Hey folks,
I recently bought an 86 Mazda B2000 pickup that was converted to a 13B rotary setup (http://www.cardomain.com/ride/1650712) The engine was torn apart when I bought the truck, due to damage to the internals. (The owner said someone drained his oil, I think he ran the motor too hot without an oil cooler) But I'm trying to find out if it's a Series 4 motor, or a Series 5 motor. How can I tell the difference between the two? Also, what are the major differences, if any between the motors? Does one produce more power then the other? Thanks in advance folks, and I'm glad to be part of the Rotary community.

 

uh oh

 

be nice

 

i didnt say anything lol
i just know someone will though

 

Sorry, I'm guessing that's a newbie question, but I've been a car mechanic in the Air Force for 5 years, and we don't have any rotaries... I know the obvious difference is that they came in different years of the FC, but what else?

 

S5 produces more power than the S4 but only marginally. the easiest way to tell them apart is the S5 uses an electric OMP where the S4 uses a mechanical only OMP down on the passenger side of the front cover.

S4 has EGR whereas S5 does not, S4 has an aluminum thermostat housing where S5 has a nylon plastic one.



one of those clues should answer your question.

 

Heh, another newbie question... What's an OMP?

 

it is kind of hard to tell from those pics, but, it looks like the inner and outer water seal grooves are on your housings, if they are, that it is a gsl-se block from a 1st gen, if the grooves are on your plates than it is an s4. S5's had more casting around where it says Mazda on the top by the dowel pin.

 

I think the easiest way for a noob to tell is the egr part, its in the middle iron btw jason.

 

check the FAQ threa at the top of the forum for abbreviation.

OMP=Oil Metering Pump (your engines form of internal lubrication outside the crankcase)

 

if you post up a pictue of the upper intakemanifold i can tellyou s4 or s5 in a heartbeat

 

Wish I could, the truck is in Seattle, and I'm stationed in TX. I'm trying to get stuff together so I can work on it when I go back home in August.

 

its actully a MOP to be ****, and it stands for Metering Oil Pump, it injects a small amount of oil into the engine as its running.

After looking at your rotors it looks like they are 3mm so I would say it is from a gsl-se. but the grooves is the easiest way to tell for sure

 

looks to be a S4 but it could also be a GSL-SE like mentioned:



i do not see machining lines on the rotors indicating that they are S5 rotors but it could just be carbon still covering the compression relief pockets.

if the rotor housings do have grooves cut into them for the coolant seals then it is a GSL-SE(84-85 13B injected).

 

look at his car domain, there is a pic of a carb so I am assuming it is running of that and not stock manifolds. can anyone make out from the pics if the grooves are on that housing or if it is residue from the old seals?

 

Well the dude I bought it from said the rotors were machined for 3mm apex seals... But he did say it was pieced together in a weird way or something. I'm thinking he said something about the front cover or front housing...

 

heh, someone wasnt paying attention

 

yes, it is a pieced together motor. i feel like i'm playing "where's Waldo?" lol!

here you have a 12A carburetion setup with 4 port irons(4 port lower intake in the bed) to match the intake manifolds, so either he used turbo2 irons, GSL-SE irons or 12A irons and either GSL-SE rotors or S4 rotors.




im guessing with all of this it is a GSL-SE engine with a carburetor bolt on. but this being the second gen section i can only speculate, you would probably have better luck on the 1st gen section.

 

I just added a few more engine pics to the page that I had...

 

S4 injectors are brown where the plug goes, S5 are red and the plugs themselves are different, not just the color....

well, thats how it is on T II engines, I dont know about N/A engines.

 

the more i look the more i think GSL-SE with a carb on it.


the front cover is not off any second gen that i have seen and it is not from an FD...


those rotors are probably unusable anyhow, unless they can be milled to accept larger diameter bearings, they do not look happy...

 

Well, I have a donor 88 RX7 that has low compression. Maybe I'll say screw it with this motor and drop that one in instead. I'll use the little video I bought from Atkins Rotary to rebuild it. Oh hell, this is gonna be fun. I shoulda stuck with pistons.

 

yeah thats an gsl se block. and I would guess that the rotors werent machined to fit 3mm they just came that way for se blocks. if you are using a 4 port lower manifold on that, it is the wrong one to use.

IMO, the se blocks are one of the better ones to have. The grooves on the housings is a better way to have them, again my opinion here. If you wanted to keep that lower manifold, you can use older 4 port 13b plates or 12a plates. What has been done to the center plate for the injector holes? Are they there or has that plate already been switched? If I were you, I would use those end plates and get a different manifold, and use a 12a center plate(it has no injector holes, and has the biggest primary runners of any center plate). But get the plates ground flat, and maybe get the housings cermet coated so you will make decent compression out of the motor.

 

Cool, thanks for the info. I'll check all that stuff when I go back home to work on the truck.

 

there is no injector ports on the middle iron: