omp 2 stroke mod

[shifty biscuits]

nice one, i still have some reading up to do but im pretty sure i will go with this mod, good shout about the seals being damaged by oil additives, i will look into that some more to find a suitable semi/fully synth oil.

[Grizzly]

The Oil injectors are fed with metered amounts of oil by the OMP - the rate at which this happens is altred by revs and boost on the T2 (the old mechaninal ones were only revs as the lever was attached to the throttle mechanism).
 
The Injectors themselves have an air blow feed, which comes from the manifold, so the oil is effectively atomised into the chamber.  On the T2 there are 2 sets of injectos, one set sit on the rotor housings in the top left quandrant (intake area) and the other 2 are sat on the primary air ports.
 

May well be different on an FD but the OMP oiler has a one way valve in it, on inspection air is dragged IN to the engine via the engines Vacuum and shuts when the engine goes into Positive boost, the Pipes on the top of the Oiler are to the breather system and hold no Pressure (just there to supply air to be dragged through the oil to atomize it as it enters the engine)

After many hours of reading up and Inspecting parts i know exactly how it works now, The engine oil pressure feeds a small reservoir of oil which any pressure is bled back to the sump, from this small Reservoir the OMP feeds a small Piston pump in the side of the OMP, that is actuated by a spinning disk driven from the engines front spacer assembly, once the Piston is actuated it pushes a metered amount of oil into the omp line (x amount per rotor bath) so the Oil is force fed into the very small diameter OMP line (its small bore so the Vacuum doesn\'t pull too much oil out of the line and the Volume inside is low), next once that oil finally reaches the oiler there is two scenarios that can happen, either the engine is on Vacuum so the oil is pushed into the Oiler and the vacuum drags air through the oil as its pulled into the engine atomizing it or the motor is on boost so the oiler one way valve shuts and the oil simply carries on being pushed through the oiler into the motor in a steady metered stream. The Only variation on the amount of oil is set by the Stepper motor on the later OMP\'s this acts like a kind of oil Throttle adding more or less as the engine requires, this job on the earlier OMP\'s was done via the linkage to the throttle.  



So... it looks like the 2 stroke oil method would work fine, but the only question that remains is the Quantity of oil, as the 2 stroke oil cold is thicker than the hot engine oil would that alter the amount used? plus added resistance in the very thin bore omp lines? as it seems to work out of the box no one has tested to see how much is actually being used.

[Grant Monkhouse]

Premiixng is far simpler and superior. 2stroke comes in 500ml bottles. Poor one bottle 50 litres of fuel Simple. Better lubrication of the seals. No more dirty engine oil in the chamber. No risk of oil lines getting clogged up and not deliver oil

[Arnie_O]

Depending on placement of the reservoir the 2 stroke oil should be warmed by the heat radiating from the engine as it warms up.
Remember engine oil is also cold on initial start up too.
I would hazard a guess that cold pure 2T has a lower viscosity than say cold 15w40 (just guessing here)

[Grizzly]

Premiixng is far simpler and superior. 2stroke comes in 500ml bottles. Poor one bottle 50 litres of fuel Simple. Better lubrication of the seals. No more dirty engine oil in the chamber. No risk of oil lines getting clogged up and not deliver oil

Frankly i\'ve used stock omp for over 10 years now running over 450hp on the same engine so i see it all as a waste of time, the only time the stock OMP doesn\'t do its job fine is when the OMP oilers one way valve sticks and there are obvious tell tail signs when that happens (either oil all over the show or Popped off breather pipe on oiler)

I can\'t talk for anyone else but my oil never gets dirty (gets changed every 3k without fail) what it does do is get badly fuel Diluted which makes it thinner (you can tell when it needs changing as the idle oil pressure drops down to a bar on my aftermarket gauge) so "Dirt" or Carbon in the oil is not a problem. Using cheap oil is most people\'s problem, less refined oil - Carbon deposits as its burnt

I keep hearing Pre mix is better than omp too, yes and no...... Pre mix is not for a Road car, its simply too easy to forget if your FD is a second car or a "Weekend warrior" but like the 2 stroke reservoir, its ok if get in the habit of using it and filling it (a tip is use 2 stroke oil that is available at the same place as the fuel you use for example Shell V-power so i used there shell synthetic 2 stroke oil) i only forgot once to put stroke oil in it was 3am and i was tired driving home from London which is one of the reasons i went with omp, its also really messy i found 2 stroke oil in the Throttle body and the LIM was covered in it. Not for me.

[Grizzly]

Depending on placement of the reservoir the 2 stroke oil should be warmed by the heat radiating from the engine as it warms up.
Remember engine oil is also cold on initial start up too.
I would hazard a guess that cold pure 2T has a lower viscosity than say cold 15w40 (just guessing here)

The stock OMP is the benchmark its probably the only setup that has been thoroughly tested and set up correctly by Mazda (so lets say that works fine if all the components are in working order )

Don\'t forget that No one opens the car up cold, the engine is designed to get the oil up to operating temps as fast as possible and the OMP is designed to meter the engine oil correctly hot or cold via the stepper motor.

[Prof]

I did play about with some tests, not very scientific, but I wanted to see how the 2 stroke oil compared to engine oil in a spread test, both with the oil cold, warm or hot and the also the metal sheet cold, warm or hot.
 
It\'s no suprise that in both cases, the warmer the oil and the warmer the plate, the greater the spread was.  What was surpsising is that the 2 stroke I used (blue marine stuff), spreads rapidly on the metal if it\'s warm or hot, pretty much regardless of the oil temperature.  Even when it\'s only warm (30-40 degrees), the 2 stroke spreads faster than the hot (close to 100 degrees) engine oil.
 
What buggered my engine was the fact that I didn\'t replace the bearings on the last rebuild, and at some stage the front bearing spun, blocking the oil pathway and resulting in the front bearing disintegrating, taking with it the stack at the front (1 torrington, 2 thrust plates, and some signs of wear on the e-shaft).
 
The rear rotor looks to have been well lubricated and has very low carbon buildup, and all the seals came out easily.
 
I will definitely use the OMP / 2 Stoke mod again in the rebuild.

[Arnie_O]

The SOHN adaptor does not delete the OMP It simply redirects where is supplied with oil.