Fuel tank measurments

[danray48]

First I have a 79 CJ7 AMC 258 i6 / 4.2l . I replaced the return and supply fuel line the other day because the return was dry rotted and the supply didn't look good either. So then since I knew the gauge wouldn't go past 3/4 when full, (New gauge) I dropped the tank all the way, and am going to replace the sending unit, fill hose, and overflow hose. Sandblast the shield and paint. The tank is a poly tank that had no rubber between the shield and the tank which I will correct. Question is, how can I be sure I have a 15 gallon tank. Is there a measurement I can go by? It's just me I know, but I cant seem to believe I could get 3, 5gal cans of gas in that tank. So anyone that knows the dept, width and height of a 15 gal poly tank would be helpful thanks.

 

[Torxhead]

The larger 20 gal tanks are poly and the 15 gal is steel. Your fuel tank sensor float could just need some adjustment.

 

[danray48]

The larger 20 gal tanks are poly and the 15 gal is steel. Your fuel tank sensor float could just need some adjustment.

Thanks Torxhead, for the response. I just figured the PO replaced the tank at sometime when he changed to the fiberglass tub and did some work on this thing. And I thought he just replaced with a poly tank. I wasn't aware that some came stock with a poly tank. I will check the float. It was worked on at sometime, because there is silicone smeared around the locking ring. I thought while it's out, I'm replacing everything but the tank because it's out, and I don't wanna have to do it again for quite awhile.

 

[danray48]

I found some time to answer my own question. I looked up how to measure for fuel capacity. You take length x width x height to get your cubic inches, and divide by 231. I got 16.36 gallons, which I guess they would consider it to be a 15 gal tank. That's what I had to know before ordering a sending unit. Then take into consideration the rounded corners. So at least I know it's not a 20.

 

[ThisGuyUKnow]

I found some time to answer my own question. I looked up how to measure for fuel capacity. You take length x width x height to get your cubic inches, and divide by 231. I got 16.36 gallons, which I guess they would consider it to be a 15 gal tank. That's what I had to know before ordering a sending unit. Then take into consideration the rounded corners. So at least I know it's not a 20.

unless it is after market, the cj did not have a plastic 15 gallon tank. since your is poly I'd assume it's the 20 gallon model. the sending units have different diameters on top iirc so it may be better to pull your old sending unit and measure it and compare to the replacement your getting

 

[danray48]

unless it is after market, the cj did not have a plastic 15 gallon tank. since your is poly I'd assume it's the 20 gallon model. the sending units have different diameters on top iirc so it may be better to pull your old sending unit and measure it and compare to the replacement your getting

Now you have me second guessing what I have. I'm going to double check the calculations on this, but if the article was correct, the numbers don't lie. That's just it, I think the tank was replaced, but not 100% sure, I'll check the diameter of the sending unit thanks...

 

[ThisGuyUKnow]

Now you have me second guessing what I have. I'm going to double check the calculations on this, but if the article was correct, the numbers don't lie. That's just it, I think the tank was replaced, but not 100% sure, I'll check the diameter of the sending unit thanks...

Don't doubt yourself there are aftermarket poly conversions that are 15 gallons, i dont think they use an OEM sending unit though so you may have to do some research.

 

[Old Dog]

Heres a link to some aftermarket tanks with dimensions. MTS COMPANY, L.C. - Jeep CJ/YJ Gas Tanks

 

[danray48]

Heres a link to some aftermarket tanks with dimensions. MTS COMPANY, L.C. - Jeep CJ/YJ Gas Tanks

Thank you very much Old Dog. That's exactly what I was looking for, and now I know I have a after market 15 gal tank.