Quote:
Originally Posted by leegreen
I'd never realized that mechanical pumps used the spring to power the pump cycle and the cam arm was the return stroke. But is does make sense, the spring gives some pressure regulation, if it was the other way there would need to be a pressure relief.
So now the boost pressure bleed to pump makes sense, the spring needs the extra pressure to get the fuel pressure high enough for the carb when it is under boost. Now the electric pump makes sense too, it turns on from the manifold switch to put enough pressure on the intake side of the mechanical diaphragm to overcome he boost pressure and fill the diaphragm chamber. Without the electric pump the diaphragm would flex away from the boost pressure and the pump volume would fall off.
If you are replumbing anyway, bypassing the whole works in favor of a modern electric pump, filter, non blocking regulator and return line to tank is probably a more reliable approach. less historically interesting but your truck, your call.
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Thanks again for the input. I'm not terribly interested in keeping thing historically correct since the truck is obviously modified with the supercharger, but I am interested in updating the entire fuel system to ensure it is ethanol ready and capable of running efficiently.
I've already purchased a new fuel tank that is going to be mounted in an old steamer truck in the back of the bed. I have the new mechanical fuel pump on order from Amazon per the link provided above. Now I need to acquire the modern electric fuel pump and a non-blocking regulator.
The only unanswered questions I have are 1) what psi would be required of both the electric fuel pump and the regulator. Many of the pumps and regulators are for 100 psi fuel injected modern engine. I'm unable to determine anything from the regulator and the fuel pump since neither has a single marking on it for brand or model. Here is a picture of the old fuel pump, I've already posted photos of the regulator.
Also my original plan was to use braided stainless flexible hose from the tank to the electric fuel pump, filter, and mechanical fuel pump. I read an article this morning suggesting that was a bad idea and that I should plan on using hard lines. A friend who used to own a shop restoring classic cars calls BS on that and said they used braided stainless all the time for both fuel feed line and return lines.