{Type 356A/B Fuel Pump}
{Porsche 356 fuel pump rebuilding}
Fuel Pump Rebuilding
Pumps are stripped down and degreased in a solvent cleaner. Parts are checked for wear and sorted for reuse, repair or discard. Particular attention is paid to suction and discharge valve seat heights. I have a data base of acceptable tolerances.
I have developed a process to install a new suction valve seat ( machined from T-6 aluminum, this is a hard aluminum ) in the upper body, thereby saving many fuel pumps from the junk pile. It seems the worn suction valve seat is the Achilles heel of this pump.
(See Fig 1:4 Another Lifetime!)
The zinc base white metal used in the pump body is metallurgically very porous and soft. It reacts with heat and all of the absorbed fluids and chemicals it comes in contact with. Pump bodies become stained, corroded and discolored. As a second step, the pump bodies are further treated in a ultrasonic cleaning bath solution to further clean and help remove discoloration of the metal.
Bodies are brightened as well as can be. There is no magic wand here. No plating or coating is used. What material has been damaged cannot be put back and deep staining cannot be reversed without some potentially harmful effects.
Rebuilding
Pumps are assembled with new and select used parts.
The suction and discharge valve seats are re -cut and polished, if too worn replaced.
Mating surfaces ( flange faces ) are made flush.
Inlet and outlet threads are chased with tap, faces are recut true.
Cone top is faced true. If too deformed, replaced.
Rocker arm is refaced and here again, if too worn replaced.
These parts: diaphragm, My proprietary Teflon valve discs & Stainless steel springs, diaphragm spring, gaskets and seals, screws, washers, top bolt, rocker pin and rocker spring are all replaced new.
Diaphragm is assembled using VW tool #328B to position it correctly in the lower housing.
I have the diaphragm springs made for me to special order. They deliver a nice 2.0 to 2.4 PSI.
After pumps are assembled, checks are made for pressure, vacuum and leak down.
Pump bodies can be fifty years old. Some show this more than others.
Mechanically, pumps are all rebuilt the same. Cosmetically, there will be differences.
If you have an original pump in your car, you may want to have it rebuilt. If looking for a spare I will try to have pumps available.
Contact Doug, if you are in need of a particular service, price quote or have a question.
E-mail [email protected]
df 2024
Pix of recently finished pumps
Another Lifetime!
Here is what you can expect from one of my rebuilds.
See: Services Page for price
1, Harry Pellow from his "Porsche Engines and the Future of the Human Race" ( The ABC's and 912's of Porsche Engines )
NOTE: Weak or leaking valves can contribute to poor starting. With weak valves fuel delivery is low. Also there is no check valve in our fuel system to prevent the fuel in the carburetors and fuel lines from flowing back toward the tank, especially on hot days. Only good valves will help keep fuel in place. I keep bringing up how important good sealing valves are, and for all practical purposes the discharge valve is the fuel check valve . A faulty inlet or outlet valve can be the reason for a particularly baffling type of vapor lock! 1
I now incorporate my American made components in my bench fuel pump rebuilding. These parts have been in service on my 56 ' A coupe for years.
356 A/B early Fuel Pump
356 Pre-A & Early VW Fuel Pumps Rebuilt ; Ask!
Pix of recently finished Pre-A fuel pump for 1953 Coupe
Note: This early fuel pump although marked Deutsche Vergaser-Gesellschaft was actually made under license from DVG by Robert Kahrmann & Co " Rokal" in Lower Saxony, you will notice the Robert Kahrmann stamp, an oval with R K in it.
Post WWII occupying British authorities contracted "Rokal" to build carburetors and fuel pumps for the VW . As you know the British brought the VW plant back into post WWII production. The DVG plant near Berlin, was destroyed during the war, this production at "Rokal" gave them time to rebuild. Many early Porsche 356 fuel pumps, until about 1958 were from "Rokal".
These plants along with Porsche, were all part of the post WWII German economic recovery miracle.
These pumps, to me seem to have a denser metal and nicer finish than later pumps.
This is a high capacity pump, just like the later DVG pumps. Only difference , lacks internal filter and sediment bowl. External filter must be used.
Also note:
The upper and lower flanges have no webbing and the mounting flange has fewer supports as compared to later bodies.
I have incorporated the later style rocker arm pin with retaining clips. As an extra measure of safety.
American made components
My fuel pump bench rebuilds incorporate
American made parts including:
Premium grade nylon inserted nitrile diaphragm fabric suitable for all aromatic fuels
Proprietary;
PTFE (Teflon) valve discs
Stainless steel valve springs
Diaphragm spring
Fuel screen / filter w/ 150 micron rating
Gaskets and red vulcanized fibre compressed washers
Impervious to any fuel chemicals & last a life time with virtually no valve disc or valve seat wear, while delivering fuel at consistent 2.0 to 2.4 PSI...
