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Wed Aug 07, 2019 12:02 pm

Guys, stacking gaskets will effect the pressure a little and the volume a LOT.
If you need to lower the pressure you need to change the pressure spring inside the pump or add a fuel pressure regulator. After learning how these pumps worked from a VW mech. I set the proper height for the rod and use a regulator for pressure. If you stack gaskets you will find the engine dies from lack of fuel during a 55+ mph run/s.

Wed Aug 07, 2019 3:19 pm

jeffavatech wrote: Guys, stacking gaskets will effect the pressure a little and the volume a LOT.
If you need to lower the pressure you need to change the pressure spring inside the pump or add a fuel pressure regulator. After learning how these pumps worked from a VW mech. I set the proper height for the rod and use a regulator for pressure. If you stack gaskets you will find the engine dies from lack of fuel during a 55+ mph run/s.

The solution to the OP's problem or anyone else who buys an economy fuel pump is to ditch it and buy a used German Pierburg fuel pump and rebuild it or purchase one already restored.

The Effbe rebuild kits have the correct lower diaphragm spring mounted. The spring tension is whats controls most of the fuel pressure. As someone mentioned accurately, over shimming these pumps up and away from the push rod will lower the stroke and then volume and pressure. It's basically a band-aid repair to make a lower quality part kinda work.

Also, everyone should measure how much their fuel pump push rod sticks up at it's highest travel above the fuel pump plastic stand with the pump off. See picture below. It needs to be 13mm. It was mentioned that there are different thickness plastic fuel pump stands which makes measuring the push rod height critical.

I've never had more than 3.1 PSI with only one thin gasket under the pump after rebuilding a German Pierburg dome top or square top fuel pump. The fuel pump push rod measured 13mm sticking above the pump stand. This when using NOS rebuild kits or new Effbe rebuild kits.

Wed Aug 07, 2019 3:57 pm

You are right with the info and having had the fun with finding and installing lighter f/p spring and re-installing it only to see its still off a bit is a PIA procedure. So many folks here believe adding gaskets will work. I've had my fun when carb went dry due to lack of fuel. The secret is in the spring pressure.

Wed Aug 07, 2019 5:07 pm

jeffavatech wrote: You are right with the info and having had the fun with finding and installing lighter f/p spring and re-installing it only to see its still off a bit is a PIA procedure. So many folks here believe adding gaskets will work. I've had my fun when carb went dry due to lack of fuel. The secret is in the spring pressure.

Yes, you're exactly right. Many people argue of the value of adding or subtracting gaskets to lower the fuel pressure 2 pounds or more. :roll: I remember one person piled a big stack of gaskets to lower his fuel pressure. He then went down the road and under load the pump could not keep the fuel bowl full because of lack of volume. The engine started dying out. It's spelled out perfectly clear in the Bentley shop manual from 1961-1965 for bugs. It talks about different color springs to distinguish between the type 3 main diaphragm spring and the the type 1 spring.

I have buckets of old original Pierburg logo'd lower diaphragm assemblies with the springs from rebuilding these pumps. I've mailed a few folks original springs who bought the low quality rebuild kits. They found their fuel pressure was 6 psi after a rebuild. They then took the pump back apart and changed the lower diaphragm assembly spring to the original. They reassembled the pump and then had 3 psi with the original spring in place.

Yes, you can fine tune the PSI with gaskets but I wouldn't personally want to lower or raise the PSI more than 1/2 pound with gaskets. Example, if I rebuild a German Pierburg fuel pump with an Effbe kit and wanted to get 2.5 PSI. I could add some gaskets to lower it that much from 3psi.

Wed Aug 07, 2019 5:18 pm

Do the new Wolfsburg west kits work correctly?

Wed Aug 07, 2019 6:49 pm

wcfvw69 wrote: I've mailed a few folks original springs who bought the low quality rebuild kits. They found their fuel pressure was 6 psi fuel pressure after a rebuild. They then took the pump back apart and changed the lower diaphragm assembly spring to the original. They reassembled the pump and then had 3 psi with the original spring in place.
I'm one of those with the original spring mailed to me by wcfvw69 after getting 6 psi with the then-available rebuild kits.

I think the WW kits have been modified since then and are better.

Thu Aug 08, 2019 10:03 am

i have used many (like five) gaskets under aftermarket pumps to obtain correct pressure, dropping several psi. still have adequate flow volume.

Bug On!

Thu Aug 08, 2019 7:15 pm

I think the height of the plastic flange is also critical. I have measured a repro flange to be thinner (about 1mm IIRC -- will need to check) than a VW flange. So, 5 gaskets under a repro flange may be ok, but 5 under a VW flange may give different results.

Thu Aug 08, 2019 7:47 pm

bnam wrote: I think the height of the plastic flange is also critical. I have measured a repro flange to be thinner (about 1mm IIRC -- will need to check) than a VW flange. So, 5 gaskets under a repro flange may be ok, but 5 under a VW flange may give different results.

Correct. This is why you measure the amount of the pushrod sticking up above the flange at its highest travel.

Personally, I'd source an OE original fuel pump stand before I'd buy an aftermarket one. The aftermarkets also like to squeeze the fuel pump pushrods and in some cases stop them from moving when they swell.

There's still thousands of the original bakelite fuel pump stands out there and we also support the sellers in The Samba Classifieds.