D3rELiC

hi rotary fellow
i've just bought a 4 port from a guy that had it in his 510
i wanna put this engine in my 81 FB, but first i'd like to know some little things.

i know the early 4 port 13b had bigger ports,
i'd like to know if someone would be able to tell me if my engine is an early model or not by looking at a pic of my intake ports

i also have an s5 6 port engine laying in pieces somewhere, both rotors seems to be good and since they should have better compression ratio and better weight, i was wondering if i could use the complete e-shaft assembly, and the flywheel/clutch i have laying arround.

the carb looks like a stock nikki, is it ?

Jeff20B

iTrader: (13)

It might be Hitachi, which is the stock carb of most or all four port 13Bs. Yes, you could swap the entire rotating assembly, but be careful about the stupid oil resistrictor inside the '86 E shaft. Either replace it with an Atkins or similar plug kit, or use the old E shaft. In other words, use whichever shaft is in better condition.

If you could post some pictures of you engine, I could probably tell you which type of ports it has.

D3rELiC

fine i'll get pictures soon
the stupid oil resistrictor is the thermal pellet ?? and i have to remplace it with a solid one or something like that, so the oil always get into the shaft assembly ?
im planning on getting some new stuff like springs (ive broke/bend 2 or 3 while trying to get em out of the rotor slots) so i might change every spring on the rotors and i might buy some new 2 pc. apex seals if i can safe enought money selling my S5 side housings.

will i have to use the crank angle sensor gear, oil pump sproket, Needle bearing, ect ?

D3rELiC

got pictures, here they are, sorry for their size :

rxtasy3

iTrader: (2)

looks like my '74 13b from an rx4. i think the '70s cosmo had the tall ports in the center housing.

Jeff20B

iTrader: (13)

I don't mind the size at 1158x768 but it's hard to see details. Anyway, you have a '3B' 13B. If you look down past the flywheel on the rear plate, you'll see 3B in raised letters cast into the iron. These have tall juicy intake ports. The exhaust ports are really small though. That engine will make a very fast car with minimal intake porting and a decent amount of exhaust porting. If the carb is still good, it can be used after the porting job. It's an Hitachi. It's great for engine break-in because it runs smooth. After it's broken in, get an aftermarket carb for a serious power gain.

I have one of those 3B 13Bs with a few later components like a 1st gen water pump and a light steel flywheel in my MG Midget. It needs a rebuild because the rotor housings are missing a lot of chrome, but the apex seals and springs are still good so I'll just run it like that for a while. It always fires up cold and has a good idle. It's just slightly down on power because of the chrome and the wrong intermediate plate. I have a genuine 3B intermediate to throw in there when it's time to rebuild. I've just gotta get some rotor housings.

For your engine, you'll want to swap in an '81-'85 distributor and waterpump because the one in the picture has different inlet and outlet angles.

D3rELiC

Thx for your reply Jeff
i cannot remove the flywheel right now, but i saw a single number right behind the flywheel, almost at the bottom of the side housing. this number was a 7 if im not mistaken (it was hard to read since the engine is sitting 5 inch to the floor and also there was some grease) .

the distributor swap was also on my checklist since i wanna run DLIDFIS (thx to you for the very complete writte-up)

now lets get some stuff to have the engine rebuilt!

before i send this i'd like to know what is the triangulated (sp) blockoff plate on my intake manifoil ?

Jeff20B

iTrader: (13)

Are you going to rebuild it yourself? A 'standard '74-'75 gasket set is what I've used, and is has the correct intake manifold gasket. It's the cheap set too. Don't get the one for the Cosmo because it's more expensive and has the wrong intake manifold gasket (tall intermediate ports and no EGR cover etc).

Here is a link to the gasket sets I've been getting. It's still under $100. You'll still need oil O rings, apex seals, springs etc. This is just the soft seals and gaskets (that's why it's so cheap). Oh, you also need front and rear eccentric seals and etc http://www.mazdatrix.com/getprice.as...m=99-100D-3565

The triangle shaped thing is the ACV (air control and check valve) blockoff plate. It prevents the exhaust from blowing through the EGR port when the ACV thing is removed. I just made one the other day out of 1/8" aluminum and installed it on my 20B. I still need to make one for my '74-ish manifold to replace the thick steel one the moronic PO (previous owner) installed.

About the rear plate, look from the top down where the inspection cover is. The 3B should be near a freeze plug if I remember right.

I just checked my dead 3B plate and it's right above the uppermost freeze plug right above the stationary gear (at the 12 o'clock position) and right below the edge of the inspection cover opening. Look there.

DLIDFIS helped my 3B engine substantially over standard '81-'85 ignition back when it was in my REPU. I also set up DLIDFIS in my MG and the engine runs fine it too. Actually, it runs even better thanks to a better fuel pump, and possibly a better designed exhaust (they're both custom, but the REPU's was done badly by a PO).

The carb is on a fresh rebuild right now, for the reasons mentioned above, but when it's done, the carb will go back on the MG. I'll be able to drive my 3B engine again!

D3rELiC

why dont you live closer ! hahaha
thx alot for the info,
and yes im gonna rebuilt it myself (with some help from friends) my block off plate is also made in thick steel, im gonna find something to replace it sooner or later. i unscrewed this block off plate to a look inside and it was horribly dirty, im gonna have to clean that too.
im very happy with my purchase, paid 500$ cnd for the engine + 200 $ for shipping.
i'll let you know when im gonna be ready to order the stuff for the rebuilt, to make shure i get everything.

rxtasy3

iTrader: (2)

something else i noticed, that sensor in the top of the center housing, i did away with it on mine and just made a plate to cover it.

d0 Luck

is the e shaft from FB 13B have same weight as the 89-91 e shaft?? if not, would the lighter rotors from the s5 work perfectly w/ the ones on the FB 13b?

D3rELiC

correct me if im wrong, i think every rx7 13b e-shaft are the same.
to be able to use the light weight rotors, you need both counterweight (the front c-wright and the flywheel)

Siraniko

iTrader: (13)

All 13-B e-shafts are the same. Except the 86+ has a t-pellet for faster oil warm up. I prefer not to use it to eliminate another source of oil failure.

DriveFast7

iTrader: (1)

except the e-shaft is balanced for the rotor weight used in the specific motor.

Siraniko

iTrader: (13)

it shouldnt matter as long as you use rotors and front counterweight from the same engine. Meaning if you use the 89+ rotors, take the front counter weight as well

D3rELiC

im looking for a new flywheel as well, any suggestion ? is there a limit in weight i should not cross ?
car wont be daily driven, but will be used on the street and on the track as well.

Jeff20B

iTrader: (13)

Some say an aluminum flywheel is hard to drive unless the vehicle has lower gears or is light in weight. I like the light steel flywheels myself. It depends on what the engine will be used for.

D3rELiC

thx for the flywheel suggestion,

i've also found a weber 45 DCOE for cheap, would only have to buy the lower intake manifoil. i think the carb will be ok for the light porting i intend to do