Pre-mixed oil in petrol

[mattmaclennan]

Lee, don\'t worry, the car looks after itself. The Mazda Rotary has small oil injectors down by the inlet manifold. These allow a dribble of oil into the rotor housings. A small oil pump down at the front of the engine near your turbos, meters an amount of oil into the engine. This oil helps lubricate the tips as they go flying round inside. As you rev the engine and put more load on the engine (open it up) the pump pushes more oil in to the housings. If the pump fails or is disconected, the ECU will not allow you to drive with any load, limited to about 3500rpm (TII and FD only, earlier were mechanical). The Apexi Power FC aftermarket ECU has all the hardware to controll things like the OMP (Oil Metering Pump), ECUs like Microtech and independant fuel/ignition controllers don\'t. So if your running an ECU that doesn\'t keep the OMP running your stuffed. The OMP is only any use up until the rev limit of the standard engine, if your going above that, you\'ve not got enough oil. Premix is 2stroke oil mixed with petrol in the fuel tank. This means that as you open the throttle and more fuel is injected, more lubriacting oil is injected. A mix of 100-1 seems popular. The only draw back, is that it\'s another system to maintain, making sure you\'ve always got 2stroke oil in the boot and remembering to add the right amount when you fill up.

[LeeHall]

Thanks Matt  :god

If I started putting a little 2 stroke oil in with my fuel, should it be mineral or synthetic? And if I did it once, would I have to keep on each and every time? i.e. does it matter if its forgotten on occasion? Or is it something which when started MUST be continued?

Thanks again for the help!!!!! :bandit

[asp]

every thing uv asked has been said in this thread,
carl recons mineral oil.i cant remember what i use,
if uv still got the oil metering pump u can stop premixin

[andrewrx7]

Thanks for the discussion! Interesting to read the comments!

I started the topic, \'cos of comments and pictures on rx7.com, I think, although I can\'t find the thread now (have you seen how many threads/entries there over there?!). Some guy was showing the internals from an engine which still had the OMP running. Where the oil was injected into the engine, there was a nice shiney streak where the apex seals are highly lubricated and take the oil away. The builder was suggesting that the oil was not properly dispersed along the whole length of the seals, and that this may lead to premature failure of the seals. Hence the suggestion that people should really use a pre-mix, even with the OMP running, just to ensure complete lubrication of the apex seals.
Just wandering whether this suggested streaking is seen on engines over on this side of the pond, or whether it was more of a one-off that has been blown out of proportion? He seemed pretty convinced that it was was common place!
Any further comments?

Cheers!

[mattmaclennan]

The middle of the tip gets the hottest, and is the most likely place for it to warp. In the earlier engines, the oil was injected in to the air stream as well as the path of the tip, Mazda decided with the advent of new technology, that they only need to lubricate the tip via the housing (maybe because there are already so many lubriacnts in comercial petrol these days??). They haven\'t changed there mind with the RX8. Premixing (if you can remember to do it!) seems the best way to get lubricant in to the combustion chamber. Wheather or not you loose any important features by completely removing the OMP remains a mystery. Personally I think you do.