MK1 GTI Fuel Tank...

Discussion in 'Engines' started by Zender Z20, Jan 17, 2022.

  1. Zender Z20

    Zender Z20 Paid Member Paid Member

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    Random questions, if you've recently bought a repro. tank may be able to answer some of them.

    Relates to a 1983 1.8, from end of production and more or less bog standard, it's likely even the original tank.

    Not in bad nick, but going to change it as it's stood in excess of 10 years and there's now a sticky tar like coating on the inside.

    Below is a copy of the 7zap schematic.

    7zapA.JPG

    I'm not finding much in the way of other useful images on-line to compare against.

    I understand there are dfferent tanks and that it's the K-Jet. / Diesel one I'm supposedly after.

    Have read there is (or was) a swirl pot in these, partly borne out by there being a lidded plastic box affair in mine that the filter (28) sits in. Unfortunately I couldn't get you a good image, but I'd describe it as visiually akin to the one on MK2's, less all the pump gubbins.

    The yellowed filter pictured is seated in it.

    tank filter.jpg

    This repro. tank is from a seller on eBay - I'm guessing it's a view of inside the tank through the fuel level float aperature?

    ebay tank.JPG

    Hard to tell if that's a latter day alternative to a swirl pot, or it's instead just a cup for the filter and there is none.

    On those filters... There are replacements available (now blue if it matters) but any images I can find have 'For Diesel Only' molded on them. The mesh in the pics also seems to be much less fine a weave than the original - despite what the adverts say are they suitable?

    I've salvaged everything from the old tank, including the flap at (27)... it seems to be a sort of non-return for fuel that enters the tank via the filler pipe. Do modern repro's have this or do you re-use the original?

    It's got it's own part number and was relatively easily removed.

    Also, the bracket at (1D)... is it on all tanks whether GTI or not, I may be missing it?


    tank flap.jpg
     
    Last edited: Jan 17, 2022
  2. rubjonny

    rubjonny Administrator Staff Member Admin

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    thats a repro tank, the filter wont fit inside it. genuine tank have a plastic pot assembly inside which takes the filters, plus it has rubber seals which is the downfall of them as the rubber rots away and the pot stops working

    not sure on the filler neck non-return if it doesnt have one then I'd swap it over if it'll fit nicely
     
  3. Zender Z20

    Zender Z20 Paid Member Paid Member

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    Cheers...

    From what I can find there doesn't seem to be many (if any) different brands of repro. tank available.

    Two names I've seen are Blic and Prasco, but possible just one and the same?

    I know you can't obviously rely on pictures alone, but it does seem to be the same makers mark on the VWHeritage, VW Classic Parts and various eBay / other sellers images.

    That being the case and they're all pretty much the same thing, there's no point choosing one seller / make over another other than on price.

    To clarify then... repros. don't have a swirl pot and that has the knock on effect of making the in tank filter redundant?

    Leaves me wondering that if presumably VW fitted both for a reason, is there potential for a problem / what's a get around - putting an in-line filter before the pump for example, to compensate?
     
  4. rubjonny

    rubjonny Administrator Staff Member Admin

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    some have said the more primitive aftermarket tank pot design can cause issues but I've no direct experience using one. without the internal filter yeah I guess more potential for crap getting in the inlet of your main pump. some make have a little mesh basket in the inlet of the pump also, when I tried to retrofit one to my bosch pump it wouldnt pickup any fuel so I had to take it out again (I had a genuine tank with in-tank filter)
     
  5. Zender Z20

    Zender Z20 Paid Member Paid Member

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    I was talking to Heritage just after my last post, more to sound them out about why they've 2 x tanks for the GTI with one being noticibly cheaper than the other.

    If I've understood correctly the cheaper one's made for them in the UK, didn't mention who that was other than to say they also make panels for them.

    The more expensive one is EU made (possibly Forst, but I maybe misheard then got side tracked so didn't think to go back and ask again)

    Bottom line was neither have a swirl pot and there's nothing to filter fuel before it reaches the pump.

    Not fitting any of this anytime soon, so no urgency, but would like to know if someone has installed a workable solution.

    Got a new Bosch pump and the last thing I want is risking damaging it.
     
  6. rubjonny

    rubjonny Administrator Staff Member Admin

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    the cup thing is a swirl pot of sorts, just a more simple design but as you say no filter inside. a possible solution is extrnal swirl pot fed by pre-supply pump of some kind but if you have a standard GTI there isnt a lot of room under there thats the trouble. even if oyu found a good genuine tank chances are the rubber seals on the internal pot have gone which stops it working as effectively
     
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  7. Zender Z20

    Zender Z20 Paid Member Paid Member

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    Have since been reading other things on the inter-web (so must be true!), and though not specific to MK1's they are for similar set ups in older vehicles.

    For every case for pre pump filters put you'll find someone who advocates the exact opposite

    People talking about how fuel pumps can handle the debris and it's the filter after it that's more important. Others saying filters before the pump strains them causing premature failure... don't know what to think.

    At the moment I'm going to assume the repro. tanks and lack of filter don't cause problems... I think Hertiage said they've been selling their own for over 8 years without any known issues which must count for something.

    Thanks for the input, all food for thought!
     
  8. rubjonny

    rubjonny Administrator Staff Member Admin

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    the original main pumps will definitely jam up if too much debris gets in, they are very fine tolerances inside which is why mk1/2 have mesh filters before the lift pump and main pumps. but as long as you keep your fuel system in tip top condition you'll be fine, main issue with the mk1 is fuel filler neck rusting allowing crap to get into the tank
     
  9. Zender Z20

    Zender Z20 Paid Member Paid Member

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    Surprised someone hasn't considered making a straight swop replacement plastic one, maybe a market for them?

    Side issue of no swirl pot could possibly be the potential for fuel starvation under heavy braking / cornering etc... only speculating.

    Filler neck will need replaced also, had looked at Crazy Quiffs stainless ones and I'm sure they're a fair price for what you're getting but unfortunately every penny matters for me.

    Then I wondered too what the wisdom of fitting an upgraded neck to a standard steel tank was as well.
     
  10. rubjonny

    rubjonny Administrator Staff Member Admin

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    yeah that was the main complaint regarding the simple metal cup swirl pot design on the aftermarket tanks, but as I say I've not ran one myself to confirm one way or another.

    the neck is isolated from the tank with a rubber hose so no worries regarding differing metal corrosion so I cant see any issues going stainless over the original steel version. the steel ones are fine too just have to inspect every now and again to make sure they are well protected. I was lucky enough to score a citigolf neck from my local scrappy in tip top condition, I gave it a going over with por15 paint to make sure it would last and away we went
     

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