55 Fargo Posted November 26, 2007 Report Posted November 26, 2007 Hi all, started to install new gas tank on Sunday. So far, I have been able to use the original tank brackets with the new straps that came with the tank. The sender unit hole lines up with the hole in the trunk floor, the filler neck will also line up.The tank is a close match but is not identical to an OEM tank. The only prolem I have is, with the OEM braces and thestraps from the new tank, it positions the gas tank right up to the bottom of the trunk floor, right tight. The problem with this is, the vent valve fitting goes on the top of the tank, it requires about 3/4 of an inch of clearance. Now do I make the brackets lower to provide clearance, or do I make a hole in the trunk floor over the vent fitting, then run the vent hose through trunk and out the side somewhere. Any ideas, this is not as easy as swapping diffs, it seems alittle complicated, as fabbing up mounts, is not my strong point.................Fred Quote
Plymouthy Adams Posted November 26, 2007 Report Posted November 26, 2007 you can use strips of 3/4 inch spruce...paint it up nice..should last a long long time...glue these strips in place while you jostle it about mounting it.once in, firmed up they should be there forever..as for venting the roll over...there should have been directions... Quote
55 Fargo Posted November 26, 2007 Author Report Posted November 26, 2007 Hi Tim, we have plenty of spruce here, could use cedar, never rot for years or pieces of pressure treated spruce. Never dawned on me to use wood in there. No the directions are vague and very little.............Thanx Fred Quote
Plymouthy Adams Posted November 26, 2007 Report Posted November 26, 2007 (edited) well by definition the roll-over valve is such that if case of a titz-up condition of your vehicle..it is designed to relieve any pressure in the tank and also drop down and block the gravity flow of fuel from entering the line...this is probably mandated by law even for new tanks for retrofit...they must pass a 360 roll without any leakage of fuel. you definitely do not want it to be in aposition of restriction by jambing it against the body...but of course..with these old cars..the inlet hose is still not anti-siphon and leak free..but at least it should prevent major spill or fuel present in the eingine compartment.. Edited January 11, 2013 by Tim Adams Quote
Norm's Coupe Posted November 26, 2007 Report Posted November 26, 2007 Fred, I have the rollover vent hose going through the trunk on my car. Then up the side of the inner fender inside the trunk. Drilled a hole in the inner fender for the hose to go through near the top of the inner fender. Hose goes to the rollover valve that I mounted as high as I could between the outer fender and the inner fender. Mine came with an L Bracket to mount the rollover valve to. If yours didn't, just make one out of a piece of steel. That said, I really don't like the vent hose in the trunk. I plan on replacing the hose in the trunk with steel gas line, then a short flexible hose to the fitting on the tank and valve itself. As I mentioned before and Tim also mentioned, you do need the rollover valve. Even if the car isn't upside down, the vent also prevents any buildup of fumes to build up inside the tank to help prevent possible explosions. The way I look at it, the gas tank is just as important as the brakes are when it comes to safety. To see just how much gas fumes will build up and expand it's container. Take a half gallon of gas in a metal 1 gallon gas can. Set it in the garage on hot days with the vent and cap closed tight. Leave it there for a few days during hot weather. Come back, and just open the vent cap only. You will see the can collapse a little as the pressure is relieved. You will also hear it hiss as you open the vent. A plastic gas container will show this test even better. Those really expand with the pressure bottled up. I've had those blow the vent cap open before when the pressure got too great. This is another function of that rollover valve, to relieve that pressure when it gets too great. If you shake up the 1 gallon can with the gas, that expansion will happen even faster, even in cold weather. Quote
55 Fargo Posted January 11, 2013 Author Report Posted January 11, 2013 I am reviving this thread for the benefit of those who may be doing this very install of a Tanksinc 41-48 Mopar universal gas tank. This thread is old, and I can't remember if I thanked Tim and Norm for their coaching but will do so now, thanx Guys. This tank is A-okay, and has been in service 5 years now. The filler neck flange on tank, you will need Permatex Aviation gasket sealer, very sticky odd smelling brown stuff. You do not tighten flange screw to tight, or it will twist gasket, the little rubber O ring must be used on the screws. The filler neck will line up, to this, when you use rubber filler neck hose and clamps. Rollover vent valve fitting on tank, you will need to make spacers on gastank brackets under floor to space gas tank away from trunk floor pan to allow clearance. I custom some asian hardwood pieces, then primered and painted, worked great. I would install fuel sender unit, and make sure it works, and does clear, the baffles inside of tank, and is functioning prior to bolting up tank and adding gas. I also ran a separate ground wire from fuel sender to the frame. This is not a 2 hour job, but if you have everything ready, it is not a huge deal either. Feel free to post/and/or ask questions relating to the install of a tanks inc Mopar gas tank, or any other custom/universal type gas tank installation too..... Quote
Frank Elder Posted January 11, 2013 Report Posted January 11, 2013 Don't forget the rubbers.............:eek:No I'm not drinking! Fred knows what's what. Quote
47heaven Posted January 11, 2013 Report Posted January 11, 2013 Fred...most of what you said seems to make sense. As I was reading the paper they sent me it mentions: "Most of our tanks our designed to work with your stock-style vented cap. We have provided and additional vent opening in many of our tanks to help with today's reformulated fuels. If you have changed to a non-vented cap, your installation may require additionalventing through the neck or the sending unit to prevent pressurizing the tank." So does this mean that the top vent is optional since the vent is additional? In other words, if I use a vented gas cap instead, will I have to still vent it from the top? The only thing I'm confused on is if I do have to place this vent flange on the tank, and space it from under the trunk floor, how is the sending unit going to mount to the tank? I'm thinking of the gap between the tank and trunk floor, or is the sending unit no longer going to be mounted to the floor of the trunk, but to the tank? Quote
Frank Elder Posted January 11, 2013 Report Posted January 11, 2013 The threaded fitting in the top is for a ROLLOVER VALVE.......not a vent, although you may use it as such if you wish. Yes the sending unit mounts to the tank and not the trunk floor. Use a vented gas cap or run a line from the top up into the wheel well above the top of the tank to prevent syphoning of gas when you fill up. It would also behoove you to use some sort of rubber coating or rubber strips for anti squeak or chafe tape between the straps and the tank....... Quote
Plymouthy Adams Posted January 11, 2013 Report Posted January 11, 2013 (edited) ...the added vent is as stated..designed for those systems/application where the system is closed and or very near the top of the tank..and the added vent will go from the top of the tank to near the top of the spout of the fill tube so to allow smooth filling without burping back all the time making refill abother and a mess...as your stock filler tube is long and way above the tank in stock location you really do not need this..further the tube is quite large and does not have restrictions in it as the modern anti-siphon fillers have...your system requires a vented gas cap..you can plug this top hole with a flush style plug and just back exactly as your original set-up Edited January 11, 2013 by Tim Adams Quote
55 Fargo Posted January 11, 2013 Author Report Posted January 11, 2013 I would just install without the valve, and go with a vented cap as suggested, maked life easier.... Quote
47heaven Posted January 11, 2013 Report Posted January 11, 2013 I would just install without the valve, and go with a vented cap as suggested, maked life easier.... I think that is what I'm going to do. I want the gas tank snug against the botton of the trunk. BTW...do the new straps go in like the old ones? Can the old ones still be used on this tank? Quote
55 Fargo Posted January 12, 2013 Author Report Posted January 12, 2013 I think that is what I'm going to do. I want the gas tank snug against the botton of the trunk. BTW...do the new straps go in like the old ones? Can the old ones still be used on this tank? I used the old oem top bracket straps and the new universal straps together. If your old straps are in good condition, why not use em. I would drop old tank, clean up trunk pan from underside, get hangers ready, prep tank, with fittings, and do a test hang with new dry tank, get it all worked out before adding gas, all gas line, sender unit, and filler neck. Darin, you can do this job, with all prepping a weekend thing...take pics and post your progress, will try and help you through... Quote
47heaven Posted January 12, 2013 Report Posted January 12, 2013 I used the old oem top bracket straps and the new universal straps together.If your old straps are in good condition, why not use em. I would drop old tank, clean up trunk pan from underside, get hangers ready, prep tank, with fittings, and do a test hang with new dry tank, get it all worked out before adding gas, all gas line, sender unit, and filler neck. Darin, you can do this job, with all prepping a weekend thing...take pics and post your progress, will try and help you through... Fred, I took the gas tank out originally when I first bought the car. I was a little thinner then, too, so it was easier to get underneath it. What brand of black paint do you suggest that I use to paint the gas tank? Quote
47heaven Posted January 12, 2013 Report Posted January 12, 2013 Sending unit mounts to the tank before, and after. Trunk floor just has an access panel.Keep in mind that the stock sending unit has to be reworked to fit in the tank, and clear the baffles in the new tank. I believe Fred covered that in his tank thread. If need be for the moment to get back on the road you can just isolate the wire terminal, and put a solid cover over the sending unit mounting hole. Just remember to keep fuel in the tank until you get a functional sender/gauge set up completed. I have an aftermarket, one wire, sending unit that I was already using with the previous tank. Just have to see if it will fit into the hole of the new one. I was just curious why this new tank has baffles? I thought it would have been straight through all the way across just like in the original. Are they to make the tank stronger or control sloshing of the gas? Quote
55 Fargo Posted January 12, 2013 Author Report Posted January 12, 2013 I have an aftermarket, one wire, sending unit that I was already using with the previous tank. Just have to see if it will fit into the hole of the new one. I was just curious why this new tank has baffles? I thought it would have been straight through all the way across just like in the original. Are they to make the tank stronger or control sloshing of the gas? The baffles control gas from sloshing around. You have a 1 wire sender? Why? You 12 volts with aftermarket fuel gauge or something custom? Again no big deal, is your sender and adjustable typ for the float arm, you may have to shorten it a bit to reach the bottom and not hit nearby baffle, again no big deal. Just try sender in new tank, to see if fit and swing arm moves through the entire range of switch. You can get it all done, not a big deal, just some time and playing around, make it a fun job, if you can, take some time and enjoy it... Quote
55 Fargo Posted January 12, 2013 Author Report Posted January 12, 2013 Fred, I took the gas tank out originally when I first bought the car. I was a little thinner then, too, so it was easier to get underneath it. What brand of black paint do you suggest that I use to paint the gas tank? You can use whatever you want, go pricey on trunk floor bottom, with POR 15 or Zero-Rust. How about clean it up, primer with rusty metal primer, and Black Rustoleum type paint, good to go for another 40 years, under this area. I did not paint the gas tank, and it looks great years later, and I drive on gravel roads, if your painting it, scuff it with 3m scuff pad, or 400 sand paper, shoot on some enamel paint of your choice and color, but I would leave it alone... PS you could take the tank, and have some body and paint place, paint it in a black urethane, but I would consult TanksInc, to see what is sprayed on tank from their end first, easy enough to spray witha quality enamel rattle can prior to install, give it a few days too dry good. Quote
47heaven Posted January 12, 2013 Report Posted January 12, 2013 The baffles control gas from sloshing around.You have a 1 wire sender? Why? You 12 volts with aftermarket fuel gauge or something custom? Again no big deal, is your sender and adjustable typ for the float arm, you may have to shorten it a bit to reach the bottom and not hit nearby baffle, again no big deal. Just try sender in new tank, to see if fit and swing arm moves through the entire range of switch. You can get it all done, not a big deal, just some time and playing around, make it a fun job, if you can, take some time and enjoy it... Yes, I'm running 12 volts, and a few years ago I switched to a one wire sending unit and gauge (I have a new gauge, but the old face is still being used). Quote
55 Fargo Posted February 22, 2013 Author Report Posted February 22, 2013 47Heaven, what happened to your new gas tank install? I am wondering if you completed this job, as you have posted no follow-up to this task. If you have done the job, please post with your results, and pics if possible, this will be of help to anyone contemplating this particular install.... Quote
47heaven Posted February 28, 2013 Report Posted February 28, 2013 Fred, sorry about that. I still have to get the muffler moved out of the way on the left side. Have gotten extremely busy, and other things have had to come first. I may have the muffler work done tomorrow so I can install the tank. As I had mentioned before, it seems pretty simple, but I just hope the gas line, which is all steel now, will make it to the outlet all right, since this new tank is not as wide as the other. Quote
Frank Elder Posted February 28, 2013 Report Posted February 28, 2013 I just hope the gas line, which is all steel now, will make it to the outlet all right, since this new tank is not as wide as the other. Cut the steel line, deburr, add the right length of rubber fuel hose and tighten down your 2 clamps and you are in business! Quote
47heaven Posted February 28, 2013 Report Posted February 28, 2013 Cut the steel line, deburr, add the right length of rubber fuel hose and tighten down your 2 clamps and you are in business! Thanks, Frank! Quote
TodFitch Posted February 28, 2013 Report Posted February 28, 2013 (edited) Cut the steel line, deburr, add the right length of rubber fuel hose and tighten down your 2 clamps and you are in business! Don't know about the P15 era, but with the fabric anti-squeek between the tank and the frame and the straps and the tank on my '33, I suspect that the fuel tank grounding is mostly through the metal tubing. If you replace a section of that with rubber you might have to run a ground wire to get the fuel gauge to read properly. Edited February 28, 2013 by TodFitch Quote
Frank Elder Posted March 1, 2013 Report Posted March 1, 2013 Don't know about the P15 era, but with the fabric anti-squeek between the tank and the frame and the straps and the tank on my '33, I suspect that the fuel tank grounding is mostly through the metal tubing. If you replace a section of that with rubber you might have to run a ground wire to get the fuel gauge to read properly. So run a grounding strap...... Quote
55 Fargo Posted March 1, 2013 Author Report Posted March 1, 2013 So run a grounding strap...... I did just this, ran a seperate ground wire from tank to frame, using 10 gauge wire, works for Me.. Quote
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