Help with a SD22 in Vietnam

SD diesels were widely available in the US in the 1981-86 Datsun/Nissan 720 pickups, and in Canada through '87 in the D21 pickup.

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klmlbt6
Posts: 6
Joined: 3 years ago

Help with a SD22 in Vietnam

#1

Post by klmlbt6 » 3 years ago

Hey everyone, and thanks in advance for the assistance. I was a mechanic for years in the US, but never did too much with diesels. I have a friend here with a SD22 in a late 70's International Scout. The laws here will not allow us to swap the engine, and the shop he had been taking it to has probably done more harm than good to it. Recently, it had become incredibly sluggish and would barely rev at all. I noticed the shop had made a couple washers out of plastic for the steel injector line, so I replaced those with the correct brass washers, and I noticed that when the engine was revved, it seemed to pull back on the governor lever, so I loosened that, and it seemed to help with the power quite a bit.

Now, things I know are wrong with it: 1) Broken transmission mount 2) Owner has previously broken a couple clutches, so I am thinking the crank bushing is shot, if it even has one, or there is an alignment or flywheel issue. The transmission does seem to be attached with an adapter of some kind. 3) When I reprimed the fuel system, the lift pump leaked pretty badly out the top every time I pushed the plunger down. 4) The key does not shut the engine down. We have to pull the lever on the governor to do that. 5) The front vacuum line on the governor was melted through and doesn't go to anything. From what I can find it was supposed to go to the air intake system? There may be more but that is all I can remember.

I have taken some photos and would appreciate any feedback on what you see. As this is my first time with this particular engine type, I am not sure if things look right or not. Also, I took pictures of the transmission markings, but could not identify the type of transmission by them, so help with that would be greatly appreciated as well.

And guys, just know you are helping with a good cause. This is the delivery vehicle for a local microbrewery here. Getting it running well will help many people enjoy good quality, tastey beer in a timely manner. :D

*** Getting the message "Temporary folder could not be found. Please check your PHP installation" when I try to upload the photos, so I will try to load them after this post.

Switched browsers and used a VPN. Still can't upload photos. Any ideas?

waynosworld
Posts: 505
Joined: 7 years ago
Location: Vancouver Washington USA

Re: Help with a SD22 in Vietnam

#2

Post by waynosworld » 3 years ago

I am assuming that you have an inline injection pump since you have a primer on the injection pump, so the front vacuum line goes to the air filter housing in front of the throttle body carb looking thing on the intake which basically is open to the air, the back vacuum line goes to the throttle body itself, this controls the throttle, this vacuum line needs to be in serviceable shape, otherwise the injection pump rack will not move properly, and in general the throttle response will not act normal.
I suspect that your injection pump controller is not working properly, it is the electronic devise below the injection pump that has an arm/rod connected to the injection pump arm, what you may call the governor that you pull back on to shut down the engine.
Your photos didn't appear on the post you made.
Here is the injection pump controller with the arm connected to the injection pump.
Image
You can see how it connects to the arm in this photo.
Image
Image
I don'y really know how to help you with specifics without actually having photos of your setup to look at.
I know the voices are not real,
but they have some really good ideas.

klmlbt6
Posts: 6
Joined: 3 years ago

Re: Help with a SD22 in Vietnam

#3

Post by klmlbt6 » 3 years ago

Seems I was finally able to upload pictures, so hopefully they will post and you will be able to see what I am working on. Thanks so much for the reply. I'll check on that IP controller. Is there a way to diagnose if it is working or not?
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waynosworld
Posts: 505
Joined: 7 years ago
Location: Vancouver Washington USA

Re: Help with a SD22 in Vietnam

#4

Post by waynosworld » 3 years ago

It doesn't look like you have an IP controller, as far as I know the Scout came in the USA with a choke type cable to start and shut down the engine, and that is what you appear to have.
You also have a strange fuel filter system to me, so I cannot comment on that, it seems to be very basic.
Check all your fuel filters starting at the tank, it should have a pre-filter somewhere, you also likely need a new primer if the one you have is leaking.
As for the governor arm moving, that is actually the injection pump rack moving as per throttle body vacuum, that arm needs to be able to move forwards to allow a richer mixture as you found out, the way you have it is basically a fixed position depending on where you have the choke cable positioned, there are 3 positions for that arm, start, run, and off, all the way in would be the start position(rich) for the choke cable which would have the governor arm as far forward as it will move on the injection pump, all the way pulled out(arm as far back as it will move) would be the engine shut down(fuel cut off), and in the middle between the start and off positions would be the run position, normally the arm moves forward and backward a little depending on how much vacuum is being created by the throttle body, depending on where the throttle pedal is, no pedal has the most vacuum and that pulls the rack back to idle, floored pedal has less vacuum which moves the rack to a richer position.
If the governor arm is pulled to far back, the engine will run too lean, it could be that the choke cable type setup you have is to tight and it will not allow the governor arm to move forward where it needs to be.
Disconnect that cable until you have the engine running correctly, then connect it back up so that it has full movement.

klmlbt6 wrote:Seems I was finally able to upload pictures, so hopefully they will post and you will be able to see what I am working on. Thanks so much for the reply. I'll check on that IP controller. Is there a way to diagnose if it is working or not?
I know the voices are not real,
but they have some really good ideas.

klmlbt6
Posts: 6
Joined: 3 years ago

Re: Help with a SD22 in Vietnam

#5

Post by klmlbt6 » 3 years ago

Thank-you! If there was a like button I would press it. I will follow your suggestions and check the arm movement. Are we talking millimeters of movement or inches when the throttle is opened? I have read a lot on this forum about the leather diaphragm inside the governor falling apart. Could that be the case here? It has most likely never been serviced. Yeah, the filter system is a bit wonky. That along with the transmission adapter made me think this engine was probably out of a forklift or something. There is no pre filter, which is probably why the lift pump is now leaking so badly, but mostly after shutdown, not while running. While priming it, however, it was probably spewing out a tablespoon of fuel with each pump. Is there a rebuild kit for those? Thanks again!

waynosworld
Posts: 505
Joined: 7 years ago
Location: Vancouver Washington USA

Re: Help with a SD22 in Vietnam

#6

Post by waynosworld » 3 years ago

klmlbt6 wrote:Thank-you! If there was a like button I would press it. I will follow your suggestions and check the arm movement. Are we talking millimeters of movement or inches when the throttle is opened? I have read a lot on this forum about the leather diaphragm inside the governor falling apart. Could that be the case here? It has most likely never been serviced. Yeah, the filter system is a bit wonky. That along with the transmission adapter made me think this engine was probably out of a forklift or something. There is no pre filter, which is probably why the lift pump is now leaking so badly, but mostly after shutdown, not while running. While priming it, however, it was probably spewing out a tablespoon of fuel with each pump. Is there a rebuild kit for those? Thanks again!
If you disconnect the choke cable from the arm you will be able to see how much movement it has, and you should connect the cable so that it uses all the movement, all the way forward is the start position(very rich), and all the way back shuts the engine down, and in the middle is the run position, very little movement can make a big difference in how the engine runs.
The diaphragm does control the rack in conjunction with the throttle body venturi, when idling the vacuum created by the venturi in the throttle body pulls the rack to the idle position, and when you press on the pedal/throttle, it looses vacuum which moves the rack to a richer position, at the same time it gives the engine more air, so the engine revs, the hose between the throttle body and the injection pump needs to be air tight, as that is what controls the engine.
If the diaphragm was cracked and had a hole in it, the engine would likely not idle properly as the rack would not be pulled all the way back to the idle position, it would likely blow black smoke all the time from running rich.
Another thing to keep in mind is that the diaphragm can get stiff, it is nothing but leather, if the oil drains out of the injection pump in that area, it will dry out and not flex like it is supposed too.
I think this is the primer you need on ebay, but you can likely find it somewhere else like a forklift parts supply local to you, or possibly a marine supply.
http://www.ebay.com/itm/1981-86-Fuel-Fe ... r7&vxp=mtr
How long has it been since the fuel filter was replaced?
I know the voices are not real,
but they have some really good ideas.

klmlbt6
Posts: 6
Joined: 3 years ago

Re: Help with a SD22 in Vietnam

#7

Post by klmlbt6 » 3 years ago

I just replaced it, but it looked as though it had been years since it was done. I also replaced the air filter, intake hose, and throttle body gasket. There was a good layer of sludge on the intake tube, and it was slightly open to atmospheric air not going through the filter. I also replaced a banjo bolt on the fuel rail going to an injector because the shop had used a bolt that was too short and put plastic washers in instead of the brass or copper ones. There is still a lot to do, and parts are a bit hard to find over here, but I will do what I can and keep you guys posted. Thanks for the help!

klmlbt6
Posts: 6
Joined: 3 years ago

Re: Help with a SD22 in Vietnam

#8

Post by klmlbt6 » 3 years ago

Hey guys. Sorry it has taken so long for an update. The truck is a couple hours from me so I don't get to work on it that often. Before we start working on the running issues again, there is a more pressing problem. I thought the transmission mount was broken. Turns out, the right side engine mount and bracket were both broken, completely, which is what was causing the fan and A/C lines to run into everything. We jacked up the engine and got the old ones off, but they have been modified, so buying an off the shelf replacement is not an option it seems, though I hope I'm wrong. Few things: Did Scouts ever come with these engines from the factory? If so, any idea where I could buy the correct mounts. If they did not, can anyone tell what application the engine bracket is off of? I know we may still need to weld a plate to it, but it would be easier to start with the proper bracket than to create a new one from scratch. The engine mount they used looks more like a tranny mount to me, but again, any idea what the application for it might be? I cleaned and searched both parts and could find no numbers whatsoever, so no help there. Thanks again guys! Any help or advice is greatly appreciated.
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klmlbt6
Posts: 6
Joined: 3 years ago

Re: Help with a SD22 in Vietnam

#9

Post by klmlbt6 » 3 years ago

Just to update anyone following this:

We could not find a bracket or mount that was close, so we had one made. It took some massaging, but we have it in there and the whole engine/trans are not mounted in securely and seem to be positioned correctly. After finishing that, we noticed that the engine was leaning so much it was pulling on the shut off cable, the AC lines, and the bottom of the homemade AC bracket was riding on the front diff cover and had actually worn a whole in it. Got the cover welded up and back on. New u-joints installed and greased. The thing started right up, revved better than ever, but still seems to be missing the top end power it had before. Any thoughts? I'll be checking the fuel rail movement, governor, and other things next time. Immediate thought is that the lift pump leaks, so maybe it can't maintain enough pressure for higher RPM's?

waynosworld
Posts: 505
Joined: 7 years ago
Location: Vancouver Washington USA

Re: Help with a SD22 in Vietnam

#10

Post by waynosworld » 3 years ago

I suppose it depends on what you consider high RPMs, the SD22/25 series engines don't like revving over 3000rpms, the redline may be 4000rpms but it don't like high RPMs, in all gears except 5th gear, I normally shift at around 2600rpms, and in 5th on the hiway I will run it up to 3000, maybe 3200rpms if going down hill, but that is about it, these diesel engines were not made to rev high.
I know the voices are not real,
but they have some really good ideas.

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