Matty's first 1st Gen

Hey guys just going through a service manual for the first gens compaired to the second gens, and from some calculations when the engine is run at 2,000 RPM the first gen will dispense on average 0.375 cc's each minute, while the second gen Non-turbo on average will spit out 1 cc per minute, now considering the 1.3 is is only 18 percent bigger in displacement than a 1.1, why does it get 266 percent more oil. I know my reasoning with the displacement is wrong, and the surface area and other friction factors should be used, but the basic idea stands. My second question: is it a direct swap to use a second gen OMP, and just tune it down a bit by choking up on the actuation lever? Maybe its just me but 266 percent seems like a whole bunch more oil, perhaps mazda realized that the rotary needs more lube, either way I'll take the oil comsumption for some extra protection, especially after having lost 2 engines to broken Apex seals. If anyone can clear this up for me i'd apreciate it.

Thanks Matt

lovintha7

I think FC OMPs are electronic, and have 4 tubes coming out.

Pele

iTrader: (28)

Only electronic OMPs on the 89-91 cars (Series 5)... 86-88 (Series 4) is mechanical.

Not sure on the number of tubes.

Also not sure on why the amount of oil moved differs. Be interesting to find out.

79+80+84_rx-7

i have an 86 block with the omp ect sitting in the back yard.... Ill play with it in the next few days....

Matty's first 1st Gen

so no one has any good reason to why the second gens get so much more oil. seems like a good longevity mod, to increase its output.

calvinpaul

iTrader: (2)

Or you could continue to use the omp AND premix....like I do.

vipernicus42

iTrader: (4)

OMP and Premix = too much oil = more carbon buildup

No thanks, I'll stick with my freshly-rebuilt, perfectly working OMP thanks

Jon

nevarmore

I'll toss out a few ideas. They are educated guesses and wild *** guesses just to get people thinking.

1. IIRC 12a has a wider bearing area than the FC. Lubrication is being spread elsewhere.

2. The 12a is carbureted. Generally non-FI engines will tend to run richer than FI's. They lack the fine and instantaneous adjustment and most people will tune them slightly rich to be on the safe side. While not exactly a lubricant, things with gas on them will slide better than things with no gas on them.

3. The 12a was the first widespread rotary engine and they learned some things and made improvements to it.

4. Oils. 13b's came along as synthetics and new oil additives were coming along. These are rarely tested by the makers for rotaries and Mazda opted to dump more oil in rather than risk some chemist chunking up thier motors.

5. The 12a drips oil down the Nikki, the 13b has ports elsewhere. It's easy to get a constant small flow to one source. It's probably harder to get flow to more openings so they have to up the pressures.

6. Oil pressure, my 12a should run around 60psi. Do 13b's run a higher or lower pressure?

7. Seal material. Newer seals may have behaved better than old ones.

IanS

iTrader: (4)

When you say 60 PSI what weight of oil are you using? I am currently using 10W-40 and I get almost 60 (on stock gauge) when driving.

d0 Luck

our OMP's not even bad as you think it is.

Bolox

isnt asking why did we get the wussy OMP's lioke asking why didnt all the first Gens hav 13b's?

just because thats what was availabe at the time

seems simple to me

nevarmore

20w50 and 60psi occurs anywhere above 3000, its around 40 or 50 at idle.

I'm going to 5w20 this winter. On a friends FB he runs around 30 and rarely more than 60 with the thinner oil

Matty's first 1st Gen

I'm sure that mazda had the technology to make the OMPs pump out more oil, its just a matter of turing, it would seem to me that its probably a result of research, and wear tests. And that makes me want to get a bigger OMP, so does anyone know if the later generations will fit no problem?