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Distributor wiring from scratch


gromit

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HI Guys, I have an odd one here I need to sort out.

I have a Nissan Z24 powered Austin.

yup.

 

Anyway, I need to wire the distributor up properly. It has a harness of 4 wires, and a separate wire that goes to a terminal on the side of the dizzy. 

 

from the "harness" white wire, sealed off  Black with white tracer to coil Power and coil +ves. Blue and red to  coil -ves

 

The separate wire is black, it goes to a plug and  black thing (condenser?) it has a black wire with white tracer coming out of the unit, and a brown wire to power.

 

where does this wire go?

 

 

Car sort of runs, but backfires and has no power to speak of. it stalls out easy. very low vacuum which may or may not be related to this (for some reason it has a Ford carburetor.. don't ask, I didn't build it. A few years ago this was a strong runner, but it has been in another's hands and has been played with. The person who played with it passed away.. can't ask what he did to it.

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Pull each coil wire from the distributor cap and put an old spark plug in the end. Lay on a grounded surface and have someone crank the engine over while you watch for spark. Confirm that both coils are sparking. If they are the distributor must be working.

 

 

 

It's very easy to get the wires mixed up, very easy. Number one intake is about 9 o'clock on the cap. Number one exhaust is about 4:30 o'clock.  Check your wires carefully.

 

720timing002Large.jpg

 

 

The caps usually have the plug wire labeled. Below.. finger is on Intake one and thump is on exhaust one. The firing order is 1342 counter clockwise.

 

721ignition002Large.jpg

 

If backfiring then the distributor is working. The spark may be going to the wrong cylinders. 

 

Another thing to check is the valve lash.Intake and exhaust are 0.014" on a warm engine.

 

Ignition timing is 3 degrees BTDC.

 

 

 

Correct plug wires, correct valve lash and correct ignition timing and this will likely fix your problems. Or allow us to move on to something else.

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Thanks man,

I am pretty sure the plug leads are right, but the primary wires (power to distributor etc).. the black/white blue and red etc is what I'm checking on. It only backfires on start up. (I am starting to suspect a fuel issue)

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It was the "extra
black/white I was concerned about.  (see quote)

 

".....The separate wire is black, it goes to a plug and  black thing (condenser?) it has a black wire with white tracer coming out of the unit, and a brown wire to power.

 

where does this wire go?....."

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This is an Austin and has Austin harness. Check for spark from both coils. If you have spark you're good.

 

Back firing can be from many things. Too tight a valve lash, plug wires mixed up. Too lean a carb mixture.

 

 

Rather than jump to conclusions, eliminate the three things I posted first, then they can be forgotten. If the back firing continues we can move on to other things like the carb.

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It's an Austin with a Nissan Harness. I do have spark at both coils, I put labled NGK plug leads on it so I wouldn't get the wires mixed up...That's all good.   I just have a wire hanging loose I think may be important. The one that appears to have a condenser involved.. I don't have a good wiring diagram, was hoping someone could confirm where it went. That;'s all.  (FWIW I am a semi retired red seal tech,,, just need a hint here on this Frankenstein from a Nissan person!)

 

I'm pretty sure the backfiring is a lean condition, (there is little to no vacuum) I'll deal with the carb later, I want to ensure proper wiring before proceeding. This whole thing has been too much of a challenge not to proceed in some sort of order.

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Wires colors changed all the time.

 

The two wires to the condensers each go to the + terminals of the coils. The Black wire is a ground and goes to the distributor case.

 

In my case the condenser wiring is... Brown is the power to the intake + terminal. The Black/White stripe is power to the exhaust coil + terminal.

 

Power to the intake coil generally comes directly from the ignition switch. Power to the exhaust coil comes from a fuse (this is true for the 720 but the Austin? don't know)

 

In operation the distributor module opens and closes a ground to both - sides of the two coils. Both coils fire together. Intake and exhaust coils, wiring or plug wires can be interchanged by mistake and this will have no effect on running.

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It's -ve ground.  I actually have converted all my Brit cars to -ve because I like to run alternators, and =+ve earth alternators are hens teeth. (I have seen 0ne only)

 

Are we sure the timing is 3 btdc? I looked it up and say 15+/- .

 

Timing set, carb re-sealed, moving on to valves cause she backfires under load. Runs fair light throttle, ut won't do a hill without clearing her throat.

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It's wrong. Dual plugs run much less advance than a single plug set up. Light both ends of a candle and it lasts a shorter time. Two ignition points and gas burns fully sooner so you start the burn later.

 

The actual setting is 5 degrees BTDC + or - 2 degrees. This is for variations in elevation gas octane and outside temps.

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