Conversion complete, tank won't take fuel! HELP!

Propane, Butane, LPG, GPL, C3H8, C4H10
alehander
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Conversion complete, tank won't take fuel! HELP!

Post by alehander »

Hello, folks. Just finished my second conversion - a 1968 Volvo 144S. Under the hood, things are fine. But the tank refuses to take more than a 1/4 gallon or so of fuel from my spare (a 5-gal forklift tank).

I routinely use this method to fill the tanks in my other conversion and the spare empties completely. I understand that passive tank-tank transfer only happens as long as there is a pressure differential, but why the difference between the two cars?

I am using a new 10-gal forklift tank, as you can see in the pics. The tank came pressurized with something (air?). I simply let the stuff out, though the tag called for the tank to be "purged by a professional", whatever that means.

I understand that the tank needs to be oriented correctly when it is mounted horizontally, as in my case. I did not see any "this end up" indicators, so I took a guess at the orientation - please take a look at the pics. To use the tank in the conversion, I removed the fill valve and mounted in on the body with a length of fuel line in between. When removing the fill valve, I did not see any OPD devices "in the hole". Do modern forklift tanks come with built-in OPDs?

I have not tried filling at the pump yet - any ideas why this thing is not cooperating? Thanks again for the help!


Under the hood: mixer, converter & lockoff. Weber intake manifold, "custom" linkage.
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10-gal LPG forklift tank.
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Lenin zhil, Lenin zhiv, Lenin budet zhit'

alehander
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Post by alehander »

OK, think I got some of this sorted out. Tell me if I'm way off.

1. Forklift tanks are NOT OPD-equipped. That said, tank should fill completely in ANY orientation. The "proper" orientation has the round hole on the collar pointing "down", the blow-off valve pointing up and the gauge level... more-or-less what I've got.

2. The tank size determines how easily or how difficult the tank will be to fill. That is, my 25-gal tanks, when completely empty, will accept a full 5 gal from my spare. This 10-gal tank will not. This makes some sence, though I still cant get a good grip on how the pressure behaves as a tank is being filled or emptied.

3. A suggestion from a local propane guy to force-feed this setup: Cool the receiving tank w/water, etc. Heat the spare in the sun (or.. nah), then fill.[/b]
Lenin zhil, Lenin zhiv, Lenin budet zhit'

sleepybu
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Post by sleepybu »

i'd say you may have some safety issues with that tank in a trunk :?

itsmejto
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Post by itsmejto »

I second those trunk safety issues, you need to totally enclose the tank head and let it breath to the outside world at least. Those home made straps are questionable too. as for your filling problem, I think you may be mistaken about fork lift tanks not being opd, also they require to be filled standing upright. Looks like you have removed the filler valve and screwed a hose directly into it, also not good, make an extension if you must, but retain the fill valve. You may have an older tank in your other vehicle that may or may not be an opd. have you rotated any of the hose points from the original, if its an opd, it may have the float closed if not positioned correctly. I'm not sure of fork lift and opd regulations, just poking suggestions your way.
Johnny O

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Post by alehander »

Crud. I have vented the blow-off outside the car, same with the 20% line. Do I need to isolate the entire HEAD of the tank?

From my discussions with 2-3 propane shops, these tanks are not OPD. When removing the fill valve, it screwed into an ordinary female thread in the tank, no float valves, etc attached. I then ran a line to the same fill valve, now mounted on the car body.

My other tank IS opd-equipped. When filling at a pump station, fuel flow shuts off reliably at ~25 gals.

I have not rotated any other plumbing on the tank. But where would the OPD be, if not on the fill valve? I understand these tanks are also filled thru the liquid outlet - opd here, maybe?

If the tank location is really a heinous mistake, I would certainly consider relocating it "outside", though there are no obvious locations which will not result in counting speedbumps.
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Frank
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Post by Frank »

You did a nice job putting everything together. Very neat and clean. However, your installation with the lift-truck fuel tank will NOT meet NFPA 58 for a number of reasons. An important one is that there is no enclosure around the fittings so that a blow-off from the safety relief valve (SRV) will fill your trunk with explosive vapor. The enclosure is required in case your fittings start to leak and not just for SRV blow-offs. I believe the SRV for your tank is the fitting with the blue cap. I also think you would also be happier with a larger capacity ASME tank. Please look for the correct tank as soon as possible and do NOT try to fill this tank.

As for mounting lift-truck tanks, the round hole in the rim should be pointing downwards. Normally, lift trucks have a special bracket that has a pin to properly locate the tank. Next time you see an LPG lift truck, have a close look at the brackets.

Since the tank seems permanently mounted, how would you know when the tank is 80% full? Your tank is designed to be filled in the up-position and liquid flowing from the spit valve indicates when it is time to stop filling. The reason that LPG tanks are only filled to 80% is that if you overfill the tank, the liquid could easily expand to point where it blows off in the SRV.

Purging the air from the tank might make it easier to fill. The Ontario Propane Association has a procedure for purging the tank. Make sure your new tank is properly purged.

alehander
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Post by alehander »

Frank, I understand that these tanks are not road-certified. I'd like to clarify a couple of installation issues and get your opinion on whether these mitigate some of the safety concerns.

Firstly, both the blow-off (SRV) and spit valves are routed to the car's exterior. This is not shown in the pics, but has been done. So, a blow-off will not flood the trunk. A serious leak still may - would a propane detection device help with this?

To fill to 80%, would the same spit valve not start flowing liquid in the horizontal position at roughly the same fill level?

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I understand that the best way to fix all this is with a road-grade tank, mounted under the car. I'd still like to salvage this installation, if possible.
Lenin zhil, Lenin zhiv, Lenin budet zhit'

franz
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concerns

Post by franz »

Alehander;
The tank you are using is not certified by any authority in either the US or Canada for use on a motorvehicle in over the road use. All laws require the use of a sealed container with venting to the outside. It is not as simple as just encapsulating the tank, that was done in the 60's and 70's but not since then.
Your installation looks first rate though, but that is our opinion. If you are involved in an accident and even though the accident may not be propane related, you will no doubt be cited for an illegal LPG tank installation. In the US, any DOT roadside inspector can tag you and if a DPS officer recognizes the installation, they can too.

Be careful how you progress and lets stay in the law. Thanks;

Franz

sleepybu
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Post by sleepybu »

alehander, where you from :?:

MLGPropane
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Post by MLGPropane »

As mentioned, there are a ton of legal issues with this set up... But all that aside, if I am following correctly - are you attempting to transfer fuel into the forklift cylinder from a bar-b-q 20 pounder equipped with an OPD?

alehander
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Post by alehander »

Franz, thanks for the heads up. I understand that the installation is not road-legal, no matter how safe I make it. I'm gambling that it'll never be inspected. I'm also not willing to pay $400-$500 for a road-grade tank and cant find anything cheap & used locally. This (new) 10-gal forklift tank was $160, delivered.

Sleepy, I'm from Russia, now living in California. This may explain some of the partial disregard for safe, legal installations - I'd give some examples of how things like this are done "back home", but I'll just use this: :shock:.

MLG - I use a 5-gal forklift tank (not a BBQ bottle) as a spare. I've used it successfully on my other conversion, which uses 25-gal road tanks. When those are empty & I'm stuck in the middle of nowhere, my 5-gal spare will empty completely into the 25-gal tanks. Not so with a much smaller 10-gal I am using here. The spare in NOT opd-equipped. My car-mounted 25-gal tanks ARE opd-equipped. Here's a pic of that install:

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Thanks for all the help, guys.
Lenin zhil, Lenin zhiv, Lenin budet zhit'

MLGPropane
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Post by MLGPropane »

What part of California...? If at all possible perhaps you could swing by the conversion shop here, we could take a look at the install and perhaps find a suitable tank for you to install....

franz
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Take advantage

Post by franz »

Alehander;
Take advantage of the offer by MLGPropane, its a rare opportunity to work with a company of this caliber, the folks there are first rate. Tell them Hi for me!

MLGPropane
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Post by MLGPropane »

:D Thanks much, Franz! A great compliment indeed...

Frank
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Post by Frank »

Regarding your request for information about a propane detection device, your car (or any car) is already equipped with one. The device(s) are all the electrical contacts inside your vehicle. The spark from the door switch for the dome light could easily ignite the fuel mixture from a leaking tank fitting. The explosion will tell you that you have a leak.

About the operation of spit valve in a horizontal position. My understanding is that these tanks were designed to be only filled upright. Without knowing the dimensions of the valve placement, I wouldn't even be able to guess at which point it would start to flow. Your tank manufacturer would best know this information.

None of the regulations in the LPG installation codes are there to make your life more difficult or to cost you more money. Anyone thinking about cutting corners should think twice about how much a little violation could potentially cost.

That offer from MLGPropane is excellent and I too would would take them up on it. Don't put any more fuel into your tank until your conversion passes the safety inspection.

I think there are standard ASME in-trunk tanks that should work fine for you. I looks to me like you installed a Manchester PN 5590 (9.9 US gallon capacity, 33.3" overall length, 12.2" overall diameter). A similar sized ASME in-trunk tank with the fitting enclosure is Sleegers PN 12x32 SBTO. You could probably even get them to make it about 6" longer since it looks like you have the room for it. Even though such an ASME tank would cost a bit more money, you'll appreciate the extra capacity at every fill-up.

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