My 1980 Datsun 720 diesel dually

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Re: My 1980 Datsun 720 diesel dually

#141

Post by wayno » Sun Dec 17, 2017 7:54 pm

A little less power off the line, but being I am turning 330 gears in the rear it has a shitload of power, what really counts is on the freeway with the trailer.
Keep in mind that I put tires on it that are 3 inches shorter, it is like dropping the gearing to 350 gears, I really have not driven this truck much, it has been more or less a test engine to try and sort out the turbo which finally happened last spring.
The issue I have with this truck/engine/turbo is that the guy I bought the engine from had machined the intake vane side of the turbo to except a larger vane so that it spins up at lower rpms, well that has a down side, at freeway speeds it wants to be at maximum boost, when I let off and then step on the pedal slower it still goes right up to maximum boost which I set around 15psi(I have seen over 20psi), I don't want to set it at 5/6psi because when I am accelerating it will only get to 5/6psi, I would rather it act like my 521 turbodiesel where it can get up to 15psi speeding up, but on the freeway it averages 5psi going 75mph, this truck will peg 15psi and stay there at 60mph, but I don't do a lot of freeways for long around here working, so it will make a good backup work truck.
Being he did modify the turbocharger the way he did(he also turned up the injection pump), it has a shitload of torque, way more torque than the 521 turbodiesel being they are the same engine, it might make a great work truck, but everyone knows my 521 truck I have now, I plan to keep it my work truck until I retire.
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Re: My 1980 Datsun 720 diesel dually

#142

Post by wayno » Mon Dec 18, 2017 10:17 pm

Well this evening is the first evening that I don't have band-aids on my fingers. :lol:
I have quite a pile of them now, every time I changed them the pile grew.

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I cleaned out gutters today and pressure washed a steeper driveway so it would not be slippery over the winter, I guess i am going to survive. :lol:
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Re: My 1980 Datsun 720 diesel dually

#143

Post by wayno » Sun Dec 31, 2017 6:32 pm

So I put some helper leafs on this truck today, they likely raised the rear of the truck at least 4 inches. :(
I took it for a drive, it will do for now, I suppose it is time to check the trailer wiring and if that works properly it will be time to start the 521 conversion/frame swap.
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Re: My 1980 Datsun 720 diesel dually

#144

Post by wayno » Sun Jan 07, 2018 10:59 am

I made a removable ladder rack, front one is full width of the cab angled with the sides of the cab, the rear is a stand alone rack made for an extension ladder, that one can be put on either the passenger side or driver side, it will not drop into the 2 center stake pockets as they are farther apart.

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Re: My 1980 Datsun 720 diesel dually

#145

Post by DRIVEN » Sun Jan 07, 2018 11:52 am

Looks sturdy enough. What's that black knob in the background? Liftgate control?
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Re: My 1980 Datsun 720 diesel dually

#146

Post by wayno » Sun Jan 07, 2018 7:36 pm

The black knob sticking up in the second and third photos is the control knob for the Tommy Gate, but unless the thing has power it will not raise back up after lowered, that switch is in the cab, the knob has to be on top as one has to be able to control it standing on the ground or standing on the Tommy Gate while raising/lowering it.
This is all temporary, while I am changing the 521 cab to the new frame I need something to do work with, once the work truck is back in service, the 720 long box will go back onto the truck, I will likely try to sell the flatbed with the Tommy Gate first while it functions.
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Re: My 1980 Datsun 720 diesel dually

#147

Post by wayno » Mon Jan 08, 2018 2:17 pm

So I had to cut these 5 inch long pieces of metal off the bottom sides of the 2 inch square stakes to get them to fit in the stake pockets, I welded them pieces to the sides of the horizontal rack tubes to keep the ladder on the rack.
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Re: My 1980 Datsun 720 diesel dually

#148

Post by wayno » Mon Feb 26, 2018 5:05 pm

So today I replaced the 1980 Datsun 720 brakes with the brakes I had on the 521 work truck(1990 Hardbody V6 2wd dual piston/vented rotor brakes), it stops way better now, I bled it and bled it and I had to continue to pump the brake pedal twice to get it to the top, it turned out all I had to do was adjust the rear brakes and all appears to be good now, the pedal stays the same no matter how many times I pump it, once or 3 times it doesn't matter.

I did have to fabricate a short piece of brake line on the passenger side front brake line, that rubber hose has a block on the end of it instead of a brake line fitting, for some reason I thought the brake assembly would just bolt right in, but in this chassis year they put this NLSV that connects into the right front brake circuit, what a pain, I just made a 3/4 inch brake line that went in between the 2 rubber hoses, it works fine and so far has not pulled one way or the other while braking, I suppose I should now make something that holds that area of the brake line in one place as right now it floats and I expect it could find a way of wearing a hole in the brake line or brake hoses somehow.
Here is the brake line section I made, you can see the brass block also, I was hoping the photo would be in better focus.
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I thought about putting one of the sets of drop spindles I have in this truck and likely will in the near future, but it was more work than I wanted to do today, I am trying to use all the stuff I have around here for my rigs as I am going to start cleaning up around here again, I make a little more progress at cleaning up every time I clean up, I get rid of a little more than the last time I cleaned up, one day it will be cleaned up meaning I will not have even 10 percent of the Datsun parts stored that I have stored right now. :lol:
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Re: My 1980 Datsun 720 diesel dually

#149

Post by wayno » Mon Jan 07, 2019 6:07 pm

I decided to play around with a lower turbocharger mount for the 720 today, I made some progress, I believe I will try this turbocharger on the 720 as it is not modified, I took the turbo apart and assembled it with the oil feed at the top, the compressor output(boost) straight to the side, and the piece of angle iron is bolted to the exhaust manifold as you can see in the photos below.

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As you can see the turbo is being held in position with a pair of vise-grips, the piece of angle iron is bolted onto the exhaust manifold using the heat shield mount holes(12mm head), there are 2 more holes on the bottom of the exhaust manifold that I am going to use also, I believe these 4 holes plus a brace coming from the top motor mount bracket bolt on the side of the block will hold it there, but first I need to pipe the turbo to the exhaust manifold from its stock outlet, I have the room in the 720 to route the turbo exhaust out going more or less straight down in front of the starter.
I plan to remove the turbo on the truck as it is not freeway friendly modified the way it is, if it works out great, if it does not work out I hopefully will use what I have made to mount that turbo to this lower mount, I want to put my regular hood back on without a hole in it.

This might actually end up on my friends truck, it's a slightly larger turbo than what is on the 720 right now, or my friend might end up with the modified turbo as he has an SD22 and that one is smaller, it all depends on how it runs and drives on my SD25.
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Re: My 1980 Datsun 720 diesel dually

#150

Post by wayno » Tue Jan 08, 2019 12:22 am

I did a little more on this after my late dinner.

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And then there is this, the 2 bolts that do not go thru the exhaust pipe flange, I decided I am going to put threaded studs in them holes and tighten them like they are now but with extra threads sticking out, I will then use a couple of them thick washers that hold the intake/exhaust on the L block on the threads sticking up and then put another nut on and tighten them down, it will be like the exhaust flange has 4 bolts holding it on instead of 2 bolts you can see one of in the photo below.

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I will do more tomorrow, I need to make a flange for the head pipe connection to the exhaust side of the turbo, that is way more complicated.
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Re: My 1980 Datsun 720 diesel dually

#151

Post by wayno » Tue Jan 08, 2019 12:25 am

I am making this shit up as I go right now.
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Re: My 1980 Datsun 720 diesel dually

#152

Post by Taterhead » Tue Jan 08, 2019 12:46 pm

That’s what I always do

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Re: My 1980 Datsun 720 diesel dually

#153

Post by wayno » Tue Jan 08, 2019 5:35 pm

Well I made headway today, I got the exhaust pipe from the exhaust manifold to the turbo done.

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I also got the flange made for the turbo exhaust exit.

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I got the braces on the bottom supporting the turbo mount plate made, installed, when I can see I weld pretty good.

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I also did the thick washers on the sides of the turbo exhaust flange, I took a photo before I put a small washer in there to have the washer level.

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I believe I am going to have to go to the exhaust shop and buy a scrap piece to fit the turbo flange with a sharp bend in it, I will not be able to complete the exhaust past the torsion bar until it is in the truck, I am getting close to needing gaskets.
I also will likely have to cut the corner off the turbo mount plate as the exit pipe needs more room to get by the manifold to turbo pipe, I already cut it some but this cut will delete the back plate support.

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Re: My 1980 Datsun 720 diesel dually

#154

Post by wayno » Wed Jan 09, 2019 5:51 pm

I did some running around today about this, showed 3 different places the turbo and not one could figure out what it came off of, I did get some exhaust gaskets for it though at the muffler shop along with a bunch of pieces of 2 inch exhaust pipe, I had just enough to make what I needed, well at least as far as I can go without it being in the truck itself, I will have to get it past the torsion bar on that side after it is in.

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I suppose it is time to remove all the stuff in the 720, it is not going to be easy, not sure how I am gong to get to some of the manifold bolts, the guy put a lot of stuff in the way, I was hoping to just disconnect everything and pull the manifold complete with everything in place but when I looked at it yesterday it didn't look possible.
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Re: My 1980 Datsun 720 diesel dually

#155

Post by DRIVEN » Wed Jan 09, 2019 8:05 pm

You'll figure it out. You always do.
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Re: My 1980 Datsun 720 diesel dually

#156

Post by wayno » Wed Jan 09, 2019 8:34 pm

Yes I will figure it out eventually, I wish I could figure out how not to catch myself on fire all the time, yesterday it was my Levi type sheepskin coat, not too bad, but today it was my pants, I didn't even know it, and there were actual flames but I had work gloves on and put it out pretty quick, but not before burning all the way thru the outside layer of the pants and thru one layer of the pocket my cell phone was in(cell phone appears to be alright), them pants are worthless now and are in the garbage, there was one pocket layer left before getting to my boxers, it was a 4 inch sized hole.
I sure hope this turbo works the way I want it to, I am putting a little bit of time into this, and I am making this stuff without it being in the truck, I am doing a lot of measuring though.
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Re: My 1980 Datsun 720 diesel dually

#157

Post by DRIVEN » Thu Jan 10, 2019 2:59 pm

Nice to have a mock up engine, I bet.
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Re: My 1980 Datsun 720 diesel dually

#158

Post by wayno » Thu Jan 10, 2019 7:07 pm

Yea, but I still had to make adjustments, the "S" shaped exhaust from the turbo hit the frame a little, and then my adjustment to fix that put the end pointed at the transmission edge so another adjustment had to be made, it has been a fight the whole day since I got out of bed.
I got up and had a bowl of cereal, put the dishes in the dishwasher and I started it, a little while later I got dressed to start the work, went out in the garage and there was a small river of water from the washer drain flowing to the other end of the garage where the garage door is, so I tried for a while to force it open with a garden hose with no luck, what would happen was when I made a good seal at the washer drain the water would come up out the sink drain in the house and fill the sink(both sides), so then I sealed one side of the sink and used a plunger on the other side, it just drained out the seal I made in the garage drain slowly while still filling the sink on the side I was using a plunger on, I stopped and disconnected the hose from the faucet and let it drain in the driveway.
I had went under the house and tapped on the drain pipe till it sounded hollow after a bend, so it was plugged at the bend, so next I went to Parkrose Hardware to rent a snake, they would not rent me a snake for cash, they wanted a card, so I gave them my Visa, it denied me twice, I had used it less than a month ago for a purchase without any issues as all I had was a $100.00 dollar bill for a $10.00 purchase and she didn't have the change, but it would not accept my card, so I went to the plumbing section and bought a 2 inch rubber coupler with hose clamps on both ends.
I drove home and got 4 buckets, my Dewalt battery powered skillsaw, another hand saw, a long screwdriver, a 2 foot long piece of strapping and a pair of pliers to bend the end of the strapping to pull crap out of the pipe and a 120 volt trouble light, I got under the house and cut the pipe a foot and a half from the bend over a bucket, nothing came out, I was expecting a mess, so I looked real close at the end of the pipe and it was solidly filled with whatever the clog was made of, I stuck the screwdriver on the pipe towards the washer drain and slowly it started coming out, I filled a 5 gallon bucket with water before it quit coming out, next I stick the screwdiver in the pipe towards the bend and it was solid, once I made a hole I used the strap with the last half inch bent down 90 degrees and started pulling the blockage out into the buckets, once I got most of it out I pit the rubber coupler on the pipes connecting them together and then got out from under the house and i turned the hose on and went to the sink, nothing was coming up so I went back under the house and listened to the pipe, I could hear the water making the turn in the bend, I put everything(tools/buckets) back where they belonged and called it good, if it ever plugs up again it will be easy to unplug now as the pipe is already cut.
I started on the truck, it came apart fairly easy but was time consuming, then everything was a fight after that, I noticed this exhaust manifold was the same as my mocked up exhaust manifold(they are not all made the same), so instead of changing it all out I removed everything from the mock up manifold and I put it all on the exhaust manifold that was already on the engine, the turbo exhaust was hitting so i removed it and then the rest of the stuff went on without any more fighting, I had to move the throttle bracket out the the way, then I could twist and turn the exhaust pipe for the turbo in and out of there till I got it to fit, then I mounted it back on the turbo, next I checked hood clearance, I think it might be rubbing in one spot but the hood closes.
Next I started looking at stuff, I test fitted all the rubber elbows I had and none of them fit the top of the throttle body without getting crushed when I closed the hood, so I modified what was on there before as I had to point it another direction and it had to come straight out sideways instead of being pointed slightly down, I cut a "V" in it and bent it up and welded it back together then I piped the turbo to the throttle body, I piped the turbo intake to the filter, this rubber piping is what is likely rubbing on the hood but other than starting over I cannot do anything about it right now, it was dark so I will deal with it tomorrow.
The oil line fitting will not fit on this turbo, but I found a bolt with the right threads, I will go to the auto parts store tomorrow and buy a fitting(I hope), next I will figure out the water cooling of the turbo part and pipe the oil drain hose, I will figure out how to use the drain hose I have even though it is way too big for the drain fitting on the turbo, the hoses are the same, the fittings are way smaller than the hoses and the hardware from the other turbo does not fit this turbo, all that will be left after that is piping the vacuum throttle, putting the battery cable back on the starter and battery, and to make an exhaust pipe that will point at the ground instead of my floor boards and get it past the torsion bars, I can likely use flex exhaust pipe to get it to the exhaust shop.
That oil hose fitting is a big deal, I hope that fitting can be bought easily, I have samples of the threads in the turbo and the oil line end also.
I still have no idea what this turbo is off of.
Oh yea, I still need to put the gaskets on the exhaust pipe going to the turbo and the turbo side of the mount also, that will likely take an hour,12 or more bolts/nuts will have to be loosened or removed and most of the piping, I probably should have done that on the bench but I had no idea if this was even going to fit, I think I can do this without removing the turbo exhaust pipe.
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Re: My 1980 Datsun 720 diesel dually

#159

Post by wayno » Fri Jan 11, 2019 10:00 pm

I did all the piping today except for the oil feed line, the one of the fittings I ordered was wrong, the right one is supposed to be in tomorrow morning, so the coolant lines/hoses and oil drain line are done.
The exhaust is past the torsion bar and pointed at the ground.
I still have to glue the 2 ABS pipe joints I used, and I still need to put gaskets in between the turbo and mount plate, and the turbo exhaust feed pipe and the mount plate, I also need to put the EGT sender/sensor in that pipe, but I believe I will start it and drive it just to be sure the turbocharger works properly, if it has a bad exhaust leak I will shut it down and do all that, the setup I took off did have one between the turbo and mount plate, but the in feed did not have a gasket.
It is almost ready to start, the weather is real nice, I am not getting rained on which is nice.
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Re: My 1980 Datsun 720 diesel dually

#160

Post by wayno » Sat Jan 12, 2019 5:54 pm

So the correct fitting came today, I have been told that the one fitting I need is not available, so it takes 3 fittings to make what I need to connect the oil line I have to this turbocharger.

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After I connected the oil line I started it up and then drove it(without functioning EGT gauge), I seen just over 10psi boost going maybe 55mph, and when I let off and stepped on the pedal again it was under 5psi at a steady speed unlike the other turbocharger which would have still been 10psi.
I have not driven it on the freeway yet, I went home after that drive and pulled out the exhaust manifold to turbo pipe and out of the truck and welded in the bung I made last night to hold the fitting that the EGT sender/sensor connects to, it went back in way easier than it did when I put it in the first time, the EGT gauge appeared to work but I didn't drive it anywhere, it got up to 300 degrees when I revved the engine.

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The hood closes, but it is rubbing where the rubber hose goes onto the compressor outlet, I cannot clock the compressor clockwise because the outlet will be pointed down too far so I will have to live with this.

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I also made a brace that goes from the second headbolt/stud to the top of the turbocharger where there was a bolt for just this purpose, it's kinda ugly but it will work for now and maybe forever, I need to decide if I want to make a nicer one.

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