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Re: [T3] addendum to vapor lock question


On 18 Nov 2005 at 22:06, David Y wrote:

> Responding to Steve and Jim's points:
> 
> At 09:01 AM 11/18/2005, you wrote:
>     Do you have the little anti syphon valve that VW supplied in some 
>     years?
> 
> No anti-syphon valve. Should I try to locate one?

Probably very hard to find, and I thought they tended to fail in some 
way anyway.  

>     Where is your filter located, before or after the fuel pump?
> 
> Filter is plastic in-line type, inside the engine compartment, before 
> the fuel pump.
> 
>     If the problem persists with a full tank, then I'd suspect a blockage 
>     somewhere 
>     (check this by just removing the hose from the pump inlet and seeing 
>     if gas 
>     flows out on its own) or a problem with the anti-syphon valve or the 
>     fuel pump 
>     or the float valves (very unlikely.)
> 
> Before filling the the tank (which was only 1/2 full) I decided to 
> drain it and check the filter at the outlet pipe, which I know hasn't 
> been checked in 20-35 years. Well...the result was WHAT BRASS 
> FILTER? It had long decayed/disappeared all the way down to the top 
> of the tube, which means it was providing absolutely no filtering, 
> and thus was not the cause of my blockage/vapor lock problem. I blew 
> out the line from the fuel pump back out to the front and didn't see 
> any chunks or other obstructions. After I replaced the lines and 
> reconnected everything, I went and filled up the tank all the way, 
> and fuel flows all the way to the pump just by gravity on flat 
> ground, so I assume any blockages in that part of the system are 
> cleared (if any existed) so I guess the next step is to get it hot, 
> park it for 15 min, and see if the problem is solved (?)

Okay, it sounds like you've got that part covered. I'll be interested 
to see if the full tank "cures" your problem.

> Related questions: Would a fuel tank outlet kit for a Btl 62-77 and 
> Ghia 62-74 work with our T3 tanks (mine is originally a 68). I ask 
> because I noticed a crack in the nut when I was retightening it 
> (perhaps overtightened it) and would like to replace it ASAP when I 
> install the screen, but the only kits available with the nut in the 
> Mid America catalog are the btl and ghia kits. Or does anyone know of 
> a source for a T3 outlet kit/parts? Also, what is the difference 
> between 63-67 and 68-73 T3 tank screens? They look virtually 
> identical. Since I have a 67 carb setup, would I go with the 63-67 
> screen or 68-73 screen?

I can't answer all your questions since I don't have the type 1 parts 
lists printed out, but here's what I see on the type 3 parts:

The nut was the same for all years.
The outlet pipe was 6mm up thru '67, but changed to 8mm in '68.
I see 2 different screens and gaskets, but VW doesn't show the 
difference or when either was used.

I have some good used parts, including the nut, that you need. I 
don't know if my gaskets are still good, but between the 2 of us, we 
ought to be able to come up with 2 good gaskets.

If you have a '68, then it is probably a FI tank (with the extra tube 
for the FI fuel return line.) That tank has a kind of "cup" around 
the center which works with the returning fuel to scavenge fuel from 
the main tank and keep that central "cup" full. If the entry port on 
the bottom of this cup was blocked, by rust or crud or an aftermarket 
fuel tank interior coating, this could lead to fuel starvation. I 
can't say whether this might be part of your problem(s) or not, but 
it seems possible.

You should be able to look down the fuel sender hole sometime when 
the tank is less than 1/3 full and see if the central cup fuel level 
is below the main level or not.



-- 
*******************************
Jim Adney, jadney@vwtype3.org
Madison, Wisconsin, USA
*******************************

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