Installing new Dansk gas tank - having issues |
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Installing new Dansk gas tank - having issues |
DC_neun_vierzehn |
May 28 2024, 11:11 AM
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#1
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Member Group: Members Posts: 437 Joined: 16-November 20 From: Delaware Shore Member No.: 24,893 Region Association: MidAtlantic Region |
I have a '73 2.0.
About a year and a half ago, when we pulled the motor and trans for sending out to the rebuilder, I did a lot of research on whether to try and restore my gas tank or buy a new aftermarket tank. The inside of my tank is grungy. Most of my research and most of the helpful folks here on 914 World guided my decision to a new Dansk tank. I called George to make sure I was ordering the Dansk tank, and all of the correct additional parts (sock, washers, replacement lines, clamps, etc.). Because I had read/heard so many stories of the original batch of 914 Dansk tanks not fitting, I also made sure to ask if I was getting a newer Dansk tank that would actually fit. The tank and parts arrived while I awaited the conclusion of the motor and trans rebuild. Now ... fast forward to last weekend, when I finally could dive in and swamp out the tanks. I used several old posts here on 914 World and Pelican to help me with the step by step remove and install process. Thus, I WAS ALREADY aware of the issue I would need to tackle of either shimmying the plastic bridge under the strap or removing some material from the top rib of the tank as detailed in THIS POST. However, one of my last steps before tackling that was to install the expansion tank and fuel filler on the new Dansk tank. That's where I ran into problems. If I install the fuel filler first, I cannot get the expansion tank on. if I install the expansion tank first, I cannot get the fuel filler on. They interfere with each other indicating that the mounts for the expansion tank are too far over on the passenger side (or the fuel filler hole in the tank is too far toward the driver side). Also, it looks like the fuel sending until it not resting in the indented section on the bottom of the expansion tank further preventing installation of it. Before calling Auto Atlanta, I wanted to check here to see if anybody else has run into this exact issue installing a new Dansk tank? Does it sound like I have sent an old non-fitting Dansk tank? Other thoughts/ideas/suggestion? |
Superhawk996 |
Jun 26 2024, 06:58 PM
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#2
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914 Guru Group: Members Posts: 6,469 Joined: 25-August 18 From: Woods of N. Idaho Member No.: 22,428 Region Association: Galt's Gulch |
Adding something more than my previous non constructive sarcasm - I really shouldn’t have posted that. . . . But I did. (IMG:style_emoticons/default/sad.gif)
So why is the sock there? All pumps do a much better job of pumping than sucking. This is the reason filters go on the pump output. Putting a filter on the pump inlet decreases pump efficiency at best. At worst, not having a filter at all on the pump inlet means the pump has to pump whatever comes its way. Pumping rust, sand, or other debris that ends up in fuel will shorten the life of the pump. Old fashioned diaphragm pumps aren’t nearly as easily damaged or clogged by debris as is a rotary pump. If enough large debris is present, it can even block the pump inlet. Fuel injection components want a 10 micron filter. Carbs about 30-40 microns. Used alone, these filters can clog very quickly and would starve the pump both of fuel to feed to the engine but also the cooling fluid for the pump (which also happens to be the fuel). Clogged inlet or outlet = burned out pump eventually. The solution? Put a coarse 100 micron screen mesh filter on the pump suction side to protect the pump. The filter is coarse enough that it won’t be easily clogged. If the screen is repeatedly clogging there are bigger issues (rusted tank, massive fuel contamination) that need to be resolved. This 100 micron pre filter is large enough to keep big abrasive debris out of the pump without limiting fuel flow at all. Then an appropriate filter is put on the pressure side of the pump to keep fuel injectors or carbs clean. The pressure side of the pump is much more capable of overcoming back pressure caused by such a fine filtration media as it becomes loaded. That is why the sock is there and why it is needed. |
wonkipop |
Jun 27 2024, 03:53 AM
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#3
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Advanced Member Group: Members Posts: 4,611 Joined: 6-May 20 From: north antarctica Member No.: 24,231 Region Association: NineFourteenerVille |
Adding something more than my previous non constructive sarcasm - I really shouldn’t have posted that. . . . But I did. (IMG:style_emoticons/default/sad.gif) So why is the sock there? All pumps do a much better job of pumping than sucking. This is the reason filters go on the pump output. Putting a filter on the pump inlet decreases pump efficiency at best. At worst, not having a filter at all on the pump inlet means the pump has to pump whatever comes its way. Pumping rust, sand, or other debris that ends up in fuel will shorten the life of the pump. Old fashioned diaphragm pumps aren’t nearly as easily damaged or clogged by debris as is a rotary pump. If enough large debris is present, it can even block the pump inlet. Fuel injection components want a 10 micron filter. Carbs about 30-40 microns. Used alone, these filters can clog very quickly and would starve the pump both of fuel to feed to the engine but also the cooling fluid for the pump (which also happens to be the fuel). Clogged inlet or outlet = burned out pump eventually. The solution? Put a coarse 100 micron screen mesh filter on the pump suction side to protect the pump. The filter is coarse enough that it won’t be easily clogged. If the screen is repeatedly clogging there are bigger issues (rusted tank, massive fuel contamination) that need to be resolved. This 100 micron pre filter is large enough to keep big abrasive debris out of the pump without limiting fuel flow at all. Then an appropriate filter is put on the pressure side of the pump to keep fuel injectors or carbs clean. The pressure side of the pump is much more capable of overcoming back pressure caused by such a fine filtration media as it becomes loaded. That is why the sock is there and why it is needed. except (and i don't mean to be picky) but the stock factory set up is 1) the sock and 2) one of those old school cube VW fuel filters just before the line goes into the pump when located under the engine - all before the pump, which was a roller cell pump. and nothing after the pump. these days i still have not put my rebuilt roller cell pump back in. i run a turbine pump with a high pressure filter after it to protect my precious L jet NOS injectors. because a turbine pump (modern) can spit its guts into the line and ruin the injectors (unlike the original roller cell pumps). i still have the cube before the pump. and the sock is long gone, lost in conversion to right hand drive when we had to cut the bottom of the tank down to half its width for a footwell on the right hand side. but i know what you are saying. the sock is there for a reason. if nothing else it also acts as a kind of a baffle too? i'd have it there still if i had a left hand drive car. but originally they also did run that filter right before the pump not after. |
Superhawk996 |
Jun 27 2024, 06:50 AM
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#4
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914 Guru Group: Members Posts: 6,469 Joined: 25-August 18 From: Woods of N. Idaho Member No.: 22,428 Region Association: Galt's Gulch |
but originally they also did run that filter right before the pump not after. Yup. And having a fine filter at the pump inlet was part of the vapor lock problem. Along with a very long suction line and of course having the pump so close to the engine and exhaust heat. Add to that, a plastic fuel filter in that same hot location and it’s susceptibility to engine fires. (IMG:style_emoticons/default/chair.gif) Mistakes were definitely made but a mesh sock on the inlet wasn’t one of them. The fuel pump and filter location wasn’t the smartest packaging job and not VW/Porsche’s finest moment. I chalk it up to how difficult it is to package a mid-engine vehicle. The roller pump is pretty susceptible to wear due to abrasives and contamination of the little relief valve. It was not a cheap pump in a day and age where engine driven mechanical diaphragm pumps were still the norm. Development and testing over the past 50 odd years has served to confirm that the fine filtration FI requires, belongs on the pump outlet. However, I do admire how many things they did get right, and I do wonder how much better 914s would have gotten if it had more than its short six year lifecycle. |
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