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Vintage Does a 140 mechanical fuel pump need a pressure regulator?

bwright002

Active member
Joined
Feb 12, 2005
I'm replacing the mechanical fuel pump for my 72 142s (b20b w/dual SU's). Bought the IPD pump and spacer. The previous owner had a fuel pressure regulator in the fuel line after the pump. I've read some posts that say the mechanical fuel pump puts out between 4 to 6 psi and that the SU carbs only like 1.5 to 3 psi.

Would you recommend me keeping the fuel pressure regulator in the fuel line? Any good way to determine if the old regulator is actually keeping the right psi?
 
We've found that new easily available fuel pumps have a tendency to put out too much pressure and I believe this is due to the cheap check valves that are used in them and that's just 1 thing that's wrong with them.

We've had to deal with the screws that hold the top on repeatedly coming loose, so we now install longer screws with lock nuts and it's not unusual for 1 or both of the inlet or outlet tubes to fall out because they are glued in instead of press fit.

Because we've seen so many of these pumps with too much pressure, we now stock a high quality fuel pressure regulator made by Holley.

When you consider the costs including a high quality regulator and fittings and the other issues with the new mechanical fuel pumps, it makes more sense to us to rebuild the original fuel pumps, if possible.

So, we are now recommending the rebuilding of more fuel pumps because the new ones have so many problems.

FYI, the new fuel pumps being sold in a Pierburg box are a rebox and are not made by Pierburg. The last mechanical fuel pumps made by Pierburg were sealed with a crimped on top and no screws and AFAIK, not rebuildable.
 
Why not check the fuel pressure as it sits now and then make a decision after you see the results?

Probably dating myself, but pressure/vacuum gauges used to be pretty cheap. I mean the diagnostic tool, not a gauge that you'd install inside the car.
 
Of course, always check the fuel pressure.

About 6 months ago, a customer drove in for some maintenance and when he got to our shop, the front SU carb was leaking out of the vent.

The customer is a DIYer and he had changed his fuel pump with 1 of those new pumps and when I checked the fuel pressure it was a little over 4 psi and it turned out the float valve was bad.

When I told him of the potential issues with the new fuel pump he installed, he told me he was going to put the old sealed Pierburg fuel pump back on as there was nothing wrong with it.




Why not check the fuel pressure as it sits now and then make a decision after you see the results?

Probably dating myself, but pressure/vacuum gauges used to be pretty cheap. I mean the diagnostic tool, not a gauge that you'd install inside the car.
 
Does anyone in this impromptu mech fuel pump info thread know where to get a rebuild kit for the OE SEV pump that came on the B21A with the dual screws holding the top on? Mine is good for now, but it sure would be good to have a kit for later.

UhtGfVX5_o.jpg
 
The B21 Sofabex pump uses the same rebuild kit as the B20 Sofabex pump so it's all good. That said, the rebuild kit has been discontinued and the part number, 276308 updates to the B21 Pierburg pump which is weird since the kit also fits B20 which uses a different pump.

https://www.tascaparts.com/oem-parts/volvo-fuel-pump-1336185?c=cT0yNzYzMDg%3D

GR-20080.jpg

Rats :(.

I've got an older B230-based Penta pump with thread-in fittings and crimped top, so I guess that'll be my backup when/if this one goes. Thanks for the help :).
 
So, we are now recommending the rebuilding of more fuel pumps because the new ones have so many problems.
....
The last mechanical fuel pumps made by Pierburg were sealed with a crimped on top and no screws and AFAIK, not rebuildable.

So, just to clarify this, I gather that if you have a Pierburg pump that is old enough, it can be rebuilt. And the kit is available...?

https://www.tascaparts.com/oem-parts...cT0yNzYzMDg%3D

And I further gather that this link is for a B21 pump?
 
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