Hecubus84

iTrader: (1)

Swapping a S4 NA into my FB right now. I ran into an issue with my old school 13b (REPU) front cover. It uses the old style bottom-feed twin output OMP like the 12a's. Obviously this design is incompatible with the rear-feed quad output OMP the FC's use.

Is it possible to simply "Y" the nipples of the old style OMP to lubricate my engine or am I stuck fabbing an adapter plate in order to employ the FC pump?

bumpstart

to fit the s4 OMP to the FB timing cover requires you to tap one hole and notch the oil gallery to match up,, could not get any simpler

RX-7 Chris

iTrader: (19)

the best way to do it is to install a GSL-SE front cover. it will have the right OMP.

Hecubus84

iTrader: (1)

I neglected to mention that I've already installed the engine into the car, access is somewhat limited.





Bumpstart, do you have any pictures of the modification you mentioned?

bumpstart

the typical mods needed to make a 12a timing cover suit the s4 4 way OMP , with a turbo oil drain

steve84GS TII

If Im not mistaken,the last versions of Cosmo and S6 RX-7 engines only ran 1 injector per housing and they did just fine.Over the years oil got better and Mazda slowly reduced the amount of oil that was injected into the engine.Of course the material quality and SIP process improved as well on the rotor housing running surfaces.

Don't quote me on this,but I'd bet the 2 pipe 70's-80's pumps puts out more oil than the 13B 4 pipe unit on the injected engines.

j9fd3s

iTrader: (3)

i suspect you are right, however the FD pump spec isn't in the FSM, so its hard to say. i bet it is in the cosmo book though

bumpstart

i actually have the numbers and they go up with the expected engine output
the s4 NA is less than the s4 turbo
,, and both are more volume at full stroke than the carbed engines
also have an output graph for the s5 EOMP somewhere

IIRC the carb 2 oiler ( no banjo fittings ) is 1.8 -2.2 cc @ 2000 rpm /5mins
the s4 NA is 2.1- 2.8 cc ( suspect 12at and GSL-SE are the same )
the s4 T is 2.6-3.3 cc


if you have housing injectors then you need a mech linkage pump that has the banjo fittings ( 12at , GSL-SE , s4 NA and s4 turbo )

Jeff20B

iTrader: (13)

Agreed. If you use the the carb version with housing injectors, it will blow out the seal in the OMP. I've had it happen a few times before I caught on.

Take-7

Premix. it just got simpler.

Kentetsu

Premix is what I was thinking too.



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j9fd3s

iTrader: (3)

the GSL-SE and S4 na use the same N246-14-600 pump, and i have no 12A turbo parts catalog, but i would also suspect N246 is a 12A-T part number.

there are a couple different carb pumps too, the late N249-14-600 is the 1.8-2.2cc one, the earlier 1757-14-600 puts out a little more 2.0-2.5cc/6 minutes, although .3 of a cc, is like half a drop....

Jingkun

iTrader: (4)

Just premix, my omp broke and that's the route I went. No drop in performance and proven longer engine life, what's wrong? Also as a note, if the idea of carrying around a jug of oil sounds off then just get a mason jar from some spaghetti sauce and one of those premix syringes from Walmart.