It was the distributor...

[Spades]

So yeah, the distributor was the cause of my NAPS Z24 timing problems all along. I am assuming it was the ignition module that started to fail, because there is no slop, ect. in the distributor. I went through the lists of parts and found out the "new" distributor that came with the motor I bought was actually a Napa reman unit.

 

Today it started misfiring really bad and running VERY rich...the vacuum advance is still functional, but even though it will hold vacuum and physically move when you apply vacuum, it will not advance the engine timing. I checked my fuel and everything else, it is ignition. I am still getting spark and the coils are working great, but every now and then the spark goes weak on one of the cylinders or it will misfire...and it runs the same if you advance or retard the timing (the advance picks up or drops a little bit, but the motor speed is unchanged and the timing light is hardly noticing a difference).

 

Now I am left without transportation again, and wondering why I did not swap in a Chevy 4.3l V6 instead of these damn naps motors I have been screwing with the last year and a half.

 

So, any ideas? I don't really want to put in another reman'd unit, and I am guessing the Nissan part is worth its weight in gold, and I don't want to play Russian roulette with a distributor from the junkyard (there are no trucks in nearby pick and pulls, so it would have to be shipped in, I wouldn't even get to check it out before buying it). I haven't seen any aftermarket units for a NAPS Z24 8 plug motor, but right now I am frustrated and my interweb search skills are sucking.

[datzenmike]

You need a module? 3 or 4 wire??

 

[Spades]

You need a module? 3 or 4 wire??

 

I can't remember, I will have to check tomorrow, been a stressful day and my memory is shot. I will open it up tomorrow and find out. I still am not 100% sure it is the module, I will need to pull the distributor apart and inspect it...I know when some companies reman distributors they put cheap wiring and magnets in them, so I need to make sure it is the module before I bite the bullet and buy a new or used module.

[HRH]

When was the reman dist. bought? Those do have a warranty. Not sure how long, but at least a year I'm pretty sure. I haven't ever had any issues with a Z24 distributor going bad, but likely is just the ignition module, or perhaps the ignition control unit in the truck depending on what age. Some have a box I think, the others are controlled by the ECU. Datzenmike should know more about those.

 

 

BTW, we can test the modules at NAPA.

[Sealik]

I believe it will be the 4 wire.

Early 720s ...80-82 had the 3 wire...?

There are 2 tests to confirm IC integrity.

I was thinking magnets or springs....not the module.

But....I have been wrong before :D

[datzenmike]

The later 720 Z24s with the TBI had an ECU alright but the dizzy was a CAS (crank angle sensor) Not what you have.

 

The California electronic feedback carb had an ECU and O2 sensor but a regular dizzy with EI module.

 

Some Z24s had spark shut off under full throttle. These will have the 4 wire modules, the forth wire is grounded by a vacuum switch to convert the 8 plug into 4 plug by disabling the exhaust side plugs. When in single plug mode the dizzy (somehow) advances the timing to compensate for the longer burn time.

[Sealik]

The later 720 Z24s with the TBI had an ECU alright but the dizzy was a CAS (crank angle sensor) Not what you have.

 

The California electronic feedback carb had an ECU and O2 sensor but a regular dizzy with EI module.

 

Some Z24s had spark shut off under full throttle. These will have the 4 wire modules, the forth wire is grounded by a vacuum switch to convert the 8 plug into 4 plug by disabling the exhaust side plugs. When in single plug mode the dizzy (somehow) advances the timing to compensate for the longer burn time.

 

 

Yes...the removal of the ('4th') white wire from dizzy will result in the exhaust plugs firing all the time.

[MicroMachinery]

Would the Z22 dizzy work? I have one of those.

[Sealik]

Would the Z22 dizzy work? I have one of those.

 

Z22 is a 3 wire

I believe so.......cap and rotor are different than the Z24 though

[Spades]

The car is parked at my parents house unable to move at the moment and the rotor and cap are for a 83-85. Tomorrow I can get the numbers off of the distributor(it had factory numbers stamped on it) and I can pull it apart to find out how many wires it is.

 

Maybe it was my fault, I asked on the forums a while back how to wire it up and went off mitchell diagrams, maybe I wired it up wrong somehow...it sure had a nice ignition pattern and it ran so well when I first swapped the motor in though, and prior to the last few weeks, no misfires or anything unusual other than low power.

 

The distributor was purchased YEARS ago, my boss bought it for his roadster he still has yet to put together, even though the part was unused and sitting in a box with the rest of the motor parts waiting for assembly, the slip says it was purchased about 7 years ago, good luck with a warranty on that.

 

If I do buy a new distributor, what should I get? the motor has no thermal switches or EGR on it, no ECU, ect. The block was from a FI truck, but it has parts from a pre fuel injection NAPS on it and I removed all of the smog accessories(the EGR system was plugged and the valve was inop as well as most of the lines were trashed, so I ditched it all). Should I try to find a Nissan distributor for it, or will they ever work right without all of the emissions stuff? I don't like the idea, but should I look at a MSD or other aftermarket ignition system? If I get another Nissan distributor, what year should I go with and can they ever be wired to work without the vacuum switch stuff?

[620racer]

I have a few just lmk

[Spades]

Z22 is a 3 wire

I believe so.......cap and rotor are different than the Z24 though

 

Is the shaft long enough? I know the Z20S is shorter...and can I integrate it to a non emission motor? I can buy a new cap and rotor for cheap where I work, the distributor will be much harder to track down.

[Sealik]

Pretty sure..

I have a 4 wire Z24 dizzy in my LZ23.....with a Z22 TC cover.

Only difference is the taller TC cover....3/4 inch between the Z22 and Z24

Just get an 84 ...obviously the white wire coming from your dizzy you have in your 510 swap is not connected to anything?

 

 

 

81-85 should all work....

[HRH]

Oh btw, Spades, don't give up, fuck that 4.3l conversion! :D If you want a heavy pig, just yank the Z24 and put a big rock in the engine bay. What year is your truck, what can you bypass? Do you have to be smogged?

 

Not knowing what's on there, sorry if it's been posted I haven't seen, I'd put a 32/36 weber or a 38/38 weber on it, and either do a single plug distributor from an L in there, or wire up the dual spark but figure out what's dropping. I had the Z20 with dual spark and it ran better with it. Ran it 4 plug for a while. If you're bypassing stuff, an L matchbox will work much better for 4 plug application.

[DISLEXICDIME]

Pm sinner720 he might have a z24 dize he will sell you . And he is local

[datzenmike]

You can tell if it's a 3 or 4 wire by looking at the harness going to it.

 

 

4 wire: Has three wires and a fourth white wire with it's own connector plug.

 

 

 

.

[Spades]

Pretty sure..

I have a 4 wire Z24 dizzy in my LZ23.....with a Z22 TC cover.

Only difference is the taller TC cover....3/4 inch between the Z22 and Z24

Just get an 84 ...obviously the white wire coming from your dizzy you have in your 510 swap is not connected to anything?

 

 

 

81-85 should all work....

 

I found my notes from when I did the swap, I will know for sure when I look at the wires on the car, but according to my notes, it was a 4 wire and I left the white wire off, and the three wires are connected. Is that right? I am guessing the wiring is right, because if it wasn't, it should have never had a good ignition pattern on the labscope.

 

I will PM some people about a distributor...I usually hate buying used parts, but it will be as much of a crap shoot as buying reman stuff I suppose.

 

oh, and where I live is smog exempt, even if it wasn't, it is old enough to be considered a classic car and doesn't need emissions equipment. I used our scopes gas analyzer and before the timing issues, the engine was running clean enough to meet the standards of a new vehicle with a full emissions system, so I am not worried about killing any baby seals or having the cops come after me.

[ggzilla]

The genuine Nissan ignitors are dime-a-dozen at the wreckers. The genuine Nissan units (made by Hitachi or Mitsu) just about never fail. The Remans do. Depending on the one you have, Mazda, Honda or Misubishi -- and other Nissans may fit (the two-wire units do). Easiest to snag one from a 720 you know it has the four wires..

[Spades]

The genuine Nissan ignitors are dime-a-dozen at the wreckers. The genuine Nissan units (made by Hitachi or Mitsu) just about never fail. The Remans do. Depending on the one you have, Mazda, Honda or Misubishi -- and other Nissans may fit (the two-wire units do). Easiest to snag one from a 720 you know it has the four wires..

 

The big question is if it is for sure the module going out (I am assuming that is what you mean when you say igniter), and I won't know for sure until I tear the distributor apart and inspect it, and even then it will be hard to tell without a baseline to compare it to.

 

I am going to see if I can buy a factory unit from someone nearby on Ratsun, sounds like there are a few people with them around here, unless I find some serious proof that the module did go out. I don't want the hassle and expense of buying a module from a Ratsuner or shipping one in from a junkyard if the magnets are crap in this reman unit.

 

I will see if I have time to pull the distributor apart today, I doubt I will have time though, I will be at the hospital all day having some more tests and evaluations.

 

Oh, and one last question...with all the emissions stuff removed, I had to switch over to manifold vacuum advance(rather than ported)...that wouldn't fry a module, would it? These problems all started before I started experimenting and reading about ported vs manifold vacuum. Without an EGR or other emissions systems, my car needs more base timing at idle, and if I put it on ported vacuum, the car will need a ton of base timing, but then will get a HUGE amount of advance when the throttle is hit, the opposite of what I want. Just wanted to make sure that wouldn't affect anything.

[Sealik]

 

 

Oh, and one last question...with all the emissions stuff removed, I had to switch over to manifold vacuum advance(rather than ported)...that wouldn't fry a module, would it? These problems all started before I started experimenting and reading about ported vs manifold vacuum. Without an EGR or other emissions systems, my car needs more base timing at idle, and if I put it on ported vacuum, the car will need a ton of base timing, but then will get a HUGE amount of advance when the throttle is hit, the opposite of what I want. Just wanted to make sure that wouldn't affect anything.

 

No...it wouldn't fry a module

I initially said your problem was the dizzy because they were awfully similar to mine.

The springs and or magnets were toast....dizzy was sticking in an advanced position.

Was obvious after the fact....with the engine running and the timing light pointed at the timing marks....the timing was jumping around about 8 degrees, that was hooked to ported vacuum...not manifold

The technical term for the 'igniter'...is the IC....Ignition Control Module

 

Your intake and exhaust coils are hooked up correctly to the dizzy cap?

That could throw a 'wrench' into a proper diagnosis

[banzai510(hainz)]

Told ya swap the EZ stuff first!!!!!!!!!!! dizzy or carb! no need to look at O scopes and Vacuum gauges. works or it dont.

 

if motor is timed mechanically ,its good! You have to believe the timming marks

[Spades]

Told ya swap the EZ stuff first!!!!!!!!!!! dizzy or carb! no need to look at O scopes and Vacuum gauges. works or it dont.

 

if motor is timed mechanically ,its good! You have to believe the timming marks

 

Heh, yeah...here is the thing, the labscope and the other stuff I already have at work or in my toolbox, and it doesn't cost anything...the distributor costs money...and I wanted to rule out everything else and make sure the engine was running properly.

 

Hainz - 1

 

Modern Science - 0 (until the distributor completely fried and showed steady misfires :D )

[ggzilla]

The technical term for the 'igniter'...is the IC....Ignition Control Module

 

Nissan calls it "TRANSISTOR IGNITION UNIT". This Z24 unit combines the ignitor, control module and pickup in one:

1985 Z24 carbureted has the 4-connector unit as pictured.

 

1985 Z24 injected doesn't use this, has a crank angle sensor and (i think) spark controlled by the ECU.

[Sealik]

You're right...it is a unit....not a module :D

What was I thinking....

My FSM....calls it a IC Ignition Unit

Would assume the IC stands for Integrated Circuit.

[Spades]

So, between the distributor I bought from Micro and the spare distributor I have(looks like both are Nissan, not rebuilds) I will be able to put together a working unit.

 

To make sure before I install this, is this the right wiring?

 

White Wire: Disconnected

Red Wire: Exhaust -

Blue Wire: Intake -

Brown Wire: Ignition on power wire to run dizzy

 

I was using the '72 Datsun 510 Station Wagon's power wire that went to the factory distributor as power for the naps dizzy, is that ok? I think it is a black and white or black and yellow wire(going by memory here).

 

Also I was advised it was OK to use both coils on the same power source...is that a no no? If so I will run another power wire over to the exhaust coil.

 

I just want to make sure the wiring wasn't what caused the reman unit to have problems.

 

For kicks and giggles, on the "Transistor Ignition Unit", what do the letters E B C I stand for? I forgot to look at which wires went there while I was at my parents house looking at how everything was wired up, and I wanted to make sure wires weren't somehow hooked up wrong on the module side.