Pertronix 1761

[Bertoldo Beyer]

Thismorning i decided to swap the ignitor installed on my 240z and after opening the distributor cap i notice something is missing, i guess it could be the ground wire,so i fabricated one with 2 terminals and installed a new pertronix ignitor model 1761 together with a 40511 new 3.0 ohms ignition coil.

The car cranked up fine, but whenever you step on the gas the tachometer does not read correctly. Once it reaches to 5,000 RPM it jumps to 7000 goes back to zero, etc. If you have the car parked and step on the pedal it raises to 5,000 goes back to zero. Bottom line it is not Reading as it used to read with the former ignitor. What could be wrong here? Could i have missed something?

It looks to me like that module is not designed for ECU control at all. The B & C pins are the coil connections, the I & W connections are for an idle switch and thermo switch, probably adds a fixed amount of advance under certain conditions.

Yes, if you pull that E12-92 box off the side of your distributor there will be two wires that connect from that to the reluctor pick-up inside the distributor. Google pics show a red and green wire, I cant find any info on polarity but conventional logic would suggest red is the +ve and green is the -ve. Connect the red direct to trigger 1 on the ECU and the green to sensor ground.

The second triggerscope looks like there is a faintest of signals there but not enough voltage to be useful. They have a pretty odd looking reluctor in those things and there is not a lot of info around about them so it may not be suitable. Can you try spinning it faster (pull it out and use a cordless drill or similar) and do a scope then to see if we get anything more useful out of it.

Sadly they are unicorns, from the turbo l28 and are next to impossible. But I'm not worried, I'll grab a fresh battery and see if I can up the crank speed. I am happy to have a second set of eyes on it to make sure I didn't goof something up badly. I'll play with it this week and let you know where I land

After more digging I can get the pictured pick up coil, seems to have the same screw pattern as the NA dizzy, I should be able to remove my existing stator and put the new pick up and get a timing wheel instead of the reluctor

Yes, this would be fine, you will also need the thin metal chopper disc that goes in the middle of it too. The original Nissan one has 360 slots or you can get aftermarket ones with 24 slots. The 360 slot can be an issue at high RPM if there is significant backlash in the drive system. Probably the same as one of the other common Nissan ones - CA18/VG20/RB/SR/KA.

Seems odd, I cant quite work out what would cause that. Does the pertronix pickup have a good path to ground inside the distributor? Try temporarily wiring an old ign coil to the pertronix red/black and see if the voltage looks better (ground the HT lead).

- Recently Remanufactured Hitachi 3 screws SU CARBS, Scheider 274F Cam with new lash pads, retainer springs and NIssan OEM Rocker Arms. THe engine was overhauled by DATSUN LLC with cranks and rods from a L26, special oversized84 mm pistons from DL POTTER ENGINEERING, Pertronix ignitor 1786 and 3.0 ohms coil, MSA Fan Shroud, Champion 3 row radiator.

The problem is that whenever the car warms up and i get in the middle of a traffic jam, the idle starts to become rough and suddenly drops to 500 RPM. The NGK BP6ES spark plugs start to foul and eventually the car shuts down. This car is supposed to be driveable and mantain its idle even under any kind of heat and traffic conditions. Well, it is not. I changed the plugs like 6 times, spark plug cables, distributor cap and rotor, checked for leaks with carb cleaner and NOTHING!!!

Not a fan of these, as all they do is get rid of the points. A later EI distributor not only gets rid of the points but allows the use of a 0.75-1.0 ohm coil that draws more current and provides more spark. I doubt this is your problem but nice hot spark is always good for idle.

2. I am using the original single point Hitachi upgraded to pertronix electronic ignitor 1761 with 3.0 0hms pertronix ignition. Also think this is not the problem. Although if i pull the spark plug cable from cylinder 4 the rpm drop is not as noticeable as in the other 5 cylinders. I am using NGK blue wires and NGK BP6ES spark plugs gapped at .031.

If YES... what fuel pump are you using? Mechanical, electric? Have the fuel pressure checked. It should be no more than 3.5 or the pressure may be over powering the needle valve and flooding the carbs. See what Z Therapy recommends for pressure.

Airtex 8012S electric fuel pump which is pumping 4 psi and not overflooding the bowls at the moment! the rpm does not drop with any of the other wires. It remains the same. Plugs start to carbn foul when the car warms up and hits a traffic light or gets stucked in traffic. Idle becomes unstable and suddenly engine shuts off once the plugs are really fouled. If i should replace this pump with another one which one then?

Mechanic tested the car this morning. Got trapped in traffic temperature raised to 3/4, rough idle and car stalled. Isnt this a heat soak vapor problem? It doesnt happen with the car parked under a garage roof while at idle.

i have a champion 3 row radiator with an MSA Fan Shroud installed! The Temperature here in Panama is 33 degrees Celsius wth 80 per cent humidity. I havent flushed the radiator or cleaned it inside. will test the lower hose. DOes the heat affect the idle and consequently make the car stumble and stall in traffic??

If it was heat soak of the fuel lines (vapor lock) the plugs would be white from an ultra-lean condition. It still sounds more like it's flooding, BUT you could have an ignition problem instead (losing spark). When you mean fouled, you mean wet with fuel or black and covered in soot? Need to test for spark when it dies and won't restart, but it has to be in the non-running condition for it to be any value. It's possible the coil is overheating.

Electric fuel pumps combined with no return path are notorious for forcing the needle valves in the carb bowls open and flooding the carbs. You won't notice an external leak, though, unless you left the pump on with the engine off and it finally would overflow. Not sure where on an SU that overflow would happen.

Well i will try to explain this better. It seems as i am not making myself clear. The car accelerates fine even though some very slight hesitation if you dont step on the gas pedal properly. Car gets into a traffic light or traffic jam. After 2 minutes, idle starts to become rough and after 7 to 8 minutes the RPM starts to drop from 950 to 500 and rise again to a point where it just stalls in the middle of the Street. To avoid this i need to pull out the choke and drive with the choke on. Once back at the garage, if i pull the plugs they all come out black and sooty but not wet. THe heater is not working as i had to remove the heater box to install a Vintage Air Gen II mini evaporator and needed the space. The heater hoses were bypassed.

FSM says 4.3 mximum psi pressure. I am at 4 psi. So i should be okay! I still have the original ballast resistor. Should i connect the 3.0 pertronix coil to it instead of bypassing it with a jumper cable?

OK, your added info changes things. If closing the choke makes it run rather than due, that starts to sound like a pretty major vacuum leak. One that happens when it heats up. With no airflow (from not moving), everything under the hood gets hot so it's possible something is opening up that isn't supposed to, so one thing I would check is make sure the carb-to-manifold bolts and the manifold bolts themselves are tight, because that's a good place for a vacuum leak to happen. And I do hope you have the thick phenolic spacers between the carbs and intake (with gaskets on each side); I've actually seen folks omit them and the carbs heatsoak badly. Plus most SU setups had a heat shield between the exhaust and intake manifolds, you have that?

And check to make sure the brake booster is working. I've seen the diaphram go bad causing a vacuum leak, though it's generally not heat related (would happen all the time), but having the brakes on in traffic would change the amount the booster "leaks" of it was leaking.

i meant pulling the choke when the idle starts to get rough to avoid stalling in traffic. i do have the spacer between the carbs and intake on! I still need to know if in order to avoid the 3.0 pertronix coil from heating up so badly i need to connect it to the ballast resistor and not bypass it! I am using a Pertronix 40511 coil with 1761 ignition module.

Do you have the proper factory air filter housing??? They have a hot idle compensator inside that corrects an abnormal rich condition during very hot idle conditions. It's a pair of small air bleeds that allow added air into the intake to correct this..

I don't know anything about after market parts. The best parts are what came with the car... these I trust above all others. I can only assume the Pertronics coil and module work alright together as per the installation instructions. I would guess the ballast should not be used with the Pertronics 3 ohm coil.

I still need to know if in order to avoid the 3.0 pertronix coil from heating up so badly i need to connect it to the ballast resistor and not bypass it! I am using a Pertronix 40511 coil with 1761 ignition module.

That's what I understood. Pulling the choke (that's closing it, open is when it's pushed in, where it SHOULD be once the engine is warmed up). If it won't run with the choke open, it's going lean, probably from a vacuum leak, and closing the choke makes it rich. But apparently too rich if the plugs get sooty, but with the choke shut with a hot engine, it IS too rich.

Now, there is 2 different issues that could happen, but I'm assuming it won't run at all once it starts misfiring unless the choke is closed. If it will run but not IDLE with the choke open, that's a different problem, an idle circuit issue. But I don't think that's it.

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