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Exciting 720


jagman

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1/ Did you finally put the 180F thermostat in?

2/ Did you empty and flush the rad and the block of the CLR? that was in it?

3/ I can't go back through dozens of posts to find out what year or engine you have so add this info to your profile

 

Timing should be 12 BTDC on L20B and 5 BTDC for the Z series engines. Retarding the ignition below these numbers reduces the engine efficiency and dumps more exhaust heat into the cooling system. Avoid this.

 

Did you borrow an infra-red gun and shoot the thermostat housing to prove that it's actually running hot and not a bad sender gauge reading??????? Half way up the gauge is around 180F

 

Can you spin the clutch fan? Can you get it to spin by itself if you give a very strong spin with your hand?????

 

Is the heater by passed by joining the heater hoses???

 

 

 

 

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Mike, I have a z24 in an 86 720.  1.  I have installed the 180 thermostat.  I have flushed the system of CLR.  ( there seems to be a greenish hue that appeared in the last day or two so I will have to look into the origins of that.)  Timing was set for 12 degrees BTC.  I did read the factory manual and reset it for  5 degrees BTC.  Today I reset it for 0 degrees TDC and it seems to run better than before.  I can spin the fan but it stops quickly.  The heater is factory and I believe properly connected cause it works. I will keep playing with it until I can get it right.  If I am not towing the trailer it stays in the center of the guage. It is only when I tow that the temp creeps up and never seems to go down until it steams and I shut it down.  On Monday I will deliver some customer machines and test the new timing setting to see if that helped. I have also ordered a new lower hose just in case that may be collapsing at 3000 rpm.

Thanks for your patience and advice.

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In a lot of ways I'm like Joe Biden. Ok everything sounds right but the timing. Check the notch on the pulley and be sure you are setting the timing on the TDC. As I mentioned retarding from the proper timing advance will not capture the energy from the expanding gasses from combustion and more of the heat will be absorbed by the combustion chamber and exhaust ports. This heat will end up in the water jacket around them. It will run hotter and have less power.

 

As to the fan it should feel like it's in thick honey and should not spin after letting go no matter how hard you spin it. The looser it is the more it will slip at higher speeds. 

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Well Mike I took your advice and replaced the lower hose, the water pump and again flushed the system.  I took her out for a delivery and she ran with the temp guage in the lower 1/3 quadrant of the gauge ( just below the thermometer on  the face of the gauge ).  I did notice that the vanes on the old pump seemed smaller than on the new one and the fan is stiffer on the new one so I was not aware how stiff it should have been when I was checking it before.  My STUPID.  THANKS FOR THE HELP!!!

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 I would expect it to run about half way in the 'run range'. Be sure you have the 180F thermostat. This is a Z series? (you should put this in your profile 'cause I can't seem to remember)   It's designed to run 180-190F for longest life, best performance and economy. There's no advantage to running too cold (or hot)

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Mike, I have been running at 184 degrees since I replaced the water pump and lower hose ( I found an aluminum radiator from an automatic and replaced the old one with that).  The temp is good now.  I tried to time it and found that the intake plugs aren't firing.  I checked the coil for output and nothing,  I checked for power to the coil and have power. The wiring schematic shows a red  and black with white (BW?) to the coil not working.   The coil with brown and white blue (WL?) is working I have it on the exhaust side for now.  Could the condenser be bad? According to the schematic only one coil has a resistor in the circuit.  Is one coil different than the other?  Does one need a resistor and the other not?

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The coils are identical and fire together. The intake is wired directly from the ignition. The exhaust goes through the fuse box.

 

You're sure the non firing coil has 12v on the positive side??? 

 

 

Do you have this distributor? Three wires on the main harness and a single white? wire with it's own plug????

Xla5VTk.jpg

 

If you do, unplug the single wire and see if that gets the coil firing.

 

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I took your advice and disconnected the single wire on the distributor and the truck still runs!  I will check to see if the exhaust side is firing this weekend.  I have been hearing a metallic sound coming from the rear of the truck for about a week now.  I was able to get it on the lift for an hour to check it out and found the rear universal joint was compromised so I changed the rear shaft using one from the junker and ordered 4 universal joints for  a rejigger of the original shaft.  Haven't driven far but no mettalica now.  How sweet it is!

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I thought I had a wire hanging under the truck so I made an appointment for lift time to check it  The only thing I found was a broken front shock.  It broke at the bottom  I ordered a new set of gabriels and while I was at it a new set of AC DELCO upper and lower ball joints.  What problems are there in installing the ball joints?

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I keep having to go back and check what year you have.

 

The upper and lower ball joints bolt in so you should have no problem. You will need a tool to loosen the ball joint from the spindle, but if replacing anyway a 'pickle fork' might work.

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It's a ball joint separator.  I've seen ball joint nuts loosened but left on and with wheel on the ground and the torsion bar bearing down, hit the spindle and the LCA with ball joint will separate down against the nut. Then jack up to take the tension off the nut and remove it. Striking the spindle at the ball joint deforms the hole and it's tapered fit for a split second and the downwards pressure from the torsion bar snaps it apart. A tool is better to rent.

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I have one in my tool box -- always wondered when I would get the chance to use it.  The manufacturer has been out of business since Truman was president.  I have never had to take them out of a vehicle with torsion bars.  I assume it's the same process as  the more modern setup?

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Where can I find the clips that hold the shifter boot in place on the 720?  Redlinegoods has the proper boot but have no clips.  Any sources would be appreciated.

In addition, I bought new tires for the front yesterday and the shop boogered up one stud and lug nut.  I have the aluminum wheels and they take a lug nut with a flat washer. If anyone has a clue as to where I can get one  I would be grateful.  I will check at the local nissan dealership but don't hold out much hope there. 

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