NAPZ 20 spark plugs help please

[SpikeEjayR]

Hi everyone im itching to hear my new project turn over. I have a napz20s inside my newly acquired 510, it also has that cross flow head. I purchased a datsun 720 manual but it wont be here for a while. Im stuck on figuring out the spark plugs and where they go. for those of you familiar with this engine you know that it has 8 spark plugs. By word ill try to explain the distributor cap and head and then maybe you can draw it.

 

distributor cap:

the (xx) is a circle and the [xx} is a square. going clockwise and in a circle, starting at 1200: is a (E3), [i4], (E1), [i3], (E2), [i4], (E4), [i2]. In the middle of that circle of letters and numbers is: [iN] and (EX).

 

Engine head:

on the left side or intake side is spark plugs 1-4. 1 being closest to the radiator and 4 being closest to the tranny. on the right side or exhaust side is 5-8. 5 being closest to the radiator and 8 being closest to the tranny.

 

I know this all sound kinda stupid but if anyone can decipher this and send some help i would be very thankful.

 

Thanks

Rudy

 

 

 

 

[datzenmike]

No problem I can supply that info when I get home. You sure it's a Z20... look below the #2 plug on the exhaust side, it's stamped on that flat spot.

 

A 720 manual will only have info on the Z20 used in the 720. That motor has a higher compression (9.5) and knock sensor and related electronics to retard the timing. You sure that motor isn't from an '80-'81 HLA10 (new 510)??? That would be a better manual if it is.

 

Either way most of the 720 Z22 information will apply to the Z20 and I have the Factory Service Manual for the Z20 used in the truck if you need it.

Edited June 5, 2009 by datzenmike

[hang_510]

dont the [ I ] wires go to the respective intake side plug and the (E) goto the exhaust side plug???

[SpikeEjayR]

No problem I can supply that info when I get home. You sure it's a Z20... look below the #2 plug on the exhaust side, it's stamped on that flat spot.

 

A 720 manual will only have info on the Z20 used in the 720. That motor has a higher compression (9.5) and knock sensor and related electronics to retard the timing. You sure that motor isn't from an '80-'81 HLA10 (new 510)??? That would be a better manual if it is.

 

Either way most of the 720 Z22 information will apply to the Z20 and I have the Factory Service Manual for the Z20 used in the truck if you need it.

 

thanks datzen i would really appreciate that very much. i rechecked under that plug and it said Z20 and then a serial number. The head says W78. it kinda sucks not knowing what engine it has. what other car manuals do you recommend me buying? wikipedia said that the stanza had a z20 in it. are you willing to part with your FSM for the Z20? i think im gonna start doing like most of you guys and have a collection of datsun manuals, it looks like im going to need to.

 

thanks again

rudy

[SpikeEjayR]

dont the [ I ] wires go to the respective intake side plug and the (E) goto the exhaust side plug???

 

thats what i figured too but im still stuck when it comes to the order on the intake side and exhaust side

[hang_510]

thats what i figured too but im still stuck when it comes to the order on the intake side and exhaust side

 

confirm the firing order, and route em in that order (start w/#1 @ TDC)

[datzenmike]

http://i138.photobucket.com/albums/q251/datzenmike/720%20stuff/dizzy720004Large.jpg[/img]"]

 

On the NAPS 8 plug Z engines there are two completely separate ignition systems working side by side but sharing the cap and rotor. In the middle of the cap are the two coil wires one for intake and one for the exhaust plugs. If you lean over the driver's side fender and look at your distributor you will (or should) see the dizzy cap more or less in this orientation. If you look closely you will see that 4 of the terminals are on the outer edge of the cap, while the other 4 are closer to the center of the cap. The outer ones are the intake the inner ones are the exhaust. If you look at the rotor you will see two contacts, one on the side to contact the outer terminals and one inner. Both coils fire together and at that time the rotor is pointing to the intake and exhaust plug wires of the same cylinder. Or should be.

 

In the picture, you can see the intake coil wire terminal at 12 o'clock and is marked In inside a square. The Ex is inside a circle. At the 9 0'clock position (toward the rad) is the ' I1 ' (Intake one) inside a square. It's no surprise that this wire goes to the number 1 plug at the front of the motor on the carburetor side. Now, going counter clockwise the next terminal is E2 going to the number 2 plug on the exhaust manifold side, then the I3 going to the #3 plug on the intake side, then E1, I4, E3, I2, E4.

 

As to which coil is the intake or exhaust... It doesn't really mater. The way you have it looks fine. Keep it.

Edited June 5, 2009 by datzenmike

[SpikeEjayR]

that was heaven sent mike!!! thanks very much im going to try to fire her up tomorrow with this information.

[datzenmike]

 

Just looking at this picture I can see some wires that are wrong. For example the two plugs at the front, (rad side) both go to the intake side. The next two wires clockwise both go to the exhaust side. This is wrong as the cap is wired IEIEIEIE.

Edited June 5, 2009 by datzenmike

[SpikeEjayR]

HAHAHAHAHAHA!!!!!!!!!!!!! she fired right up and sounds pretty nice. i put the sparkplugs in according to the instructions you gave me. that pic i have is me trying to put them on according to length. the dumb and wrong way. thanks for the help mike. CHEERS TO YOU MAN!!!! AND THANKS TO EVERYONE ELSE THAT CHIMED IN!!!!

 

Rudy