1987 Spacecab - diesel fuel tank questions

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cocheeze
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1987 Spacecab - diesel fuel tank questions

Postby cocheeze » Mon Dec 02, 2019 3:33 pm

Hey all,

I am officially giving up on the fuel tank on my 1987 Spacecab. It is just too far gone and keeps plugging internally due to the accumulation of rust and gunk from the previous owner running poorly filtered fuel.

I have flushed the tank with a transfer pump and filter quite a few times in an attempt to remove enough gunk and rust to solve the issue, and it has worked pretty well (removed about a mason jar full of sediment) but the issue just keeps coming back. I am also pretty sure that the filter at the bottom of the tank is partially torn as well because I am getting a lot of sediment in the bottom of my filter that shouldn't be able to pass a screen. Blowing air backwards into the tank to clear obstructions has become less and less effective over time, regardless of how much gunk I clean out of the tank.

My questions:

- What years/models of P'up can I procure a tank from? I am assuming any shortbed diesel tank from 1981-1987 works, right?
- Can a tank from a gasser be modified to work in a diesel by adding a port at the top for the return line?
- How hard is it to drop the tank? Any pointers for a first timer?

As always, thanks!
Casey
His:
'81 Isuzu 4WD P'up Diesel (310k)
'87 Isuzu P'up Spacecab Turbo Diesel (228k)
'81 Isuzu I-Mark Diesel (220k)
'81 Isuzu I-Mark LS Diesel (219k)
'69 Subaru 360 (22k)

Hers:
'82 Isuzu I-Mark Diesel (135k)

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Halden
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Location: Everertt, WA
Isuzu vehicle(s): 1983 Diesel LS Long Bed 4x4

Re: 1987 Spacecab - diesel fuel tank questions

Postby Halden » Mon Dec 02, 2019 11:51 pm

The gas and diesel tanks have the same number of inlets and outlets. I've never heard of someone swapping the tanks when they do a conversion. I won't speak as to the Space Cab and Shortbed tank sizes. I am having a hard time interpreting my parts catalog. Isuzu did not make this very easy to understand. The only thing that the gas tank won't have is the drain plug.

I might recommend to you doing an interior coating with some "RedKote" on your current tank. I did that with my long bed years ago and haven't had any issues. The only thing I would recommend is trying to get all of the excess out when you're done. I know it's kinda hokey, but I drilled a hole in a corner and drained out the excess that way. Then patched it with some JB weld and fiber glass or something. Removing the drain plug wouldn't get enough out before it began to set, Also get some gravel or something in there and shake the living crap out of it when you clean it to bust some stuff loose. It may damage the screen, but my guess is the screens in most of these trucks are long gone from rusting away. I know when I peered in my tank before I did that a chunk of it was missing. I haven't had any issues from a fuel line clogging.

The tank is pretty easy to drop. It's a bit of a pain to get to those lines at the top but it's doable without removing the bed. And there are -I think- only 4 nuts and bolts holding that tank in. Don't forget to undo the sending unit.

Hope that helps.

Halden
It's not pronounced "Ih-soo-zoo", it's pronounced "It-screws-you"
83 LS Long Bed Diesel 4x4
82 LUV Short Bed Diesel 5 Speed 2wd
64 Chevy C20 w/ 283 & 4 speed.
05 Sonata with a standard

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cocheeze
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Re: 1987 Spacecab - diesel fuel tank questions

Postby cocheeze » Tue Dec 03, 2019 12:09 am

Thanks, Halden!

The reason I am asking about using a gasser tank is that i happened to snag one from a pick in pull years ago and that one might be a good candidate provided that i can plumb it correctly for diesel.

Does anybody know of a reason that i shouldn’t use the gasser tank?

Casey
His:
'81 Isuzu 4WD P'up Diesel (310k)
'87 Isuzu P'up Spacecab Turbo Diesel (228k)
'81 Isuzu I-Mark Diesel (220k)
'81 Isuzu I-Mark LS Diesel (219k)
'69 Subaru 360 (22k)

Hers:
'82 Isuzu I-Mark Diesel (135k)

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Halden
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Posts: 2985
Joined: Thu Mar 29, 2012 5:20 pm
Location: Everertt, WA
Isuzu vehicle(s): 1983 Diesel LS Long Bed 4x4

Re: 1987 Spacecab - diesel fuel tank questions

Postby Halden » Tue Dec 03, 2019 12:13 am

You could get under the truck, compare the length and where it needs to go around the frame rails.

I can't think of a reason. Having no drain plug really shouldn't be an issue. If you are super worried about it you could always just get a separate clear sedimenter bowl/water separator that holds a greater volume than the factory filter. They work pretty well.
It's not pronounced "Ih-soo-zoo", it's pronounced "It-screws-you"
83 LS Long Bed Diesel 4x4
82 LUV Short Bed Diesel 5 Speed 2wd
64 Chevy C20 w/ 283 & 4 speed.
05 Sonata with a standard