Crank, No Spark

[NickCrawler]

A little backstory. 1984 Nissan 720 Z24, Previous Owner put another motor in and only thing I can figure is it is from a later year 720. Distributor is different from the one original to the truck and thus no spark. Wires were cut and hacked and spliced. I’ve been trying to test everything and figure out how to wire this up.

 

Coils are hooked up according to the wire diagram. Coils have been tested and are within spec.

I have the old distributor but has a different style shaft and won’t drive the oil pump I assume.
Kinda at a loss of how to get power and spark. 

 

 

 

The 3 ring terminal wires that would connect to the 3 distributor wires all have 12.6V with ignition on, I’m not sure if this is right.

 

 

The current distributor has the square style plug into the bottom of it and came to a plug end but PO cut it off and tried to hook up the wires to the old style.

[datzenmike]

 

This looks like a later CAS or crank angle sensor used on the later Z24i in the 720 and the early D21 Hardbody till '89-ish. It has an optical wheel with 360 divisions and a photo cell to read the marks. This information is sent to the EFI computer and it figures out where the crankshaft is and with other information computes an ignition timing and fires the coils. This is a long way to say this will not work on your '84.

 

 

 

 

 

 

It will have this splined end on it. Crucial to a stable ignition for lower emissions.

 

So here's the two things you'll need....

 

1/ Any Z series distributor from an '80-'82 A10 510, '80-'83 S110 200sx, any Z20/Z22/Z24 from a 720.

 

2/ An oil pump/distributor drive spindle from one of the above Z series engine.

 

 

The Z series distributor will have the other end and will join to your 720 harness...

 

 

Use the timing scale bolted to the timing cover and the v notch on the rear pulley to set the engine to TDC. (top dead center) There are 2 TDC you want the number one compression stroke. Confirm by lifting the valve cover and looking at the two front valves. They should be closed with both cam lobes pointing. With the distributor out you should see this...

 

Ignore the splines. The large and small half moon shapes should look like below.

 

If you see the above, unbolt the oil pump and lower it. Have rags ready as oil will drip. Keep pump vertical so it doesn't empty. The spindle will likely drop out with it. Install the proper Z spindle in the same position and reinstall the pump. Refer to the above picture for correct positioning. The spindle fits to a worm gear and may turn as it slides into placce so you may have to mess with the positioning to get it like the picture. Once in, the distributor can only fit it in the correct position. Probably won't hurt to time the ignition on an unknown distributor, 3 degrees BTDC

 

You probably know how to swap this and what to do I'm just trying to cover everything.

 

Only the later Z24/Z20 distributor had the 4 wires. The earlier 3 wire ones will work. The 4th wire is for shutting off the exhaust side coil under certain conditions. If all you can find is a 3 wire it will be fine. If you want, you can look for a 4 wire and replace at some later date.

[NickCrawler]

3 hours ago, datzenmike said:

 

This looks like a later CAS or crank angle sensor used on the later Z24i in the 720 and the early D21 Hardbody till '89-ish. It has an optical wheel with 360 divisions and a photo cell to read the marks. This information is sent to the EFI computer and it figures out where the crankshaft is and with other information computes an ignition timing and fires the coils. This is a long way to say this will not work on your '84.

 

 

 

 

 

 

It will have this splined end on it. Crucial to a stable ignition for lower emissions.

 

So here's the two things you'll need....

 

1/ Any Z series distributor from an '80-'82 A10 510, '80-'83 S110 200sx, any Z20/Z22/Z24 from a 720.

 

2/ An oil pump/distributor drive spindle from one of the above Z series engine.

 

 

The Z series distributor will have the other end and will join to your 720 harness...

 

 

Use the timing scale bolted to the timing cover and the v notch on the rear pulley to set the engine to TDC. (top dead center) There are 2 TDC you want the number one compression stroke. Confirm by lifting the valve cover and looking at the two front valves. They should be closed with both cam lobes pointing. With the distributor out you should see this...

 

Ignore the splines. The large and small half moon shapes should look like below.

 

If you see the above, unbolt the oil pump and lower it. Have rags ready as oil will drip. Keep pump vertical so it doesn't empty. The spindle will likely drop out with it. Install the proper Z spindle in the same position and reinstall the pump. Refer to the above picture for correct positioning. The spindle fits to a worm gear and may turn as it slides into placce so you may have to mess with the positioning to get it like the picture. Once in, the distributor can only fit it in the correct position. Probably won't hurt to time the ignition on an unknown distributor, 3 degrees BTDC

 

You probably know how to swap this and what to do I'm just trying to cover everything.

 

Only the later Z24/Z20 distributor had the 4 wires. The earlier 3 wire ones will work. The 4th wire is for shutting off the exhaust side coil under certain conditions. If all you can find is a 3 wire it will be fine. If you want, you can look for a 4 wire and replace at some later date.

Thank you!! I’ve read multiple of the topics on the forum and see that you live and breathe these things. I’m a decent mechanic, just starting in my electrical training at work as a tech.

 

Luckily the old motor is sitting in the back of the truck just had a bad block/head surface and some other issues according to PO.

 

So late last night I was starting to lean towards I think that I need to change the oil pump drive and such but wasn’t sure what that entailed and wasn’t sure if I could do that or not with this engine (taking a newer engine and pulling older parts into it).

 

Again thank you! Tonight I’ll be trying to get this done and be back with an update.

[datzenmike]

What does the 'new' engine have for intake and carburetor??? Does it still have the EFI equipment on it?

[NickCrawler]

Well they hacked and the snipped but after rewiring the old distributor, changing the oil pump shaft, finding all the old parts and pieces, I GOT SPARK!! But no start.. think I may be off on my timing so gonna redo all that in the morning. 
 

and here are the pictures I took of my intake. Weber Carb, and some real redneck engineering.

 

 

[datzenmike]

 

You can pull those hoses and plugs off the TVV  (thermal vacuum valve) and even remove it if you plug the hole as it goes into the coolant system.

 

In operation the bottom two lines are for the vacuum signal from the old carburetor for the EGR and the ignition vacuum advance. The top hose goes to the air filter. When engine coolant is less than warmed up filtered air is allowed in and destroys the vacuum signal preventing EGR and any vacuum advance. When engine warms up the leak is plugged and vacuum is allowed to EGR and vacuum advance. Thus no EGR or vacuum advance on a cold engine.

 

I don't see a vacuum advance hose coming from the Weber although it may be there somewhere. That would be handy to have connected up for part throttle response and mileage.