Big incredible mess, and now I own it

[dropnosky]

Hello, new to the forum and farming for information. ok, ive been looking for a long time for a small diesel truck and finally found this 86 extended cab beautiful nissan that has a diesel conversion. The motor is I believe an 80 or 81 SD22, and It has quite a few things I need to take care of.
I know nothing about this motor, but first and foremost I need to rewire almost everything.
question #1- the glow plugs are currently wired to the horn relay (dont ask), what is the durability of these plugs? do I need to install a timer? can I just use a momentary switch when I rewire?
question #2- Starting process is to hold the horn/glow plugs, then crank, but stopping process requires me to pull on a cable coming from the base of the injection pump to shut the engine off. How was this originally done? was there a small electric servo that cut off fuel flow?
question #3- The diesel is I believe currently using the radiator that came with the 86 gas motor. Is this certain death? do I need to find a radiator that will work with the diesel? if not, what pressure cap do I need to use that will work with this diesel?
question #4- I immediately need to install a temperature gauge, where is the original location for the sensor?
question #5- Right now I have an interesting arrangement where the gasoline AC compressor is mounted to a custom bracket on the driver side of the motor, and sharing a belt with the power steering. The belt must be 5 feet long. I am going to remove the the AC, is there a belt that just drives the power steering?

Thats the first 5 for now- I have a couple thousand more as I undo the gas stuff, (some if it melted from a car fire, some just laying in there) that I will ask later.

I am currently trying to get it to start again, wont crank, and was running 10 seconds earlier for more than 100 miles, plenty of juice. Instead of trying to undo the rats nest in there, I am going to rip everything out and put in a push button starter, hopefully its just a malfunctioning neutral safety switch or something.

At any rate, I look forward to long and prosperous ownership of this truck. I cant wait to learn everything I can about it. I am sure you all will be hearing back from me endlessly as I sort this madness out.

[asavage]

Welcome. Please edit your Profile (click on "Profile" at the top of any page) and add at least your geographic location to the appropriate field, and edit your Signature with your ride's decription -- these will save a LOT of time later, believe me.

You will want to pick up a 720 Factory Service Manual (FSM) sometime; it's quite good, and they can be had on eBay for reasonable prices fairly often. You will want one for a 1982, because the 1981 FSM does not have any diesel info in it (that came in a separate Supplement, 1981-only), and the 1983 FSM will have SD25 info as well as SD22, which can be confusing.

86 extended cab beautiful nissan that has a diesel conversion. The motor is I believe an 80 or 81 SD22 . . .

Pretty much that describe's what I'm doing: '82 SD22 (from "Bellingham Truck") into an '86 non-KC ("Arlington Truck").

question #1- the glow plugs are currently wired to the horn relay (dont ask), what is the durability of these plugs?

The SD22 GPs are reputed to be darn near un-killable, though several of us have found one or more with a hole burned in the tip and non-op. If your rig comes up shaking and clouds of white smoke, pull all the GPs and bench test them with a battery or battery charger.

do I need to install a timer? can I just use a momentary switch when I rewire?

No, and yes. The GP Controller on the 720 SDs is pretty good though. But a momentary contact switch is simple and will work. You will have to count, of course. Can you count? Up to forty? It's getting cold around here.

question #2- Starting process is to hold the horn/glow plugs, then crank, but stopping process requires me to pull on a cable coming from the base of the injection pump to shut the engine off. How was this originally done? was there a small electric servo that cut off fuel flow?

What you have described is what people do when they can't figure out how to get the OEM STOP/RUN/START electric motor system to work, or can't be bothered learning. It's called The DPC System. It's basically a wiper motor bolted to the right front lower of the engine, with a rod up to the IP, and a bunch of contacts and a controller. Excellent pictures and description of the system is in this thread.

What you are doing works, but lacks in two areas:

• The DPC system will shut down the engine if oil pressure drops to dangerous. You cable system won't.
• The IP has an "Excess Fueling" mode: START position on the fuel control lever. It allows a bit more fuel to be injected at cranking speed. Your cable system can't duplicate that. Some people find that their SD starts OK (in their climate) without needing the IP fuel control lever in START position during cranking; others do need it.

question #3- The diesel is I believe currently using the radiator that came with the 86 gas motor. Is this certain death? do I need to find a radiator that will work with the diesel?

If the plumbing has been worked out, the gasser radiator is sufficient to the diesel's heat load. Don't let it worry you. The hoses locations are better on the diesel radiator, but again if the plumbing's been worked out to your satisfaction already, run with it.
(I have an SD radiator available for sale)

question #4- I immediately need to install a temperature gauge, where is the original location for the sensor?

See where the GP wires are in this pic? Follow them to the left, and they go to the GP temp sensor. The gauge sender is just above it (two items below the heater hose elbow).
(click on any image for larger)



Different view, now you can see them both:
(click on any image for larger)







Read up on the correct thermostat -- this is a very common error.

question #5- Right now I have an interesting arrangement where the gasoline AC compressor is mounted to a custom bracket on the driver side of the motor, and sharing a belt with the power steering. The belt must be 5 feet long. I am going to remove the the AC, is there a belt that just drives the power steering?

I'm leaving this one to Philip, our SD moderator. He knows the ins and outs of the rare PS-equipped SDs better than I.

Make use of the Search feature, and read read read, it will educate you on the SD, and will usually entertain you as well.

[philip]

Whew.

1. How do you know the current diesel is SD22 ... and not SD25? Stamp on the block side, facing the Injection Pump.

2. The radiator outlet is on the left side. This is the SD part.


3. Your SD22 (assuming it is), did not come with a steering pump AND an A/C compressor ... that I know of. But when those SD22 did had A/C from manufacture (like my '82 SD22), there was no power steering. Now for the SD25, both items were available together. You'll find this in the Factory Service Manual 1984-on which also had SD25. There is aftermarket A/C for everything SD online ... which we have posted in detail on that thread. "Search"

[asavage]

question #5- Right now I have an interesting arrangement where the gasoline AC compressor is mounted to a custom bracket on the driver side of the motor, and sharing a belt with the power steering.

It's not a factory setup, Philip.

I'd be interested in pictures, if you have time. Upload them here, then PM me that you did.

[dropnosky]

thanks for the great information! I have been super swamped at work since I got the truck, but still no start, and there hasnt really been enough time to fiddle with it.

I will have to borrow a camera and get a photo of this to you guys. The custom AC bracket is actually crooked now that I look at it, so it will have to go, and the wiring situation is almost impossible to figure out. I think I am going to be forced to COMPLETELY remove all the wiring, down to the lighting, everything is so messed up. Ive got grounds going from the lighting down to locations near the starter, loose harness everywhere, melted stuff, additional power cables from the battery here and there. I am tearing my hair out frustrated because there is no diagnostic strategy to how I can "fix" what was hacked in the first place.

I think tonight I am going to bypass the ignition and try and get this started. The starter could also be having a problem as well, I dont know.

[glenlloyd]

This is the problem you face with conversions done by unqualified people.

This is also one reason why when I purchased a Toyota 2L 2.4L diesel engine out of the salvage yard the entire wiring harness, underhood and dash, came out with it, including the cluster and anything attached that could be unscrewed or unbolted.

Fortunately the old IDI diesel setups requires very little in the form of electrics to run.

good luck and please post pics

steve a

[asavage]

I have the 1982 EL (Electrical) section scanned and online.

There are many extra mini harness pigtails on the '86 that I will be lopping off -- in addition to the computer under the driver's seat. Fortunately, I have the engine harness and firewall harness from the '82 SD to splice in to the gasser engine bay harness. I will have to add a wire for the GP indicator (will be the EGR light in the cluster). And I'll have to put the GPC somewhere and run the harness to it. I may put the GPC underhood.