xrotaryguy

I have a 75 Rx4 sedan that ran fine till I took it to emissions. It was way high on CO at cruise and was at the limit at idle. I was running a cat with an air pump and aparently no trailing ignition. Well I didnt find about the no trailing ignition thing till after I rebuilt the carb. Though I should have put 2 and 2 together in retrospect seeing as how the tach doesnt work. any how I rebuilt the carb and the car ran like crap. I took it apart again and really gave it a good cleaning and in the process of cleaning it i found that the body of the carb is no longer the correct shape. the threads are bent up a little here the gasket mating surface is sagging down a little there. So I guess thats why the first carb rebuild failed. I used lots of high tach spray too. The carb leaked when I tipped a little to the driver side from the gasket that seperates the gasket from the outside of the carb. So now I got a tube of gas resistant plyable silicone and put the top cback on with that. I figure that should fill any gaps that the carb's sagging body had created. Man I gotta say that for being the same age as me this carb sure is sagging an awful lot more than I am. So now it idles great. Till I put it in gear. Then its iffy. It also missses inconsistantly at throttle. It pretty much runs ccrummy but not as crummy as before. I dunno. maybe I should get another carb. I may have clogged some jets with the silicone Sorry this is so long winded.
Now for the timing. It looks like this car is supposed to have two settings for leading and one for trailing. maybe it was 2 for trailing too. I dont recall on the trailing thing. The wiring has been repaited by some one some time and I am certain that they did it wrong. theres like 6 or 8 wires going into the first connector comming from the distributor and only 3 comming out. One of which was going no where. Yellow with a green stripe. Well the one that was going somewhere (also yellow with green stripe) was connected to the trailing coil and the trailing coil was doing nothing. I put the other y/g wire on the trailing coil and viola! spark. but Its not sparking at the right time. It adjusts at the same rate that the leading does. but not to the same time. None of the manuals that I have collected over the years has a diagram that is detailed enough to re wire this thing. I know people like to say I should go to electronic but this car is very close to stock and I dont want to mess it up now. I have after all not ever seen another one in person. ( a sedan that is ). Not to mention that the distributor that I have now doesnt use vacume. I doesnt have spring loaded weights either. It has seperate circuits vor leading advanced and retarded and I think that trailing just had the one setting it doesnt advance or anything. so where do I hook the advances to? I know that the leading and trailing advances do not get vacume from the same place on my 84 gsl. so I dont think that they are supposed to do the same thing.
-So Ideas on the carb? Is it time to talk to paul yaw yet? I hear he lilves in town.
-Any of you have 4 port 13b carbs you wanna get rid of?
-Do you know of a good place to find another?
-How about the timing?
-Any one have a wiring diagram or know by memory how to hook it up?
and if i do go to electronic where do i run the vacume to and what do I time it to?

Ok Im finally done.
thanks for any help you can give.
Brian

Crit

iTrader: (6)

I have a Dellorto 48 DHLA and manifolds if you're looking.

xrotaryguy

Do you think the car would poass emissons with a 2 barrel carb of that size? Maybe with enough alcahol in the tank? Is this carb suitable for a blow through set up? Aka does it have a float vented to the throat of the carb and perhaps less importantly sealed throttle shafts?

xrotaryguy

Oh by the way... I have ordered a wiring harness from the distributor to the coils. Does anyone have a wiring diagram? The wiring was changed by someone who had less of an idea of what they were doing than I do. And thats bad.

xrotaryguy

well heres the update... the carb is warped and I think that it was not the problem in the first place. so now i have taken it apart and it will not go back together and no one has one that I can rebuild that i can find. do you know of one that i can get my hands on?

Wankelguy

If I remember correctly, the 1975 distributors have three sets of points. One is a retard set for ease of starting. Anyway, the thing is needlessly complicated compared to the electronic distributors found in '81 and above 1st Gen. RX7s. The easiest thing for you to do would be to get an electronic distributor and coils from a junk.. er.. SALVAGE yard and retrofit them rather than having to mess with a new harness just to make the old archaic system work. All you have to do to make the system work is provide 12V to the coils when the ignition switch is on. Then you need to run 12V to the ignitors from the coils and hook up the trigger leads to their respective coils' - terminal. You end up doing away with the ballast resistors and their associated relay in the process. Nothing could be simpler.

xrotaryguy

Yeah Im looking into doing this swap. I actually bought a distributor and coils with the wiring in tact so Im good to go I guess. Do you know which timing mark im supposed to time it to? The book says that I should have 3 marks on the crank oops E shaft pulley but I only have 2. Any how. Im definately considering going this route. I finally have the car running well again But the rear end of the cat is back to glowing red as well. The ignition system seems to be functioning fine but I dont think I have it timed right. I also have a feeling that the carb is jetted too rich to be using with a cat. Do 81-85 Rx7 primary jets fit in this carb?

Siraniko

iTrader: (13)

Just time the engine using the 2 marks in the pulley. Mark towards the driver side is Trailing while the other is leading.

You can use a FB carburator with a slight mod on the 13-B manifold like the picture below.

Siraniko

iTrader: (13)

sorry, it should be leading then trailing.

xrotaryguy

well I'll give that a shot... again lol. I havent had any luck getting the trailing to adjust one way or the other. but we'll see

Siraniko

iTrader: (13)

try the west forum...we have members from AZ who can help ya.

xrotaryguy

I'll do that

xrotaryguy

Oh bu the way the car passed emissions with... well less than 30% alcahol. Im sure that some of it evaporated by the time that i got to the testing station

Tom93R1

iTrader: (2)

hey Brian, Congrats on the pass. You driving it around now?
You should bring it up to the Pavillions for the local rotary club meeting saturday.

xrotaryguy

Thanks Tom. Im working saturday though. Now I have to get the thing to pass a level 3 "drivability" inspection. Which brings me to my next problem. Theres a rubber joint on the steering column in the engine compartment that is worn out. I can still steer but theres like an 8th of a turn in the wheel. Do you guys think that they will care? Everyone who has sat behind the wheel seems to get kind of a scared look on their face.

xrotaryguy

Well I finally got the title for the rx4. Its street legal now;. Thanks for all the help.

xrotaryguy

Ok guys the rx4 has a title and plates and all that good stuff. thanks for all the help

rowtareh?

iTrader: (1)

Are'nt cars that are older than 20-25 years emissions exempt? Arizona has some really weird laws. You could be running a BP with full exhaust and header and they would not care. Weird man, really weird.

Tom93R1

iTrader: (2)

It all varies state by state. In AZ anything older than '67 is exempt. From 67-80 it needs tested every year and after '80 needs tested every year. Also we are (I believe) the only state that requires motorcycles tested, and that is every year as well for any bike. AZ is the most pain in the *** emissions, CA is a close second.

Tripple 7's

Alright congradulations you finnaly did it. Lets go for a ride... um after you fix that rubber joint though .