'86 720

[datzenmike]

My time is at like 5 degrees and the sight glass is.half full.

 

Perfect. What about the choke does it open fully when the motor is warmed up?

[P.Rubber]

No. Its half open.

[datzenmike]

It should be fully open within 8 min after start up.

 

Bet the plugs are black with soot and you're getting crappy mileage. There is a plug at the back of the carb with two wires. One is red and is for the idle cut solenoid, the other is blue and powers the choke heater. The idle cut should have power to it when ever the key is turned on. You can check operation by listening at the carb for a click sound when the key is turned on/off/on/off. The choke heater only has power when the motor is running. In a pinch you can power both from the idle cut wire to get it working.

[P.Rubber]

What plugs are black with soot?

[datzenmike]

Spark plugs. Choke on, even partly and it will run too rich. More gas than needed and not all of it will burn. The rest will just collect as carbon on the inside of the head ... and the plugs.

[P.Rubber]

That makes sense. I.just did wires plugs etc last week. But could that be why its dieseling?

 

[datzenmike]

It shouldn't diesel. This is what the idle cut solenoid is for. It cuts fuel to the idle circuit to stall the motor quickly when the key is turned off. But if the choke is on it will be getting gas even if the idle circuit is shut off.

[P.Rubber]

Okay, so my choke is fully open. I ran again this morning and choke is fine..I read something, somewhere that my fuel pump could be pushing too much fuel which is causing the diesel. But I'm not sure how much its supposed to push, volume wise.

 

[SHORTDOG]

I'll save you the heartache and give you $600 for it. :thumbup:

[P.Rubber]

Already been offered 1700 for her. She sat in my driveway for 6 months while I waited for my license to get reinstated . This is my first Nissan and I know some people who are serious about theirs locally. Figured I'd see what it was about. Now I regret not getting one sooner. Hah

[elmerfudpucker]

Let me give you something to chew on, I have a 81 720 KC with the "garbage z24". From Tacoma, WA to Danville, KY with a trailer and literally over a ton of stuff @ 75 miles per hour during June heat with no issues from the motor averaging 22MPG! :thumbup: the only mods was a weber 32/36 and pacesetter header + electric fuel pump. If your gonna spend money on it Bro just slap the weber to it, use NGK wires and plugs and replace the exhaust from the end of the manifold back with some 2 1/4" pipe and a good muffler. then get back to us with lots of pics! check "my lil mule" thread in the 720 section if you need more info.

[P.Rubber]

Yeah that's probably what I'm going to do. Minus headers. And lots of body work!!!

[_chiefjt]

WOW! Nice truck for 500 BUCKS! Paid $850 for mine and doesn't even compare to mine. Looks very original.

[P.Rubber]

I'm the third owner on it and I got it so cheap cause it wouldn't run. Some tinkering and I got her home. Its stock all the way through.

[P.Rubber]

I'm the third owner on it and I got it so cheap cause it wouldn't run. Some tinkering and I got her home. Its stock all the way through.

[P.Rubber]

Any ideas on a muffler I should get?

[elmerfudpucker]

I just used a magnaflow, it is pretty quiet if you stay out of the secondaries, but the key thing is stay at 2" or 2 1/4" pipe, I will go back to 2" if I get a chance, you lose too much back pressure on anything bigger. I started with a Z22 and the bigger exhaust is good at the top end but I feel it costed me just a touch too much of my torque for take off. It got better with the z24 but I think I will still drop it to 2" anyway. But on the highway my truck will fly. Hell I hit the 512 hill to Meridian from 167 side, I slowed to 50 on 5th gear at the bottom and punched it, I had it to 70ish by the time I was under the overpass!

[P.Rubber]

Nice!!! I'll look into it

I don't want anything too ricey though.

 

[Guam_Guy]

Don't believe everything you hear about the Z24 being junk. There are a couple of Civic Si's and RSX's in my area that were heart broken when a little bitty truck smoked that ass. If you know what you are doing you can get some power out of the motor. Not everything is about what you can bolt onto the engine. Everything has to work together. Engine, trans and rearend. Also on a side note...probably gonna get banned for saying this but when a site admin comes on a thread and tells you what you should and shouldn't do to your truck and acts like an arrogant ass, I think that is kinda shitty but to each his own. Search for my username if you wanna see what you can do to the Z24 motor. It takes some money and know how but it can be done. Now is it a V8 killer...he'll no but you gotta choose your battles wisely. Good luck and do what you want bro it's your truck.

[datzenmike]

Geez you've got to mean me I guess. Read my posts.

 

It's a lot of bother and a lot of parts to buy plus some custom modifications. Your compression will be at least 9.4 so some pinging or more expensive gas. You will need an L20B head and the two manifolds. Because of the difference in the way both motors are tilted (there is about 22 degrees) the L series head and manifolds will be tilted down on the driver's side. The L20B air filter won't clear the 720 master cylinder. Timing chain cover must be built up or welded by 3/4" to mate with the L head. The timing chain has to be lengthened. You will need an L20B distributor. L20B exhaust does noy fit the 720 down pipe. Throttle cable moved to the left side of motor or changed.

 

Get a new replacement 32/36 Weber and call it good.

 

This is my reply to a previous post about converting the Z24 over into an LZ24... basically an L head and intake and exhaust manifolds added. This is a major changeover and the Z24 no longer exists and becomes in effect an L24. Can't make it any plainer that the Z24 is just fine as is and just needs a Weber carb. I would hate to see someone start this LZ conversion and not finish it.

 

RUBBISH. 102 feet maybe!

 

The head on the Z24 isn't easy to modify for performance but it still runs good. It's 20% larger than the L20B and has about 30% more torque. Your truck and motor looks fine don't fuck it up... drive and enjoy it.

 

No 720 made is going to go 102 in second gear! More support for the Z24. Mods are fine if you don't get in over your head. Seen this many times and the project ends up unfinished and sold.

 

Doesn't matter no one can see it.

 

 

 

All that stuff has a reason for being there so don't start ripping it off. None of the Z24 emission controls are working at full throttle so it won't run any better and can only run worse.

 

I don't get this. It's fine right now, leave it alone. Next week you'll be back needing help because it isn't running right, won't start, getting shitty mileage, back firing..... You get discouraged and end up selling it.

 

Again a caution to keep this great looking truck running as is. Just because someone (like myself) would like to see this 720 be enjoyed does not mean the owner has to do it. He's entirely free to rip it apart if he chooses. I'm only urging caution and not rush into things without some research.

 

Part of the reason I was even looking into any upgrades is because it diesels, it won't idle while cold did a full tune up adjusting the timing did everything i myself know how to do.

Anyone have any ideas?

 

Well at this point I can see why the owner wants to jump into some up grades. Perhaps with a little help it can be running properly and this won't be necessary or at least not right away.

[datzenmike]

When warm is the choke plate still closed, or not fully open?

 

On the front of the carb there is a small round sight glass. The fuel level should be near the middle....is it?

 

What did you set the time at?

So what did you set the timing at?

 

They only came with electric.

Perfect. What about the choke does it open fully when the motor is warmed up?

It should be fully open within 8 min after start up.

 

Bet the plugs are black with soot and you're getting crappy mileage. There is a plug at the back of the carb with two wires. One is red and is for the idle cut solenoid, the other is blue and powers the choke heater. The idle cut should have power to it when ever the key is turned on. You can check operation by listening at the carb for a click sound when the key is turned on/off/on/off. The choke heater only has power when the motor is running. In a pinch you can power both from the idle cut wire to get it working.

Spark plugs. Choke on, even partly and it will run too rich. More gas than needed and not all of it will burn. The rest will just collect as carbon on the inside of the head ... and the plugs.

It shouldn't diesel. This is what the idle cut solenoid is for. It cuts fuel to the idle circuit to stall the motor quickly when the key is turned off. But if the choke is on it will be getting gas even if the idle circuit is shut off.

 

Help to solve the running problems.

 

I have no idea what the owners mechanical abilities are or if he has tools or experience or has done this before. This will come out in subsequent posts I imagine, but for now I see someone perhaps rushing into something. This can end up with a non running problematic vehicle and disappointment. I'd like to see this truck running well and being enjoyed.... plenty of time for major changes later... and that's fine with me. Just an opinion.

 

Arrogant ass??? :lol: :lol: well maybe it might seem that way to some.

[P.Rubber]

Yeah I was just bouncing ideas. I am not doing any major engine mods until i know more about this motor.. like I said I have never owned anything that isn't American car. I know there is a devoted following to datsun/Nissan. And after I bought mine, I became one of those people.

[elmerfudpucker]

 

Arrogant ass??? :lol: :lol: well maybe it might seem that way to some.

 

I meet him at Canby and was the most...well... he slept under the ass of his Datto! :rofl:

[Skib]

I loled.

 

you better get in here Rhapakatui Texas is loosing points again hahahaha

[Rhapakatui]

Texans need educations too. Looks like professor Mike has it handled.

 

 

 

Except I remember the score being higher... did you really dock the whole state of Texas?

 

Guamian boy, do you see what you did? Now do something cool to earn us points back!

Edited August 19, 2012 by Rhapakatui