MikeD72

Hello , for my 72 L48 auto I need please some direction regarding my fuel tank . I'm looking to get a bigger fuel tank because mine is only holding around 12/13 gallon and I have to frequent stop at the gas station is becoming annoying !! I have blocked off the the vapor canistor line to the tank and got a vented cap . Also I have a returned line from the fuel pump to the tank . Ok which tank would be recommended and since I'm not using the vapor canistor i wouldn't need the vent line also should I cancel the returned line from the fuel pump with a new fuel pump ?? Thx in advance !!

MelWff

The tank is rated at 18 gallons so something else is going on. The return line should be left it prevents vapor lock.

Mike Ward

Deleting the vapour canister and return line would be mistakes, neither would solve the gas tank capacity issue.

Look elsewhere.

doorgunner

Mike Ward......rookie question: Could it be possible that his tank float rod is bent upwards more than needed causing the dash gauge to read Empty/low when it still has 4-5 gallons of fuel left in the tank?

(I set my float-rod angle for the gauge to read Empty when there is still 2 gallons of gas left in the tank when I cleaned/repaired the tank....that way I have another 30 miles of fuel left in the tank just in case I haven't paid attention to the gas gauge until "the last minute")

That gives me a 200 or more mile range, which, by then is time to stretch my "Nam legs"!

MikeD72

I'm not sure but I know that I have changed out the sending unit about a month ago but in any case is it something that I should be looking into getting a bigger fuel tank ? Or just keep stretching my legs every 2 or 3 days ??

rajin cajin

I recently replaced mine with the OEM 18 gal. (I think that was the capacity). There are some 22 gal. tanks out there on the market. However, if you are only getting 13 gal. in the existing tank, something else is going on inside of it. Also consider the actual dash fuel gauge reading wrong. The opening to the tank is large enough however to actually look down into the tank and visualize if you are in fact empty or not. If you go with one of the 22 gal aftermarket tanks (as those on flee-bay), most I looked at do not have the port/tube for the return line from the fuel pump. Just something to consider. Does it appear to be the original tank or could it have been replaced some time in the past cause 12/13 gallons is just strange. Unless you have 5gallons of debris in the tank now.

MikeD72

Hi when my fuel gauge reads empty I know that there is some gas in the tank how much ?? Maybe 2 or 3 inch left from the bottom of the tank when I look in there and so when I fill it up to the top I only can get 13 gallon in it also my fuel gauge reads always a little shy of full ?? Thx

doorgunner

Each inch is approx one gallon of fuel maybe you could use a larger tank! Filling up once a week is better! (And I don't spend cash unnecessarily).

mrvette

Yeh, about a gallon/inch....I just stick a wood stick down into the tank, make sure to mark it and not be on anything but metal bottom mark the top, that is 18 gallons....measure down 1/2 way, that is obviously 9 gallons, etc......my tank tended to 'run dry' at about 1/4 tank, because I run Fuel Injection and if the fuel sloshed to one side too much it would uncover the pickup, and so be a stumble/die with engine.....

I added a 5 gallon sump tank in place of the spare tire.....so that is not an issue anymore.....

I would stick a stick in it, and measure just WTF is going on for sure.....

Mike Ward

Very possible, and I am guilty of ***-u-ming that the OP already checked the obvious.

Easy Mike

About 3 gallons.

Alan 71

Hi,
With replacement sending units sometimes the float supplied isn't buoyant enough, so it floats below the surface.
If this is so the float may be touching the bottom of the tank while there's still gas in the tank…. sending a signal that the tank is empty.
I'd think you'd also want to verify the position on the inlet pipe and filter sock to ensure they're at the bottom of the tank.
Regards,
Alan

Navy01Coupe

You could always live dangerously...

Fill your tank and take a 2 gallon spare tank in the car and drive it till it is empty. Drive around on roads where you are never too far from a gas station. Then immediately top it off and see exactly how many gallons of gas can really fit in the tank and how many miles you can go on a tank.

Best part...You HAVE to spend a whole day driving your car!!

MikeD72

Lol , wouldn't want to stall in the middle of making a left turn but I like the wooden stick idea so one inch is one gallon . Thx like always u guys are awesome !!!!

Dino_'72

I'm pretty sure our 72 tanks have a rubber bladder liner. Yours may have collapsed somewhat restricting how much fuel you can put in.

Last I heard replacement tanks cannot be purchased with the bladder.

Bladders were used to provide protection in case of a tank puncture from a rear end collision.

Mike Ward

No bladder on any '72 tank.

Dino_'72

Ok. So I guess I don't have a bladder. Now I know why I have a 1 beer limit.

69L46vert

If you do replace it, beware of the cheap tanks a lot of places sell. (Platinum) They may not have the return line port. I had to drill the tank and solder in a return port for my 69.

Sigforty

My 71 had about the same issue, but I think it was the sender. Your 72 should use the same tank my 71 does. It is listed as a GM33D gas tank. While everyone indicates the same tank dimensions of 38" x 15-3/4" x 11-3/4" for the tank. You will find the capacity listed all over the place.

Here it is 18 Gallons.
http://www.tanksinc.com/index.cfm/pa...140/prd140.htm

Here it is 20 Gallons.
http://www.ebay.com/itm/1970-1974-CHEVROLET-CORVETTE-GAS-FUEL-TANK-WITH-EEC-2-VENTS-GM33D-/271564127145?pt=Vintage_Car_Truck_Parts_Accessories&fits=Make%3AChevrolet%7CModel%3ACorvette&hash=item3f3a7bbba9&vxp=mtr
Here they claim 24 Gallons.
http://aftermarketautostore.com/ecom...ific=jrcnpmcse

Based on all those different capacities I think it is best to run it empty and measure yourself. I did find on google this corvette book list the capacity at 18 gallons. http://books.google.com/books?id=lX5...201971&f=false