Fuel tank baffle clogged? ...and other fuel questions

[buck380]

New to me 68 fastback. I removed the fuel tank level sender to repair it. (That went well enough thanks to everything I've read here!) Reinstalling the sending unit I noticed a layer of rust at the bottom of the tank. Seems to be a common problem so I removed the tank today for cleaning.

As I was syphoning the tank through the sending unit hole, I dropped the hose into the circular baffle in the tank. While the tank was draining, I lost syphon as the fuel level went to the top of the baffle and then the baffle only drained.

Having already done a lot of reading here before draining the tank, it seems Russ Wolfe's constant reminders NOT to seal FI tanks is not unfounded. This tank appears to have been sealed in the past as the inside of the tank has a whitish color to it. But I'm wondering, since the baffle drained dry and there was still lots of fuel in the tank...and this car was previously FI, could that little passage between the return pipe and baffle have gotten clogged?

Is that passage at the fuel return the only place the fuel from the tank can enter the baffle? Obviously, the fuel pump draws fuel from the fitting in the center of the baffle, but I haven't had the car long enough to let the tank level get to the baffle.

What do you think about possibly running a drill through that hole to open it back up? My car is now carb'd and the fuel return (and venturi scavenging) is no longer used.

Another fuel question, the electric fuel pump constantly runs. How is the low fuel pressure maintained? Does the pump maintain pressure by bypassing fuel or is it supposed to cycle? Should I get a separate inline fuel pressure regulator (the carbs are Weber 44 IDF's).

Last question of the day...While I have the tank out I'm going to replace all of the lines (the lines at the carbs are dry rotted and cracking). Generally, are the the rigid lines a problem? Should I replace just the flexible lines or should I replace the whole shebang, front to back?

Thanks!

[Spezialist]

The novel solution would be to replace the tank with a new one for carbs.
_________________

[Tram]

[Spezialist]

[buck380]

Well, so far I've tried drilling a 1/4" hole where the return line is...no help.

Also tried drilling two additional holes in the baffle (being careful not to drill completely through the bottom of the tank)...and no help there either.

The small space between bottom of the baffle and the bottom of the tank must be completely sealed solid. I guess my only recourse, other than replacing the tank, will be to drill a couple holes low on the vertical portion of the the baffle and rest assured knowing its "better" than before I started...any other suggestions?

[buck380]

Things have kinda worked themselves out. I acid washed the tank interior and now have full flow through the baffle...from 3 holes now

So I guess most of that gunk under the baffle must have been rust.

[Spezialist]

[vlad01]

Any one got a physical pic of these baffles? I never seen a carb tank with them or am I missing some info?

but I am more interested in seeing inside an efi tank.

[buck380]

Heres a view through the fuel level sending unit hole (top looking down) and a flashlight through the filler hole:

(note the auxiliary flow holes )

And here's the view through the filler hole and the flashlight through the sender hole:

It basically prevents fuel from sloshing away from the outlet when you turn, brake, accelerate.

[buck380]

[vlad01]

wow thats cool. never seen a tank with that in it. Not a single tank of mine have had that that I looked inside or cut open. So the EFI tanks all have this?

[DQDan]

I've got the same problem, fuel in the tank but not inside the baffled area. Drain holes must be plugged by the guy who refurbished my tank. I can't see the pics above to know where I need to create drainage in the baffle.
Anyone have pics of where the drain holes are?

[Bobnotch]

[DQDan]

Hi Bob, I think you are right. My treated 69 FI fuel tank those slots were filled by the sealant applied during refurbishment. The inside of the ring you might be able to get a pick into but not the outside. Using this tank would only get gas when the tank was over 2/3 full, or over the baffle!
This must be why they say you cant refurbish or reseal a FI tank.

I ended up coming at the problem baffle from the fill tube with a long sharp screwdriver and tried to knock a couple of low slots into the baffle.
I clumsily ended punching a hole thru the bottom of the tank, it is impossible to see where I was headed. A quick pay pal to boo kooZ and a fresh tank is on the way. That old one was shedding its innards so I'd rather start fresh than try to weld an inside rusty tank.

[KTPhil]

Some info/photos here:
https://www.thesamba.com/vw/forum/viewtopic.php?t=424132

[Bobnotch]