Why do I have high fuel pressure...

[patrickt]

Once you get her home, whether you limp her home under her own power or use a flatbed, I'd like to see you just Tee in a fuel pressure gauge right before the carb. Chances are you have AN fittings there, with a nice fat braided steel line coming from the fuel pump, so Tee'ing in a gauge is a quick and simple process. Russell, Earl's they all make little AN "Tee" fittings that have a hole for the NPT fuel pressure gauge to go in. Ten minute job at most and I'd really like to have the luxury of knowing what the fuel pressure is without relying on your existing gauge. You can always remove it when we're done.

[steve meltzer]

OK, here's the plan. I'm gonna take one of the big paper clip like deals that will hold 150 pages of BS and clamp that hose (I got it off with my little "Leatherman" like too). My wife can follow me the 6 miles home and, as you said, I can get 'er home and go from there.

WOW, Dan Ec....I had totally forgotten about the post back in '06....thanx so much. I did wrap the fuel rail/log with some foam rubber insulation and I think that helped. Hadn't been an issue since. I don't drive the car too often when it's really hot, as if I get stuck in traffic, the car gets hot (100-105C) and it makes me too nervous to be much fun. Today, it's a gorgeous 60°. thanx again. s







More later. thanx again. s

[jhv48]

Correct me if you've already tried this, but why don't you bypass the mechanical pump altogether and just run off of the electric pump? Two pumps, twice the potential problems.

[steve meltzer]

Well, despite my best intentions, the neither the clip nor a surgical clamp from the office worked to obstruct the hose, so, I'll go back to the office on Sunday with a proper hose clamp, block the errant hose and drive her home for the repair. More later.

JHV48, I've not tried anything in the past. The car is now, as it has always been. I understand your point about twice as much potential trouble, but...if the e-pump fails (and it did about 5 years ago), i could make it home on the mechanical pump. Thoughts? thanx. s

[patrickt]

If that Carter mechanical pump that I gave the link to fails in the next ten years I'll have RodKnock dance naked on the hood of his Kirkham with a rose clenched between his teeth. Yes, I'm that sure it won't fail.

[steve meltzer]

hmmm....might dent the hood! s

[patrickt]

And now that you had the little "flood" out the secondaries, you know we'll have to pull the bowl off to inspect the float, its hinge, and the little springy thing on it and, of course, replace the needle/seat. So, you'll need the two little round gaskets over and under the seat adjusting nut, the bowl gasket, and you might as well unscrew the metering plate and clean it out with carburetor cleaner -- another gasket is in there. And, you'll need the little "clutch" screw fitting to get those six screws out of the metering plate. Ehhh, just order the Holley tool for that -- it'll make your life easier. Why they used clutch head screws there I'll never know.... You'll need the plastic bowl screw gaskets, instead of the paper ones, and, if you're doing this on the secondary side, you might as well do the primary side. So, buy this fast rebuild kit, which is what I like and has everything that you need: https://www.summitracing.com/parts/HLY-37-1542/ and if you don't have 1) a "clutch" bit (I think 5/32", but I have the Holley tool), and 2) a "pointer" type inch/lb. torque wrench then pick one up. I take my Holley apart all the time and I've even cracked the bowl from tightening the screws by hand without using my pointer torque wrench. My "click off" inch/lb torque wrench just isn't as sensitive as I need for the low torque numbers on the screws. Those screws require 25-30 inch/lbs. Anything over about 50 inch/lbs will crack your bowl. I now torque everything on that carburetor, as if it were glass. My hand just can't tell the difference between two foot/lbs and four foot/lbs... but you generally hear it "snap" when you crack the bowl and the stream of gas once you fill it with fuel always tips you off. On the plus side, after we fix the pressure issue, and do a "quickie rebuild" of the carb, your car will run better than it ever has before.

[steve meltzer]

WOW! Thanx Patrick for the tips and great info. I ordered the Carter FP and i do have the clutch head driver attachments, tho' having two 'Vettes with Holleys, i may just order the correct tool. More later. I can't get the car today and it looks like rain here in Houston tomorrow, so we'll just have to see when i can get the car. thanx again. s

[patrickt]

I think I could even lead my brother, who barely knows a screwdriver from a hammer, through a rebuild of a 4160. And over the last 40 years I've made every mistake humanly possible to make -- so I can see them coming and tell you how to avoid them. The first step, though, is to temporarily plumb a new pressure gauge right in front of the carburetor. The second step will be to conquer your fuel pressure issue. The last step will be to rebuild the carb with that kit. It's a better than fair chance that the 9psi that you were seeing resulted in the secondary flooding out by eating the needle/seat valve for lunch. So there's no sense in even touching the carb until we have a nice, clean, even 6psi feeding her.

[steve meltzer]

OK, home again. Gotta way and, with a proper automotive hose clamp, clamped off the aorta, oops, i mean the secondary feed line. With out the e-pump on, and after about 10 minutes of slow speed running the gauge again read 9 PSI! DX: bad mechanical pump, and it's on its way out! Opening the gas cap didn't change a thing.

When you seal the bowls to the body, do you put anything on the gaskets, like Permatex 518? thanx s

[patrickt]

Originally Posted by steve meltzer

When you seal the bowls to the body, do you put anything on the gaskets, like Permatex 518? thanx s

No, absolutely not. We will use the BLUE gaskets that come in the kit and spray them lightly with silicone spray lubricant. Cleaning off the old gaskets is imperative. I like to use wooden toothpicks to clean off the old gasket material. Cleaning the needle/seat nut is usually the most time consuming. Never use anything that can scratch the metal.

[steve meltzer]

got thanx. s

[steve meltzer]

After I change the fuel pump, i was gonna drive the car and see about the pressure (secondaries to remain blocked). If it's a steady 6 PSI, then I was gonna tackle the carb, if not, check and probably impugn the gauge in the dash. Right?

And...when you change the fuel pump, I assume that, like a 'Vette, the engine needs to be a TDC for #1. Right? thanx steve

[patrickt]

Originally Posted by steve meltzer

After I change the fuel pump, i was gonna drive the car and see about the pressure (secondaries to remain blocked). If it's a steady 6 PSI, then I was gonna tackle the carb, if not, check and probably impugn the gauge in the dash. Right?

And...when you change the fuel pump, I assume that, like a 'Vette, the engine needs to be a TDC for #1. Right? thanx steve

OK, we can skip plumbing in a new gauge... unless the new fuel pump starts pumping at 9psi too. And you don't have to go to TDC at #1, just make sure the fuel pump arm is on the camshaft eccentric. Clean the old gasket off, and use a little oil resistant gasket goo on there.

[patrickt]

Here's a pic that I found for you.

[steve meltzer]

great shot! but me thinks it will be hard to see in there with the front chain cover off, so, if I'm at TDC, i'll be OK, right? s

[patrickt]

Originally Posted by steve meltzer

great shot! but me thinks it will be hard to see in there with the front chain cover off, so, if I'm at TDC, i'll be OK, right? s

Just point the lever arm down when you're putting her on. I can't think of a single time anyone in the local Cobra club has actually managed to get the lever on the top of the eccentric, making it not pump, but I think it is possible. So if you do get it bolted on and it doesn't work, that's why.

[steve meltzer]

excellent. probably, old pump off tomorrow. new one should arrive Tues. thanx...another exciting saturday nite for both of us, i see! s

[steve meltzer]

Whata fight gettin' that fuel pump out without removing everything within 2'. So, now I wonder if I should just block the block and skip the mechanical pump altogether, or am i just being lazy? Pros and Cons? Your take? thanx. steve

[patrickt]

Originally Posted by steve meltzer

Whata fight gettin' that fuel pump out without removing everything within 2'. So, now I wonder if I should just block the block and skip the mechanical pump altogether, or am i just being lazy? Pros and Cons? Your take? thanx. steve

Personally, I am partial to mechanical pumps. And the new one will go in easier than the old one came out. Do you have a UV flashlight? The reason I ask is that, because you had the secondary flood, it will make being sure you've sealed everything off a little tougher. Generally, after you've done your carb work and put everything back together, you tuck paper towels under the bowl, crank it up to fill the bowls, and if you don't see obvious gushing leaks, you pull the paper towels out to see if you have any dribbles, or seeping leaks and then you put them back in and let them sit there overnight. But the fact that you've had gas everywhere, you're going to get witness marks on that paper towel that might be real, or might be leftover gas. What I like to do after I've had my carb apart, and I think it's done, is put an eyedropper full of UV dye down the vent of the bowl I was working on. You would be surprised at how many times doing that has tipped me off to a problem, or confirmed the fact that the gas stains on the towel were not from the bowl because there was no dye in it. It really takes the guesswork out of leak detection. Here's the stuff I use and it's fantastic. I use an eyedropper from an old Rogaine bottle, which puts the perfect amount in to a Holley bowl.



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