Is this a 356 part?

[Doug Naef]

I got a box of Porsche "stuff" when I bought an early Pre A several years ago. This apprears to be a vacuum of some sort or primer device for something? The knob appears correct for our cars. Any information would be appreciated.

[Jim Breazeale]

I got a box of Porsche "stuff" when I bought an early Pre A several years ago. This apprears to be a vacuum of some sort or primer device for something? The knob appears correct for our cars. Any information would be appreciated.

It resembles the pump that is used to check the fuel level in 54 and 55 356s. It isn't quite the same, though. I'm saying it is not a 356 part.

Regards

Jim

[Mike Wilson]

Wasn't there a pump to pressurize the gas tank or am I having a CRS attack?!

[Jim Breazeale]

Wasn't there a pump to pressurize the gas tank or am I having a CRS attack?!

Mike


That is what I was referring to.

Regards

Jim

[Mike Wilson]

Thanks, Jim. Maybe somebody can post a pic of the parts diagram or one in place.

[James Davies]

Doesn't look like a 356 part to me.

Here's the pump for the fuel tank used on pre-A Porsches 1953-55.

[Mike Wilson]

Thanks, James. Doug: what is stamped on the face of the knob?

[Martin Benade]

Isn't that pump to pressurize part of the gauge, not the tank itself?

[Mike Wilson]

James would know. I'm pretty unknowledgeable about the very early cars.

[Doug Naef]

Nothing is stamped on the front of the knob. Smooth face.

[Alan Hall]

Isn't that pump to pressurize part of the gauge, not the tank itself?

Yes, the pump just pressurizes the fuel gauge line into the tank, not the tank which is vented to atmosphere. The fuel gauge reads the "head pressure" of the fuel in the tank. The small pump is used to pump any fuel out of the tube that goes into the tank so that you are reading the full "head pressure" of the fuel. Originally the pump also had a check valve function so the pressure was retained and did not leak out. When these systems were new you only had to use the pump after you filled the tank, or if you went from a high altitude to a lower altitude, and even then it was only to correct for small errors in the reading. Pumping beyond the "head pressure" just bubbled out of the line in the tank and was vented away.

These pumps can fail from age and perhaps the part shown was someone's attempt to use a another pump for the system, but I agree not a 356 original part.

[Mike Wilson]

Thanks, Alan. I can add this to my memory bank.