Cleaning a new gas tank

I am finally going to get around to installing the 16gal gas tank this morning. I was looking inside it yesterday and noticed some 'stuff' in it that I should probably clean out first. I was talking to my neighbor last night (my dog wouldn't stop barking and was keeping him awake) and he suggested rinsing the tank out with gas, pouring the gas out, and then lighting the gas that was clinging to the sides of the tank and thereby cleaning the inside of the tank. I mentioned the idea to my wife and she was saying I could probably even look in the hole and see how it was going. I hadn't thought of that! Anyways, I'm just wondering if any of you have tried this, and if the burnt gas will leave any residue inside the tank, or does it burn clean enough that it will be ready to install in the car right away?
Ron.

Uh, you're joking, right?

I think that perhaps your wife ( after that conversation)has surely updated your personal lines /life insuranse. I also think that your neighbor is going to get you back for the late night dog thing..... by, taking bets from your other neighbors as to the distance you will travel after ignition.

Seriously....... do not even consider such a stunt, best to wash the tank with a small amount of gas. What you are probably seeing in the tank is "weld dirt" so to speak. A good in line filter will also be needed.

I'd use a small amount of kerosene. Shake and swish it around and drain it out the best you can. I think it to be safer than using gasoline. The amount of gas then put in the tank at the initial fill-up will greatly dilute any traces of the kerosene.

JMO

BD

Bill is right ! ( ty sir!) Alan

Also, check out this article in the knowledge section:

Coating the inside of a new and used gas tank

Ron

That method might be considered for a Darwin award, though.

I remember when I was in high school (just a few years back) someone decided to clean out a Mil Surplus 5-gallon Gerry Can with a similar method.

When he put the match near the opening there was this tremendous "Whooosh!, a 4-foot flame came out of the can, and the can took off across his yard like it was posessed, spinning around and bouncing off of anything it met. It put a considerable dent in his mother's car, a major ding in the garage door, and took out the bird bath in the flower garden before coming to rest a lot warmer than it started.

He's lucky he wasn't killed, either by the flame, the flying can, an explosion or shrapnel (but those Mil cans are pretty rugged). And no, it wasn't me who tried that.

Do a search on gas tanks on this forum - there have been several good threads on how to properly clean your (new) gas tank.

be safe.......gn

Your daughters seem quite bright...now I know where they got their brains from....MOM
Ron

Funny thing but when I laid the gas tank down in the driveway near my neighbors new Mercedes, he came running out of his house waving his arms and yelling something about my mother's ancestry and the end of the world...

It was a slow morning and my strange sense of humor got the better of me, hense the stupid post. I did get the tank installed, had to cut clearance in the hood for the gas cap though. In the process I checked the sender. It goes from 3/4 full to empty with just over 1" of level change. The tank is 10.5" deep. No wonder it's so hard to tell when it is getting low.
Ron

Ron,

I've got the 13 1/2 Gal tank in mine and it seems to stay on F for a long time and then dives toward 1/2. Start looking for a gas station because I think you only have about 2-3 gallons of petrol left. Once I found that out, and I was warned about it from John Steele, it is no big deal! Mr Steele was right. It really does increase the cruising range though and for that it is worth it.

Bruce

While we're on the subject, I had reset my sender before the Carlisle meet. Had it set to have 2 Gals. when the needle hit"R". I had also bought a fuel gauge vibrator. These came installed on VW's to stabilise the needle from wig-wagging. I put the vibrator in line the day before Carlisle and the needle went from 3/4 to 1/4! I'm just wondering if all these errant readings and the gauge taking forever to drop off from full is related to not having the vibrator inline. My tank is still too full to re-adjust the sender with the vibrator inline, so I'll post any results I get as soon as I have a chance to play with it.

BD

One of the problems with fuel gauge readings in Porsche replicas seems to be that the imedance of the Brazilian repo gauges does not match the impedance of the stock VW fuel tank sender most builders use. Palo Alto Speedometer or North Hollywood Speedometer can redo your fuel gauge to match the stock VW tank sender, then it's a matter of getting the tank sender float in the right position to give reasonably accurate readings.

As far as that gauge reading. I have played with three sending units (an old one, and two new VDOs) and it took quite a bit of bending and spreading the stops just so-so to finally get a semi decent reading on the big tank. It holds on full for around 75 miles, then creeps to under 1/2 and then I know I have around 6.5 - 7.0 gallons left. But it is nice to go 300 miles before pumping and not feel like you are pushing it.... having 3 -4 gallons left.

I was looking at the picture section and saw what I have thought would be a cool way to set up a tank.... powder coat it, then use faux SS straps, 2 each, to give a neat look. Annnnd... you know those VDO generic senders they always sell at the shops that can be custom set for any depth (using a sliding float)? Well, of course they dont fit the VW 5 star bolt set up on the tanks.... but, I think with a good welder, grinder, drill and tap set I could make one of those work... accurately. So, powder black tank, stainless straps, stainless Hex heads on the slider VDO sender,,, using the original carpet around the base and foward of the tank.... Maybe a winter project.

As far as the hole you cut in the hood inner... I cut mine in a triangle rounded out like a pool rack... it gave more room for the vent hose to make a loop back (the big tanks have the vent tube pointing inboard) and also clamp the vent hose on the firewall at a height just above the fill line. Then I took the original hood carpet liner and had it cut and lined to match.. then 3M'd it back up.

My 3 pesos worth.
Jim

The reason they don't change much and then drop like a stone, is the angle the float rod is on as it moves through its active range. It is almost vertical and therefore moves through it's entire range with about an inch of fuel level change. If the arm didn't have to be bent downward it would work a lot better.

I am ordering a vertical unit that has a float the simply travels up and down a center rod. They even have senders that are calibrated to work with VDO gauges.
Ron

That's the one Ron...... the VDO Slider. Problem is it doesn't match the VW bolt pattern... (even if they call it universal) see above post.

I think this one will match as it is not made by VDO. I have one at the shop. It's too short for this tank, but the bolt pattern is the same. I'll check the bolt pattern next week to see.

As far as the standard 8 gallon tanks are concerned, I had one of those VDO sliding float senders that came from the 1969 donor Beetle - unfortunately, it never worked correctly, so I ordered a new sender from Kirk, which I promptly wired wrong and destroyed.

Thought of the Palo Alto route, but it would have cost more to get that one fixed at P-A than to get another one from Kirk. He says he uses stock 1969 senders, and then bends the float arm on a jig he's made to make them work bass-akwards to be compatible with the Brazilian gauges. With a little bend-tweeking once they're in, you can get them set pretty accurately. Mine goes just slightly over 4/4 when really full, then drops more-or-less linearly down to just about "R" when I have about 1.5 gallons left. Took me maybe 3 - 4 sessions of bend-tweeks to get it homed in (that's probably why my sender gasket needed to be replaced just before Carlisle!).

Those sliding float senders have a reasonably wide mounting flange (mine was a cast flange) - why can't you just turn them 20 degrees or so and drill a new set of holes in them to fit the new tank mounting holes? You could use the old sender's gasket as a drill template.......I assume they don't have to be mounted perfectly vertical, so they might be easily modified - I would also (from experience) NOT use the rubber gasket, but make a new gasket from 3/16" thick rubberized cork gasket stock (from NAPA or others).

Do those float-style senders come in different lengths to accomodate different tank depths? I've only seen that one, but they were also pretty common on snowmobile tanks for a while, too.

Yes they come in lengths from 6" to 30" or something.

I read your post about bending them to run backwards and remembered that my gauge output negative ohms, not positive, and as I think about it, was bent backwards as well. I may have to look into this a bit more before I order one. Maybe I will just install the one at the shop and see if it works before I order one that is longer.
Ron

Turns out that the gauges don't read negative, just in reverse. I have checked the bolt pattern on the senders we have at the shop, and the pattern is correct to mount on a VW tank. Also, they sell senders calibrated to work with VDO gauges, and in the correct range. I'll order one on Monday and let you all know how it works.
Ron