Purolator Electric Pump Blues

[DrDano]

Alright, I'm at the breaking point of fustration with my shoebox over the weekend. Here's the story and my question:

Over the weekend I attempted to install an electric fuel pump to run my flathead in my '51 Ford sedan. The stock 8BA fuel pump takes over a minute to get fuel from the tank to the motor and that is a lot of cranking on the battery and starter.

I installed a Purolator 12S that I had sitting around. Its this one:
http://www.midwayautosupply.com/images/purolator/pro12s_3X.jpg

The pump has enough muscle to get the gas to the 2 94's I have, but will only keep up for about 5 seconds before the carbs run dry, the engine dies and the pump has to play catch-up.

Ok, heres my question: Does Purolator make a decent pump, or are they all trash? This pump is rated at 35 gallons/hr, do I seriously need to look for something more along the lines of 60+? The motor is a mild .030 over 239, 77B cam and 2 94's.

I've heard recommendation for the Carter 4070 which runs at 72gph @ 6psi.
http://static.summitracing.com/global/images/prod/large/crt-p4070_w.jpg
With the rotary vane design, is this pump likely to have a little more pulling power as compared to the clunky Purolator which wants to be gravity fed on the intake side? I only bring this up because my shoebox gas tank and location of where the pump must be mounted roughly 3" from the tank and the pump must first suck the gas out of the outlet pipe on the tank which is roughly 6" tall, then it will gravity feed into the pump. clear as mud? good. http://www.jalopyjournal.com/ubbthreads/images/graemlins/tongue.gif

Anywho, if someone could give me some opinions on the Carter pump and if there is a suitable Purolator replacement, that could be nice too because I already fabbed up a mounting bracket for it.

[yorgatron]

that Carter looks like the pump i've had on my Olds ever since i got it about 6 years back.mine is mounted in the engine compartment,pulls plenty of gas (almost TOO much,i put a regulator on when i switched the original 2 bbl WGD to 3 94's) never had a problem with it EVER,also didn't know it was a Carter 'til now,as it had no markings on it whatsoever,but it looks almost identical to the one in the second pic-george

[Bugman]

I'll second the Carter pump. problem free for 5 years now. You'll need a pressure regulator though.

-Jeff

[Yo Baby]

Ther is something wrong with any picture that includes a flat head using over 35 gals. per hr,unless it's Nitro.

Check the pump with a bucket and a stop watch or a watch with a second hand and see what it is really delivering,almost anything should be enough.

No telling what you might find. http://www.jalopyjournal.com/ubbthreads/images/graemlins/grin.gif

Or try making the regulator a return type deal,You can return it into a bucket just to see what hapens. http://www.jalopyjournal.com/ubbthreads/images/graemlins/cool.gif

[Fat Hack]

I have that Carter pump on my 49 Chevy...had to install a Holley low pressure regulator to dial the pressure down to 4psi, which is what the carb seems to like...but the pump will EASILY flow enough fuel to feed your combo!

(It's really overkill for my application! http://www.jalopyjournal.com/ubbthreads/images/graemlins/crazy.gif http://www.jalopyjournal.com/ubbthreads/images/graemlins/cool.gif)

As for the mounting issue, you'll be fine. My pump is mounted slightly higher than my tank and about five feet of fuel line lies between the inlet on the pump and the gas tank. It flows fuel RIGHT NOW with NO lag or hessitation...you should do fine with your set-up.

I'd strongly recommend that you use a regulator, such as the Holley, though. When I was setting up my fuel system I used a pressure gauge to test the pump's output and to pressurize something while I looked for any leaks in the line. Without a regulator installed, the pressure jumps alot...bouncing between 4 and 7 psi. With the regulator installed and set, the fuel being delivered to the carb is a smooth, constant 4psi. The regulator cost twenty dollars at the local speed shop, but be weary and use a gauge to test your new regulator...the two Holley regulators are IDENTICAL on the outside, and my first one was mis-boxed! One is designed for use in applications requiring 4.5 to 9 psi, and the other is designed for applications demanding 2 to 5 psi or so.

(Keep in mind that the regulator can only step the pressure down a given percentage of what the maximum input pressure is...in the case of the Carter fuel pump in question, it peaks at an observed 7psi, and the Holley low pressure regulator can dial it down to maybe 3.5 psi at the lowest.)

All in all, I'd say that the Carter pump will fill your needs, and it isn't that expensive. Add a twenty doallr Holley regulator, and you'll be able to enjoy your ride without giving a second thought to your fuel delivery system once it's dialed in!

[DrDano]

I currently do have a regulator on the fuel rail, its dialed in at at 5psi, 2.5 psi per carb.

Watching the clear fuel filter that is just before the pressure regulator on the intake, I can see the fuel run drop down low and lag behind when the motor fizzles out and dies. So, I know that the poor power of the pump just isnt enough to feed the motor, even at idle. I think its probably a combination of a poor pump, pulling gas from the tank when it wants to be gravity fed, and distance/elevation of where the gas is ending up. I tested the volume of the pump when I hooked up to the stock fuel pump with the glass sediment bowl. It took nearly a minute just to fill the glass sediment bowl on the old pump!

Thanks for advice folks, I'll stop by Napa tomorrow and pick myself up a Carter 4070 and maybe think about using the crap-o-lator on something else. http://www.jalopyjournal.com/ubbthreads/images/graemlins/tongue.gif

[DrDano]

One more thing that comes to mind that could be causing problems is crap in the stock fuel line between the firewall and tank. I can rig up a bucket and run a solution through it to clean it out, but what should I flush the line out with?

[yorgatron]

blow out the line with compressed air,then add a pint or two of B12 chemtool to the tank.

[Mutt]

[ QUOTE ]
I currently do have a regulator on the fuel rail, its dialed in at at 5psi, 2.5 psi per carb.

[/ QUOTE ]

51leadsled - you have 5lbs to the rail - and 5lbs to each carb. Whatever you put into the rail is what the carb sees.

Mutt

[Yo Baby]

What about crap in the tank,or the supply line to pump from tank?

Always try to diagnose completely before throwing money at it.

Why did you install the electric pump in the first place? http://www.jalopyjournal.com/ubbthreads/images/graemlins/grin.gif

[RileyRacing]

Yeah, FatHack got a steal on his pump! http://www.jalopyjournal.com/ubbthreads/images/graemlins/grin.gif

That Carter was sold to me as a step up from the stock one on a mild SBC, so I guess that you would be ok on your flatty. I know, everyone else already said that... http://www.jalopyjournal.com/ubbthreads/images/graemlins/grin.gif

Jay

[DrDano]

Mutt, your right, the split wont change the pressure. . I might want to look at that. It does not seem to be causing problems, so I'm gonna leave it be until I get the pump issues solved. Good idea to check it tho, thanks.

Yo, crap is in the line. The tank has been gone through and resealed, not a speck of rust in there. Yes, diagnosing things is a good idea. Thats why I'm here, getting some knowledge from a few old dogs and a few new ones who might have some good ideas, which they always do.

I went to the electric pump because the old diaphram style mechanical pump sucks. A lot of the guys who run the flathead in the shoebox cars typically run an electric to build pressure up so the mechanical could take over after startup. The issue is that I dont like cranking on my motor for up to a minute to get it to fire everyday. I'd rather hit the key, wait a few seconds and be on my way. When the line is primed in the past with the mechanical unit the motor will fire with just a flinch of the key, which is what I'm hoping to do with the electric.

[warbird]

sled,
I've been running the Purolator pump on my roadster for a couple of years now. It's been feeding the dual quads on the Cad with no problems, using a Holley regulator to drop the pressure down. It's mounted below the tank, but since it's a top feed tank the pump has to draw fuel up the dip tube before it can flow downhill to the filter and pump.

My first thought is that you've got a bad pump, but the fact that you've had some type of fuel delivery problems with both the mechanical and electric pumps seems a little odd. Think I'd double check the fuel line and pick-up as a place to start. And the tank vent is clear, Right?

Good luck,

[DrDano]

Warbird, is your model Purolator the same 35GPH unit? I'm kinda wondering if maybe it is a combination of bad pump and bad fuel line.

This afternoon I ordered up a new Carter 4070 from Summit, they beat the local Napa store by over $31, even with 2nd day air shipping. Wow.

I'm going to clean the crud out of the line as best I can when I get the new pump, I think cleaning the line and the new pump should solve all of my problems.

[LUKESTER]

I run one of those purolator pumps and it works fine.... My tank is mounted higher than my pump. I run 6 94s and don't use a regulator. I fabbed up a return line and made it tuneable by using a holley main jet (in the line) to adjust the pressure..... LUKESTER

[fuel pump]

The Purolator pumps aren't bad. My shoebox ragtop come with one on it so I left it. If I were to buy a new one I'd get the Carter but BE SURE you have a good regulator (the Holley is so so and the round Purolator stinks). I'd get a Mallory. They have one of the best designs out there. If it were my car I'd run new fuel lines. Remember, when you clean out the old lines, the shit you bust lose will end up in yer carbs http://www.jalopyjournal.com/ubbthreads/images/graemlins/mad.gif Good luck.

[C9]

What kind of voltage are you getting at the pump?

If the battery - with engine off - is at 12.2 volts or so and you've run a long 16 gage wire to the pump you could have voltage as low as 11 volts or so.
Aside from early burnout of the pump, the low voltage can make for pressure problems.

Make sure you have a good ground as well.

If you're running light gage wire to the pump you may want to think about setting up a relay near the pump.
Feed the relay with fused 10 gage wire tapped into the battery side of the starter solenoid.
Run 14 gage from relay to pump.

Make sure the relay has a good ground as well.

[warbird]

sled,
Yep, same 35 gph pump. 3/8" fuel line from the tank to the carbs. With an inline filter just ahead of the pump and the pressure regulator hid at the base of the firewall.

Like I said, it's worked well so far but I've got a spare pump in the trunk. Just in case.....