Pollack Valve gone wrong?

[Ian Anderson]

I went to wings and wheels today and on the way home on the motorway the fuel pump made a noise. In the past when it did this I swapped tanks and ran on the other for a while the swapped back - no further problems. Always thought there was muck in the pipes or whatever.

Oh yes I run efi tanks to polack to lp pump to swirl return to tank then swirl, up pimp fuel rail to swirl Total of two pumps noisy pump is the. Hp one.

Anyway today I did just this and the pump quietened down as normal. I got home and terrible fuel smell and I found the left tank spilling out the fuel cap. At that stage I was drawing from the left tank so no way should it be full after a few miles drive!

After a half hour by which time the spilt fuel had evaporated and the car cooled down. I selected the right tank and it was showing one quarter. Ten minutes earlier it had readvthree quarters. So immediate thought is that on swapping tank to tank the Pollack valve has broken allowing fuel to draw from the right and return to the left thus causing the left to "overfill"

Has anyone had a pollack valve let go like this?

 

[Ian Anderson]

Replaced the Pollack and last week went out in the car

New Pollack valve has just gone the same way as the first

Now time to go with solenoid valves

Ian

 

[Chris Hale]

Not good Ian, I run a Pollack valve on my car and I'm on my second one now due to the first one stop working and would only run on one side and not swop over.

On my current configuration I'm using a fuel swirl pot and only using the Pollack valve on the low pressure side and this seems to be holding up fine, it's been around 3 years now.

So I will be interested in your solution as I may have to go down this route if it fails again.

 

[Andy Green]

I’ve also based my fuel system on a Pollack valve to switch between the tanks, however I’m also concerned about the valve jamming, as you folks are now finding out. I suspect that failure mode is debris been drawn into the valve and jamming the shuttle valve. <?xml:namespace prefix = o ns = "urn:schemas-microsoft-com<img src=" /><o></o>
As I’ve got the Pollack valve between the tank and the LP pump, I’ve added pre-filters on the pick-up pipes made from a very fine copper woven mesh with only a .014” openings. These were soldered onto the pick-up pipes to give a ‘fit & forget’ solution and should stop any swarf or debris getting into the system and jamming the valve.<o></o>
<o></o>
Regards<o></o>
Andy<o></o>

 

[Ian Anderson]

Andy

I have the Pollack in the same position

Tank - filter - LP pump - Swirl - Pollack - Tank

When it fails I end up drawing fuel from the right tank and returning it to the left.

It's frustrating but not insurmountable as when I click back to the left tank it draws and returns to that tank. Pollack is mounted on bottom chassis rail on left of car so left return pipes are shorter and probably cause less resistance hence it seems to work ok drawing and returning to left

Ian

 

[Andy Green]

Ian,
it sounds like the valve is jamming when under load. It may be worth trying switching the valve before the pump is running
Rgds,
Andy

 

[Ian Anderson]

Andy

No pressure on anything

The LP Pump Sucks through the pollack (Fron tank to Pollack to pump)

It returns via a 8mm fuel line wioth no restrictions to the tank

At no time does the Pollack see any pressure

Ian

 

[Andy Green]

Ian,
you're right, there is no pressure, but sucking through the valve puts a load on the shuttle valve
Andy

 

[Ian Anderson]

Andy

Perhaps it does for the 1 second it is moving.

But this will have moved about 10 times in total so not a good advert!

IAn