Blue Holley to Mallory 110 fuel pump question

[tommyg29]

Thanks Chryco, that is probably the case but before I try returning it to Summit (pita) I wanna see if others have had this issue because of the way its been mounted.
The instructions say to install it below the fuel pickup. I assume they mean the pickup in the bottom of the tank, but that would mean I need to mount it at least 6 inches lower on some sort of hanging bracket. Another thread in here is talking about that now. But I dont think this should be happening with a brand new pump and a full tank!
Does anyone think that could be my problem?

[moparmaniac59]

I've been thru some of these same problems myself and in the past had posted my trials and tribulations I had with the Holley Blue and switching to the Mallory. I believe part of the problem to be due to running a pump without a bypass regulator to return the unused fuel back to the tank (single feed). Most of these type pumps put out 12-15 psi (some even higher) while the carb only needs about 6 psi causing backpressure and thus some of the noise. I think if you use a bypass regulator & return to the tank, you'll find that the pump will run much quieter due to much less backpressure. I personally had two Holley Blue pumps burn up & I believe part of the cause to be too much head pressure for too long a duration. Holley claims the Blue pump to be for extended road use (unlike a short run down the race track), but do not provide (with the pump) a bypass regulator. The first bum pump, Holley gave a refund. After the 2nd failure I went with a Mallory and used a bypass regulator and a return line back to the tank. I would also suggest using a pump relay. Fluctuations in the car's electrical system (voltage/amperage) can also cause premature pump failure and the relay with help prevent this. The Mallory did run much quieter than the Holley.

                                                  Matt B.

[tommyg29]

Im thinking the same as you maniac. The whine definitely seems to get loud when I slow to idle for a few moments. I'm not sure because of the engine noise, but it seems to go away when under throttle. My senses tell me pressure is backing up when the carbs arent sucking it down. I think I have a "deadhead" regulator on the inner right fender, and I hate the thought now of having to switch regulators and add a new line all the way back to the tank, but...maybe thats what the doctor is ordering.
Not sure about fluid dynamics of this, bit I dont imagine installing some sort of bypass valve inline just after the fuel pump would help. It would be a lot easier to install, but I think most of the fuel would just go right back to the tank.
It seems these fuel pumps are not designed to handle a non-return type system, though the directions definitely have diagram "A" showing a non-return system.
In which case maybe Chryco is right. It could just be a weak or defective unit.

[tommyg29]

one thing I forgot after studying my layout. My fuel filter is right after the pump, and the instructions recommend two filters...one just before the pump, and another after the regulator. A second filter seems like overkill to me, but is my filter location possibly stunting the pump output? Plus, do I need a "competition" filter.

[Chryco Psycho]

there is a filter on the suction side inside the tank already , 1 filter should be lots after the pump
 I typicall mount the pump level with the sending unit , the pump has to be able to pull the fuel up that far
 with the 110 pump I have never used a return line & I have not noticed any sound change when idling , but that would make sense that the pump would work harder against the regulator