TheSamba.com :: View topic

Sat Mar 20, 2021 7:12 am

So I read a ton on this and still confused.
I have sand rail 1600...don’t know if any internal work was done.
Has dual Weber carbs.
I was as getting gas in crankcase so I am replacing fuel pump.

So my question is how to replace I have it out an pin looks shaved.
Do I measure and shine with gaskets...also have a fuel regulator so do I need to check pressure after install or will the regulator take care of that..

It a mechanical fuel pump

Sat Mar 20, 2021 8:20 am

You probably need to check the length of that pushrod to make sure it is properly matched with your pump.

I think checking pressure even with a pressure regulator would be a good idea.

Sat Mar 20, 2021 8:26 am

Matt Wilson wrote: I think checking pressure even with a pressure regulator would be a good idea.

Like Matt said verify the pressure after the reg. That type of reg has a reputation for being off some.

Also, if you keep that type of filter be sure to check and/or replace the o-rings kinda regularly. They will dry up and leak creating a potential for fire.

Sat Mar 20, 2021 8:26 am

Please get rid of that fuel regulator, a good friend had his Thing burn to the ground because of his cheap regulator.

Sat Mar 20, 2021 9:23 am

First.. regulator that was on it... would buy anything. Have any suggesting On a good regulator with pressure gage built in .. how do you adjust push rod length... if I buy a pump with push rod will it already be good... money is not the issue just trying to get it done right

Thanks

Wish one you where local in Michigan would pay for good help lol.
But in paying to take it in.. trying to learn myself thanks

Sat Mar 20, 2021 10:17 am

I’d get rid of the regulator all together and buy a pump that puts out the correct pressure from Bill. You can find him here on the forum too.

https://www.sparxwerks.com/

Sat Mar 20, 2021 6:40 pm

I would expect the gas in the crankcase to be unrelated to the fuel pump. I think you are addressing the wrong part. Pressure regulator issue maybe but more likely you have a dirty or leaking float valve or float levels excessively high.

Sat Mar 20, 2021 10:15 pm

If the fuel pump diaphragm has a pinhole or other damage, it will leak fuel into the crankcase. Valid concern. A friend of mine had that problem recently. He had to change the oil when he replaced his fuel pump that was less than a year old.

I've been using a similar regulator on my Baja Bug and on my Hi Jumper for decades. I don't expect the quality now to be what it was in the 1970s. Not all progress is in a forward direction. I bought a new one recently for another car with an EMPI HPMX carb, no problems yet, the jury is still out in deliberations. I see a lot of people talking smack about these regulators, but nobody with any concrete evidence, just smack talk. But I've seen a LOT of trouble recently with Holley regulators with the set screw on top as well. Look on Speedway Motors, Summit and Jeg's for those supposedly "better" regulators. Lots of bad reviews.

For this application, you do NOT need a bypass fuel pressure regulator with ANOTHER line going BACK to the gas tank that has no fitment for a return line. So get one with only an inlet port and an outlet port.

You HAVE the one regulator, whether others think its the cool one or not, I say roll with it until there is a problem that makes it certain it needs to be replaced.

Regardless which fuel pressure regulator you go with, you should DEFINITELY check the adjustment with a fuel pressure gauge. It can be one mounted permanently in the line between the pump and the carb, or it can be one you attach temporarily with a tee just to check it and then remove it once you have the regulator set.

Sun Mar 21, 2021 1:07 am

Thanks all....I guess I will have to and make choices.
I still don’t quit understand how to do the install and adjust fuel pump rod.
I looked and for so many different ways...this buggy stuff gets confusing, cause ther is no clear cut way. It’s gathering different information and in then end do what you want ...

Sun Mar 21, 2021 3:34 am

dustymojave wrote: If the fuel pump diaphragm has a pinhole or other damage, it will leak fuel into the crankcase. Valid concern. A friend of mine had that problem recently. He had to change the oil when he replaced his fuel pump that was less than a year old.
True, I hadn't thought of a leaky diaphragm.

Adjusting the rod length and/or shimming the fuel pump adjusts the pump VOLUME output. Yes at some point it will indirectly effect the pressure too but the real problem is the pump was built with a spring that is too stiff. Follow the action of the pump in your mind and you will come to understand that it is the spring that dictates the pressure the pump produces and the rod dictates the volume.

Sun Mar 21, 2021 7:24 am

Who is this Bill?? That stated to contact about a fuel pump....
Also what would be the correct fuel pressure for dual Weber carbs on a 1600....
Thanks

Sun Mar 21, 2021 8:01 am

Ksmit258 wrote:

Also what would be the correct fuel pressure for dual Weber carbs on a 1600....
Thanks

Webers run best at 2.5 psi, much above or below that will create problems. Do not run without a regulator.

Sun Mar 21, 2021 1:35 pm

Found this for the pushrod height

RA 70 wrote: If memory serves... 13mm is for the generator style pump and rod. The alternator style pump is 8mm shorter, and so should stick up around 5mm, which is slightly less then 1/4". When it goes down it should sit nearly flush with the flange. I find it curious that the Bently manual doesnt mention this difference....

I don’t use a regulator with my dual webers and haven’t had a problem.

Mon Mar 22, 2021 5:05 am

The stock pump is self regulating by design. It is a function of the diaphragm area vs the spring stiffness. It will only pump until it reaches that equilibrium and then it stalls, then starts to pump again as the carbs uses fuel and the pressure drops. If your replacement pump puts out too much pressure it is because they did not engineer this diaphragm/spring strength balance properly.

A regulator with a stock VW pump is not needed but with a poorly engineered fake replacement pump you may well need one.

I can draw out a series of diagrams to explain how the pump works if you like but I suspect the most of you are mechanically minded enough to figure it out if you take a few minutes and think about it. It's not really rocket science.

Mon Mar 22, 2021 8:42 am

Thanks for all the input...I will get a pump ordered and use all This information...will see how it works out.
Thought I was very good mechanically...now I realized I am only a good mechanic when you go to the store know the year and replace parts lol.
I will learn this buggy now if it’s the death of me

Mon Mar 22, 2021 6:09 pm

dirtkeeper wrote: I don’t use a regulator with my dual webers and haven’t had a problem.

What pump and what are your pressures over the RPM range?

Mon Mar 22, 2021 10:06 pm

L5wolvesf wrote: dirtkeeper wrote: I don’t use a regulator with my dual webers and haven’t had a problem.

What pump and what are your pressures over the RPM range?

it’s stock mechanical , brosal? and I don’t know what the pressures are.

Tue Mar 23, 2021 4:00 pm

oprn wrote: The stock pump is self regulating by design. It is a function of the diaphragm area vs the spring stiffness. It will only pump until it reaches that equilibrium and then it stalls, then starts to pump again as the carbs uses fuel and the pressure drops. If your replacement pump puts out too much pressure it is because they did not engineer this diaphragm/spring strength balance properly.

A regulator with a stock VW pump is not needed but with a poorly engineered fake replacement pump you may well need one.

I can draw out a series of diagrams to explain how the pump works if you like but I suspect the most of you are mechanically minded enough to figure it out if you take a few minutes and think about it. It's not really rocket science.

A regulator is NOT needed with a stock fuel pump and a stock Solex carb. Replacement fuel pumps may require one. And replacement carbs may require one.

Webers prefer less pressure than the stock Solex does. The Webers and Weber copies are more sensitive and sometimes fussy about fuel pressure. For some reason, they are not always sensitive. So it's not accurate to say that they ALWAYS need a regulator.

I recently bought a buggy with an EMPI HPMX 44 carb. It has a Mr. Gasket electric fuel pump that is supposed to make 7psi. Initially it was having fuel feed problems and I ordered a pressure regulator expecting that it would be needed. But once I tore into the carb and found the float set 19mm too low and found the fuel pump had a very poor ground connection and fixed that, all of a sudden, the fuel pressure is no problem. And the regulator had not even arrived yet.

I know it's not a real Weber. But then there are Italian Webers, and Spanish Webers, and Holley Webers, and Chinese Weber copies, and EMPI Weber copies ...

But considering all that, I still feel that it is a good idea to consider installing a fuel pressure regulator if your carb or carbs tend to flood. I don't feel the regulator needs to be an expensive one. But before you order one, check the fuel pressure with a gauge then if and whatever regulator is used check the pressure you get with the regulator and use the gauge to set the regulator.

Wed Apr 14, 2021 4:50 pm

The stock German or Brazilian made Pierburg fuel pumps for type 1 and 2 put out right at 3 PSI with a 108mm pushrod and the pushrods sticks up above the fuel pump stand 13mm at its highest travel point.
As mentioned, what controls this fuel pressure is the main diaphragm spring. The type 3 Pierburg fuel pumps had a slightly stiffer main diaphragm spring. As a result, it put out 4 PSI.

I ran dual 44 webers on a 2276 with a rebuilt/restored Pierburg fuel pump. It put out 3 psi and I never had any issues with carbs due to fuel pressure.

Thu Apr 15, 2021 10:37 am

I think someone mentioned making sure the "O" rings were good on the fuel filter. I personally would suggest you also get rid of that style filter. The ends screw on, and hold the filter together, and sometimes they work themselves loose, leaking fuel and creating a fuel hazard.
Good luck,, and have fun!