replacement fuel tank - steel or poly

[my67chevytruck]

i've heard the poly tanks collect alot of moisture internally compared to steel or aluminum, is this a myth....

[Classic Heartbeat]

Myth.... Polyethylene does not transfer heat verry well. So they do not condensate on the inside. WES

[chrislehr]

Dumb question - possible to install without removing the bed completely?

[djw32]

Originally Posted by chrislehr

Dumb question - possible to install without removing the bed completely?

Good question.

How will the poly hold up to ethanol?

[poncho_villa]

I kinda cheated on the issue of poly versus steel. I installed an aluminum marine tank. The size was perfect and installed in a flash. It even came with a sende unit but was the wrong ohms for my gauge.

[jayharrell]

poncho cheated. Made me laugh.

[Classic Heartbeat]

The Polyethyne tanks are imperviouse to ethanol. WES

[djw32]

ttt for chrislehr question

[chrislehr]

Originally Posted by djw32

ttt for chrislehr question

Thanks - I need to know if I have to undo all those bolts and get a hoist of some sort

[71tahoe]

I don't recall seeing an install thread with the bed on but anything's possible with enough determination. Removing the crossbrace shouldn't be too hard but you'll probably take a shower in sparks if you use a cut-off wheel to trim the cross support on the bed. I don't think there's enough room for a sawsall to get in there but a jigsaw might work if the base is narrow enough. Got plasma?

[chrislehr]

Originally Posted by 71tahoe

Got plasma?

The only plasma I have is the stuff I will lose trying to use a cutting wheel or sawzall in there. Guess I will leave this to a shop to do until I have a better outfitted garage.

[67ChevyRedneck]

Originally Posted by chrislehr

Dumb question - possible to install without removing the bed completely?

Originally Posted by 71tahoe

I don't recall seeing an install thread with the bed on but anything's possible with enough determination. Removing the crossbrace shouldn't be too hard but you'll probably take a shower in sparks if you use a cut-off wheel to trim the cross support on the bed. I don't think there's enough room for a sawsall to get in there but a jigsaw might work if the base is narrow enough. Got plasma?

Totally possible, total pain in the ass. But so is removing the bed completely. I installed my tank with the bed on.

Here was my "rope mock-up." Bed and rear bumper were never removed.

[chrislehr]

Cool, well that is really good to know. Thanks for posting the pic. So you did have to cut off a crossbeam with the bed on to do that?

[67ChevyRedneck]

Originally Posted by chrislehr

Cool, well that is really good to know. Thanks for posting the pic. So you did have to cut off a crossbeam with the bed on to do that?

My bed wood is deck boards my dad and I installed about 10 years ago! The bolts came out fairly easy. I don't even have the steel strips in my bed. I unbolted the cross brace from the bed, unbolted the bed, had a couple friends pick the bed up a little bit while I pulled the brace out. The bed wood is "weaK" when I step on it over the tank. I someday plan to cut the brace so it will fit over the tank and reinstall it, but until I get a garage, the truck is 100% done... until something else breaks

[michael bustamante]

this is why I love this site.
I just purchsed the LMC tank set up also. I too wont be able to install it for a couple of months but now I know what to loog forward too. Mine is going in a longbed and I noticed that I have a crossmember in the way where the tank goes but I never heard you guys mention the complete removeal of a cross member. only cutting to trim. have any of you guys put one of these tank in a longbed?


JRDV. where is Des Moines New Mexico?

[jrdv]

Michael,
I'm in the far northeast corner of the state. It's about 45 miles east of Raton. Boonies!
My tank is going in a longbed 4x4. I haven't looked to see if there is a crossmember in the way. Hopefully you will get started on yours first---Then I can steal your ideas!! I will keep a lookout for your posts.

john

[michael bustamante]

I know where you are now. way out there! I might start mine this weekend. since my bed is staying on the truck I guess I`ll be taking a shower in some sparks. I`ll keep this updated as I go along with the install. Any of you guys installed a filler neck on the inner bedside? I dont want a fuel door on the outside of the bedside. and definatly dont want the filler to on the bed floor. Any ideas?

[EAST SIDE LOW LIFE]

Steel all my life .... never let me down. Why change now?

Next thing you know you will be filling that tank up.

esll.

[MN Rooky]

Michael,
I just finished putting mine in. I couldn't find anything on the install of the tank on a long bed either. I moved the crossmember forward. There was holes in the frame where I wanted to put it.

[fishingjred73]

I'm putting a poly in mine. I chunked the straps that came with it and fabbed up a cage to hold it up to the frame. Now i'm trying to decide on the filler neck what are you fellows doing for filler necks?

[jayharrell]

I just got a 84 suburban tank today, will try to put it in my long bed with springs next weekend if the AC parts don't show up. It looks like i can move the rear cross member back, there are holes on the top of the frame rails that line up right where i need it to be. Also cut the filler door out of that suburban, might make it interesting. I'll post some pics when i get started.

[jondancer]

I want a poly tank.
Posted via Mobile Device

[dhaymaker]

I would also have to vote for steel. The reason being...

Originally Posted by crews

I vote steel.

I had put a poly tank in my 72 crew cab and I wasn't very pleased with the fit nor did I like how easily it was distorted.

[GuyO]

Poly, is simply better. I have read almost all the posts about the downsides, in order they go like this: 1) fill problems, 2) warpage due to heat, 3) fitment. For #1 the people with fill problems tend to focus on diameter of fill port because a replacement poly is a little narrower and shorter. Most overcome this by double worm clamping the hose, or creating a sleeve either made by a muffler shop or using a piece of old hose as an ovesleeve then clamp to the larger diameter. Some buy marine fuel filler hose of 1 1/4" ID as a replacement and others have fabricated new filler tubes. Conversions suffer the most complaints but almost all fill issues end up being venting issues. Because the tank fill diameter is always larger than the gas pump nozzle diameter, it is not a restriction. The problem is usually either plugged vent lines, not enough vent lines or sags in vent hoses. Sometimes even the filler hoses are too long creating a restriction for filling because of kinks or bends. For #2 distortion, distortion is not due to heat. It is due to sucking the tank out of shape, which again is a venting issue. Some use the original vent tubes to the charcoal canister (which may be plugged), some have used motorcycle type vent caps with lines of 1/4" NPT to brass hose barbs in the vent holes on the poly tank. Some use fuel filters in the ends of the vent hoses vented to outside atmosphere, but all vent lines must be raised higher and with no sags than the filler cap. Also a vented fuel tank cap helps reduce/prevent distortion due to fuel pump sucking the tank out of shape. #3, fitment is much less of a concern than numbers 1 & 2. I know for sure the old straps and old J bolts are less of a problem if in good shape, otherwise people have fought the replacement straps and bolts.

Poly works well when properly installed, they are cheaper, cleaner (no need for spay on truck bed coating to protect them) and they have the much added benefit of not rusting inside or out. During winter months condensation will form inside steel tanks when low on fuel causing poor performance and internal rusting. The rusting also usually causes problem with the sending unit. I recently had a steel tank with over 1/4" of rust caked on the bottom and the raditor shop couldn't clean it. In cold weather climates condensation (and sand/salt mixtures used on roads) are usually the reason for tank replacements. Replacement steel tanks are not perfect either, usually because of the shorter filler neck angled into the frame. The easiest fix I have seen is to use a correct diameter socket placed into the steel filler neck and with the ratchet handle as a lever bending the filler neck to gain clearance in the direction needed. Poly tanks can be heated with a heat gun and repositioned. Both tanks can leak, espeically due to loose connections at either the vents, the filler or especially the sending unit. I pay very close attention to the sending unit area with a new seal and a little bit of Permatex black silicone. To test for leaks - fill it with water, plug the vents and tip it on its end to see if it leaks before installing it. Then dump it and blow it out, I use the shop vac. Note: be very careful and DO NOT apply 12 volt current to the sending unit as I have read in this forum. That is very dangerous with a tank with fuel in it and will burn up your sending unit if you live! Gauge proplems are usually float, ground/contacts, or rusted sending units. I recommend cleaning the cluster plug with emory cloth and then adding grounding. Ground the instrument cluster from tin to firewall or dash and use corrosion blocker on tank contacts. If there is continuity to the uniit through the wire, it is the sending unit. The sending units are cheap enough too replace, I buy from Wes in Olympia. He's the best. G.

[7dee2]

I knew there was lots of good reasons to go poly and that is how I voted. I ran a poly tank in my lowered 68 GMC for many years never had any issues and it is still going strong today for the new owner. My new short wide project will get a poly tank also.