nuredbaron

ok guys good and bad i should be picking one up soon for cheap came out of a repu.

Has a blown seal it is sucking water it was still running when pulled. obviously needs a rebuild that is being planned.

Also thinking of porting her. any advice like should i even bother? i think it is a good starting point since i don't have to change the front cover.

well any help will be appreciated thanks

rxtasy3

iTrader: (2)

i'm running a '74 13b but it's from an rx4 and it's also streetported. when u get urs apart, take a good look at the housings, intermediate and rotor. check for spots of corrosion in the water jacket area near where the outter water "O" ring seals. when i did my build, i had the intermediates resurfaced and they have this currosion. i've got 20 some odd thousand miles on it right now so if it ever starts putting out white smoke, i'll know why. good luck with urs.

killjoy7

iTrader: (6)

I had a 4 port 13B in my 80 SA. With an RB racing exhaust, big streetport and Weber 48IDA it made 168 wheel hp. on the dyno with bad sparkplug wires hindering high rpm running.

4 ports kick a$$

Jeff20B

iTrader: (13)

I test ran a '74 13B in my MG Midget. It was very nice with a light steel flywheel. Those '74 spec ports are bigger than '76-'85 ports. Almost a streetport, but not quite. I've never measured it, but I believe '74 ports close at 50°. Typical street ports close at 60° and stock US spec '76-'85 ports close at 40°.

You can leave the intake ports alone if you want, but it should be ok to enlarge the exhaust ports. Don't open them up any sooner by porting down. Only port upward to close them a little later. The sleeves of '74 rotor housings are small enabling higher velocities, but this limits the port size as well. They open when a T2 opens, but close way sooner. They're also narrower by some 2mm on each side.

When I rebuild my '74 engine, I'm only going to clean the casting flash and sharp 90° edges out of the intake ports but I won't enlarge them/change the port timing. As for the exhaust, I plan to leave the openings as is and close them a little later... probably.

If anyone here has experience with '74 13Bs with or without porting them, please speak up.

84stock

iTrader: (5)

They have nice intake ports and smallist exhaust ports, this make for a nice torque curve with the engine.

Siraniko

iTrader: (13)

Rotor housings and e-shaft are the only ones I would use from the old 13-B motors. The rest are SA-FB side plates (with tall ports), GSL-SE rotors, oil pump, etc etc. Then port the hell out of the plates. Who cares about low-end, I want top end.

nuredbaron

sweet thanks guys i'll check out the housings. how is interchangability between the other 13bs. are the rotors 2mm narrower? i think thats right.

i think it is a good deal i'm trading a spare 12a tranny plus 2 hundred for it?

i think one of the water o rings is leaking? the guy i;m getting it from thinks its an apex seal??? weird i thought the apex seals deal with blow by and compression.

unless it came apart??

trochoid

iTrader: (6)

Not trying to hijack this thread, but I have a couple of questions concerning building these hybrid/frankenstien motors. I have a pair of good 74-78 13B housings, 12A plates up the wazoo and and an SE motor to tear down.

I would like to build a 4-port 13B, haven't decided on rotors yet, but I have S4 NA and turbo ones, along with the e-shafts, or the SE parts. What can I use for an intake, NA or turbo. I don't have the original 4-port intake or Hitachi, but would like to get the engine setup with eventually using a stock or hybrid TII S5 turbo. I do have the S4 turbo intake.

So the gist is, what fits for intake when going this route? Using NA rotors with the turbo might be the ticket for the REPU I bought this past weekend. That should give me some good lowend torque with a fair sized sp or 1/2 bp.

rxtasy3

iTrader: (2)

nuredbaron: intermediate and rotor housings thru '85 are interchangeable. '86 and later, the O ring grooves were moved from the rotor housing to the intermediates. then changed back in the rx8 engine.

trochoid: is the 13b housings u mention intermediate or rotor? u could actually take the 12a plates and put them with the rotor housings and internals of the SE engine and end up with a pretty good 4 port. i'm pretty sure, but not positive, that s4 rotors would work in an earlier engine. i'm actually using an early 2nd gen(86-7) e-shaft with '74 rotors in mine. NA and turbo intakes will only work with those years housings since the bolt pattern in the intermediates is completely different than the early ones. plus the NA's r 6port. if u don't plan to run a turbo, then NA rotor housings and rotors with intermediates form a turbo and the intake would make a good 4 port, provided ur planning on going FI. otherwise u'd need to use an aftermarket intake and carb.

Siraniko

iTrader: (13)

I have a several old school 13-B intake manifold along with a good set manifold/hitachi carb. Your other option is to re-drill and tap a 13-B manifold to accommodate for a 12-A carb. let me know when ur ready.

Now, if you want to use a TII intake on an old 4port 13-B block, the bolt patterns are different; either use an adapter plate OR mod a TII intake as I have done in the past.

trochoid

iTrader: (6)

How about some details on the mods required for the TII intake. That is the eventual route I want to take for the REPU. It is going to take a while for the frame off resto, so I have plenty of time to build/mod the motor. I do know I can use my early 13B housings with the 12A end plates and SE center iron for the primary injectors. I'm just not sure how much trouble adapting the TII LIM to the hybrid block will be.

I think a 300+ hp mini truck would be a blast and suprise a few of the rice boys when they get get smoked by 'That old thing', and a mini truck no less.

Wacky, how well does the oem early 13B intake match up with my proposed hybrid block. When I get some work cleared out of the shop, I will do a mockup of the engine configuration and TII intake, just trying to get a head start on the knowledge base and not have to learn it all from scratch.

Siraniko

iTrader: (13)

If you are referring to the a GSL-SE motor with 12-A plates, then the intake bolt pattern would be the same as the old 13-B 4ports. Thats what I currently have in both FB and RX-3.

To fit a TII intake, lots of grinding is involved. Thats the route that I was going to do but I decided to go with TBI injection (on hold til next year). Pix of an 13-B manifold with RX-2 carb and TII mock-up are as follows:

Midwest 7's

iTrader: (4)

so it would be an advantage to use the 13b plates over the 12a?
what could be ported larger?

Jeff20B

iTrader: (13)

Get it apart and take a look. Then decide which you'd rather use. I think the '74 3B plates (I said 3B, not a typo of 13B) can be ported larger, but don't quote me.

Wacky, I like that reversed runner manifold and the R5 rear plate. I have to use that style manifold in my MG Midget because the runners are closer to the engine enabling it to fit after some removal of the ACV casting. When I'm done, it should be easily removable with the engine in the bay.

Trochoid, the engine that's going into my MG has Y casting 12A side plates and early 13B rotor housings from the '70s. The rotating assembly is from a nitrided R5 J-spec 13B from the '80s. It came stock with a high volume oil pump, and we know the '83 12A was the first US-spec engine to get one in this size (17.5mm). I've given the side plates a '74 spec port job. Exhaust ports open later than T2 but close at T2 (this should be good for low to mid RPM torque as this engine may find its way into a baja some day)

Your engine ideas sound good. Maybe you should stiock with the older heavier rotors since it's going into a truck. Then again if you do choose to use a set of NA FC rotors, at least retain the stock flywheel.

Was there a tranny in the truck when you got it? If it's the stock ribcase style, the 6 port rotors would be best to use so you could use the '326' 225mm flywheel, disc and pressure plate and it will be fully compatible with the tranny. Just test fit the FC starter first and take a die grinder or dremel to the casting flash in the starter reciever hole. Don't mind the difference in tooth count. What matters is the ring gear circumference and location has remained constant from '74 to '92 on non T2 engines.

If you want to use T2 rotors and think you want to undertake a T2 tranny install in order to use its stock 240mm flywheel and parts, you'll definitely need to move the shifter extension housing into the SA/early ribcase position (bench seats in REPUs are not kind to funky shifters). This is easily done on FB trannies as the second set of mounting holes can be used, but FC and T2 are a little further back. Just use an FB extension housing and whatever rod and ball socket you like best (since the rod will be shortened). I prefer the threaded FB rod because I've succesfully relocated a shifter housing on an '81-'83 tranny and it fits fine in an RX-4.

trochoid

iTrader: (6)

Unfortunately it's an automatic, so I need to find the parts for the manual conversion. I have a choice of FB, FC and TII trannys to install. Even have an FC auto somewhere.
I have plenty of time to decide on engine and tranny combo. Divetrain and suspension are also options for change. I have a complete TII drivetrain and suspension and 4wd is not out of the picture yet. Oh the possibilities.

This will be another one of those projects that I spend 10 times what I paid for the vehicle, to get it on the street.

nuredbaron

ok so if i go with the fc na rotors should i go with the e shaft that mates to those rotors. is there a series that i should be looking for?

i might just pull my 12a from my gsl and combine it with my 13b and go and find the above mentioned rotors and e shaft.

i should be able to do that right from what i've been able to comprehend so far?

flight_of_pain

i have 74 irons with -SE rotating assy and a big streetport and i love it, i would definately suggest 4port 13b's . fuel is delivered by a modded nikki(140pri/170sec) on an rx4 manifold.

isaac

nuredbaron

what rotor housings are you using?

flight_of_pain

-se housings

isaac

nuredbaron

ya after i posted it i was thinking and well 13b rotors i don't think could fit in 12a housings stupid me

flight_of_pain

lol, no prob, i guess the 86+ housings have a differenet o-ring groove and they are supposed to be a different peritrochoid (ive seen new mixed with old and they run so it cant be much difference).

isaac

nuredbaron

ok i might bag the buying the engine. if i do i might just piece together my own engine. and if i do so far this is what i've got.

12 front, intermediate and rear housings
fc or se eshaft and rotors and counterwieghts
se rotor housings
would this work??

what intake and exhuast manifold should i use.

oh and of course a street port job to intake and exhaust openings.

nuredbaron

**** i hate that little button labeled aaaaaaaaaaaa

Siraniko

iTrader: (13)

Yes

flight_of_pain

if you are going carbed with a nikki, the rx4 intake works.

isaac