Fuel system advice, please?

[661]

I run a twin pump system, one Holley red top on at a time. I have had a pump fail in the past so thought I'd set up 2 in parallel. Each has a Sytec one way valve after the outlet port. Both valves have seized. I was DNS at Snetterton, which was less than enjoyable. My question is, does anyone else have a back up , 2 pump, system or is everyone running just the one?
The system has run fine for 3 seasons, I did use 99 momentum for the first time ever at this meet ( with CVL), usually Shell.
I did notice in quali that the fuel pressure was slightly lower than expected and suspect the valves were starting to stick.

[h20hamelan]

Are they Sytec valves quality, or off-shore junk?

Find a proper valve, Mercedes Audi Volvo something from the 70’s 80’s.

Pierberg is what I am using.

[elans3]

I am using a Mitsuba FP3 pump. Best of the best. Most of the Works Rally Teams used to use them thru the 70's and eighties. The one I'm using now came to me on a 289 Cobra Replica I had in the early 2000's, and was dated around 1990 (new). I have swapped it onto every classic car I've had since then, & has been on my Alfa Giulia now for 7 years. Never failed. I have another as back up in the boot. Never had to use it.

[661]

Are they Sytec valves quality, or off-shore junk?

Find a proper valve, Mercedes Audi Volvo something from the 70’s 80’s.

Pierberg is what I am using.

Well there's a question. I'm thinking they can't be that great. If I just use one pump then I don't need any flow valves and that makes the issue irrelevant. Fuelab seem to do decent ones

[661]

I am using a Mitsuba FP3 pump. Best of the best. Most of the Works Rally Teams used to use them thru the 70's and eighties. The one I'm using now came to me on a 289 Cobra Replica I had in the early 2000's, and was dated around 1990 (new). I have swapped it onto every classic car I've had since then, & has been on my Alfa Giulia now for 7 years. Never failed. I have another as back up in the boot. Never had to use it.

I assume the 'back up in the boot' is not plumbed in, hence no reason for flow valves?
It may be time to trust in one pump.

[rgh0]

I have only ever used one electric pump for 40+ years in my Elan and never had an issue. I have used various types over the years as I have needed increased fuel flow as the power in my competition engines has inceased. I have seen other people using two pumps but the added complexity as in your case can give more problems than it solves especially if it hides the fact that one pump has failed until the second one does.

cheers
Rohan

[tonyabacus]

I agree with Rohan, one pump if properly calculated is more than sufficient
Tony

[h20hamelan]

Solenoid pumps are junk, get a rotary.
Lots of people still on mechanical which is a worthy backup as long as your fuel system can survive

[661]

My memory.........I said in the post it was a Holley, they are in fact twin Facet red tops, part480532E

[661]

I have only ever used one electric pump for 40+ years in my Elan and never had an issue. I have used various types over the years as I have needed increased fuel flow as the power in my competition engines has inceased. I have seen other people using two pumps but the added complexity as in your case can give more problems than it solves especially if it hides the fact that one pump has failed until the second one does.

cheers
Rohan

The two pumps have separate switches on the dash, so you could easily work out if one had failed by the lack of pressure on the fuel pressure gauge. However, if the one way valve seized on one of the pumps, that would give the same lack of pressure. Either way, it was the ability to do something about it that I liked. But when both valves seized you are most definitely going home.
It does make me wonder if the 'pump failure' I had before was the start of the valve sticking. I'm just collecting thoughts but may well go to one pump and carry the other in the spares box. It would be simple to swap and without one way valves it would make identifying the source of the problem quicker.

[elans3]

I am using a Mitsuba FP3 pump. Best of the best. Most of the Works Rally Teams used to use them thru the 70's and eighties. The one I'm using now came to me on a 289 Cobra Replica I had in the early 2000's, and was dated around 1990 (new). I have swapped it onto every classic car I've had since then, & has been on my Alfa Giulia now for 7 years. Never failed. I have another as back up in the boot. Never had to use it.

I assume the 'back up in the boot' is not plumbed in, hence no reason for flow valves?
It may be time to trust in one pump.

No, the spare pump is in a box, just in case it's ever needed, it's a ten minute job to swap them over if ever required. I do have a one-way valve in the fuel line aswell. That way the car starts first turn, after two or three pumps on the throttle pedal.

[Vali]

I don´t use one way valves on my cars and I ask you why would you use them?
The Webers or Stromberg do have their fuel chambers. There will still be fuel inside if not standing around more than 6 months? For a mechanical fuel pump at the engine I might would like to have a one way valve but not with a electric fuel pump. Or am I wrong here? As soon as I switch on the fuel pump the fuel pipes will get pressurized and fill up the fuel chambers ready for starting the car.

Before I sold my Race Elan I used only one fuel pump (believe the Red Top) together with a Malpassi Fuel Filter/Pressure bowl.

[661]

I don´t use one way valves on my cars and I ask you why would you use them?
The Webers or Stromberg do have their fuel chambers. There will still be fuel inside if not standing around more than 6 months? For a mechanical fuel pump at the engine I might would like to have a one way valve but not with a electric fuel pump. Or am I wrong here? As soon as I switch on the fuel pump the fuel pipes will get pressurized and fill up the fuel chambers ready for starting the car.

Before I sold my Race Elan I used only one fuel pump (believe the Red Top) together with a Malpassi Fuel Filter/Pressure bowl.

The reason for using valves in a parallel system is that the fuel would otherwise pass backwards through the dormant pump towards the tank. I can't see a reason for using valves in a single pump system as the pressure comes up almost immediately

[elans3]

I don´t use one way valves on my cars and I ask you why would you use them?
The Webers or Stromberg do have their fuel chambers. There will still be fuel inside if not standing around more than 6 months? For a mechanical fuel pump at the engine I might would like to have a one way valve but not with a electric fuel pump. Or am I wrong here? As soon as I switch on the fuel pump the fuel pipes will get pressurized and fill up the fuel chambers ready for starting the car.

Before I sold my Race Elan I used only one fuel pump (believe the Red Top) together with a Malpassi Fuel Filter/Pressure bowl.

Yes you're wrong. I can't speak for Strombergs, but DCOE Webers empty their float chambers relatively quickly, fuel evaporating through the breather hole in the front of the carburettor body. After six months, they'd be empty. Hence when you switch the ignition on after a few days, the pump ticks like mad until the float chambers fill up. Remember we're only talking about a low pressure system here, not a high pressure pump for an injected engine. I regulate mine through a Malpassi Filter King to 2.5 to 3.5psi, which is optimum for DCOE's. I use the one way valve to stop fuel running back to the tank when the car isn't running.

[davidbravo]

Your dual pump system worked well for three seasons, but the seized valves might be due to using Momentum 99 with CVL for the first time. Some people stick to one pump, but dual setups like yours are common. It’s likely the fuel caused the valves to stick, or they just wore out. You could try better-rated valves for fuel additives or start checking them regularly to avoid this in the future.