[64gp4spd]

Working on the Fuel System on 1964 Pontiac GP. I tried to have my Fuel Tank Sending Unit modified by RobbMc with a 1/2 inch line and 8AN connector but being it is a bolt in style unit it cannot be modified.

In the past with a pretty stout 421 I ran the stock 3/8 line with a Holley Red mounted on the frame feeding a Carter Mechanical pump on the motor no regulator, to a Holley 950HP. I could shift at 6500 RPM and never had any issues with fuel starvation etc. However, the Carter Mechanical would not pull fuel through the Holley Pump if it was turned off.

Just want to see if anyone is using a similar set up with a Carter Electric like a 4594 or 4602 and if this would be a better choice.

Thanks

[HoneyHush]

I’ve always ran a Holley black or the carter 140gph I believe it is by the tank and with either a 3/8” line or 1/2 line to a Holley regulator (with no mechanical pump) and then to the carb on my street cars. Running as fast as 10.60’s.

[OCMDGTO]

64, I have a hardly used Holley Black pump I'll sell for $100

[Tom Vaught]

Originally Posted by 64gp4spd

Working on the Fuel System on 1964 Pontiac GP. I tried to have my Fuel Tank Sending Unit modified by RobbMc with a 1/2 inch line and 8AN connector but being it is a bolt in style unit it cannot be modified.

In the past with a pretty stout 421 I ran the stock 3/8 line with a Holley Red mounted on the frame feeding a Carter Mechanical pump on the motor no regulator, to a Holley 950HP. I could shift at 6500 RPM and never had any issues with fuel starvation etc. However, the Carter Mechanical would not pull fuel through the Holley Pump if it was turned off.

Just want to see if anyone is using a similar set up with a Carter Electric like a 4594 or 4602 and if this would be a better choice.

Thanks

1) Today I use a In-Tank Fuel Pump but years ago I used a By-Pass with a Holley Blue Pump. Today Carter Fuel Pumps actually offers that By-Pass System with their pumps. Do not see the by-pass hardware in the latest google search. Mostly used for RV Pump systems.

2) Here is a picture of the way I did my fuel pump by-pass, Not my system, but same plumbing exactly.

a) Inlet from the tank on the left, then a "Tee" (one side to the By-pass check Valve), other side to inlet on the fuel pump).

b) Outlet side of Check Valve and Outlet side of fuel pump to a "Tee".

c) From the "Tee" to the Mechanical fuel pump. In my case it was a modded
6 valve mechanical fuel pump

Tom V.

[tom s]

I have a Carter elect in the back and my Carter mech pump pulls through it with no issue.Been on the car for 20 plus years.I dont race it anymore so just use it to prime the carbs when not driven for awhile.FWIW,Tom

[Half-Inch Stud]

My decision points:

Carter pusher for 3/8 steel line fuel system.

Holley pusher with pre-filter, for 1/2" aluminum fuel system.

Neer a braided hose in hiding! Never again. Only organic hose(s) allow your eyes looking at it.

[RocktimusPryme]

Originally Posted by Tom Vaught

1) Today I use a In-Tank Fuel Pump but years ago I used a By-Pass with a Holley Blue Pump. Today Carter Fuel Pumps actually offers that By-Pass System with their pumps. Do not see the by-pass hardware in the latest google search. Mostly used for RV Pump systems.

2) Here is a picture of the way I did my fuel pump by-pass, Not my system, but same plumbing exactly.

a) Inlet from the tank on the left, then a "Tee" (one side to the By-pass check Valve), other side to inlet on the fuel pump).

b) Outlet side of Check Valve and Outlet side of fuel pump to a "Tee".

c) From the "Tee" to the Mechanical fuel pump. In my case it was a modded
6 valve mechanical fuel pump

Tom V.

Does the bypass do the same thing for you that a return line does? Keep the pump from working as hard? Maybe reduce heat?

[Tom Vaught]

It allowed the Mechanical Fuel pump to draw fuel from the fuel tank even when the Holley Vane Blue Pump was not operational, in my case.

When you turned on the Blue Fuel Pump, the "By-pass Check valve CLOSED so that fuel would not loop the blue pump circuit and take away fuel needed at the mechanical pump.

All the rear pump by-pass did was allow the mechanical fuel pump to draw fuel from the tank when the blue pump was off.

Tom S says the Carter Electric Pumps have a built in by-pass when they are off.

Tom V.

(My picture was showing how the By-pass circuit was plumbed)

[64gp4spd]

Tom, Nice Set up

Thanks to everyone for the replies
A lot to think about

OCMDGTO, I think the Black pump
would be overkill for my set up but
thanks anyway.

Rich

[lust4speed]

Mallory 140 and 110 and Holley 125 and 150 all have brushes in the motor - and it seems I only get about 8,000 street miles or less before brushes need to be replaced. Had some bad luck with Mallory and then Holley so switched to the Carter which is a brushless pump and it just keeps on pumping. Mallory changed the brush design and quit supporting my early 140 pump, and then did a design change to their deadhead regulator, and both the new designs look like the old but new replacement parts won't fit. The Holley 150 just seems to really wear down the brushes and I spent a lot of time checking wear and replacing brushes. When I took the Holley out of service it had some unusual wear inside the pump and might not have been much longer for this world anyway. Carter has been maintenance free.

[64gp4spd]

Hi Mick, what is the part number of the Carter pump you are using?

Thanks, Rich

[Cliff R]

Running an electric pump as a "pusher" then installing a mechanical pump in front of it sort of defeats the purpose. Electric pumps don't use valves that open and close so have constant pump output. Most decent electric pumps are at least 100gph and any sort of a mechanical pump up front is just a stumbling block for it...IMHO.

Anyhow, I've been down these roads many times and have had just about every possible system on the Ventura over the years. As I made changes to make the car quicker I kept running into issues with fuel delivery. I tried a Holley Red pump to a Carter 120GPH mechanical pump briefly and it didn't work for chit. I removed the mechanical pump and went to a Mallory 110gph, then a 140gph, and still had issues on really hard runs.

I was completely baffled at one point and even installed a 1/2" pick-up and sending unit assembly into the tank and relocated it as far back as possible/practical. I really thought that deal would make the grade but son of a ditch it still gave issues. At that point I even built and installed a Holley 4781-2 850 DP and with Tom's help got it dialed in where it was flawless. Back to back track testing didn't show any improvement in ET or MPH, so bigger fuel bowls weren't the problem.

The complete once and for all cure was to sump the tank and pull the fuel out the rear and mount the Mallory 140gph pump behind the tank and 8an lines/fittings everyplace. That completely cured ALL fuel delivery issues and was worth a solid .3 seconds and 2mph at the track with both the Q-jet and the Holley 850dp carb. I was remarkably surprised at that point because the car was running deadly consistent but the engine was just going "flat" over 5000rpm's and I just figured the "little" Crower RAIV cam wasn't big enough. The very first runs with the new system the engine revved right past 5500rpm's so quick I didn't get the shifter moved fast enough to complete the shift before 6000rpms! I was stocked at this point, but sadly however running it "dead-head" fried the brushes in the pump in short order (about 2 months of street driving and racing the car couple of times a week). At that point I decided to install a return system back to the tank. That ended up being the right move and the brushes in the pump lasted almost 20 years before it started making noise and needed another set. That was just recently. I'll also add that adding the return system made the pump just about silent when running. Dead-head it was unhappy after half hour or so of street driving and vibrated, hummed, buzzed and just flat let you know it didn't like that deal at all.

The problem with this topic is that some folks are able to get away with things that others can't. Over the years we've worked on hundreds of cars and set up scores of street/strip cars that saw a decent amount of track time. There will always be a few that can run really quick with a stock fuel system and others that can't get out of the 13's trying to do the same thing.

I'm not really recommending anything here, but I do know that IF you want to cure any and all issues with fuel delivery install a system good for at least as full second quicker than your car will ever go, and using a fuel cell or sump and rear mounted pump with at least 8an lines/fittings everywhere is a permanent solution to any of these issues. I also see a lot of folks going to in-tank electric pump set-ups, which would work well for those that don't want to sump tanks and have electric pumps mounted up under the rear of the vehicle.......FWIW......Cliff

[Tom Vaught]

Carbs get blamed for a lot of other issues.
Glad I could help you on your 850 DP Carb, Cliff. That was a long time ago, lol.

Your 750/800 Q-jet should work as well as the Holley carb (or better in some cases) if the Holley carb needs work, or you have OTHER fuel system issues, like fuel trying to go in one direction (due to acceleration) be drawn down a pipe in the opposite direction.
Carb of one brand will work as well as a carb of another brand if set up properly.

The old By-pass Fuel Pump system was to give the engine a bit more fuel vs the factory pump but the "Blue Pumps" were noisy, had a lot of Vane Sticking Issues if the pump was not used often, and the fuel pressure regulators at the time were terrible.

A lot of those issues have gone away with modern fuel systems, as we all know.

Even modern systems can be wired with too small of a power wire and the pump will not perform properly. Be it "Near Rear Bumper" mounted or mounted inside the fuel tank.

Tom V.

[Formulajones]

Originally Posted by lust4speed

Mallory 140 and 110 and Holley 125 and 150 all have brushes in the motor - and it seems I only get about 8,000 street miles or less before brushes need to be replaced. Had some bad luck with Mallory and then Holley so switched to the Carter which is a brushless pump and it just keeps on pumping. Mallory changed the brush design and quit supporting my early 140 pump, and then did a design change to their deadhead regulator, and both the new designs look like the old but new replacement parts won't fit. The Holley 150 just seems to really wear down the brushes and I spent a lot of time checking wear and replacing brushes. When I took the Holley out of service it had some unusual wear inside the pump and might not have been much longer for this world anyway. Carter has been maintenance free.

I've had nearly identical issues you've had with those setups. I've been using the Mallory 140's since the early 90's on a couple cars. On one in particular it was pretty routine to replace brushes every 4-5 years with a mix of street driving and racing. I use a return style system on that car as well. After more than 20 years I've gotten tired of rebuilding the pumps and when I got in that time frame I always got nervous driving the car anywhere and I just wasn't comfortable with that anymore, that's not a way to enjoy a car.

. Several years ago thanks to Tanks Inc I started just swapping the whole tank and putting Walbro pumps in the tank and just completely got away from external electric pumps all together. I couldn't be happier.

For the OP that I believe has a car that a tank isn't offered, I'm in the same boat with one of the cars here. Sometimes the Aeromotive in tank retrofit setups are an option in cases like that. I can't even do that with the 56 Nomad here. It's in desperate need of a better system but the tank is so funky in shape and design you can't retrofit anything in it successfully, and no baffled tank is made for it. The only option at this time is an external pump so that car sits stagnant for the time being.

[TedRamAirII]

Originally Posted by Formulajones

I've had nearly identical issues you've had with those setups. I've been using the Mallory 140's since the early 90's on a couple cars. On one in particular it was pretty routine to replace brushes every 4-5 years with a mix of street driving and racing. I use a return style system on that car as well. After more than 20 years I've gotten tired of rebuilding the pumps and when I got in that time frame I always got nervous driving the car anywhere and I just wasn't comfortable with that anymore, that's not a way to enjoy a car.

. Several years ago thanks to Tanks Inc I started just swapping the whole tank and putting Walbro pumps in the tank and just completely got away from external electric pumps all together. I couldn't be happier.

For the OP that I believe has a car that a tank isn't offered, I'm in the same boat with one of the cars here. Sometimes the Aeromotive in tank retrofit setups are an option in cases like that. I can't even do that with the 56 Nomad here. It's in desperate need of a better system but the tank is so funky in shape and design you can't retrofit anything in it successfully, and no baffled tank is made for it. The only option at this time is an external pump so that car sits stagnant for the time being.

These guys list a FI Tank for Nomad, https://www.rockvalleyantiqueautopar...anks_chevy.pdf

[Formulajones]

Originally Posted by TedRamAirII

These guys list a FI Tank for Nomad, https://www.rockvalleyantiqueautopar...anks_chevy.pdf

Thanks for that, I'll give them a call

[Formulas]

Having a mechanical pump in front of a electric helps to prime a high mounted and dry electric pump
Not much more advantage after that
I will say a mechanical pump will probably pass through all the fuel a entry level electric pump can push. .. kinda the sum of both might be a bit more than both used alone but not by much

[Tom Vaught]

Many Years ago, Marty Palbykin used a factory Pontiac Pump to fill a Surge Tank mounted on the drivers side fender area. The mechanical pump just dumped the fuel into the surge tank and any excess volume went right back to the fuel tank thru the return line.
No back pressure un the system so the mechanical pump was able to move a lot of fuel.

So from the surge tank, (which had a EFI Pump inside it), the fuel for the engine went to the fuel rails and to a fuel pressure return style regulator. Finally any returned fuel went back to the SURGE TANK. Much like the Modern Front Mounted Race Fuel Tanks on a funny car except using cheap components vs using $$$ parts. Same idea though.

So the electric pump would not be "dry" if you put it into a proper surge tank.
The Robbmcc fuel "Power Surge Tank" being an example of a modern available part.
Tom V.

[tom s]

When I built my tempest like 22 years ago I did not have a mech pump.Was out driving at night and blew the fuse on the electric and did not have a spare.Walked home because I was close and made up my mind I was not going to walk again and put the mech back on with a switch under the dash to use the electric when racing or to prime if necessary.Still carry a spare fuse in the glove box.FWIW,Tom

[lust4speed]

Originally Posted by 64gp4spd

Hi Mick, what is the part number of the Carter pump you are using? Thanks, Rich

Carter pump number is P4601HP which I believe is the stoutest of the Carter pumps. They have over a half dozen pumps that are milder in pressure and/or volume. My Carter makes noise but once the engine fires you don't hear it. I received an email that says the Carter still has brushes so now I'm not sure. I do know it is a sealed unit and has worked for many miles. The description says "no points to wear out" which is vague at best.

Recently there have been some good alternate choices available and I would definitely consider a combined tank and internal pump. Have two friends in our GTO club that have went that route and so far the units are quiet and trouble free.