My 1980 Datsun 720 diesel dually

[wayno]

I connected up the U320 to the 720 turbodiesel and took it for a 5 mile drive, it ran fairly warm, but I kept going until I got to my first hill/upgrade, that is when it went to 1400 degrees and stayed there for a while, it smelt hot for a while.
So I will be driving this to Blue Lake tomorrow, the only time I am going to worry will be on my way back, crossing the 205 bridge going home is going to be a feat, that is a mile of upgrade that I am not looking forward to.
I am hooked up to the U320, just a few things left to do then I will be on my way about 9:30am tomorrow.

[wayno]

Here is the cover I made to cover the hole in the hood, it's not pretty, but it will keep the rain out for now.
I thought about a lot of styles, but none would look good on the 720, so I made this to get by, and it's free.



It's a crappy hood, but I decided to cut a hole in it, rather than my good hood.

[DRIVEN]

Flip that thing over and make some brownies.

[wayno]

I am hoping to lower the turbocharger eventually and then put the stock hood back on, but that is not going to be happening soon, so I will live with this for now.

[Taterhead]

One of these might look good if it clears.

[wayno]

One of these might look good if it clears.

It has to be 10.5 inches wide, 2 inches tall to clear the oil line, I am not screwing around with the oil line, if that thing fails, I lose everything.

[Taterhead]

Yeah I figured you wouldn't have made it as large as you did if it wasn't a necessity. I was thinking more of when you lower the turbo. Width probably still wouldn't work.

[wayno]

If I lower the turbo, I will put my stock hood back on that doesn't have a hole in it, I did not cut a hole in my good hood as that was my plan.
I have not done much with this, as I consider it a fail, the injection pump on the engine just is not made for a turbo, I am not sure that anyone can make this work correctly without putting a VE type injection pump on it, or going with an inline made for marine or a stationary pump like a generator or vacuum pump, but these pumps were never meant for an auto, just like the inline injection pumps in the 720s were never meant for a turbocharger.
I have an idea about how I could control the injection pump rack, but at the moment it's on the back burner.
I do have a VE type injection pump I can put on this engine, just had not given up on the way it is till just recently.
The biggest issue is that when on the freeway, it runs to hot, and there is nothing left power wise, and that is a problem for me, as I am happy with my diesels around town, it's on the freeway that I want more power.

Yeah I figured you wouldn't have made it as large as you did if it wasn't a necessity. I was thinking more of when you lower the turbo. Width probably still wouldn't work.

[wayno]

Well I have not done much to this truck over the last couple years, today I started installing the injection pump in the photo of my last post, I went golfing today, and when I got back home I tore into it, it actually already has a turbo in it already, I bought a turbo diesel engine from a guy that did a lot of research when he built the turbocharger he put on the SD25 engine, I will bet his wife was happy to see the car go away, but the engine runs to hot, the inline injection pump just doesn't like to be turbocharged, I cannot go 70mph on the hiway, it gets to hot, so i decided to put the inline IP I have that is metered like a VE type pump, and I will say this, it barely fits.
He is what the engine looked like before I tore it down.

I tried an inter-cooler, it made no difference, it still ran hot.

Here it is all buttoned up.

Here the new IP is installed.


I had to install a remote oil filter setup, it just would not clear the oil filter.


I had to remove a plug on the side and put a plastic plug in it's place, I am hoping this is not a pressure situation, you can see it next to that big nut, it's blue.

I goofed when I started this project, I thought that the front gear can only go onto the IP one way as the shaft is keyed, so I marked the gear and the housing so I could put it back on exactly in the position it came off, well when it came time to put the gear back on, I checked the pump key position of the IP I took off, and then I checked the new IP pump position, they were exactly the same just sitting there, I thought that was great, well it turned out to be a major pain in the ass, what happened was when I removed the gear, the IP gear shaft had moved, what it had done was move to the bottom of the internal lobe, well when I would try to move the shaft to where I needed it to line up my marks and the key way, it would flip back like a spring to where it was before I moved it, this was a major problem, I could not get the gear on, the teeth on the gears, and the key way have to be aligned to get it to drop in where I had it when I pulled it apart, I didn't dare move the crank, I then would have to pull the whole front of the engine off to align everything, so after looking at the pumps for a while, loosening the IP and turning it as far as I could, I gave up, I had to think of something else, see the hole in the end of that shaft, well I tapped an easy out into it while on the engine, then I started to install the gear onto the IP shaft in the position it needed to be, then I put a tool I have for tapping holes on the end of the easy out, then I turned the injection pump shaft until the key way lined up with the gear and it dropped in, it took a couple tries, but I could do nothing else except pull the whole thing apart, it dropped in, and I put the nut on and tightened it up before it came off for some reason.

It started to rain on me, so I packed it up, and called it a day, I will work on it tomorrow, it is close to starting it up, I just want it to run, then I will pull the turbocharger off and lower it, I don't like it sticking out the hood.

[wayno]

Well I started it yesterday, it sure makes a lot of noise, not sure why.
This morning I set to make a throttle setup, it took a while I I succeeded, when I went to take it for a test drive, I had issues getting it to move, the left back drum had locked up, so i had floor it to get it back in the driveway, I could only get it to move 4 inches at a time, it took a long time to get it back in the driveway, I pulled it apart, but could find no issue, but I got the thing freed up, and took it for a drive, I didn't even get it a half block and I knew there was something wrong, it will barely move the truck in first, so that is why I could hardly move it, my lawn mower has more power.
I am going to figure out where top dead center is on this engine, then I am going to figure out if the pump is off a tooth or two, if I cannot figure it out, I am going to have to remove it and put it back the way it was, or pull the SD22 VE type pump off it and put it on this engine, the last couple days have been a fail I think.

[Laecaon]

I dont know the nissan diesels well. But I do know of the VW diesels, and they take some special tools to time correctly, something I would never try to do without.

[wayno]

I dont know the nissan diesels well. But I do know of the VW diesels, and they take some special tools to time correctly, something I would never try to do without.

I put it back together the way I pulled it apart I believe, I did look for marks on the pump gear and could not find any, so I am going to need to do a little homework.

[wayno]

Well this was a fail, I could not get it to run properly with the new injection pump, I had it in and out several times, it just would not run properly, so I gave up and put it back together the way it was, I will try another way I have been thinking about.

[DRIVEN]

Disappointing.

[wayno]

OK, so I got up this morning and looked at the 1980 Datsun 720 and decided to see if I could do something with it, so I decided to put the throttle body in front of the turbo as the way it is doesn't work, it just gets to much fuel and gets to hot, I started it up and let it get warm so it would be easy to start after I changed things.
So I moved stuff around, amazingly things actually went together without issues, I wired the original throttle wide open so it would not restrict flow, I put another throttle body I had in front of the turbo and then I plumbed the throttle vacuum line, I then started it without a throttle cable and I used the fast idle adjustment cable to keep it running, at first it didn't act properly, it had a lot of lag and would die when I let off the throttle abruptly, but I worked with it, the first thing I noticed is that the rubber piping would collapse after revving it up and letting off as the airflow was cut off, but the engine is still turning and sucking in air, but once I seen that it was controllable I shut it down and put in a throttle cable and then took it for a drive, I could get 4psi on the hiway, I drove it about 10 miles, I took it up the hill that I always dreaded because it would get over 1400 degrees and I would have to let off before I got to the top of the hill just to keep it from going over 1400 degrees, well it only reached 1100 degrees floored, my naturally aspirated kingcab 521 gets hotter on the same hill.
So I went back home and started messing with the boost controller and took it for another drive, I reached 10psi with the bypass closed off, it could not move anymore, it had a little more power, not a lot more, just a little more, same result, 1100 degrees on the hill, I returned home and decided to clean the install up.
I removed the original throttle body and made an adapter to replace it, that actually went alright, I put it back together and it looks a lot cleaner now, but I do have an eighth inch lip on the inside of the adapter, that likely isn't good, I will deal with that later, I could only get to 7psi on the hiway that last drive, so I must have a leak somewhere, I will try again tomorrow , I noticed that my adapter had a slight bow to it when done, that may be the issue, I used a gasket, but it was a thin gasket.
I noticed another thing that needs to be addressed, when I let off the pedal, I have minus 10psi, I now have a vacuum between the turbo and the valves/pistons, this is bad as it pulls oil thru the turbo seal and it goes into the engine, one would think it would burn it, but I have no smoke at all out the exhaust, I mean no smoke at all after start up, I have a blow off valve but it doesn't do what I need, I need a valve that will let air in the system when I let off the pedal so that no vacuum is created, but when I give it the pedal it will close and let the turbo build up boost, I have decided that even though it would get air, I don't believe it will get fuel because the throttle body venturi is functioning pulling the injection pump back to idle when my foot is off the pedal even though it would be getting air to keep the vacuum from being created after the turbo, my throttle is vacuum operated.
I am making this up as I go, but so far except for the vacuum being a negative, it doesn't get too hot anymore and it is predictable, before at a steady speed(40mph) it would surge, meaning I could not hold a steady speed, either it was slightly picking up speed, or it was slightly losing speed, it would just continue speeding up even though my foot was not moving, so I would have to ever so slightly let off the pedal, and then press just enough to try and hold a steady speed and it would start over again, it just would not hold 40mph.
I am also convinced that it is not getting enough fuel now, this truck doesn't smoke at all now, I am used to seeing black smoke coming out of the tail pipe when going up a hill, I see nothing now, it also really doesn't have a lot of power on the hiway, maybe it has something to do with me using a SD22 throttle body before the turbo instead of a SD25 throttle body, but I will fix that tomorrow, as I removed the SD25 throttle body when I made the adapter, I will make another adapter and install the SD25 throttle body tomorrow and take it for a drive, I will also take more photos tomorrow, today I just worked on getting it going, I didn't think about taking photos.
I am also thinking that maybe the turbo intake being so close to the throttle body venturi might have something to do with it not getting enough fuel, it has to lose vacuum in the venturi for the injection pump to move to a more rich position, but it is very close to the turbocharger intake fins, but again I am using the smaller SD22 throttle body, with the bigger SD25 throttle bady it might not create as much vacuum in the venturi area.
I was kinda wondering what would happen if I used the inter-cooler as a intake buffer, but I am thinking it would cause a lot of lag and make it to rich, I will eventually figure it out or just let it sit for another year while I think about it some more.
Here is how close the turbocharger intake is to the throttle body.

My intake adapter I made to replace the throttle body, it's hard to understand the photo without having a before photo, I will take a photo of my diesel kingcab tomorrow to show what it looked like before.

A photo from the side, it helps me more than any of you guys, but it is a photo to post.

[wayno]

I got bored, so I made the adapter for the SD25 throttle body tonight.


Here is the throttle body.


Put together

Doesn't have nuts on it yet, just mocked up.

I might use this one on the intake manifold and use that one for the throttle body in front of the turbocharger, I will decide tomorrow.

[wayno]

So I went to the auto parts store this morning and talked with the turbocharger guy this morning after talking with the other guys while waiting for him to get to work, it was obvious that they didn't understand what I was talking about, I told the turbo guy I needed a valve that let air into the intake manifold when when I let off the pedal because it created an intake manifold vacuum of 10psi, this created an issue of oil being pulled thru the turbocharger seal as the turbo is lubricated with engine oil.
He got on the computer and read about my issue online and found that my system needed this particular valve and my system would not work correctly without it, and surprise, surprise they actually had it in stock, so now I need to stay inside to save myself as what are the odds that something I need on such a rare application would be in stock.
This little guy is spendy, it was $212.46 out the door.


The two vacuum lines on the end go to the intake manifold, they will sense the vacuum and open the valve up.

The allen head screw on the top in the photo below needs a fitting goes to the turbocharger waste gate signal, if I want to have more than 7psi boost I have to splice into the vacuum/boost line there, otherwise if I only want to run 7psi boost I would just leave the allen head bolt in there.

I have to have that mount fitting welded onto an aluminum tube, I don't know how to weld aluminum, , but my Miller Passport Plus welder is capable of welding aluminum, I just don't have the spool trigger/gun to weld aluminum, but the guy across the street does, but I think he went to eastern Washington to get more rocks.

[wayno]

I put the new adapter I made last night on the intake, and I used the intake one on the throttle body in front of the turbocharger, I didn't take any photos because it looks exactly the same, it runs good, waiting for the neighbor to come home so I can ask him to weld the aluminum.
I did re-do the e-brake system today, I think it will work great now, but didn't lower the truck on the ground to find out.
Here is the main cable mount from the e-brake lever to its new mount on the frame, I used a shorter cable I had.

Here is the cable extension I made going from the frame mount to the center bellcrank.

Here is the bellcrank I made and welded on to the frame, this is where I get my leverage, it goes thru the frame cross member to the e-bake cables in the rear.

Here is the center pull shaft coming from the bellcrank to the rear e-brake cables thru the cross member, the cables were to long, so I looped the cables and clamped them together real tight, they are not going to be slipping, I only needed to use one, but I used two clamps as a backup.

I don't want to drive it to much till I get the valve installed to fix the vacuum issue, when I pulled the hoses apart there was oil in them.

[wayno]

Well I decided to do another job that could likely get put off till another year went by, I had all these 720 tanks in my back yard, all the kingcab tanks I had left had the bottom caved in for one reason or another having nothing to do with me, so I cut the top off one of the kingcab tanks, then I cut the top off of one of the big tanks, well today I welded the top of the kingcab tank to the good bottom of the other tank, I believe I did a good job, I will only be able to tell when I fill it up with water on a dry day to tell for sure, I used gas on this job with solid wire, I didn't think flux-core would be a clean enough weld.



Now I don't have to worry about this anymore, another thing I don't have to do.

[wayno]

I found this in my driveway today, the neighbor welded it together for me, Thankyou Ray!!!!


Here it is sitting in position.

Unless it is raining, I will likely install it tomorrow and see how it goes.