one, so the amount of air to oil injected is something like 2,500,000 to one. Are the oil injection ports 1/2,500,000th the size of the intake ports?

on a stock turbo fd, the oil is totally broken down by 2000miles, it comes out like water, even if it went in like gear oil.



the non turbo cars by contrast dont seem to dirty the oil much at all

On my N/A ive changed oil at 3000 miles that still had a transparent golden color.

Heat kills. Alot of guys with piston engines that are modded tend to change it alot also. Its just better to have clean oil. If you beat on your car alot, your oil gets beat too. I dont think ive ever let any of my cars get to 3k on an oil change.