Stock in-cab fuel tank use in diesel swap???

[ChaseTruck754]

I noticed the editing thing. I tend to do that a bit as well as I often re-read my post and add more info or fix spelling/gramatical errors. Thanks for the cap info - I'll see what I can find. Too bad I am just now getting to this as I just a week ago bought and put on the Alfa the same cap that I will be taking off the crew now. Oh well - I guess I will now have a spare cap for the Alfa I'm not sure if Theodore Robbins has the old parts books either, but it has been a while since I've paid the counter a visit - maybe I'll go say hi

[NumberDummy]

Originally Posted by ChaseTruck754

I noticed the editing thing. I tend to do that a bit as well as I often re-read my post and add more info or fix spelling/gramatical errors.

Thanks for the cap info - I'll see what I can find. Too bad I am just now getting to this as I just a week ago bought and put on the Alfa the same cap that I will be taking off the crew now. Oh well - I guess I will now have a spare cap for the Alfa

I'm not sure if Theodore Robbins has the old parts books either, but it has been a while since I've paid the counter a visit - maybe I'll go say hi

If you do go, say hello to Milan (the parts manager) for me. He's been there for over 25 years.

We used to work together at Crenshaw Motors.

[ChaseTruck754]

Ok - now that I've got the vent figured out - here's pics of the tank as it sits now. It looks like I'll just get some barb fittings to run 1/2" hose and be done with it...

Stock tank (don't mind the seatbelt - it's just up there to keep it out of the way for now)


Stock/current fitting for vent line to charcoal canister


Stock/current fitting for supply line

[Festus Hagen]

Yea, you're definitely not going to want to use that canister line, Notice the Orfice crimp!

Then you are going to use a vented cap?

When you get it running, keep an eye on the pressure/vacuum in the tank, make sure your venting enough.

The line the you are connecting your seat belt to... Is that the filler vent?
If all else fails, You just might get away with T'ing that, the problem I see with that is the vent should go up, no place to go!

Guess you could run it up the B pillar then down and out.

Cool, Whats next!

-Enjoy
fh : )_~

[ChaseTruck754]

Originally Posted by Festus Hagen

Yea, you're definitely not going to want to use that canister line, Notice the Orfice crimp!

Yup - getting a 90* to barb for 1/2" rubber line.

Originally Posted by Festus Hagen

Then you are going to use a vented cap?

That's the plan as of now.

Originally Posted by Festus Hagen

When you get it running, keep an eye on the pressure/vacuum in the tank, make sure your venting enough.

The line the you are connecting your seat belt to... Is that the filler vent?
If all else fails, You just might get away with T'ing that, the problem I see with that is the vent should go up, no place to go!

Guess you could run it up the B pillar then down and out.

Yes that is what I was calling the "fill vent". I'm not 100% sure that's what it is, but that is what it looks like. It just runs from the base of the fill neck to the top of the tank.
I was thinking possibly a T in that as a secondary or "extra help just in case" vent. If I did I would loop up above the tank a bit and then down and out, as like you pointed out - without cutting a hole in the body there is no where to go up and out.

Side thought here though. An idea came to me mid thought while typing the above...
What if I T'ed a 1/4" line or so off that filler vent and ran it out the rubber gasket/sleeve that the fill neck comes in? I haven't had the tank out to see how much room/play I have in that area, but I will look. That keeps it going up and out, while not cutting a new hole in the body or being some super long run.

Originally Posted by Festus Hagen

Cool, Whats next!

A whole lot
I've got a bunch to keep welding on the motor mounts and cross member, and then I'm starting the steering box swap.
I am also planning on taking the tank out and getting it clean and the lines started.

The next thing that will need some "thinking" is the clutch master (didn't we just go voer this), throttle cable and cable for shut off valve.

[Festus Hagen]

Originally Posted by ChaseTruck754

What if I T'ed a 1/4" line or so off that filler vent and ran it out the rubber gasket/sleeve that the fill neck comes in? I haven't had the tank out to see how much room/play I have in that area, but I will look. That keeps it going up and out, while not cutting a new hole in the body or being some super long run.

Would it be visible from the outside by the filler cap?
Don't remember what they looked like.

-Enjoy
fh : )_~

[ChaseTruck754]

hopefully not - and it would all depend on how clean my work is... My goal would be to not see it.

On the cab tanks for these trucks there is a rubber boot that goes around the fill neck where it exits the cab. I would try to melt/cut a slightly undersized hole in the boot and then slide the 1/4" breather hose in the hole. If I could make it work the way I picture it in my head all you would see from the outside (if you got up close and looked) is a hole in the boot - which would be the ID of the hose.

Clear as mud?

[71cc]

From what I have read diesel fuel will attack the galvanizing inside the tank.It makes it release from the metal and get into your fuel system.I would research some more.I ended up using a poly tank on mine behind the axle.Of course filter before lift pump,finer after lift to injection pump.It would be nice to have some way to drain water off the tank as well.

[ChaseTruck754]

Originally Posted by 71cc

From what I have read diesel fuel will attack the galvanizing inside the tank.It makes it release from the metal and get into your fuel system.I would research some more.I ended up using a poly tank on mine behind the axle.Of course filter before lift pump,finer after lift to injection pump.It would be nice to have some way to drain water off the tank as well.

Thanks for the input. That is something I had not heard. I have a spare 36 gal poly tank here. I was kind of saving it as a spare for the race truck, but maybe I'll use it...

[Festus Hagen]

Clear as a NorCal stream...

That is what I was thinking they looked like.
(Gee, My memory does still work -*- Sometimes!)

I suspect the vented cap will be enough though, you really only have to vent what the motor eats. I would wait on this till you find out if it's needed.

-Enjoy
fh : )_~

[Festus Hagen]

Originally Posted by 71cc

From what I have read diesel fuel will attack the galvanizing inside the tank.

Hmm, Interesting, Never heard of that, The tank can be coated pretty inexpensively. Had a 150 gal tank done and it cost like 45 bux, but that was a few years ago! It was a steel tank and done do to rust.

-Enjoy
fh : )_~

[ChaseTruck754]

I have heard the cheaper coatings (Eastwood, etc.) come off and eat carbs, etc. I have never heard about diesel fuel doing wonders on the galvanization though.

As for coating the tank - the good stuff lasts forever. Costs $250 or so though

[Festus Hagen]

The one I had done had lifetime warranty... They filled the tank with stones (abrasive stone) and tumbled it, cleaned it, added an acidic etcher, tumbled it, dumped it, added a neutralizer, tumbled it, dumped it, added the liner, tumbled it, dumped the excess and let it cure... It was a white rubber like stuff.

But like I said, that was a few years ago, it was done in Pittsburg Ca. by a radiator/muffler shop.
And I have no clue how well it held up, it worked fine for the years I had it, stopped the rust problem.

-Enjoy
fh : )_~

[ChaseTruck754]

OK - back at this.

I went to the Vatozone and had them cross reference the part # that NumberDummy had. It turns out to be the same part that I just bought for my alfa romeo project.

Since I had one I grabbed it off the alfa and tried to put it on the crew cab - but no luck. It would not go on. Pics below show why...

New cap is one I bought for the alfa - old one is what was on the crew




The "neck" (for lack of a better term) on the new cap is to short to engage the fill neck on the truck - as seen in the last pic above.

Neither of these caps look "vented" to me, but that is very possibly just my untrained eye.

Seeing as both caps look the same aside from the length of the part that locks into the fill neck, it is very possible the one already on the crew is vented. Therefore I think I'm just going to leave it.

Any comments or advice?

Last - here is what I believe is the "vent" on the fuel cap. Not sure how this is a "vent" as if the seal works I'm not sure how it could get in/out
Sorry for the crappy pic - flash didn't help things

[BradyCouchman]

that looks different then my gas caps, i dont have that part in the center. and i konw that mine is not vented because my tank can build presher.