Gas tank modification?

[McCoyAZ]

Lets not debate moving the tank under the bed.

I picked up a 25 gallon Chevy Blazer tank that has the filler neck in the center rear portion of the tank and the filler spout is not vented like you see in more modern tanks.

I want to close the current filler hole and move the neck to the rear side of the tank where it would come out in the step side fender well and then add a fuel door on the back side of the step side fender.

The question is:

What size filler neck should I use and do I need to consider if it is vented or not? How did they vent the early 70's Blazer tanks?

I know we will have to cut a hole in the frame rail and then add some support, that isn't an issue.

The mod will be somewhat like what Lake Roadster did with his.

[tincan1966]

Assuming my Suburban tank is similar, the fuel inlet is about 1 3/4" and right next to it on the tank is a 5/8" nipple for the vent hose, which runs parallel to the filler hose to about 2" below the gas cap.

Hope I understood your questions correctly and help a little.

[McCoyAZ]

I just saw pictures of where the sending unit fits and it appears that there is a vent tube in it.

Here is what I want to do with the filler tube.

[tincan1966]

Yes that is the tank vent which will have a roll over valve on the underside of the sending unit. The vent tube I meant is actually to assist in filing the tank. sorry I wasn't very clear. You'll want to relocate it too.

[McCoyAZ]

Originally Posted by tincan1966

Yes that is the tank vent which will have a roll over valve on the underside of the sending unit. The vent tube I meant is actually to assist in filing the tank. sorry I wasn't very clear. You'll want to relocate it too.

Relocate the vent tube? How would I go about doing that?

[tincan1966]

When you move the filler neck, add a 1/2" or 5/8" nipple on the tank next to filler tube and one on the filler tube about 2" down from cap. it'll help when filling the tank.

I didn't mean relocate the vent on the sending unit.

[Captainfab]

First of all is this tank new or used? If it is used, anytime you do any sort of soldering or welding on a used gas tank, you have to be EXTREMELY careful and fully aware of the dangers of working on a used tank.

[Rich 5150 69]

Try and find a filler in the wrecking yard with a vent tube that runs all the way up, this will aleviate any filling issues..using the cap that came with ths one I just drilled 1/8th hole straight up almost thru then a 90 degree out the side..

[McCoyAZ]

Originally Posted by Captainfab

First of all is this tank new or used? If it is used, anytime you do any sort of soldering or welding on a used gas tank, you have to be EXTREMELY careful and fully aware of the dangers of working on a used tank.

It is a used tank and it will be fresh from being boiled out from the radiator shop.

I have a machine shop friend that will do the modification for me so safety is well covered.

[McCoyAZ]

What do all these tubes do on the sending unit? Looks like there are 4 different ones.

[kieth]

Originally Posted by McCoyAZ

I just saw pictures of where the sending unit fits and it appears that there is a vent tube in it.

Here is what I want to do with the filler tube.

HOW ABOUT JUST STRAIGHTENING THE FILLER NECK AND PUT A DOOR ON THE FLOOR OF THE BED LIKE THIS....

SURE WOULD BE A LOT LESS TROUBLE:

http://kieth.smugmug.com/Trucks/66-GMC/i-34PhZ8x

JUST CLICK ON THE OTHER THUMBNAILS TO SEE HOW IT WORKED. KIETH

[McCoyAZ]

Originally Posted by kieth

HOW ABOUT JUST STRAIGHTENING THE FILLER NECK AND PUT A DOOR ON THE FLOOR OF THE BED LIKE THIS....

SURE WOULD BE A LOT LESS TROUBLE:

http://kieth.smugmug.com/Trucks/66-GMC/i-34PhZ8x

JUST CLICK ON THE OTHER THUMBNAILS TO SEE HOW IT WORKED. KIETH

Trouble is my middle name.

Personal preference I guess....Hate the idea of having to reach over the side or tailgate and dumping gas all over the bed.

[ljackson]

Originally Posted by tincan1966

When you move the filler neck, add a 1/2" or 5/8" nipple on the tank next to filler tube and one on the filler tube about 2" down from cap. it'll help when filling the tank.

This is good advise. I went with a modified through the bed fill. I put the vent in the top portion of the cross hose on my son's 64. It is very slow to fill. I thought it would vent better. I'm going to re-due it this spring. Planning to put a door in the bed side.

I used the modified neck and cap from an '81 donor truck. It was 1 3/4 OD.

[mjh1965]

Originally Posted by ljackson

This is good advise. I went with a modified through the bed fill. I put the vent in the top portion of the cross hose on my son's 64. It is very slow to fill. I thought it would vent better. I'm going to re-due it this spring. Planning to put a door in the bed side.

I used the modified neck and cap from an '81 donor truck. It was 1 3/4 OD.

Another great solution and it makes me wonder about what I want to do (Grizz reckons this is a better solution )

BUT ......

I am currently working on relocating my tank and filler to rear but need some info please, see link :

http://67-72chevytrucks.com/vboard/s...d.php?t=612734

[McCoyAZ]

Originally Posted by mjh1965

Another great solution and it makes me wonder about what I want to do (Grizz reckons this is a better solution )

BUT ......

I am currently working on relocating my tank and filler to rear but need some info please, see link :

http://67-72chevytrucks.com/vboard/s...d.php?t=612734

I am of the "I have all the parts now, lets make them fit" school of building things.

I would think that you should install the tank and then decide where the filler location needs to be simply because it will be right there for you to locate.

[Grizz1963]

Originally Posted by McCoyAZ

I am of the "I have all the parts now, lets make them fit" school of building things.

I would think that you should install the tank and then decide where the filler location needs to be simply because it will be right there for you to locate.

Hi McCoyAZ, I think what mjh1965 means to find out is the distance of peoples fillers from the side so that he can direct the guy who is going to build his tank here in England as to where to place the filler neck that is fits exactly in the centre of a plank or bed board.
Hope that makes sense.

[luvbowties]

Originally Posted by McCoyAZ

Lets not debate moving the tank under the bed.

I picked up a 25 gallon Chevy Blazer tank that has the filler neck in the center rear portion of the tank and the filler spout is not vented like you see in more modern tanks.

I want to close the current filler hole and move the neck to the rear side of the tank where it would come out in the step side fender well and then add a fuel door on the back side of the step side fender.

The question is:

What size filler neck should I use and do I need to consider if it is vented or not? How did they vent the early 70's Blazer tanks?

I know we will have to cut a hole in the frame rail and then add some support, that isn't an issue.

The mod will be somewhat like what Lake Roadster did with his.

Think I know what you are asking. Pls. see attached pics. I used 1.5" filler tube that had approx. 0.5" vent tube made into it. Cut the 1.5" and 0.5" holes in my fuel cell to match the fixed distance between fill neck & fill-vent tubes; welded short tube extensions. Then went to front of cell & cut a 0.5" vent hole, welded short nipple, ran a flex. tube upwards/over top of frame & above level of tank top, attached an inline filter, & left other end open to atmosphere--clamped it appropriately to keep it steady.
Eyeballed frame where hole needed to be cut for fill tube-and-its-vent-tube to pass thru. Rather than notch frame & go back & reinforce, I just drilled 'limit-holes' to outline where an oval hole needed to go thru frame & cut it out with a hand-held, 3-inch cutoff wheel--no square corners! This oval/rectangular hole left enough 'meat' around it & in the surrounding frame that frame needed no reinforcement! Gotta love the strength advantage of an oval opening vs. a square opening!!!
**NOTE: Cell was lowered several inches after the 'under construction' picture was taken.*
HTH,
Sam

[luvbowties]

Originally Posted by McCoyAZ

Lets not debate moving the tank under the bed.

I picked up a 25 gallon Chevy Blazer tank that has the filler neck in the center rear portion of the tank and the filler spout is not vented like you see in more modern tanks.

I want to close the current filler hole and move the neck to the rear side of the tank where it would come out in the step side fender well and then add a fuel door on the back side of the step side fender.

The question is:

What size filler neck should I use and do I need to consider if it is vented or not? How did they vent the early 70's Blazer tanks?

I know we will have to cut a hole in the frame rail and then add some support, that isn't an issue.

The mod will be somewhat like what Lake Roadster did with his.

OOPS! Sorry for dual quote. But this 2nd one has tad better/more pics & info.

Think I know what you are asking. Pls. see attached pics. I used 1.5" filler tube that had approx. 0.5" vent tube made into it. Cut the 1.5" and 0.5" holes in my fuel cell to match the fixed distance between fill neck & fill-vent tubes; welded short tube extensions. Then went to front of cell & cut a 0.5" vent hole, welded short nipple, ran a flex. tube upwards/over top of frame & above level of tank top, attached an inline filter, & left other end open to atmosphere--clamped it appropriately to keep it steady.
Eyeballed frame where hole needed to be cut for fill tube-and-its-vent-tube to pass thru. Rather than notch frame & go back & reinforce, I just drilled 'limit-holes' to outline where an oval hole needed to go thru frame & cut it out with a hand-held, 3-inch cutoff wheel--no square corners! This oval/rectangular hole left enough 'meat' around it & in the surrounding frame that frame needed no reinforcement! Gotta love the strength advantage of an oval opening vs. a square opening!!!
**NOTE: Fuel cell was lowered several inches after the 'under construction' picture was taken (to allow for added height of newer style float-less sending unit).*
HTH,
Sam

[ljackson]

McCoyAZ, I know you already have your tank but I thought I would throw this in. I looked at lakes thread before doing mine. I thought the 25 gallon Blazer tank hangs down too low with the depth to get 25 gallons between the frame rails. I made my tank. I used 12 ga. mild steel. I had a local shop break and shear for me. I used 1 1/2" I.D. exhaust tubing for the inlet. I used a 3/8 I.D. elbow and nipple for the vent to match the 5/8's O.D. vent at the other end I stick welded the seams and brazed the fittings. It cost me $75.00 for the material including the brake and shear. It goes under the bed between the frame rails where the spare could go. It is a 16 gallon tank. I used an adjustable lenght, correct ohm sender for the stock gauge from the web.

[mjh1965]

Thanks for the pictures Zack . I haven't had my tank made just got a price from a company in the Uk . It's about £200 about €300 but that's still cheaper than getting one shipped . I have got the filler though and was just going to go straight up from the top into the bed floor. The main question is to get the distance from the side correct so if I change to wood later it would be in the centre of a board
See filler cap photos





Thanks Martin

[McCoyAZ]

Originally Posted by Grizz1963

Hi McCoyAZ, I think what mjh1965 means to find out is the distance of peoples fillers from the side so that he can direct the guy who is going to build his tank here in England as to where to place the filler neck that is fits exactly in the centre of a plank or bed board.
Hope that makes sense.

No problem.....but the fact remains that each installation is different and unless all the parts, pieces are laid out and dry fit in place there really isn't a good way to estimate where things will end up.

[McCoyAZ]

Originally Posted by ljackson

McCoyAZ, I know you already have your tank but I thought I would throw this in. I looked at lakes thread before doing mine. I thought the 25 gallon Blazer tank hangs down too low with the depth to get 25 gallons between the frame rails. I made my tank. I used 12 ga. mild steel. I had a local shop break and shear for me. I used 1 1/2" I.D. exhaust tubing for the inlet. I used a 3/8 I.D. elbow and nipple for the vent to match the 5/8's O.D. vent at the other end I stick welded the seams and brazed the fittings. It cost me $75.00 for the material including the brake and shear. It goes under the bed between the frame rails where the spare could go. It is a 16 gallon tank. I used an adjustable lenght, correct ohm sender for the stock gauge from the web.

The tank I have is about 28 inches square and close to 10 or 11 inches deep. I can't be sure how far down it will hang but I don't think it will be too far.

Building my own tank would be fun but I would have to rent/buy a welder and locate all the material and being in a little town in Northern Arizona it just isn't as easy as it should be.

[McCoyAZ]

LuvBowties.....thank you for the pictures.

What did you use for a fuel door and how do you like that floatless sending unit you used?
It comes in the right ohm rating for the original gauge cluster used in a '64?

[ljackson]

Originally Posted by McCoyAZ

The tank I have is about 28 inches square and close to 10 or 11 inches deep. I can't be sure how far down it will hang but I don't think it will be too far.

Building my own tank would be fun but I would have to rent/buy a welder and locate all the material and being in a little town in Northern Arizona it just isn't as easy as it should be.

I may be thinking of a different tank that hangs down pretty low. You may have seen these. They helped me do mine.
http://67-72chevytrucks.com/vboard/s...d.php?t=304853
http://67-72chevytrucks.com/vboard/s...=353749&page=2
http://67-72chevytrucks.com/vboard/s...d.php?t=391990
http://67-72chevytrucks.com/vboard/s...d.php?t=395966

I understand. It might be a little more than a person would want to take on if you are not an experienced welder with your own equipment. It does take a good weld and some patience to get the tank air tight. I used a stick welder. I believe a person would have more pinholes if using a MIG. I didn't try it but I understand that MIG welds are more porous.