My 1980 Datsun 720 diesel dually

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wayno
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Re: My 1980 Datsun 720 diesel dually

Postby wayno » Wed Mar 16, 2016 7:50 pm

devilsbullet » Wed Mar 16, 2016 8:22 pm wrote:Always fun to see what you come up with man. And honestly, you have to be the only person I know with a turbo that hates the sound of boost being let off lol



I hate weird noises, the less noises the better as far as I am concerned, that way I know when I hear a noise something is wrong.
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Re: My 1980 Datsun 720 diesel dually

Postby devilsbullet » Thu Mar 17, 2016 5:29 am

Same reason I haven't ran a stereo in a Datsun yet lol
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Re: My 1980 Datsun 720 diesel dually

Postby wayno » Sun Mar 27, 2016 6:26 pm

I worked on this today, I had to make several of the lower templates before I finally got it right.
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I still have to paint it black, I also need to silicone the blue part in permanently.
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I need this because I need 4 gauges, boost, EGTs, oil pressure, and volts, at the moment I only have boost and the EGT gauges.
The gauges in there now are for test fit.
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Re: My 1980 Datsun 720 diesel dually

Postby Laecaon » Mon Mar 28, 2016 12:46 am

I would sooner run an Oil Temp gauge than a Voltage gauge. I could care less about voltage. Either the alternator works or it doesnt.
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Re: My 1980 Datsun 720 diesel dually

Postby wayno » Fri Apr 08, 2016 10:27 pm

Today I also worked on the gauges between painting the patio exterior walls, I installed all the gauges, they all work except the oil pressure, I need to mount the sensor on the engine, I also fixed the sloppy shift lever.
Image
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I have no idea why the pyro needle is where it is at in these photos, I turned the ign. on and it settled at "0" and stayed there.
I got lazy and didn't paint the blue part black, and right now I don't care, I hope to have them all working tomorrow, I bought the parts I needed today to mount the oil pressure sensor, I have to extend it out away from the engine as the sensor is to large to fit where the oil light sensor is on my diesel engine, I bought a three and one half inch extension with a angled fitting that the dual sensor screws into, I am hoping it don't leak.
I will try to remember to take photos of the stock sensor, sensor position, and how I am going to fit the larger dual sensor.

I believe I need a new SD card for my camera, the one I have is old and starting to act up.
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Re: My 1980 Datsun 720 diesel dually

Postby wayno » Sat Apr 09, 2016 10:14 am

I piped the oil pressure sensor this morning, I extended the mount for it three and one half inches, it didn't want to thread into the hole until I took the part out back and threaded it into the hole of another engine and compressed the end of the extension more or less, but I used lots of pipe tape and it doesn't leak.
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You can see the angled fitting on the end of the extension in the photo below, I only have so much room down there, it had to go at an angle.
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I am thinking that the engine is not as wore out as the former owner thought, it holds around 45psi at an idle, but it is not warmed up yet.
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I was lucky about my diesel wiring harness having the wiring for the console gauges, I never seen a oil pressure sensor on a diesel engine before, just the light sensor for low oil pressure, but the wire for the oil pressure gauge was in there, it just dead ended at the plug, so I tapped into the wire before the plug.
Progress is progress, even if it is not a lot of progress.
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Re: My 1980 Datsun 720 diesel dually

Postby wayno » Sat Apr 09, 2016 2:32 pm

Well that was a short but sweet modification, that extension broke on me between points C and D, and it broke off right at the block.
I tried removing it with a flat edge screw driver, but it would not grab it, so I went inside Wallmart and looked for an easy out, they didn't have such a thing, so I walked the two and a half miles home, threw everything I needed to tow the truck home, I also threw everything in the other truck to fix it, and I drove back to Wallmart, it was easy to remove the part left it the block with a proper easy out, I put the original light only sensor back in the hole, put about 4 quarts in the block and drove it home, there doesn't seem to be any damage so far, but now I cannot take it on a trip till I know everything is alright.
Here is what broke off.
Image
I was lucky I didn't run it out of oil, I guess my truck didn't want to go to Wallmart, so it taught me a lesson, I went to the local nursery but they didn't have cucumber plants, so I stopped by Wallmart to see what they had, big mistake, but in reality, if I had continued on home I would have run it out of oil, I guess my engine just wanted to leave a big oil slick in the Wallmart parking lot, and it did!!!
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Re: My 1980 Datsun 720 diesel dually

Postby wayno » Sat Apr 09, 2016 3:44 pm

OK, so I ordered this sandwich plate(GS AF1) to mount the oil pressure sensor on, it is made just for such stuff, the second guy I talked to about this sensor clearence issue suggested going this route, I would never have thought of this way.
https://www.google.com/url?sa=t&rct=j&q ... 8448,d.cGc
I hope this thing works, and I hope my engine is OK, I didn't hear it rattling, and it was still pumping oil out, but it left quite a long trail of oil, likely a mile long, and I am not talking about a few drips, a visible trail.
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Re: My 1980 Datsun 720 diesel dually

Postby RedBanner » Sat Apr 09, 2016 9:40 pm

damn, hope its all right, turbo and all.
wayno » Sat Jul 12, 2014 9:40 pm wrote:Everything is either tight or actually rubbing.

Taterhead » Tue Aug 05, 2014 2:29 pm wrote:Datsun gods will give you one working gauge, gasoline or speedometer; you can't have both.
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Re: My 1980 Datsun 720 diesel dually

Postby wayno » Sat Apr 09, 2016 10:12 pm

RedBanner » Sat Apr 09, 2016 10:40 pm wrote:damn, hope its all right, turbo and all.


I drove the 521 kingcab diesel today to either tow or fix the 720 turbodiesel, I believe it is alright, well I determined from that drive that even though the 720 weighs a lot more than the 521 diesel, the 720 turbodiesel has more power until above 65/70mph, that is when my 521 diesel shines, it will outrun the 720 turbodiesel on the hiway, but I still don't know what kind of mileage the 720 is getting.
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Re: My 1980 Datsun 720 diesel dually

Postby Justinberni » Mon Apr 11, 2016 9:57 am

next time you break down give me a call if you need a ride or tools man, im always in your area.
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Re: My 1980 Datsun 720 diesel dually

Postby wayno » Thu Apr 14, 2016 7:33 pm

Well the sandwich plate came today, and it has the wrong adapter, I was given the wrong information and ordered the wrong one. :(
So I drove around trying to find the proper adapter and Tonys Auto parts is going to have one for me tomorrow.

I also am going to drop the Z22 short block off at the machinists tomorrow as they are across the street from Tonys Auto Parts, I am going to have either a 2.1 longrod block made up, or another LZ23 made, I already have a head for the LZ23, I will talk with him more tomorrow, I like trying new things like a longrod block, but if it is to much of a hassle, I will go with what I have done before.
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Re: My 1980 Datsun 720 diesel dually

Postby Laecaon » Thu Apr 14, 2016 9:54 pm

I knew of a vw diesel rabbit that was getting its oil changed, and as the oil drained the guy went inside to grab lunch. Well his sister hopped in the car and drove to Seattle thinking it was ready to go. It drove all the way back home too. Then they put oil in it and kept driving it.
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Re: My 1980 Datsun 720 diesel dually

Postby wayno » Thu Apr 14, 2016 10:44 pm

Laecaon » Thu Apr 14, 2016 10:54 pm wrote:I knew of a vw diesel rabbit that was getting its oil changed, and as the oil drained the guy went inside to grab lunch. Well his sister hopped in the car and drove to Seattle thinking it was ready to go. It drove all the way back home too. Then they put oil in it and kept driving it.



Well I am hoping it is alright, this is the kinda thing that comes back and bites one in the ass later when one doesn't think there was an issue, I will be happy when a few thousand miles goes by, and I get the oil gauge working again to see if the oil pressure has dropped any from what it was before.
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Re: My 1980 Datsun 720 diesel dually

Postby RedBanner » Fri Apr 15, 2016 2:11 pm

wayne, I was just thinking about this o.p.s.u. being on the end of that pipe... and thought, could you make a block for the fender or firewall, and run a softline from the oem location to your block and hook your o.p.s.u. to the bock?


edit*I see you found the right part at tonys. glad you got it worked out, or at least potentially
wayno » Sat Jul 12, 2014 9:40 pm wrote:Everything is either tight or actually rubbing.

Taterhead » Tue Aug 05, 2014 2:29 pm wrote:Datsun gods will give you one working gauge, gasoline or speedometer; you can't have both.
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Re: My 1980 Datsun 720 diesel dually

Postby wayno » Fri Apr 15, 2016 2:43 pm

RedBanner » Fri Apr 15, 2016 3:11 pm wrote:wayne, I was just thinking about this o.p.s.u. being on the end of that pipe... and thought, could you make a block for the fender or firewall, and run a softline from the oem location to your block and hook your o.p.s.u. to the bock?


edit*I see you found the right part at tonys. glad you got it worked out, or at least potentially


The part was not the right one, I am just going to start over and order the proper setup, and when I can remember to call back east, I will try to have the proper part shipped to me from the manufacturer(GlowShift), right now I just want something that will work and it is just easier/cheaper to order another one on ebay.

I was just down at the tubes and hoses place on 4th plain, but didn't have the sensor with me, maybe I will take it down there tomorrow and have them make a hose to mount the sensor remotely, but I am positive it will cost more for that hose than to just buy another setup with the proper adapter.
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Re: My 1980 Datsun 720 diesel dually

Postby wayno » Sat Apr 16, 2016 9:20 pm

I have been driving this truck as much as possible, took it out today on a Datsun Cruise, I determined that I had the wrong vehicle as everyone else had cars, and then there was me in my dually diesel truck trying to keep up on winding Mountain roads, one of the guys behind me said I had one rear dually side wheel airborne and spinning, I don't believe it is true, as I didn't feel it break lose, but the front tires were squealing and my front brakes almost caught fire.
Anyway my throttle cable dropped out of position and rested on the exhaust manifold head pipe and all of a sudden I had throttle issues, it would not drop to idle anymore, well after we got to the top of the hill the guys stopped and had to repair another guys throttle return spring, so mine cooled off enough to act normally again, but I started having issues again on my way home, that is when I figured out my issue, after I got home.
So I got the throttle cable moving slightly better and went to the auto parts store and ordered a new one(supposed to be here Monday), so I went home and then made a modification to my engine, I put a hose from my vacuum throttle control line to my boost gauge line with a boost controller valve in the middle, I believe that the boost will help push the rack to a richer position when I have boost, but when I let off the pedal I will have vacuum, this will help pull the rack to the idle postion, my thinking is that I cannot seem to get enough fuel, especially on the hiway, so after talking to the guy that did the turbo bomb thread, I decided to try this mod.
I entered the hiway and opened up the boost control knob and I could feel it, that dead spot at 2500rpms was gone and I kept gaining speed, I noticed at about the same time that I hit 18psi that something came apart, I let off and slowed down some, as that was the fastest I had ever went in this truck, I was of the opinion that I lost a transmission bearing, I tried 4th gear but it didn't seem to change, so I made a quick decision to get off the freeway now and limp home, I tried all the gears and the sound continued till I got home.
Once home I popped the hood while it was running to see if I could figure out what the noise was, my idle was also a little high but I thought it was a throttle cable issue, well it didn't take long, my home made vacuum release valve made of PVC had blown apart, I figure that it was just to hot in the engine compartment for the PVC material, and 18psi was just to much for it to hold together, where the cotter pin was had just pulled thru the hot PVC material till it let loose, I will take a photo of the part later, I just drilled another hole 90 degrees off and put it back together.
I am happy to say that the modification worked, I had way more power on that last test drive, it quickly went up to 70mph+ just before blowing the valve apart, but I didn't have enough time to get a lot of input, I was looking at the gauges, boost controller adjustment, and the road ahead of me along with all the traffic, I have no idea if it was blowing black smoke, nor did I have enough time to see what the EGTs were going to do, I believe I will need a 20 mile trip on the hiway to get a good idea of what is going on.
I also need to make a metal valve, as the PVC is not going to hold up, but first I need a good throttle cable that doesn't stick.
I learned a lot today, one was that if I go on another Datsun cruise, take the Roadster!!!
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Re: My 1980 Datsun 720 diesel dually

Postby wayno » Sun Apr 17, 2016 2:50 pm

So this is what happened, and why the valve came apart.
Image
The other side.
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This is the new one I made, there is more meat to hold it together where I drilled this one, but that doesn't mean it will not do the same thing.
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Fact is on that winding road I was driving on yesterday the engine got mighty warm, the EGTs were over 1200 degrees, that likely didn't help, it likely had been coming apart the whole day, and that 18psi was the straw that broke the camels back.
I am hoping this one will last longer till I find something that will work that is all metal.
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Re: My 1980 Datsun 720 diesel dually

Postby wayno » Wed Apr 20, 2016 8:16 pm

So I have been thinking the last few days what should my maximum boost PSI be, today when driving down the freeway I was seeing 15psi quite a bit, but when I search the subject I find very little about the SD series engine, and when I do see a reference made it is low, somewhere around 7psi or less.
Well i have been driving it quite a bit lately and I have seen that all my power is created above 10psi, but I just figured out how to get more fuel to the engine, and it is a different engine now, before I had to floor it to get to 65mph on the speedo at about 10psi, now I am only using the top 20 percent of the pedal to easily show 65mph on the speedo, the concern is that I am over 10psi on the hiway all the time, if I give it to much pedal it goes over 15psi, where is the line I ask myself.
This all happened after I made that small modification, where I connected a small hose/line between the boost gauge line, and the injection pump rack control vacuum line, that wall I was bitching about at 2400rpms is gone, that wall was a lean fuel issue, I don't have that issue anymore, and I build up boost fast now.
I have a waste gate in the turbo compressor, but it is cranked all the way shut, as before I was having issues building up boost, now I don't have that issue anymore, but I need to adjust the waste gate, and the question is what PSI should I set it at.
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Re: My 1980 Datsun 720 diesel dually

Postby Laecaon » Wed Apr 20, 2016 11:16 pm

So the whole problem with boost is going lean. New diesels make crazy psi. I would check what vw and Mercedes were doing at the time with their indirect injection motors. I wouldn't hesitate at more boost if you have the fuel to keep up. I would focus more on egt than boost at cruising speeds.

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