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My 1980 datsun 720 diesel dually


wayno

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I don't think I ever started a thread for my 1980 720 diesel, I never really thought to much about the truck, other than using it to tow datsuns home. :lol:

I have had big plans for the truck for a long time, I bought and shipped a diesel engine from Australia a year and a half ago or more, with plans to use the VE type injection pump on one of my diesels, the reason I bought the engine was to turbocharge the engine, as the US model diesels had inline injection pumps which are difficult to turbocharge, I have yet to see/hear of a working/driving turbocharged SD22 engine that worked with increased power, that actually didn't have any issues.

I have had this parts engine in the shed for a long time, and I decided that it was time to quit thinking about it, and actually do it, so I got off my ass this morning and started the transformation.

I got it out of the shed, and took some photos of how I have had it stored, I have actually had a SD25 diesel engine running and warmed up on this contraption I made, it had a radiator on the metal uprights.

 

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I totally bent the piece of rebar trying to get the harmonic balancer off.

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This is what I started with this morning.

 

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I will continue in the next post.

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So I started tearing down the front of the parts engine, and found no surprizes except that this injection pump doesn't have an advance type gear on it like the US models do.

US model type below.

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I pulled the front apart on the running diesel and was amazed how much crap there was compared to the Australian version, but I figured out how to make the fuel piping work, I removed all the front gears and exchanged them, cleaned all the doner parts and got it to the point where I cound actually try to start it, funny thing here, I have been trying to figure out how it pulled the fuel to the injection pump, and I forgot to put in the electric fuel pump by the tank, and push the fuel up to the engine, anyway I connected my remote starter switch, put power to the injection pump to open the fuel silenoid, turned the ignition on to warm up the glow plugs, and started turning it over, it actually started, and I am not sure why now, as I forgot the fuel pump, but all I can say is, "IT'S ALIVE", I shut it down after about a minute and then put the engine back together, power steering pump, ect.

I did forget something though, I forgot the 4 oilpan bolts, it puked oil everywhere underneath there, diesel oil turns everything black, what pain that turned into, I had to loosen all of them to get the holes to line up in the front four bolts, oh well, "IT'S ALIVE", I warmed it up till it cycled and the radiator was warmed up, and it kept on running, it must have a pump inside it.

This is what it looked like when I put all the tools away.

 

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I also took the carb looking thing apart and removed the butterfly valve and put it back together, as I wanted to use the stock air filter system for now, since the injection pump is controlled by a metering valve now, and not vacuum, I had to remove that valve, when I first started it, the intake was just a hole open to the air.

All I have to do now is wire the injection pump silenoid to the ignition, go to the wrecking yard tomarrow and find a throddle cable, and I should be able to take it for a drive.

 

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I went to the wrecking yard today and grabbed a napZ throddle cable, brought it home, and it fit perfect, which is lucky, as they didn't have napZ engines when this injection pump was built, and where the engine came from, it was RHD, so it had a short throddle cable.

I also had to put a relay in the truck to start the engine, I could not find any wires in the engine compartment that had power when the engine was being turned over except for the starter wire, I got this bright idea that I could grab power from two differant places, one for running, and then grab off the starter wire for turning it over, well when I turned on the ignition, the power went backwards to the starter exciter, the starter would turn over, I guess I hadn't given it enough thought, so I wired a relay in that kept the run power separate from the start power, and it works great now.

It's still gutless, but the first step has been taken towards the last step.

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I made an offer on a VE type diesel injection pump on ebay this evening, it is the same type as I just installed on my truck, it has been totally rebuilt about 6 months ago, weird thing is, it accepted my offer fairly quick.

I was actually embarrassed a little with the offer, as the price had already been dropped, and I sent a message saying what could it hurt to make an offer.

So if the 720 diesel truck becomes a viable turbo diesel, then maybe I will make the 69 KC project into a 1969 datsun 521KC turbo diesel, I like the sound of that.

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I found a sd25 with ve pump with a transmision and all the electronics the perfect candidate for a turbo conversion, but I dont have the time for that right now.

 

You should buy it, they are very rare around here, I had to buy and ship an engine from Austrailia to get what I needed, but now that I have it, I can see how to do it with american hardware, except for the actual pump and injection lines.

Is it a good deal?

Is it an electronic(brain/ECU type) engine/pump, or a mechanical like the engine you and I have now?

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Ya I think I will get it it is good deal. Even if it sits in the corner of my garage at least I will have a spare if I ever need it.D21s in Canada had a diesel option that came with sd25 so there is few around here. They are all mechanical like ours with the pump control and glow plug control the only diference is the sd 25 has a fast glow type glow plugg set up

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Ya I think I will get it it is good deal. Even if it sits in the corner of my garage at least I will have a spare if I ever need it.D21s in Canada had a diesel option that came with sd25 so there is few around here. They are all mechanical like ours with the pump control and glow plug control the only diference is the sd 25 has a fast glow type glow plugg set up

 

I'm not sure what you mean by pump control, as my VE type pump doesn't use the DPC module at all, I just have a wire going to the ign.

I have not tried removing it yet(DPC module), to see if it causes any issues with the glow plug timer, but the pump controller isn't on the engine anymore, nor is it plugged in either, that was an issue for me, I couldn't find a hot wire in the engine compartment that was hot while turning the engine over except the starter wire itself, and I couldn't tie into that one without a relay.

I did find a hot wire in the pump control harness with the key in the start position, but when you added power to it from another source, it kept turning itself off resulting in no power to the pump while turning it over.

I spent a couple hours trying to figure it out, and finaly used a relay directly off the battery and used the starter exciter wire to activate the relay while turning the engine over.

I found my best used SD25 engine on the side of some guys house in the mud, with bent injection lines, and mud in the open fuel lines, it sat for years on the side of that guys house, it started on the second try on my garage floor.

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You can remove the dpc modual it will have no effect on your glow plug control. You should have been able to find a hot on start coming out of the 7 pin on dpc modual not sure witch one but it sounds like you got figured out with the relay.

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You can remove the dpc modual it will have no effect on your glow plug control. You should have been able to find a hot on start coming out of the 7 pin on dpc modual not sure witch one but it sounds like you got figured out with the relay.

 

 

I will try to explain this, I found a hot(key in start position) on the engine/injection pump controller plug, and I am using the the window washer plug for the run power(key in on position), as it is a plug I am not using, but when I connect them two wires together, I was assuming that when in the start position, the injection pump hot would work, and in the run position the washer plug would work, but it was not to be, when the two wires are connected together, the injection pump hot never becomes hot, but when the wires are separated, it does become hot in the start position.

In the start position, other than that injection pump controller hot, there are no other hot wires except the actual starter exciter wire that go cold in the run position, and I can't use the starter wire without a relay, as when I connect it to the other wire(windshield washer plug), and turn on the ignition, the starter starts turning over because that wire(washer motor plug) is hot in the on position, I guess I needed to give that option more thought before I tried it. :rofl:

The relay isolates the two power sources, and it is was only thing I could think of at the time, and since it worked, I have not thought about trying it any other way.

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  • 4 weeks later...

So with a standard US market SD22 inline type pump, why couldn't you use an actuator like the altitude compensator or a wastegate actuator connected to the rich/lean lever so that it just pushes forward toward rich as you add boost? Rather than trying to get the vacuum lines to the throttle body to run the fuel mixture...

 

I removed all of the electronic devices from the engine and will hook up a throttle cables/ hood popper cables for startup enrichment and lean/shutoff.

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So with a standard US market SD22 inline type pump, why couldn't you use an actuator like the altitude compensator or a wastegate actuator connected to the rich/lean lever so that it just pushes forward toward rich as you add boost? Rather than trying to get the vacuum lines to the throttle body to run the fuel mixture...

 

I removed all of the electronic devices from the engine and will hook up a throttle cables/ hood popper cables for startup enrichment and lean/shutoff.

 

In my opinion you should have the electronic devices to turn the engine off and on, I think of it as a safety thing mostly.

I have thought about a few ways to do what you are trying to do, fact is the engine I have in my 521KC diesel was a turbocharged engine, and it did work/run the way it was set up, don't know if it had anymore power, but it seemed to run fine.

Here are some photos of the setup as it was when I got it, as you can see, the normal exhaust outlet was welded closed, and a new outlet was cut right into the side of the manifold.

 

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I did run this engine on my test stand, the two uprights in the front hold the radiator.

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Now that you have seen the original setup, i'll tell you why I don't like it.

When the engine rpms are up to say 2800rpms, and you let off the throddle, that carb looking device in front of the turbo that was connected to the intake manifold has a butterfly that closes, when it closes, the air is cut off, that creates vacuum that pulls the injection pump back to idle, which is how it is supposed to work, but when the turbo is spun up, and the air is cut off, then it is cavitating in there, trying to suck air from anywhere it can find it, if it can't find air, eventually it will find something else, like pulling oil threw the turbo shaft seals, if there was a major seal failure, you would be pumping oil into the engine, I can only imagine what 22 to 1 CR can turn into with oil going in there, maybe a vapor type lock that would just start breaking rods/crank/pistons, frankly I don't want to be anywhere near it when that happens.

The way a turbo diesel is supposed to work, is the intake is a hole open to the air that the turbo connects to with a air filter on the intake side of the turbo, and metering the fuel determines if the engine is under power or not, there is no blockage of air at the turbo intake.

Here are some guys that have went this route back in 2006, and I am not sure how it turned out, because they had issues, and they never seemed to have an answer to the issues except to conclude that maybe a VE type injection pump was the way to go, and then the thread just faded away without anymore progress other than talking about some electronic type of throddle control on the pedal itself.

http://nissandiesel.dyndns.org/viewtopic.php?p=3659&sid=8d04d514b441605ec144b8f19bf75500#3659

I had an idea a while back that I thought might work, but I never followed threw, because I shipped a diesel engine from australia with a VE type injection pump, that is now in this diesel truck(the injection pump only), but I have so many projects that I have not got around to piping a turbo in yet, recently I thought about just using the exhaust/turbo manifold I have without the throddlebody on it just to see if there is any more power to be had with that setup.

Anyway, the idea I mentioned above was to put a tee on the vacuum hose right at the top of the injection pump that controls the throddle, have one of the tee outlets(rear pointed end) go to the alternator vacuum pump that controls the power brakes for a vacuum sourse, the other outlet pointing up I would connect a RC airplane carb, the idea here is to control the vacuum right at the pump, as when the carb is open, vacuum is lost, that adds more fuel, close it and it creates vacuum and pulls the pump back to idle.

I have not thought about this for a while now, so I didn't bother working out the bugs, like if you step on the brakes, will it effect the throddle, as that would be very bad.

If your good at fabricating things, you might be able to figure out how to control the throddle mechanicly by modifying the back of the injection pump somehow, or even a better way would be to buy an injection pump like this that is already set up this way, I bought this a few year ago on ebay, before I found the VE type injection pump.

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See how it is controlled by a lever, but this is an injection pump that is meant for a boat, or a big water pump, or a generator, something with a fixed rpm, but I was going to try using it, I had the govennor ajusted for an auto application.

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So if you put the throttle body in front of the turbo, the vacuum signals to the injection pump should be the same as running N/A, right? Throttle % vacuum behind the throttle plate, and almost atmospheric in front of the throttle body(the reference vacuum).

 

 

if the throttle reference is under boost pressure, and the reference is pre-turbo, it could possibly control fuel mixture automatically but would be putting a lot of stress on the governor diaphragm...

*** Just thought about this... running the engine like this would probably send the engine into a frenzy when it hits boost, pegging it wide open until it loses a connecting rod. ***

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I beleave that having the vacuum line on the throddle body(lets call it that) in front of the turbo will work, or maybe I should say it will run, and the breather line also has to be in front of the turbo also, it worked properly on the engine test run I did in my garage on that stand with the wheels and radiator.

As I said in my previous posts, others have done it by putting the throddle body in front of the turbo, like the owner of my SD25 engine before me(photos in previous post), but I never drove it with the turbo to this day to find out if it was set up correctly and actually had more power than stock, but i have been tempted recently to try it for grins, although since I have a VE type injection pump, I could skip the throddle body, I just am not impressed with the exhaust manifold.

One must also remember about the history of the engine I have, I found it on the side of some guys house in the mud, there is a reason it was in the mud, quite likely it could have been another turbo conversion failure.

Others have tried on Ratsun also, and they have had issues.

Every thread I have ever read has faded away without satisfactory results.

There is something else that one needs to keep in mind, the SD22 engine has been called bullit proof, there is a reason for this reputation, the engine isn't strong enough to tear itself apart, as long as one keeps oil and antifreeze in it, it will keep going like the energizer bunny for a very long time.

I had my 521KC set up sorta like yours at first,

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If I were you, I would do a lot of research into finding the correct turbo size, and give it a try, I posted the photos of how the previous owner did it to my engine, which has not hurt my engine, as it is the best engine I have running ATM, and it is naturally aspirated, and will likely stay that way till I have it figured out completely with another guinea pig engine.

I bought a 1600cc turbo for my SD22 2200cc engine, as that is what I beleave it needs to be for this size diesel engine, all the others that have tried to turbocharge there SD22 have used a way bigger turbo and had complaints about no boost, along with the other issues.

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So to get around the cavitation issue, run a blow off valve setup for recirculation behind the throttle plate but in front of the turbo's inlet.

Reference photos from my sd22 diesel service manual:

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The arrow pointing up is the vacuum line to the pre-throttle plate vacuum line.

The arrow pointing to the right is the push rod that is connected to the below pictured control rack/ plunger mechanism X4. movement to the right of the push rod(toward the front of the engine) is toward rich.

I do not think there is any need to mess with any of the speed limiting mechanism as it cuts fuel off around 4000 RPMs. Since the speed limiting mechanism forces the engine to run lean at high RPMs, I would think it is a bad idea to run the engine onto the limiter at boost as this will run the engine lean(won't detonate like a gas motor, just won't be optimal for power)

 

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Im still trying to think how would transitional throttle work out? If you were at light throttle and just starting to build boost, the vacuum signals would tell the engine to run lean because of the mostly closed throttle plate and turbo creating vacuum as it spools., which is where the enrichment actuator attached to the rich/lean lever would push the control rack toward rich. The key would be to figure out how much rotation needs to be put into the control lever for a certain amount of boost/enrichent for the optimal mixture. I guess with a diesel it's fairly easy because you can start overly rich and dial it back until the smoke goes away.

 

 

I'm just thinking out loud here... not really directed at anybody...

I wonder if you could use a boost reference and use it to somehow close off the throttle body vacuum line... If a boost actuator operated a ball type valve that was inline with the throttle body vacuum signal. That would leave vacuum on the pre throttle side which would allow the governor spring to push the control rack toward rich as you close off the throttle plate vacuum signal. This way you could simulate boost going to the governor without actually putting pressure inside of the diaphragm/regulator.

This may help with transitioning into boost, but probably won't move the control lever enough for total fuel enrichment. I don't think the diaphragm spring is very strong to push against the control rack too much.

 

I do not think I would ever try to go past 7psi boost on the street for reliability reasons, and probably only a few psi for offroading to keep engine temps down. A 3 main engine/crankshaft shouldn't be expected to reliably double the power like you can do with a 5 main L series block.

Not looking for all out power, just enough to be safe in traffic with huge tires.

 

Im running Delo 400 15w-40 crankcase oil because that is what I have heard all the big rig guys swear by... Any other oils that people like to run in their diesels?

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The arrow pointing up is not the vacuum line, it is the breather line, the front outlet(line) is the vacuum line, in this photo it shows a line going to a small throddle body picture.

 

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Thankyou for this photo, it is always interesting to see all the parts.

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The one that counts is the one that goes to the throddle body, the other one has a line because it goes to the air filter also, as to keep dirt out of the injection pump.

If you disconnect the breather line nothing happens, if you disconnect the throddle body line, the engine goes crazy, it gets a lot of fuel, but since the butterfly isn't open in the throddle body, it can't get no/enough air.

I have been messing with the concept of what your trying to do for several years now, and so have several others, there have always been issues, but I will say this, except for the possiblity of oil being pulled threw the turbo shaft seals, most of the issues they have been having recently have been the incorrect size turbo charger, the earlier issues have been routing the vacuum lines incorrectly, as they have had no one else to get information from, as they were the only ones doing it.

I have a injection pump partially disassembled so I can see how it works, if the side plate is removed, you can see the plunger assembly, when one is moved, they all move the same, I was debating if an arm could be connected to one, and have all of them move when you step on the gas, but I also noticed that the external arm does the same thing, but it would be a complicated mechinism to work the throddle and be able to shut it off also, if it is possible at all.

For now, if I were you, I would get the proper sized turbo for a diesel engine of this size, which is not a gasser turbo made for a 2200cc engine, a 2200cc gasser turbo is to big, and set it up like the photos I posted, as that engine did run correctly, I just never had it in a truck.

Here is the latest attempt I have seen, lots of information, don't know how this one turned out either, he started with to big of a turbo charger.

http://community.rat...__fromsearch__1

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  • 3 months later...

Hey Wayno,

 

Sorry it's been a while but I did come close to completing the 720 SD22 turbo. I purchased the GT25 turbo designed for higher boost with lower rpm's and got an amazing 14psi out of that jewel. It helped the power alot but my greedy self got to far involved in modifing the IP. So I gutted the throttle body and made a mechanical lever on the IP. It as you would imagine did work but had idling issues or reving up issues. I could never seem to get it to idle. I assume it had something to do with the factory govenor. So I sold it not running because I jacked with the IP enough that I couln't get it to run anymore...sad outcome but I just purchased a 1985 kingcab 720 4x4 with a SD25 that is in great shape. It has the in-line IP that has the TB as well. I hope to get a VE pump for it later from Australia if I can find one so I can turbo up...

 

 

Hope to hear from you...

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Hey Wayno,

 

Sorry it's been a while but I did come close to completing the 720 SD22 turbo. I purchased the GT25 turbo designed for higher boost with lower rpm's and got an amazing 14psi out of that jewel. It helped the power alot but my greedy self got to far involved in modifing the IP. So I gutted the throttle body and made a mechanical lever on the IP. It as you would imagine did work but had idling issues or reving up issues. I could never seem to get it to idle. I assume it had something to do with the factory govenor. So I sold it not running because I jacked with the IP enough that I couln't get it to run anymore...sad outcome but I just purchased a 1985 kingcab 720 4x4 with a SD25 that is in great shape. It has the in-line IP that has the TB as well. I hope to get a VE pump for it later from Australia if I can find one so I can turbo up...

 

 

Hope to hear from you...

 

 

In april of this year I purchaced another VE type injection pump on ebay, I referenced it earlier in this thread, I will have to have injection lines made for it, but otherwise it should work fine.

I searched nissan diesel injection pump, I bought it from this ebay seller "79pace", it was rebuilt by that sellers company, I paid $500.00 shipped, and I still will have to have it governed for an auto application, as it is a forklift injection pump i beleave.

This guy is from your neck of the woods(east coast), you might be able to find him by searching his ebay user name.

One of the issues with the inline injection pump on US autos is the control lever, as it is how the engine is turned off, so one has to figure out how to control the fuel and still have a way to shut the engine down electronicly.

Even on this new injection pump I bought a few years ago, the lever has to be pulled backwards to shut the engine down, so how does one connect a throddle cable to this pump to control it with the pedal, yet shut it down when needed, I thought about using the stock engine controller, while in the run position it would keep the lever from being reversed far enough to shut it down, like when you let off the pedal, but when the key was turned off, it would pull the lever all the way back, and the result would be the pedal being pinned/held up, and only when you hit the starter would the pedal be released to work properly again.

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I talk about this type of stuff because it helps me remember what I have thought about trying, and gives others ideas also.

I think that unless you have the money to buy proper injection pumps for turbocharging, either you will need to put the throddle body in front of the turbocharger with all the air lines hooked up in the stock configuration and live with the possibility of oil getting sucked threw the turbo seals some day, or figure out how to control the vacuum to the injection pump not using the throddle body.

BTW firemedic, I have a SD25 in my 521KC, I can go 80mph all day long except for the steeper hills like the grapevine in southern ca, which I have gotten down to 55-60mph while floored.

I am not in a giant hurry to do anything as it(521 diesel) goes down the freeway fine, and that was my biggest bitch about the other diesel engines I have, I am/was almost floored trying to go 70mph getting 28mpg or less, now I can go 80mph and get the same mileage or better, but I am not floored, and the engine isn't running hot because I am floored/almost floored.

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