Fuel Pump(s) Reliability

[330GT]

...You also mentioned the check valve in the mechanical pump. I don't know how this check valve is supposed to work, but I always thought that the the whole point of running the electric pump until the clicking slowed down before starting the engine was to fill the float bowls, because they drained back to the tank while the engine was off. If the check valve functioned, this wouldn't occur, would it?

...

The fuel in the float bowls evaporates from the engine heat after the car is shut off.

[jroswell]

Thanks 250GT and DWR46.

[tyang]

Tom:

I still think the double banjo is the more elegant solution, and certainly easier than machining a special outlet. If leakage is a problem, I would try the same type of copper gasket/washers that are used for similar sealing in many other locations. An '84 Mercedes I once owned had those washers on both sides of the banjo at the fuel pump and filter.

When you first mentioned (many years ago) hearing about people adding a modern electric pump to replace both pumps , you said "with a pressure regulator to provice approx. 5 psi to the carbs." This was probably because a pump used for a modern fuel injected engine has a very high output pressure that would force fuel past the needle valves flooding the carb. The Facet pump however, is available in 4 pressure ranges, all below 9 psi. (Does anyone have any experience selecting one - I would assume the 4.4 to 6 psi is most compatible.)

You also mentioned the check valve in the mechanical pump. I don't know how this check valve is supposed to work, but I always thought that the the whole point of running the electric pump until the clicking slowed down before starting the engine was to fill the float bowls, because they drained back to the tank while the engine was off. If the check valve functioned, this wouldn't occur, would it?

BTW - all this is nothing new. Back in the early 50's hot rodders were regularly bypassing mechanical fuel pumps with electric ones.

Sorry I have not replied earlier, but I've been slammed at the shop the last few days!

The double banjo fitting would be more elegant, but I still feel we would have problems with fuel leaks. Everyone says they don't have problems with these fittings, but we must be the only ones. Fiber, copper, and aluminum washers have all been used with eventual success, but I feel why add another sealing surface to fail? I'm in the process of having my nipple design fabricated, and I think it'll be easier for everyone to install.

We'll see!

Tom

[hgraham]

I'm ready to take the plunge on doing this upgrade. I'd like to do it the way you did on your car, Tom, but I'm not entirely clear on the setup. Is the new Facet pump installed near the electric fuel pump? If so, how are the flexible lines shielded from the heat of the exhaust? Was there ever a consensus on the model of Facet pump to use and/or the psi rating?

[tyang]

I'm ready to take the plunge on doing this upgrade. I'd like to do it the way you did on your car, Tom, but I'm not entirely clear on the setup. Is the new Facet pump installed near the electric fuel pump? If so, how are the flexible lines shielded from the heat of the exhaust? Was there ever a consensus on the model of Facet pump to use and/or the psi rating?

My interim fix was to tap into the short hose between the filter and the line running to the mechanical fuel pump, but I want to eventually mount a more permanent set up with fittings I'm making that will come off the electric fuel pump. I fabricated a separate plate that bolts to the electric fuel pump stand that shields the new pump from the heat of the mufflers, but again, I will make a more permanent piece when I install the final version. For now, I have the little square pump (facet makes these too) but when I plan on using the larger facet pump running the lower pressure.

I'd like to assemble a complete kit that owners can buy that will supply everything they will need to install a retrofit fuel pump.

Tom

[hgraham]

Thanks Tom! As far as the pressure rating of the pump, I've read on this forum that fuel pressure at the carb should be 4-4.5 psi, but does that translate directly to the replacement electric pump way back by the tank? Would you have any interest in making a prototype of your kit for a willing guinea pig?

[tyang]

The guinea pig will be my car, but I'll keep you updated.

Tom

[hgraham]

I just finished installing my new Facet electronic fuel pump and all I can say is wow. I never realized how many problems were being caused by fuel starvation, from vapor lock to hesitation under acceleration, to overall lack of power especially in warm weather. I would recommend this conversion to anyone who isn't planning to have his car judged for originality.

For those (like me) who are less experienced mechanically, I wanted to share what I did. I followed the method described by Tom as his interim fix on his own car. Thank you very much for the idea Tom!

The pump I used was recommended on ferrarichat.com and was a Facet 476087E, sold through Napa as a Balkamp 610-1074 for around $160. Yes, it's pricey, but it was in stock at my store around the corner. You will need adapters to step the fuel pump's threaded connection up to a 3/8" hose barb. I found that I needed connectors with a 90 degree bend to help everything fit into such a small space. I removed the flexible hose between the fuel filter and the hard line that leads to the mechanical pump. The factory hose barbs have spiral grooves, so the hose can be "unscrewed" reasonably easily rather than the usual type that has to be pried back and forth. For the new pump to fit well, I installed it in reverse, where the inlet faces the front of the car and the outlet faces the rear. I then connected the 90 degree barbs facing mostly towards each other so that the hoses could have a more or less straight run to their respective connections. To mount everything and protect the pump and fuel lines from exhaust heat, I fabricated a heat shield from galvanized steel sheet that connects at the fuel pump bracket and a small tab on a frame crossmember about 16 inches away.

I've included photos of everything so that anyone attempting this for the first time won't have to spend as much time as I did trying to find a way to get all of this to work. I apologize in advance for the sloppy metal work as this is the first time I've done anything like this and I was armed only with a drill and tin snips. I also welcome any comments or criticism from those with more experience (basically everyone!).

[tyang]

Hi Hgraham,

You should be congratulated simply for rolling up you sleeves and doing the work yourself. Bravo!

The only comment I have is to check to make sure the pump is oriented correctly. I seem to recall these pumps like to be mounted in a vertical position, but the documentation that came with the pump should confirm this. If there is nothing in the paperwork that requests this mounting position, and the pump works with all levels of fuel in the tank, then I wouldn't worry about it. When I get the fittings made up for the banjo fittings, you should be able to convert it easily, or leave your set up well enough alone.

I'm glad I could help, and enjoy the summer drives!

Tom

[hgraham]

Thanks Tom! The instructions for this particular fuel pump did say that it was favorable but not necessary to mount it in a vertical position. I didn't think that my sheet steel was thick enough to make a strong 90 degree bracket for that scenario. As I understand it, the vertical mounting is designed to allow any vapor trapped inside the unit to escape back towards the tank and is critical in the square type pump due to the placement of the outlets. You mentioned that there may be problems with a horizontally mounted unit at certain tank levels. What process is going on there and at what tank level? If it looks like it might be an issue, I'll dig around for some heavier bracket material and change things around.

Hudson

[tyang]

Hi Hudson,

My theory has to do with the amount of "head pressure" on the pump to help it move the fuel. With more fuel in the tank, the pressure against the inlet of the fuel pump will be higher, thus helping it pump fuel. If the pump has less pressure, and there is a condition for vapor in the line, you could have problems. I know Francois took a F1 car to Monaco a few months ago with a similar fuel pump, and the shop that did the installation mounted the pump horizontally. They had all sorts of fuel starvation issues because of this, but I also know a Ferrari F1 car from the same era is a lot thirstier!

Tom

[tim]

greetings... I've been looking a doing something similar so thanks for blazing the trail. The Facet 476087e is also available from Racer Parts Wholesale for a bit better price http://www.racerpartswholesale.com/prod ... Fuel_Pumps This seems to flow sufficiently (36 gph) compared to the Facet cubes (15 gph). Anxious to hear how it works out for you. Tim

[DWR46]

Facet/Bendix pump 476087E is the SAME pump that Ferrari used when they switched over from the Fispa pumps in the late 60s. It is the old "silver cap" Bendix pump.

[hgraham]

I really needed to post a followup for anyone wanting to do this upgrade. While on my second drive after installing the electric pump, I had a coil fail and limped back home. After replacing the coil, I went out for a drive which was cut very short by fuel starvation. I decided to go back to the new electric pump to investigate and when I took off my homemade heat shield I found that one of the new fuel hoses had settled in and kinked. This allowed just enough fuel supply to idle perfectly, but caused stalling under load. Since I had everything accessible again, I decided to make a new mount for the pump so that it could be in a vertical position (outlet OVER inlet as recommended in the instructions) and used much longer soft lines so that they could have a very gentle curvature and would never kink and restrict flow. I've now driven over 100 miles with no issues at all and hope that this is the ultimate solution for the problem. I'll post a photo of the fuel pump bracket setup when I have a chance.

Hudson

[tyang]

I really needed to post a followup for anyone wanting to do this upgrade. While on my second drive after installing the electric pump, I had a coil fail and limped back home. After replacing the coil, I went out for a drive which was cut very short by fuel starvation. I decided to go back to the new electric pump to investigate and when I took off my homemade heat shield I found that one of the new fuel hoses had settled in and kinked. This allowed just enough fuel supply to idle perfectly, but caused stalling under load. Since I had everything accessible again, I decided to make a new mount for the pump so that it could be in a vertical position (outlet OVER inlet as recommended in the instructions) and used much longer soft lines so that they could have a very gentle curvature and would never kink and restrict flow. I've now driven over 100 miles with no issues at all and hope that this is the ultimate solution for the problem. I'll post a photo of the fuel pump bracket setup when I have a chance.

Hudson

Hudson,

You have proven that most of this stuff is not rocket science, but simply a matter of logic, persistence, and the right knowledge. Congratulations! I've got my fingers crossed for your permanent success on the fuel issue!

Tom