just bought a 13b series 4 for offroading purposes, it has carburetor conversion and omp block off, the engine came with no thermal pellet or thermostat. my question is are these necessary components for this engine build? I would assume they were lost and that they're necessary but as I am new to rotaries and this is a custom setup I am unsure, any advice or direction would be much appreciated

 

You can run it with the carb or FI depending on what you need, you will probably want to use a carb, and the OMP you can keep it blocked off but you have to premix your oil with a special lubricant called Idemitsu. designed for rotaries, you mix it in the gas like chainsaw oil. I believe at least 1 oz per gallon if you have no OMP, this means 1 quart of Idemitsu Premix will only last 32 Gallons (2 Tanks in a car, 4 with OMP). Rotaries burn oil to keep lubed like a 2 stroke, If you are in a bind you can actually use 2 stroke oil. But be generous that is what lubricates the rotor and apex seals. The thermal pellet, I cant tell you much about, but the thermostat should be fine,just DONT overheat the engine. As you said it is a custom build, I would recommend an 85 psi oil pressure regulator upgrade if you are going to be wailing on it, but again being a custom build there is some stuff that is just owner preference, I am building a 12a engine for my 7, I am going to put the 85 Oil Regulator and Mazda Race Rotor Bearings, and a couple other goodies on the list. my nickname for that motor is Wankel9000, 9000 being the target RPM before each shift

 

you can live without the thermal pellet, if anything its better as it lets the rotor bearing get oil all the time, versus only when the oil is warmed up

the thermostat, you'll want one, it will help with cooling and not let the water go through the engine so fast that it cannot absorb heat