My 1980 Datsun 720 diesel dually

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Re: My 1980 Datsun 720 diesel dually

#161

Post by wayno » Sun Jan 13, 2019 4:55 pm

Today I removed the flatbed and put the dually box back on it, it took most the day, tomorrow I will remove the helper leafs so it doesn't stick up in the back so high.
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It was kinda a pain to do this, it didn't go on there easy and it doesn't appear to be at the correct height at the back of the cab(half inch low), so I might loosen the bolts and add a spacer to bump up the front of the box a little.
I also need to change out the hood, get that ugly one off there.
I didn't drive it today either. :(
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Re: My 1980 Datsun 720 diesel dually

#162

Post by wayno » Mon Jan 14, 2019 7:29 pm

I took the helper springs/leafs off, it looks much better.
I fixed the box so it aligns with the cab, it looks much better.
I put the good hood back on, it looks much better.
All that is left to do is put the adapters on the rear axle and then put the dually rims back on, but I have so much money into the tires on the aftermarket dually rims(white ones) that I will likely just use them for the winter.

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I also started mocking up the turbocharger I took off the truck in case I do not like the one on the truck right now, it is mounted a lot lower now, likely 5 inches lower, a couple inches lower than the one I put together in the truck now.

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I still have not drove this truck. :(
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Re: My 1980 Datsun 720 diesel dually

#163

Post by DRIVEN » Tue Jan 15, 2019 5:07 am

That looks like it'd be a challenge in a tight parking lot.
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Re: My 1980 Datsun 720 diesel dually

#164

Post by wayno » Tue Jan 15, 2019 9:11 am

Why, cause it is so long?
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Re: My 1980 Datsun 720 diesel dually

#165

Post by DRIVEN » Tue Jan 15, 2019 3:20 pm

And has those wide hips. It's still probably smaller than the average Silverado -- just big by Datsun standards.
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Re: My 1980 Datsun 720 diesel dually

#166

Post by wayno » Tue Jan 15, 2019 3:46 pm

So today I adjusted the box first, it is all in alignment now.

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Then I decided to take it for a drive, I started it up and it was making noise, so I checked and it was the steering pump, I drove the 520 to the auto parts store and bought some and filled it up, then I started it and looked for leaks but could not find one, so I closed the hood and it was awful, the hood was rattling something fierce, I lifted it back up and it was hitting the turbo, I thought it was low enough but I guess it was not, so I cut the hood bracing off where it was hitting, I cleaned it up a little later and then took the photo below.

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So I took it for a drive, the waste gate does not function but I took a piece of hose with me on case the boost got too high I needed the waste gate to function, I seen just over 10/12psi when putting my foot into the pedal getting on the freeway, and once on the freeway when I moved to the center lane to pass a truck, the EGTs ran around 800 degrees going down the freeway and got near 1200 degrees going up a short hill while keeping my speed going up that hill, it ran slightly hotter than I thought it would but I really cannot compare it to my 521 kingcab because the sender/sensor is after the turbo on that truck(wrong place) and this one is right at the exhaust manifold exit a foot or so before the turbo where it is supposed to be, I need to drive it a lot more to really understand it the way it is now.
My drive was only around 5 miles, during that drive I noticed that when I turned on the blinker the EGT gauge was jumping around, that is when I noticed it was not charging either, so after I got home and put it on the charger I started looking at the alternator, I checked all the connections and they were good, next I went to the fusible links and checked them and they were all good, the plug for the fusible links connected to the battery don't look that great but when I tested each wire they all had power so I plugged them back together the way they were before testing them.
I had started this truck several times while checking everything, since starting this turbo lowering conversion I had had too remove the injection pump control arm because the engine would not start as the injection pump controller would not move to the run position, but if it was not connected it started just fine and I had this choke cable connected to the arm that when I pull it the engine shuts down, I have had this issue with this truck off and on for several years, well after I checked everything I started it again checking the power steering pump again for leaks, I looked over at the DPC module, I had tested another one seeing if that was the reason it was not charging and there was no change, so I took the test one out and plugged the one mounted on the inner fender back in, I was looking at the engine while it was running and all of a sudden there was a pop like what happens when the glow plugs are finished warming up, I thought that was weird, I went around the truck and looked at the volt gauge and it was charging now, I git out my test meter and it was charging 13.5 volts, I took the charger off the battery and checked again and it was still charging, I shut the engine down, started it up again and after the pop it was charging again, so now I was real curious, I shut the engine down, connected the injection pump control arm to the injection pump again, got in the truck and hit the starter and it started just fine for the first time in quite a while, I turned the key off and it died, then I started it again and waited and when it popped the alternator started charging, now I have no idea why it is working again other than I did something, I suspect it has something to do with either the fusible links, the fusible link plug on the battery, or the DPC Module, but I do know this, the diesel wiring harness is weird, it's wired into the oil pressure, it appears to be wired into the alternator also for some reason, I just went out and started it and it was charging, I was hoping my radio would start working again but no such luck, that is a different issue, it works when it wants to and it doesn't want to right now.
After I drive it for a while I will figure out if it has more power, less power, or if it is still about the same using this turbo, also we have to keep in mind that this injection pump was modified to run richer, so that may play a part in the big picture also.
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Re: My 1980 Datsun 720 diesel dually

#167

Post by wayno » Tue Jan 15, 2019 3:53 pm

This truck is small compared to a full sized truck, but it can haul weight with these aftermarket dually wheels on it, but when I put the adapters on it and use real Nissan dually wheels/rims, I don't really haul weight as they are 2 1/8th inch adapters and had to be that thick for the dually wheels/rims to clear the leaf springs, but I will tow with it anytime.
DRIVEN wrote:
Tue Jan 15, 2019 3:20 pm
And has those wide hips. It's still probably smaller than the average Silverado -- just big by Datsun standards.
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Re: My 1980 Datsun 720 diesel dually

#168

Post by wayno » Tue Jan 15, 2019 4:02 pm

I forgot to mention, you can see in the last side photo where the exhaust exits just under the drivers door, it's pretty loud exiting right there, I really could not hear much of anything at all but the exhaust while driving down the freeway even with the window rolled up, I do not have enough flex pipe to get any farther back and since I am going to have a exhaust shop make the exhaust I do not feel like buying anymore flex pipe.

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Re: My 1980 Datsun 720 diesel dually

#169

Post by wayno » Wed Jan 16, 2019 9:04 pm

I did a few things today before my Aunts birthday dinner(93), we thought 2 years ago might be her last one, but she is still around and she knows who everyone is even though after recognition she doesn't make a lot of sense.
I first made a temporary exhaust all the way to the driver side rear, it even points out the side, it is a lot quieter now, I can hear rattles and thumps I could not hear before, it is still loud, I may need a muffler, I have one of them laying around here also.
Next I did some more cutting on the hood under structure to clear the turbo, oil piping, and tubing from the turbo to the intake, the oil feed was still rubbing on something so now all the bracing near it is gone, I believe I am done it that area, next I took the intake cover which was pointed too much up(my fault) and I cut/welded it again and lowered the end just enough to clear the booster and brake lines and not rub on the hood.
Next I took it for a drive, I had it floored just long enough to see 15psi, I just don't see where I will ever see that again, it takes longer to build PSI than it did with the other turbo, and yes the other turbo has more power, but what I care about is that the engine lasts a while, and that it is pleasant to drive on the freeway, I still have not had it on the freeway long enough to make a decision there, when I got home the power steering area was wet again.
I slid the cover up out of the way, cleaned the area, started the engine and twisted the steering wheel around and it was soaked again, the pressure side hose was bad, I happened to have another one so I somehow got the old one out and the new one in without having to remove anything except the lift pump fuel line(twice), and everything appears to be dry now, I drove it to the dinner.
I will look at the pressure hose again tomorrow, it is rubbing against the battery this time, before it was laying on top of the reservoir, and it rubbed a hole in the line there, I need to figure out a way to route the line so it doesn't rub on anything, the issue is that the pump connection has a stopper/restriction to keep the line from moving too far certain ways, I might have to cut it off before it is all over with so I can have the line connection pointed the way I need it pointed, the connection that swivels is held on by a banjo bolt, the line connects to the end of that fitting.
So far the only thing not working is the radio and volt/oil pressure/EGT gauge lights, the radio will eventually come on and then keep working if I keep driving it, but when I let it sit it goes into hibernation, I guess I need to get the gauge lights working or wire lights into them if I plan on driving this at night.
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Re: My 1980 Datsun 720 diesel dually

#170

Post by wayno » Thu Jan 17, 2019 5:56 pm

I didn't do much today to this truck, I took the Optima battery out of the U320 and put it in this truck, it's a smaller battery and doesn't hit the power steering pressure hose like the bigger battery did.
I also was able to put one of the 10mm bolts in the bracket holding the power steering lines to the front cross member, the other bolt was too hard to deal with with the truck sitting on the ground, it appears I will have to bend the hard lines to get that bracket to line up with that mount hole, nothing is leaking right now so I might not do anything as them lines do not vibrate or rattle so I am not worried about metal fatigue.
I also removed the radio/CD player, it had a blown fuse, it also had power to the plug on both power wires, I changed the fuse and it still doesn't work, it will come on at some point or it won't, I do not really drive this truck much so I do not care right now.
The back end needs to be lower, I have a set of 620 mobile home leafs that I am considering using on this truck, they are flatter but stiffer, I really do not want to notch the frame on this truck, I have 4/5 inches between the axle and the frame(no bump stops) and it doesn't have any drop blocks, I do not plan on using this truck to haul any real weight, so I have a little room to play with.
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Re: My 1980 Datsun 720 diesel dually

#171

Post by wayno » Fri Jan 18, 2019 5:52 pm

Well I drove this today on the freeway, it's different than the 521 kingcab and the 720 with the other turbo on it, the other turbo has a little more power but always has the max boost, also after 65mph you have to start putting your foot into the pedal, the 521 kingcab also has more power, but after 65 I have to start putting my foot into it also, the pedal is more than half way down to do 75mph, it is a lighter truck though, Now the 720 with this turbo goes 70mph and I barely have my foot in it, I do think at this point it has the freeway power I want, but I have not went up an extended hill yet without someone holding me back, I have yet to see how well it picks up speed and how the EGTs react.
It is better over all with this turbo than the other turbo pushing a shitload of boost.
To help everyone understand, I have disabled the waste gate on this turbo, I have seen 15psi when I held it to the floor and it had to build up to that, the other turbo with the waste gate adjusted shut will go over 20psi quite fast and stay there on the freeway unless I adjust it to be open all the time, then it is at where I adjust it all the time, this turbo runs around 5psi on level ground on the freeway, but will rise as I put my foot in it, I think that one should need the extra psi when it is needed, not 10psi all the time.
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Re: My 1980 Datsun 720 diesel dually

#172

Post by wayno » Fri Jan 18, 2019 6:02 pm

I also worked on the old turbo setup as it will likely be used by someone else, or me with a blow off valve.
I bought some pre-made elbows, two 90 degree elbows and two 45 degree elbows, I made the turbo head pipe this afternoon, I weld better when I can see and the metal is clean.

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Re: My 1980 Datsun 720 diesel dually

#173

Post by wayno » Sat Jan 19, 2019 3:42 pm

I decided I wanted a radio/tunes, so I pulled the Super Tuner radio/CD out of the dash after I tested another radio/cassette deck, I removed my radio and pulled the antenna wire and the moment that antenna hit ground sparks flew, I quick isolated the antenna and then looked at the plug real close, I expected to see a melted wire but that didn't happen as I suspect I got to the issue fast, while I was looking at the plug I noticed the yellow hot wire was half pulled out of the plug, I thought it could not be that, but I put the radio back in and made sure that yellow wire was all the way into the plug after inserting it into the radio, I turned on the key and the radio/CD player work again.
The other radio(Pyramid) that I tested did fit into the hole perfectly, much simpler radio, 7 wires total which 2 are for woofers and are not used by me, the one in the truck likely has 20 wires and I do not use the woofer wires in that one either.
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Re: My 1980 Datsun 720 diesel dually

#174

Post by wayno » Sat Jan 19, 2019 4:57 pm

I bought this Volvo with this diesel engine from Larry, it had this propane injection setup on it.
I took the propane setup off so I would not have to deal with it while trying to get the engine to run properly, well it took a while but I finally figured it out and now all my diesel engines have turbochargers on them and they run great.
So I have been thinking about this propane injection, Larry put a lot of time and research into it, but I am kinda scared to install it as it is a totally different engine now, it even has a different turbo on it.
The way it is set up in the air filter is so simple it's scary, it's nothing more than a fitting end sticking inside the air filter neck.

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I removed the filter top to get the photo, when I took it out I cleaned the filter also, when I removed the filter from the top and looked inside the filter the screening inside had collapsed inward, sorry I forgot to take a photo of that, so what I did was I added a much stiffer screen inside to stop it from collapsing.

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Now I suppose I could add fittings to the inside to pipe it to the middle, and then put a 90 degree elbow on the end with a short piece of tubing on it pointed towards the turbocharger which will create a draft to pull air out of the tube creating a venturi type effect, it would likely pull more propane out that way, but keep in mind that I am not using the turbo that Larry was using either, it takes longer to build boost and it does not create the boost numbers that the turbo produced that was on it when Larry made this setup.
Larry also had the regulator set up with a bypass, sort of a primer, if I pressed the button in the middle of the regulator the idle noticeably went up(higher idle).
The turbocharger on it now is larger than the one Larry built, but Larry machined out the inside of the compressor side to except a larger vane in the smaller turbo(I still have that turbo), so the way I see it I am not moving the amount of air I was moving with Larrys turbocharger as that one was smaller so the exhaust side spun up easier/faster than the one on it now, but this is what I wanted as I wanted the boost PSI to be at 4/6psi driving down the freeway at 70mph and rise up to 12psi getting on the freeway or when I was passing someone rather than being at 12psi all the time no matter what road/freeway I was on with the turbo Larry had on the engine.

I wrote all this so anyone reading it would have all the info I could give them, it would be easy for me to install this propane system as I didn't pull it apart, I just removed the hose from the fitting on the air filter housing, disconnected it from the propane tank and I stored it in the back of the truck which has a canopy, it is all there.

I wrote/posted this on the Diesel Forums in the guys thread about this propane injection that came on the Volvo I bought from him that had this turbocharged diesel engine in it, tell me what you think, should I put the propane injection back on the engine.
Here is a link to the thread about it on that site if you want to read the whole thread, it's only one page and a couple replies long.
http://nissandiesel.dyndns.org/viewtopic.php?f=4&t=3410
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Re: My 1980 Datsun 720 diesel dually

#175

Post by Laecaon » Sat Jan 19, 2019 6:55 pm

I honestly don't know enough about diesels. But have always heard it's a bit like nitrous for them. I've heard of guys doing alcohol siphon feed on turbo gas engines. Keeps the temps down. Maybe it's between the 2 (nitrous/alcohol).

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Re: My 1980 Datsun 720 diesel dually

#176

Post by wayno » Sat Jan 19, 2019 7:35 pm

It's a test truck, I should just re-connect it up and see what happens, I have thought about getting a cover for the 520 and just driving this 720 for a while, but the 520 starts so much easier when it is cold, if I do focus on the 720 I may be able to figure everything out without blowing it up.
It does need a better exhaust, it's quite noisy but now I am thinking about doing it myself, I only have a 4 foot section of flex pipe left.
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Re: My 1980 Datsun 720 diesel dually

#177

Post by wayno » Thu Jan 24, 2019 4:04 pm

Today I went to "Oil Filter Services" and got the fitting I needed, this is before.

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And this is now, I can press down on the hood and feel it is not hitting anymore.

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Re: My 1980 Datsun 720 diesel dually

#178

Post by DRIVEN » Thu Jan 24, 2019 7:32 pm

That place has everything. Had a lot of custom hoses made there over the years.
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Re: My 1980 Datsun 720 diesel dually

#179

Post by wayno » Thu Jan 24, 2019 9:16 pm

They didn't have the type of fitting I brought as an example(out of stock) so he asked me how it sealed, I didn't have an answer, but I bought it and said if it had the wrong seat I would cut the end off if I had to and bevel it the other way.
But when I looked down the hole the fitting went into it had no seat at all, it was just a threaded hole like one that uses a banjo bolt and fitting with copper washers to seal it, I put lots of pipe tape on the threads and will watch it for oil leaks for a while.
I actually drove it today and gave it some real pedal, without anything rattling on anything and a better put together exhaust system I did today it went pretty good and sounded alright, it is louder than it has ever been before though, this turbo is not doing as good of a job quieting the exhaust as the other turbos I have used or are using, but the exhaust on it this time exits sideways behind the rear wheels, and before it dumped under the truck at the ground, while my 521 exhaust exits straight backwards.
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Re: My 1980 Datsun 720 diesel dually

#180

Post by wayno » Fri Jan 25, 2019 5:39 pm

I drove this to the wrecking yard today to look at the VW Passats they had in the yard, on the way there I thought 5th was making more noise than usual, made a metal note to check the transmission fluid, anyway none of the Passats had the turbocharger I have, but I am pretty sure that the newer ones have the same turbocharger I took off/out of my truck but they are not modified, there were maybe 5/6 of them with that turbo, but last night I searched Passat turbos on ebay and they are cheap new.
So I got home and lifted the truck up from both ends about 3 feet, got under it and removed the transmission fill plug and checked the fluid level, first thing out of my mouth was "shit", what fluid, I drained it and got less than a cup out of it, it was not a bad color, but we shall see how long this transmission lasts, 5th is not as noisy now but it still makes noise.
While I was under there I seen oil everywhere under the oil filter, so I used some de-greaser on the whole side of the engine, I have this pancake on the oil filter mount, it is there because I could not mount the dual oil sensor/sender where the oil light sender/sensor is, I tried it by using an extension and it broke while driving it, I was so lucky I didn't run out of oil and ruin the engine, anyway something in that pancake area was leaking so after it was clean I started it and it looked like the pancake was leaking so I removed the oil filter and tightened it up, put the filter back on and I drove it around the block, lifted the hood and it was still leaking, so I cleaned it again, started it in the driveway and found the leak, it was the fitting holding the mechanical oil gauge hose on the pancake, so I removed that, cleaned it up and put pipe tape on it and put it back together, cleaned it up again and started it, I believe the leak is fixed, the only concern I have is that the pancake is only held on by the fitting that the oil filter spins on to, once the oil filter has been on there a while the pancake tries to spin off with the oil filter, but I do not see a better way to do it right now, there are other access holes for gauges and other stuff on this pancake, maybe I can come up with something that uses on of them holes to hold the pancake in one position.
The truck had more power with the other turbo on the freeway, but it was always at 12psi while now it is at 4/6psi, it still has plenty of get up and go in all the gears except 5th, but it appears to still go up the hills without having to down shift so I can live with it.
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