Looking for firing order clarification.

1980-1986 Datsun 720 forums. All 720-specific topics and discussion can be found here.
Ready4Rockin
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Joined: Sun Feb 06, 2011 5:17 pm
Car: 1985 1/2 Nissan 720

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Howdy everyone. I'm doing a little tune up work to my 720 and I wanted to make sure my old Hayne's manual is telling me right. According to it, the pistons are numbered from the cooling fan (front) to the driver (back) 1-2-3-4. Simple, right? I did the plugs, wires, rotor, and rotor cap today and it still runs, so I figured it came out all right. It's still idling fairly high (1100 RPM or so) after setting the idling speed as low as I could. I nearly took that screw out. It just wouldn't lower past 11-1200 RPM. But anywho, getting sidetracked. Thanks for the help!


synack7350
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Joined: Sun Jan 09, 2011 3:08 pm
Car: nissan '83 720 king cab pickup 2wd 2.4L Z24
Location: Boaz, AL

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I thought the napz 24 was like 1324 or something like that. could be wrong though I don't have my manual handy at the moment. I'm pretty sure that napz is different than the models with out the exhaust plugs which is just 1234.

Ready4Rockin
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Car: 1985 1/2 Nissan 720

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Yeah, that's what bothered me about it. The manual says 1234 except for Z series motors. On top of the valve cover is, sure enough, a little sticker that says 'something something Z'. So ffffuuuu.....

synack7350
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Car: nissan '83 720 king cab pickup 2wd 2.4L Z24
Location: Boaz, AL

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well the napz will have 8 plugs even though its a 4 cylinder, its prolly that and the distributor for those motors that cause the napz firing order to be whack.

kickinindian
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Joined: Sun Dec 12, 2010 7:38 pm
Car: 84' Nissan 720-D King Cab 4x4
Location: North Fork, Ca

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this helped me today when i went to go change my stuffs
faq-s-look-here-before-creating-a-thread-t464778.html :dblthumb:

Ready4Rockin
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Joined: Sun Feb 06, 2011 5:17 pm
Car: 1985 1/2 Nissan 720

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Okay, I got that but I was looking for the actual piston order. And yes, the Z has that freaky 8-plug system. Both the rotor caps I have had the firing order stamped into the top which was easy enough to follow, as long as you knew which way the rotor turns and the piston numbers. My manual gives the firing order for every OTHER motor but not the 4-cylinder Z series. The most unsettling thing is that it's running FINE. The only problem is its high idle speed but that wouldn't come from a improper firing order. Eh?

By the way, this site is a life saver. Thanks for the help, everyone.

synack7350
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Joined: Sun Jan 09, 2011 3:08 pm
Car: nissan '83 720 king cab pickup 2wd 2.4L Z24
Location: Boaz, AL

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I found it.. it took some digging I never really noticed that in the haynes before page 2A-1 illustration at the bottom shows firing/ cylinder order. at least cylinder order can be extrapolated.

rotor travels counter clockwise, 1i,4e,2i,3e,4i,1e,3i,2e

so intake side is 1243 (dictates cylinder order)
and exaust side is 4312 which makes sense.

as far as high idle i dunno that's weird but you must be close to right with out backfiring or detonation? which I would think would be closer to the truth if you could get the thing to run out of order.

Ready4Rockin
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Joined: Sun Feb 06, 2011 5:17 pm
Car: 1985 1/2 Nissan 720

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Whoa, so you mean the pistons are numbered differently for each set of plugs? Like.....

(Intake)
<-Fan Firewall->
1243
0000 <-pistons

(Exhaust)
<-Fan Firewall->
4312
0000

Why did Nissan even build this ridiculous ignition system?! ><' And yeah, if I got the wires mixed up, I can't tell. It was trying to miss a little when I first started it but I plugged a vacuum line that was sucking air and that fixed that problem, as far as I could tell. And I'll bring my manual home with me tomorrow (I rent a friend's garage) and see if I can find that illustration for myself.

kickinindian
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Car: 84' Nissan 720-D King Cab 4x4
Location: North Fork, Ca

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Okay Ready4Rockin we get it :P

synack7350
Posts: 364
Joined: Sun Jan 09, 2011 3:08 pm
Car: nissan '83 720 king cab pickup 2wd 2.4L Z24
Location: Boaz, AL

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nah just the intake side would determine piston order the exhaust side is just an emmissions thing and so would fire opposite. It makes sense to me.

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breadbox
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Car: Red 89 240sx,Black 89 Koop, White 84 720 4x4KC
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The link has it right. IDK where some of these firing orders are being found.

Cylinder numbers front--->Rear 1234

Firing order 1342

dizzy order going counter clockwise starting at 1intake
1intake
2exhaust
3intake
1exhaust
4intake
3exhaust
2intake
4exhaust......back to
1intake

But the sticky has it right.


KA24e
1234 cylinder order front to back
counter clock wise on dizzy from 1
1342



V6 engine

Cylinder 1 is at front 6 at back of motor
5 6
3 4
1 2

Firing order 123456
Cylinder numbers 135 ODDS are passenger side
Cylinder numbers 246 EVENS are drivers side

The V6's have two different style dizzy caps depending on year.

Ready4Rockin
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Joined: Sun Feb 06, 2011 5:17 pm
Car: 1985 1/2 Nissan 720

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Okay, that pretty much clears it up for me. I'm gonna' go check it one more time and make sure I lined up everything right but I think I'm good now.

Thanks for the patience, guys. >>'

synack7350
Posts: 364
Joined: Sun Jan 09, 2011 3:08 pm
Car: nissan '83 720 king cab pickup 2wd 2.4L Z24
Location: Boaz, AL

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yeah my bad I read the diagram backwards, moment of dyslexia

flinterman2000
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Joined: Mon May 04, 2009 5:32 pm
Car: 2000 Nissan Wingroad, 85 Datsun 720 Pick Up.

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Ready4Rockin wrote:Howdy everyone. I'm doing a little tune up work to my 720 and I wanted to make sure my old Hayne's manual is telling me right. According to it, the pistons are numbered from the cooling fan (front) to the driver (back) 1-2-3-4. Simple, right? I did the plugs, wires, rotor, and rotor cap today and it still runs, so I figured it came out all right. It's still idling fairly high (1100 RPM or so) after setting the idling speed as low as I could. I nearly took that screw out. It just wouldn't lower past 11-1200 RPM. But anywho, getting sidetracked. Thanks for the help!
Hi idle on these engines are not always carb caused. Your ignition timing may be off a little. Some times the timing need more setting than factory specs, as much as 10 before and 10 after TDC. Try checking the timing.

Ready4Rockin
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Joined: Sun Feb 06, 2011 5:17 pm
Car: 1985 1/2 Nissan 720

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Yep, that's what's next, after the vacuum line delete. Ever done the timing before? I'm guessing it's pretty straight forward?

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PEZi
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It could also be vacuum.

As far as timing, I did mine all by ear and such because I didn't have access to a timing light. That's seriously how easy it is. Just grab a wrench to loosen the bolt on the dizzy, and spin the dizzy clockwise for advance and CC for retard.

Ready4Rockin
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Joined: Sun Feb 06, 2011 5:17 pm
Car: 1985 1/2 Nissan 720

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Nice. I'll let ya'll know how it goes!


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