Which Fuel Pump?

[Germanyjon]

I want to get a fuel pump for my 74 Spica car. I want one with a built in pressure relief valve. What's available?

[Rosenmöller]

Quote:

Originally Posted by Germanyjon I want to get a fuel pump for my 74 Spica car. I want one with a built in pressure relief valve. What's available?

[Roadtrip]

They all actually have PRVs built in, however, the trigger pressure is way above what you should have in a Spica system (17 psi MAX). The trigger pressure of the L-Jet pump is something like 50-60 psi or higher. You absolutely do not want that in a Spica system with standard fuel lines, nor is it good for the injection pump itself. Best thing is to keep the front fuel filter PRV and check the pressure with a direct read gauge to make sure that the outlet restrictor is the right size.

[Richard2]

Wes Ingram has a Pierburg pump from Centerline installed on his test stand to tune rebuilt pumps and installs them on customers cars.

[Germanyjon]

what about the Hella that Centerline sells?

[Richard2]

I'm not sure, but they may be the same pump. Give Centerline a call and ask.

[Luscombe1940]

Hi Guys,

I'm a little confused about the alternate main fuel pumps. I have a copy of the SPICA FUEL SUPPLY DIAGNOSTIC GUIDE and in appendix 1 it says that the L-Jetronics pump is a good subsititute provided you modify the outlet restrictor to 1/6" diameter.

Am I missing something?
I had planned on getting a L-Jetronics pump as a spare.

Gary

[Roadtrip]

There's a lot of confusion about substitute main supply pumps. In reality, just about any pump that can maintain a input line pressure of a least 15-17psi (with the restrictor in place and the return system working) and a half gallon a minute flow rate is ok. The flow rate is important because fuel is used to cool in the injection pump. The Bosch L-Jet pumps are good substitutes because they meet that criteria, however, they are pricey. Centerline stocked a cheap Chicom knockoff but discontinued it due to it's poor quality and reliability (imagine that). Some owners have sub'd the Master (E2000?) pump from local autoparts store with good success, and it's less expensive to boot. You might try the local autoparts store and see if they have a cross reference generic pump for an L-Jet injected Alfa or BMW.

The reason I use and recommend the Bosch pump is that it's known good-quality, it works, and is readily available . . . although inexpensive it is not.

The important points are:
1. Pump puts will hold correct pressure (10-17 psi) in the input side of the fuel supply system, with the outlet restrictor in place.
2. Volume output is sufficient for pump cooling.
3. It's an in-line pump.
4. It's designed for continuous running.

Here's a previous thread on the subject.

Fuel Pump Alternatives

[Luscombe1940]

John,

If I get anb L-Jet pump, will I need to replace fuel lines between the pump and the SPICA to handle higher pressure or does the restrictor on the pump do the job?

Gary

[Roadtrip]

Standard fuel lines are fine due to the relatively low pressure in the feed line . . . .<17 psi. If you block off the return line, however, and don't have a PRV front fuel filter, you can spike that pressure way too high. However, with at least a 1/16th restrictor hole, the pressure should be less than 20 psi at most. It's a good idea to check the exact pressure with a direct reading gauge to be sure you have the restrictor the correct size.

[Luscombe1940]

Got it! Thanks John.

Gary

[Germanyjon]

will these pumps work?


eBay Motors: NEW FUEL PUMP BMW Alfa Romeo Eagle BMW Jaguar IN-LINE (item 160260183390 end time Jul-20-08 12:30:29 PDT)

eBay Motors: New In Line Fuel Pump BMW Opel Alfa Romeo Fiat Renault (item 200238788818 end time Jul-23-08 09:02:51 PDT)

[Roadtrip]

The first one you list looks like it might work.

If you use other than a standard fuel supply pump (especially one capable of such high pressures as this one) you must be sure that the feed pressure in the Spica system is correct . . . i.e. no greater than 17 psi. The replacement L-jet pumps can produce high pressure, but that is mitigated by the restrictor orifice in the front fuel fitting. That can be modified to "dial in" the correct pressure. It's also important that the flow rate be sufficient since fuel flowing through the injection pump and back to the fuel tank cools the injection pump.

So, if using a substitute pump, you want to check the inline pressure with an inline gauge (NEVER DEADHEAD THE MAIN SUPPLY PUMP). The working pressure of most rubber fuel lines used in the Spica system is only about 50 psi. Howver, like I said the normal system pressure for the Spica system is 7-17 psi.

Further, you want to see about .6 gallon per minute flow rate out the front fitting of the injection pump (after the restrictor orifice). You can just take a yard-long piece of tubing from the front (outlet) injection pump fuel fitting and run it into a measurable container and run the pump for a minute. You want to see .5-.6 gallons pumped in one minute.

With regards to those ebay pumps. I don't know where the first one was made but my guess is the same as the second blue pump. I'm pretty sure the second one is a cheap Chicom knockoff. Those pumps have poor reputations. Centerline tried selling them for a while cause they were inexpensive, but they were getting a lot of returns defective, so they discontinued them.

[Germanyjon]

John, let's see if I understand. Because of the PRV, the PSI can not go over 17 even if the pump is capable of a lot higher PSI. Correct? Also, where can I get the PRV?

[Rosenmöller]

Quote:

Originally Posted by Germanyjon John, let's see if I understand. Because of the PRV, the PSI can not go over 17 even if the pump is capable of a lot higher PSI. Correct? Also, where can I get the PRV?