Gas tank replacement: steel or poly? 15 gal or 21?

[jonboy1919]

I really would like feedback on your opinion on my new winter project; fuel tank and pump replacement. Should I go poly or steel? Should I go 15-gal capacity or 21? Any feedback on replacement fuel pumps?

As I remove the old tank and pump, are there certain hazards I should be ready for such as broken studs or straps or skid plate? What about fuel lines, any potential problems there? I am starting this project because last summer while getting back to camp after a long day in the mountains, the Jeep would cut out, cough and sputter in the lowlands. I would then flip on the secondary fuel pump (used for high altitudes) and my CJ7 would even out and run normal.

I am assuming my main pump is going on the fritz slowly, so why not replace tank and pump while I'm there, right?

Just a few things to consider before you give your opinion: I am not a rock crawler; I run Forest Service and logging roads approx 5-7 weekends a year, mostly in the summer; my "baby" is garaged the rest of the year.

Any and all opinions, links, info and past experiences are greatly appreciated.:ty:

 

[thiswontbetooexpensive]

Speaking from other experiences, plastic is easier to maintain on a fuel tank than steel, especially with all the ethanol in fuel; it attracts and retains the moisture that is necessary for corrosion.

Have you ever had issues with the current capacity of your tank? If so, get a bigger one. If not, fuel storage might be an issue for you with a bigger tank unless you run it down or use a stabilizer of some sort.

My $.02.

 

[jonboy1919]

Speaking from other experiences, plastic is easier to maintain on a fuel tank than steel, especially with all the ethanol in fuel; it attracts and retains the moisture that is necessary for corrosion.

Have you ever had issues with the current capacity of your tank? If so, get a bigger one. If not, fuel storage might be an issue for you with a bigger tank unless you run it down or use a stabilizer of some sort.

My $.02.

Thanks, TWBTE, never considered the ethanol issue on steel tanks. Really have never had a capacity issue as I carry a Jerry can, so stock 15-gal it is.

What about puncturing the poly tank? Is it tough? or does the tank skid plate do a good job of coverage?

 

[thiswontbetooexpensive]

Well as I remember taking my CJ apart, the skid plate covered up the tank pretty well. While you have it all off and in your hands and you think the new tank is not covered well enough, it should be pretty easy to make it what you want. It is just metal after all!

 

[defibvt]

I went with steel because my poly tank was concave. Too many rocks in AZ to trust poly for me. You probably get a 50/50 split on this issue. Steel tanks can be treated to resist rust and your tank should be full when jeep is stored. I use stabil to keep the fuel good.

 

[BusaDave9]

I went with steel because my poly tank was concave.

The poly works good but mine too got a lot of mud between the tank and skidplate. I couldn't get 15 gallons in the 15 gallon tank. A bigger tank is almost always better but one drawback it clearance. a 21 gallon tank hangs a lot lower.
As for the fuel pump, If your OEM mechanical pump on the engine is working I would leave it. I had vapor lock problems and installed an electric pump near the tank.

 

[paparooster]

I have a 21 gal poly tank in my jeep, with a electric fuel pump mounted on the frame rail . The 22 gal poly tank sits way lower so sometimes it has ground clerance issuse on trails with some rocks and the tank is a tight fit I had to mount it real close to the tub to get max ground clearence, I also made a different skid plate for it to protect the front of tank . PO did'nt have the stock skid plate on it when i got jeep .If you decide on poly tank you will need the fuel tank float sending unit also .

 

[Torxhead]

I would like to hear how you hooked up that spare fuel pump. I sounds like it works pretty good.

 

[Robs85cj7]

If all you're doing with it is going on trails and clearance isn't a real big issue for you, I say go with a bigger tank and go plastic. You'll still have a steel skid plate after the swap and a few gallons more will never hurt.
Tossing in my$.02

 

[hole]

I think you'll like all the 21 poly tank has to offer, farther fuel range (why I did it) no rust/corrosion issues (bonus). I dont rock crawl just to rock crawl, but I will come across stream beds or rock obsticals in my travels, and the poly tank hasnt been an issue yet on mine.

 

[PaRenegade]

I went through 2- 15 gal metal tanks before switching to a poly tank, and haven't looked back. That was at least 18 years ago. What happens is dirt gets trapped between the skid and the tank and acts like a sponge every time it gets wet. Even with the plastic isolator between them. The only drawback I've experienced is being that the poly material is thicker than the thin steel, the inlet hole is smaller and slows down fill-ups.
My sending unit is still good but a bit rusted on top so I replaced the grounding wire and painted it with some POR. The filter and float were still good after 30 years. Oh, and I replaced the O-ring for the unit.

I do recommend some type of rust preventative paint after cleaning and etching the straps on the side and top. The top one may break upon removal but they're only like $12 to replace.

 

[jonboy1919]

I would like to hear how you hooked up that spare fuel pump. I sounds like it works pretty good.

Torxhead,

The PO set up the auxilary fuel pump, so I purchased the CJ7 that way. He explained to me that around 3000 feet altitude the manual main fuel pump vapor locks, 304cid just dies. Flip a toggle on the dash, electric pump kicks on, turn the key and away we go.

I forgot his instructions the 1st time I went up in the mountains and sure enough, she just shut down. No burps, farts or hiccups. I then remembered, flip aux pump toggle and she ran like a champ the rest of the trip.