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Post Number:#1  PostPosted: Mon Jul 21, 2014 11:22 pm 
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I finally have swapped the engine over I bought from Larry in the Volvo he sold me.
This is my 1980 720 diesel truck, it has seen many engines over the last 5 years, it is a special truck, as it has been modified, it is longer than stock.
Image
This is the engine in the truck.
Image
And this is what I did today, I fit an intercooler, it took me a few days to convince myself to move forward I was going to have to cut my core support, so today I started cutting.
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The lower sheet metal in position, at least what is left of it.
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Everything in position.
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Post Number:#2  PostPosted: Tue Jul 22, 2014 6:56 am 
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Nice !

How much boost, and did it "wake it up" ?

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Post Number:#3  PostPosted: Tue Jul 22, 2014 9:51 am 
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Nice job. I like your yellow headlamps.
BTW. you didn't see much rain lately :mrgreen:

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Post Number:#4  PostPosted: Tue Jul 22, 2014 10:18 pm 
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plenzen wrote:
Nice !

How much boost, and did it "wake it up" ?



I have only drove it twice since installing it in the truck, the first drive I didn't get over 45mph because the EGT was rising above 1000 degrees, that was the line I had drawn for that drive(no intercooler).
I put it back together without the intercooler after reading some literature about exhaust gas temperatures and realized that it is common to see 1200 degrees, even 1300 degrees briefly, so I took it for another drive, it accelerates quickly, but once it is on the freeway, it seems to fall on it's face when I give it the pedal, but I only drove it about 4 miles on level ground, and I was still fighting/driving the EGTs.
OK I am not sure that everything is set up correctly, and I was fighting to keep it below 1200 degrees also on that second drive, so I am working on getting the intercooler piped in, then I will take it on another drive, what I want to be able to do is floor it while on the hiway and simulate myself passing a car without it trying to go to 1400 degrees, because that is what it wants to do.
I have briefly hit 1400 degrees by accident 3 times so far, it happens so fast, I can only imagine how hot it is inside the combustion chamber, I am not going to drive it anymore till the intercooler is functioning, what's strange to me is that the coolant temp is actually low, so now I am going to put an EGT probe in my 521 diesel and see what the EGTs are without a turbo, as when I hit an extended hill and give it the pedal, my engine coolant temp creeps up quite a bit, I want to see what I have been doing to that engine over the years, it will give me some idea of the kind of abuse these engines can actually take, if it gets over 1400 degrees, then I am not sure what I will do, but I will not be a happy camper.
It sits at about 5psi on the hiway, I have not seen it hit 10psi yet, as I said, it might not be set up correctly yet, it's better to err on the side of to little than to much at this time.

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Post Number:#5  PostPosted: Mon Feb 29, 2016 1:13 am 
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OK, I have recently done something with this truck/engine, I changed it significantly as I could not drive it the way it was, on level ground if I tried going over 60mph the EGTs would climb to 1400 degrees on level ground, Larry the guy I bought this from drove around at 50-55mph and that just doesn't work for me, when I came to slight uphill grades the EGTs would also climb to 1400 degrees, at that point I would let off the pedal and limp the rest of the way up the hill, it was just getting to much fuel, the way it was just didn't work on the hiway, basically I believe with that turbo set up the way it was, the injection pump was either floored or in idle position, there was no in between.
I took it for a drive after I changed it, the hill that I could not get up without having to let off half way up because the EGTs went above 1400 degrees, well this time it only reached 1100 degrees floored all the way up, now I had traffic to contend with, so I had to let off, and we were only going 50mph, so I could not tell if I could gain speed or not, I just know that it didn't get hot this time.
I also believe that I am not getting the fuel I need now, I am used to seeing black smoke in the rear(rich) on hills from being deep into the pedal, this thing doesn't smoke at all now, and it doesn't have a lot of power on the hiway, but it accelerates good, it just doesn't have much left on the hiway, I find that if I want to keep going 70mph I have to put my foot in it, it just doesn't have anything left after 2500rpms, maybe this thing has a functioning governor like a forklift has instead of the 4000rpm governor the 720 truck has.
I have had it to 10psi boost now, but like I said, it's not getting enough fuel now, no fuel, no power.

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Post Number:#6  PostPosted: Mon Feb 29, 2016 6:25 am 
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What was it that you changed ? Did you wind the smoke screw out ?
I messed with mine as it was smoking too much all the time it seemed.
A 1/2 turn "out" was a LOT.
It quit smoking but would do as yours is doing and just laid down with any kind of a hill at all.
I wound it back in 1/8th of a turn and that solved the problem.
That screw is very sensitive and all you need do ( if that is what you changed ) is to wind it back in just a little bit at a time. Try a 1/16th each go.

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Post Number:#7  PostPosted: Mon Feb 29, 2016 8:00 pm 
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plenzen wrote:
What was it that you changed ? Did you wind the smoke screw out ?
I messed with mine as it was smoking too much all the time it seemed.
A 1/2 turn "out" was a LOT.
It quit smoking but would do as yours is doing and just laid down with any kind of a hill at all.
I wound it back in 1/8th of a turn and that solved the problem.
That screw is very sensitive and all you need do ( if that is what you changed ) is to wind it back in just a little bit at a time. Try a 1/16th each go.




I just know that the way it was doesn't work, at least it doesn't work for me, the EGTs get way to hot which I expect was from way to much fuel(rack in the floored position all the time), it worked fine around town where your foot wasn't into the pedal for long, but on the hiway it would get hot, it would reach 1400 degrees just entering the freeway getting up to speed.
Larry drove this engine like it was fragile, he drove 50/55mph on the freeway, I really don't see the point of having a turbo if one is going to drive like that, my Datsun 521 kingcab with an SD25 in it will go faster than this truck, granted the 521 doesn't weigh as much, but this thing will not even go 70mph on level ground right now, before it would get really hot trying even with an inner-cooler(EGTs), now it will go faster than before, but it doesn't get hot, now it just feels like it's not getting enough fuel, it doesn't smoke at all, even when floored it doesn't smoke.
Short version, he had the throttle body after the turbo(air filter/turbo/ inner-cooler/throttle body), I now have it before the turbo(air filter/throttle body/turbo), and it runs cooler without the inner-cooler now, but I have another issue now, I have almost 10psi vacuum when I let off the pedal, I need to address this issue, as I am sucking oil thru the turbo seal into the intake manifold, I have bought a blow off valve of sorts, it is supposed to open when it senses a vacuum, I am going to install this valve between the turbo and intake manifold, when I let off the pedal it will open and let air in removing the vacuum issue, but there is a possibility that it might have an effect on the IP rack, but since the turbo is so close to the throttle body I believe that it will still draw enough air thru the venturi to pull the rack to the idle position as the butterfly is not open.
I still don't know if this is going to work, and I am also of the opinion that the IP has a forklift type governor setting, as when I get close to 2500rpms I hit what seems to be a wall, this truck has 330 gears in the rear end, so I can go even with that low governor setting, but I need fuel and no oil in the system, I am waiting for the vacuum sensing valve mount to be welded to a tube, as I do not have the equipment to weld aluminum or stainless steel.
The valve has 3 fittings, the two of them go to the intake manifold to sense vacuum, the other(optional) goes to the turbo to sense boost, it is set for 7psi boost, I can live with that right now, if I want to have more than 7psi boost, then I have to pipe that 3rd fitting to the turbo, it has the two other large openings, one going to the intake system, the other is open to the air, the guy said if this works and it is sucking in air, I will need to add a filter to that opening.
I was having a lot of issues with the way Larry set it up, the rack is so sensitive that I could not hold a steady speed, that issue is gone now, and so is the EGT heat issue so far, 1100 degrees is the highest I have seen so far going up a hill.
My friend that went to school for diesel engines told me to start unscrewing that smoke /smog screw, he suggested just removing it, I am just going to baby step it, a half or full turn at a time, so that I don't get lost, but first I need to fix the vacuum issue, I had one of the hoses suck itself flat and stay flat, the engine tried running away, but it could not get air, so I put it in gear and killed it.

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Post Number:#8  PostPosted: Thu Mar 03, 2016 12:28 am 
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Well the vacuum sensing valve doesn't work, at least not the way the guy said it would, I then called another place, told them what I was trying to do and the part I bought, that guy asked what engine I had, he then said it would not work on a diesel.
I am trying another way to make it work by adding a spring to help it open, I think it worked partially, but it was dark and raining, so I need to wait till tomorrow and take it apart again and add a washer or 2 to make the spring a little stiffer, right now I am still trying to use the intake manifold vacuum to operate the valve, but I had a thought.

So I wonder how much vacuum the venturi creates when the engine is revving and one lets off the pedal, would it be enough to operate the Vacuum sensing valve bought along with still operating the injection pump rack properly.
I have to take my modification apart to add the washer/washers, so I am thinking about piping the valve into the venturi line to see if that will open the valve under deceleration, has anyone on here tried what I am trying to do?
The valve is made by "Synapse Engineering", the part is labeled "Vibrant Performance", part #16002A, has anyone on here tried turbocharging the inline injection pump the way I am doing it successfully?
I have seen/read about a lot of guys on here that attempted to turbocharge the inline pump, they get them running and have issues, then I never hear about it again, Larry had issues that he didn't really inform me about.

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Post Number:#9  PostPosted: Thu Mar 03, 2016 4:49 pm 
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I'm watching your work with interest. I'm not so familiar with the advance curves for these Nissan engines, but the Massey Ferguson farm tractors I used to work on had different advance curves for the turbo equipped engines as opposed to the natural aspired engines. Typically they advanced more with the boost... The engines themselves were well suited for boost as they were direct (into the top of the piston pocket) injection. Indirect injection as found in the SD22 et al will be temperamental to deal with since the path and behavior of the combustion gases is more complex with the pre-cup...

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Post Number:#10  PostPosted: Thu Mar 03, 2016 8:31 pm 
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I spent the day working this out the best I could, that thought I had yesterday is the way I went, I connected the valve to the venturi line that controls the rack, with my modification I made to the valve, it works pretty good, I have 1 to 2 psi vacuum when I let off the pedal, that is about the best I can do with the spring I used to modify the blow off valve, it blows off at about 7/8psi boost, I can hear it, but if I adjust it to blow off at 10psi, then I end up with 5psi vacuum when I let off the pedal, that is not acceptable to me, so I will live with 7/8psi boost.
I also was having this issue with no power on the freeway, the engine doesn't smoke a bit, so I looked at the smoke/smog screw, after getting a light out so I could see(getting old sucks), I realized that it was out as far as it would go(rich), so I completely removed the smog/smoke screw, it still doesn't smoke, but there was a noticeable increase in power on the freeway.
I now have another issue, I believe this injection pump is from a forklift or something like that, maybe Larry had the governor set at around 2600rpms, as I hit a wall there, I really have to put my foot into the pedal to get it past 2500rpms, I am only using the first half of the pedal normally, so it seems strange to half to use the other half just to get 300 more rpms, I sent am email to Larry asking about that and what modifications he made to the pump, I am hoping he responds.
To tell the truth, if I took all the shit I have in the back of that truck out, it would weigh a lot less and likely have more get up and go, but my Datsun 521 kingcab with an SD25 will easily out run this truck right now without a turbocharger.
OK, now for the photos, here is the air filter to the throttle body.
Image
The throttle body to the turbocharger compressor
Image
Image
Turbocharger compressor to the intake with the blow off valve in the middle
Image
Now everyone must understand that this blow off valve has another function, it opens when it sees vacuum, but I could not pipe in enough vacuum from either the intake piping or the venturi that controls the rack to make it work properly, so I had to modify it, so I made this, it is adjustable.
Image
Image
The waste gate is adjusted tightly closed, it cannot open anymore.
Image
I need a smaller battery
Image
I put a remote oil filter in when I tried to use another injection pump, I could not get it to run properly, so I put it all back the way it was except I got lazy and didn't remove the remote oil filter setup.
The remote oil filter
Image
The injection pump that I tried to use 6 months back that was a fail, it ran but had no power at all, I might of had it timed wrong, sure wish it would have worked.
Image
Now I am trying to get everything working in the cab, I successfully got the heater blower working on high only, now I need to see why the radio will not work/turn on.

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Post Number:#11  PostPosted: Fri Mar 04, 2016 7:05 am 
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Just a thought here.
On my pump ( VE style) the smoke screw is turned IN for more fuel and OUT for less fuel.
I would have thought it to be the same on the inline pump but I could be wrong. ( it's happened before, I seen it ) .

With this thing laying down and losing power at 2500 RPM it sounds to me like its running out of fuel.
As previously stated, the adjustments to that smoke screw are very sensitive.
If you have removed it all together it sounds like its running on the IDLE ( minimum ) amount of fuel only and once a load is presented to it it just lays down.

Just for grins and giggles put the screw back in and wind it in a bunch.
Watch for black smoke and your EGT's to start climbing. Then it should be fine adjustments to get the sweet spot.

Or,,,,,,,,,,,,,,,,,,,,,,,,,, it wont make any difference.

Keep us posted

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1987 D21-J SD25 KC
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Post Number:#12  PostPosted: Fri Mar 04, 2016 7:33 pm 
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After I took the smoke/smog screw out I had more power, the lever was able to move more towards the start position which is richer.
I do know that my other SD25 diesel engine acts like a different animal, it will keep gaining speed till it gets to 3000rpms, that is where I draw the line, I have seen 3200rpms in 5th gear, but not in any other gear.
2900rpms is about 80mph to me in the 521 kingcab diesel, I have 3.50 gears in the rear on that one, his one I have 3.30 gears in the rear, it starts out great, lots of torque, but it starts to fall on it's face in every gear after 2000rpms, Larry set this engine up for low rpm operation, probably because if one went any faster it would overheat, meaning the EGTs would get up around 1400 degrees or more, this engine really fell on its face the way it was, it didn't want to go over 55mph, three quarters of the pedal was worthless, it did nothing except get hotter and hotter(EGTs).
Now it drives fairly nice except for the fact that I have to shift at about 2000 to 2200rpms, you should feel it when I put it in 5th gear and it is at 1500rpms, the truck accelerates but it also shakes from the torque, I can almost feel every time a cylinder hits, it shakes the whole truck, my other engine doesn't have this kind of torque, but it will go way faster than this turbocharged engine, but the truck weighs less also.
I emailed Larry, but have not received a response yet, I think it is an industrial injection pump made for a forklift or something similar, when he sold it to me he said I needed to drive it at low rpms, he didn't like how I test drove it.
I am thinking it falls on its face because of the governor, I drove diesel forklifts for years with governors and they fell on there face when they got to the set RPM, but we were only driving 30mph max in the yard, so the gearing was set for hauling weight, not going fast.
To get it past 2500rpms, I have to floor it, it does accelerate, just slower, like something is holding it back.
I also have a VE type injection pump on a SD22 I have, I also have a fresh rebuilt VE type pump, both were made for the SD22 size engine, will they work on a SD25 engine or can it be set to run a SD25 engine?

plenzen wrote:
Just a thought here.
On my pump ( VE style) the smoke screw is turned IN for more fuel and OUT for less fuel.
I would have thought it to be the same on the inline pump but I could be wrong. ( it's happened before, I seen it ) .

With this thing laying down and losing power at 2500 RPM it sounds to me like its running out of fuel.
As previously stated, the adjustments to that smoke screw are very sensitive.
If you have removed it all together it sounds like its running on the IDLE ( minimum ) amount of fuel only and once a load is presented to it it just lays down.

Just for grins and giggles put the screw back in and wind it in a bunch.
Watch for black smoke and your EGT's to start climbing. Then it should be fine adjustments to get the sweet spot.

Or,,,,,,,,,,,,,,,,,,,,,,,,,, it wont make any difference.

Keep us posted

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Post Number:#13  PostPosted: Fri Mar 04, 2016 7:55 pm 
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Have you considered advancing the timing as well?

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Post Number:#14  PostPosted: Sat Mar 05, 2016 7:01 am 
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How fast will it rev in neutral (no load) if it goes up to 3500+ it's not the governor.
You can do what Ranger says too and advance it a bit. Not too much.

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Post Number:#15  PostPosted: Sat Mar 05, 2016 8:13 pm 
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plenzen wrote:
How fast will it rev in neutral (no load) if it goes up to 3500+ it's not the governor.
You can do what Ranger says too and advance it a bit. Not too much.


OK, I have not messed with the timing of the pump, when I removed this injection pump to try using that other injection pump I took a measurement, when I put it back I mounted it in exactly the same place, nothing changed, it started and ran exactly the same.
Yes I did rev it and I reached over 3000rpms, but it didn't rev like the other engine, I also messed with the governor today, it didn't seem to make much of a difference, when I first turned it out I figured out that the threaded rod was almost backed out all the way, it would not come out any more, so I drove it and it seemed the same, so I went the other way and turned it in likely 4 turns farther than it was, didn't seem to change anything either.
So tell me this, standing in front of the truck looking at the engine, would advancing the pump require moving the top of the pump clockwise towards the head, or counter clockwise away from the head?
I know that the way I measure isn't going to do you guys any good, but my Datsun 521 injection pump on a SD25 is tilted away from the head/engine two and three eights inches, while this injection pump on the 720 is tilted away from the head/engine two and one eighth inches measured from the same spot, there is a quarter inch difference from the same spot.
That is a big difference, I know the 521 engine is way better power wise on the hiway, it has an even acceleration all the way to 3000rpms, while this one has good torque from 1200rpms to about 2200rpms, then it seems to fall on its face.
Also my Datsun 521 SD25 engine has a different sound, it almost sounds like a knock for lack of a better description, but it is not a rod knock or anything like that.
I suspect that this Datsun 521 engine has less than 50,000 miles on it, it was a crate engine bought from the Nissan dealer with another one at the same time, it was put in a 620 with a home made turbocharger setup, the other went into a 521, the guy died of old age and his kids inherited the truck, it was a rust bucket, so the kid pulled the engine out and put it in the mud on the side of the house and scrapped the 620, it sat in the mud for years until I decided to talk to this kid about his 620 4X4, he told me about it, I listened and then mentioned I was into Datsun diesels, he said he had a diesel engine for sale, lucky me that it was an SD25, I bought it for $350.00 with the transmission and everything else he hauled out of the shed and threw in my truck.
The other engine in the Datsun 521 sat in a pole building up near Mt St Helens, one year they got 8 feet of snow on the pole building and it collapsed onto all the vehicles in the building, I heard it was being rebuilt(the truck), as far as I know the engine was fine.
So after seeing your suggestion on timing the pump, I now suspect that advancing it is tilting the top of the injection pump away from the head since that is how my other one is, I might move it an eighth of an inch and see what happens, I can always put it back, I have tried a few more radical things than that on this engine.

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