LFZ

I was installing my new Holley street mechanical fuel pump to feed the 650 Speed Demon carb....i notice that the old pump had vent lines which connected to the pump....this new holley pump only has lines to go in and out for fuel....what do i do? is there a pump i can replace it with that can feed the demon or can i plug off the lines and still be safe? thanks guys. :confused: :confused:

SanDiegoPaul

Sorry :nono: You need to get The Correct pump.

VETDRMS

I am going to be using a Holley VoluMAX 130gph pump, and it does not have a return line. From what I have been told you can block off the return line, as these pumps do not use it to bleed off pressure like an oil pump does.
:cheers:

EDIT: You will however need a pressure regulator (depending on pump; what model do you have)


[Modified by VETDRMS, 7:07 PM 3/23/2003]

LFZ

great...so i can block it off?? i got the "street" pump....i got it out of summit. the race pumps are the ones that need the regulator. also....how did you hook up your line from the tank to the pump??? any suggestions?

VETDRMS

Here is some good reading:

http://www.holley.com/HiOctn/TechSer.../FMFPTech.html

Albeit about electric pumps, but good reading. From what I can tell and see is that you do not really need a return line unless your using a 160+gph pump. You should be able to use your stock line, just flare it and use an AN adapter and run #6AN Lines to the pump. Your local speed shop should be able to get all the right parts, but look to spend over $100 if you use AN fittings and SS line. :cheers:

I haven't got mine together yet, but I'll be using a 750 Mighty Demon on my 406. :reddevil I will be documenting the whole buildup, so stay tuned. :cheers:

lyonsh

Yes, you can block off the line. No, I don't recommend it. It may not be "necessary" but it makes you more susceptible to vapor lock.

You can get a fuel pressure regulator with an extra port for the return line. Solves the problem. :cheers:

LFZ

i'm not too familiar with fuel pressure regulators.....does it need to be installed between the carb and the fuel pump?

Smokehouse69

Pumps without a return line have an internal bleed mechanism that keeps the pumps from dead-heading. One thing you don't want to do is use a pump that has a return line and cap it, you'll break the spring on the pump quickly. I know because I did it!

LFZ

smokehouse, so your using a pump with no return line and you blocked off the the return lines on the car? do you ever have problems with flooding or the gas tank not venting?? i know i'm sounding very paranoid about this....but its my vette! :D we're all like this! :thumbs:


[Modified by REDSHARKONBOYDS, 5:27 PM 3/24/2003]