Fuel pump for carbureted motors-EPILOG

Dick Steinkamp

Dick Steinkamp

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This is for my E3, but the mechanical fuel pumps for carbed motors are shared with the E9 and the E9 Discussion forum is read more than the E3 forum.

I have some more testing to do but I may need to replace my fuel pump (1972 Bavaria 3.0)

My current one looks like this...

IMG_9423.JPG
IMG_9421.JPG


The Pierburgs I see for sale look like this...

s-l500.jpg


Is my pump an original or something else?

Is the pump pictured that I see for sale the only (best?) pump available?

I have Weber 38/38 carbs. I have read somewhere that the Weber throttle linkage interferes with some Pierburg pumps. True? My pump clears the throttle linkage by a miniscule amount.

Recommendations if I need to replace my pump? (it does not look like it is serviceable as opposed the the pump in the last picture)
 
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Dick Steinkamp said:
This is for my E3, but the mechanical fuel pumps for carbed motors are shared with the E9 and the E9 Discussion forum is read more than the E3 forum.

I have some more testing to do but I may need to replace my fuel pump (1972 Bavaria 3.0)

My current one looks like this...

View attachment 164597View attachment 164596

The Pierburgs I see for sale look like this...

View attachment 164598

Is my pump an original or something else?

Is the pump pictured that I see for sale the only (best?) pump available?

I have Weber 38/38 carbs. I have read somewhere that the Weber throttle linkage interferes with some Pierburg pumps. True? My pump clears the throttle linkage by a miniscule amount.

Recommendations if I need to replace my pump? (it does not look like it is serviceable as opposed the the pump in the last picture)
Click to expand...


hi, mech pumps offer 0,21 to 0,25 bar pressure

check if this is what webers require


your pump is one of the original types, it seems a sealed one with metal membrane, yes, and i can see how tight is the linkage rod

the one you pictured is rubber membrane based, usually sold as pierburg, but really an Italian brand that is erased from the aluminium body

based on your setup you will have interference issues with this pump for sure,

E6602080-5354-4561-8AB7-37F95237A9A3.jpeg
4C60A750-0A20-49A4-89E5-FF101AAD2EE9.jpeg
 
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I just installed the newer Pierburg to replace a pump same as @Dick Steinkamp had.
With the dual Webers, it will interfere with the linkage and per a comment on the forum I had to grind a little material off the new pump to clear the linkage.
 
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It wasn't the pump. My symptom was the engine acting like it was running out of gas getting on the freeway. Full throttle 2nd and 3rd to about 5,000, then full throttle after the shift to 4th. At that point the nose drops and the engine starts stumbling. In all other conditions the engine ran fine.

I have an electric pump installed to fill the carb bowls prior to start. My first clue that it wasn't the mechanical pump is that I got nearly the same symptom with the electric pump on full time.

I pulled the tops off the carbs (Weber 38 DGASM) and found this...

Front carb...
IMG_9425.JPG


Rear carb...
IMG_9426.JPG


The little spring loaded ball bearing in the rear carb needle had frozen in the up position. This has the effect of extending the needle by about a centimeter which lowers the gas in the float bowl substantially. It also only allows the needle to drop about a centimeter instead of the desired 2 cm. So the float bowl did not have much gas in it at any time AND filled slower than normal. Neither the mechanical pump nor the electric could keep the gas level over the jets in the bottom of the bowl at full throttle. At least this is my theory. Waiting on a new needle and seat to reassemble the carbs.

I have no idea how this could happen. The car has run great otherwise since I finished it including a 2,100 mile trip to Legends in Monterey.
 
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