While on the subject of tanks. I would assume the 31 tank fits under the factory skid plate same as the 25 tank?
CK5
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What is the Best Brand of Gas Tank?
- Thread starter magik235
- Start date
magik235
Still Alive
I got my new 31 gallon tank, straps and sender unit with fuel pump today. Everything looked good.
Carcinogen
1/2 ton status
Ditto. Although it didn't fit that great on my stepside...
What did the baffle look like in the new tank, in case you took a peek before install, or didn't put it in yet?
magik235
Still Alive
There is a central pan approximately 8" X 12" x 4" high with 2 holes in the bottom.
I have not installed it yet but I did Herculine it.
I have not installed it yet but I did Herculine it.
Appreciate the info. Does not sound like they fixed the problem. Sumps aren't supposed to drain fuel out. 
Tank looks good! Thick/pliable enough to not use anything between the straps and tank for mounting?
Tank looks good! Thick/pliable enough to not use anything between the straps and tank for mounting?
magik235
Still Alive
I Herculined the straps as well as the tank planning to mount them without anything to trap water.
cheap-and-on-sale
I think my TBI tank was from AutoZone. Waited for free shipping and no tax sale
Asking a lot, any chance you could use a drill bit or similar to get the diameter of those holes in the sump? Not sure how I'd correct the problem, but with the design I'm real leery of running it much below a 1/4 tank when I'm not on the pavement.
I've not had a problem with starving the pump of fuel, but the factory sump wasn't all that complex and obviously worked like they were supposed to, other than breaking lol. Some pop-in one way/check valves inthose drain holes would be nice.
I've not had a problem with starving the pump of fuel, but the factory sump wasn't all that complex and obviously worked like they were supposed to, other than breaking lol. Some pop-in one way/check valves inthose drain holes would be nice.
magik235
Still Alive
A 3/8" drill bit fits the holes. They are 1/8" above the bottom of the gas tank. I don't understand what you are trying to accomplish. How would gas get into the pan without holes in the bottom?
You'd have to run one way valves I guess, I figured the diameter might give me some options.
Sumps aren't supposed to let fuel drain out, that sump fails its intended purpose. The holes let fuel drain out as easily as it will run in, should only be allowed to flow in.
I saw mention on a grand national forum that the original spectra GN tanks were incorrectly designed as well, and that the sump had been redesigned a couple of years back so that it actually worked. I had hoped/expected the same would be true of the TBI truck tanks as well. It's obviously not a Spectra only problem, up until recently, many vendors were listing the same tank for TBI vs. non-TBI trucks.
Its been a long time since I installed my tank, as I recall the spectra sump isn't very "tall" anyway (4"?), trying to correct that design would probably be futile, especially if the holes are located very near the floor of the tank. The valves would have to be fractions of an inch tall to allow fuel in at low fuel levels.
If you didn't have a stock TBI tank to compare against, you'd probably not think of it. Here's what the TBI tank sump looks like: http://67-72chevytrucks.com/vboard/showpost.php?p=4992939&postcount=10 In general concept, this is my Spectra sump http://ls1tech.com/forums/attachmen...tra-efi-gas-tank-yay-nay-fuel-sump-baffle.jpg
Sumps aren't supposed to let fuel drain out, that sump fails its intended purpose. The holes let fuel drain out as easily as it will run in, should only be allowed to flow in.
I saw mention on a grand national forum that the original spectra GN tanks were incorrectly designed as well, and that the sump had been redesigned a couple of years back so that it actually worked. I had hoped/expected the same would be true of the TBI truck tanks as well. It's obviously not a Spectra only problem, up until recently, many vendors were listing the same tank for TBI vs. non-TBI trucks.
Its been a long time since I installed my tank, as I recall the spectra sump isn't very "tall" anyway (4"?), trying to correct that design would probably be futile, especially if the holes are located very near the floor of the tank. The valves would have to be fractions of an inch tall to allow fuel in at low fuel levels.
If you didn't have a stock TBI tank to compare against, you'd probably not think of it. Here's what the TBI tank sump looks like: http://67-72chevytrucks.com/vboard/showpost.php?p=4992939&postcount=10 In general concept, this is my Spectra sump http://ls1tech.com/forums/attachmen...tra-efi-gas-tank-yay-nay-fuel-sump-baffle.jpg
magik235
Still Alive
Will brake lines bolt to the gas tank fittings without leaks or is a special fitting reguired?
Fitting is a "Saginaw", although I'm not sure what GM's name for it is. It is not a brake line fitting, it seals via o-ring, not with a flare like brakes.
magik235
Still Alive
I ended up cutting the fittings off and will clamp the fuel lines to the tubes.
If you can, I'd flare them just to be sure. Not a real hazard at the tank if they start leaking, particularly at only ~13PSI, but would be a hassle if they did.
Make sure to use ethanol rated hose if you have to join them.
Make sure to use ethanol rated hose if you have to join them.
