Ok, todays challenge is finishing my new fuel system.
I have two Mallory 140's pushing fuel forward via a single -8 braided line to a dead-head regulator up front. I know, I really need a -10 main feed with a return-style regulator for this sort of volume. That will come in the next build cycle.
I just finished rebuilding the fuel pumps and have them on the bench, trying to (re)set the pressure relief on each. As you would expect, it's a simple setscrew/locknut combo. I'm testing one pump at a time, using a 15 lb pressure gauge on the the output side. I fire the pump up, bleed any air out, and then check the pressure out. I kill the pump, tweak the set screw and repeat.
My problem is I can't seem to get the dead-head pressure to change, it just keeps pegging my 15 lb gauge. I would expect that I could set the highside standing pressure to whatever I deem appropriate, merely by adjusting the set screw / spring pressure.
For those of you in the know, what should my dead-head pressure be for these pumps ? For obvious reasons I don't want to run it any higher than is neccessary. I should also add that I *think* these are 140's and not 110's, tho I have nothing on the pumps to indicate. The 110 & 140 pumps use the same rebuild kit, so I'm not sure it matters for what I'm addressing here.
At times I can be dumb as a bag of hammers, but I don't see anything obvious I'm missing here. Any suggestions ?
Is this an 'operator error' situation? Are you supposed to manually adjust the max pressure on these pumps or do you peg the set screw all the way down and drive on ?
I have two Mallory 140's pushing fuel forward via a single -8 braided line to a dead-head regulator up front. I know, I really need a -10 main feed with a return-style regulator for this sort of volume. That will come in the next build cycle.
I just finished rebuilding the fuel pumps and have them on the bench, trying to (re)set the pressure relief on each. As you would expect, it's a simple setscrew/locknut combo. I'm testing one pump at a time, using a 15 lb pressure gauge on the the output side. I fire the pump up, bleed any air out, and then check the pressure out. I kill the pump, tweak the set screw and repeat.
My problem is I can't seem to get the dead-head pressure to change, it just keeps pegging my 15 lb gauge. I would expect that I could set the highside standing pressure to whatever I deem appropriate, merely by adjusting the set screw / spring pressure.
For those of you in the know, what should my dead-head pressure be for these pumps ? For obvious reasons I don't want to run it any higher than is neccessary. I should also add that I *think* these are 140's and not 110's, tho I have nothing on the pumps to indicate. The 110 & 140 pumps use the same rebuild kit, so I'm not sure it matters for what I'm addressing here.
At times I can be dumb as a bag of hammers, but I don't see anything obvious I'm missing here. Any suggestions ?
Is this an 'operator error' situation? Are you supposed to manually adjust the max pressure on these pumps or do you peg the set screw all the way down and drive on ?
Comment