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Its just that the rubber lines require a little more scrutiny on a regular basis and the novices either use the wrong rubber lines and/or buy screw clamps and tighten the snot out of them until they are seeping gas. Sometimes they have the lines rubbing against some sharp object and the next thing you know --- carbeque.
Likewise some of these over-springed replacement fuel pumps are cranking out 13psi and the old carbs only need 3-5 psi and so any little line defect results in arterial spurting across the motor.
I use them on occasion but try to locate those sections other than over the intake manifold.
The pumps you're talking about must be used with a pressure regulator.
If used without a pressure regulator, the floats won't supply enough force to seal the needles/seats against anything more than about 9-10 psi. I set my fuel pumps up to deliver between 5-6 psi.
1965 GM spec calls for 5 - 6.5 psi (SHP).
Last edited by 65tripleblack; Jun 16, 2014 at 11:48 AM.
Although Frankie has gotten "on my case" about my factory ('65) short rubber line from the filter to the 2818-1 Holley carb, I have not changed out my stock setup. I too tend to look over these soft trim/wearable parts more often. Changing them out 4-5 years depending on how much driving (heat/cold cycles) take place. Buying the right rubber for fuel line and using the factory clamps is a great start to minimizing any issues.
I long ago got into the habit when she's parked in the garage to having the hood up and the quick battery disconnect in place. This tends to force you to look things over and check things out before hitting the key.
I had my own near fire back in 2010. Dodge a big bullet there...not fuel related. I've also posted this before but for newbies here, this could serve you well...think fusible links!
Yeah - I know the GM fuel pressure specs with the old leaded gas...they're high nowadays. All the pumps have to do is keep your bowls full with a slight reserve capacity. They're pushing alcohol now (ethanol really) and not lead.
I run a Holley 12-804 1-4psi regulator on my Carter 3721SB and its happy as a clam at a smidge over 3psi. Not going to get in a big debate about old leaded vs new gas and psi settings; see for yourself at 1:20 seconds into the video: .
This person has about 20 AFBs that he has rebuilt for individuals and posted their performance on running engines at 3psi with modern fuel. That's all you need. I run my WCFBs at 4 to 4-1/2 psi with modern gas. (I've had eight of them over the years and all running at this pressure).
Last edited by Frankie the Fink; Jun 16, 2014 at 02:02 PM.
Yeah - I know the GM fuel pressure specs with the old leaded gas...they're high nowadays. All the pumps have to do is keep your bowls full with a slight reserve capacity. They're pushing alcohol now (ethanol really) and not lead.
I run a Holley 12-804 1-4psi regulator on my Carter 3721SB and its happy as a clam at a smidge over 3psi. Not going to get in a big debate about old leaded vs new gas and psi settings; see for yourself at 1:20 seconds into the video: .
This person has about 20 AFBs that he has rebuilt for individuals and posted their performance on running engines at 3psi with modern fuel. That's all you need. I run my WCFBs at 4 to 4-1/2 psi with modern gas. (I've had eight of them over the years and all running at this pressure).
Lead free gas has no bearing on fuel pressure. Maybe I'm missing something so you can explain it to me. If I know you, you're thimking that the old gas with LEAD in it would be HEAVIER and thus have more INERTIA (according to that genius in the video @ 1:20 in).
If you get yourself a fuel pump that's set up properly you wouldn't need no stinking pressure regulator. Totally unnecessary, and just one more thing that can fail, or leak.
Last edited by 65tripleblack; Jun 16, 2014 at 02:32 PM.
now you guys got the sheat scared out of me...
I have a holly carb with a small length of rubber line from the filter to the fuel line. see picture below... I recently replaced the sprint-type clamps with screw-type claims. The rubber is flexible and soft.... do I need to replace this? what should I replace it with?
now you guys got the sheat scared out of me...
I have a holly carb with a small length of rubber line from the filter to the fuel line. see picture below... I recently replaced the sprint-type clamps with screw-type claims. The rubber is flexible and soft.... do I need to replace this? what should I replace it with?
IF you are going to replace it with hose, i recommend getting modern day special 'fuel injection' hose.
Bill
Lead free gas has no bearing on fuel pressure. Maybe I'm missing something so you can explain it to me. If I know you, you're thimking that the old gas with LEAD in it would be HEAVIER and thus have more INERTIA (according to that genius in the video @ 1:20 in).
If you get yourself a fuel pump that's set up properly you wouldn't need no stinking pressure regulator. Totally unnecessary, and just one more thing that can fail, or leak.
I know what works for me...others can do as they like
I think the old guy in the video is a riot and could care less about his theories but the bottom line is - his carbs work and work well and on a lot less fuel pressure than most would think. I just knew that youtube flick would cycle people up
And yes, 3/8" fuel injection hose with fuel injection hose clamps will stand you in good stead on most of our old Corvettes if regularly inspected. I still avoid it over a hot intake though..
I know what works for me...others can do as they like
I think the old guy in the video is a riot and could care less about his theories but the bottom line is - his carbs work and work well and on a lot less fuel pressure than most would think. I just knew that youtube flick would cycle people up
And yes, 3/8" fuel injection hose with fuel injection hose clamps will stand you in good stead on most of our old Corvettes if regularly inspected. I still avoid it over a hot intake though..
Yes. I am throttling back on my posts and have started baiting people as above which is not my style and I'm slightly ashamed of (but only slightly). I need an intervention.
now you guys got the sheat scared out of me...
I have a holly carb with a small length of rubber line from the filter to the fuel line. see picture below... I recently replaced the sprint-type clamps with screw-type claims. The rubber is flexible and soft.... do I need to replace this? what should I replace it with?
If the piece of hose came with the filter, throw it away and get a piece of real fuel line hose that has the reinforcing in it. Many times these short pieces with filters are simply a rubber hose. Fuel line is a reinforced hose that is much tougher.
This is probably where the rubber hose to carbs got the bad reputation and created the problems, in that taking plain rubber hose with no reinforcing, they tear, cut, break when hard, and so on to get leaks.
If the piece of hose came with the filter, throw it away and get a piece of real fuel line hose that has the reinforcing in it. Many times these short pieces with filters are simply a rubber hose. Fuel line is a reinforced hose that is much tougher.
This is probably where the rubber hose to carbs got the bad reputation and created the problems, in that taking plain rubber hose with no reinforcing, they tear, cut, break when hard, and so on to get leaks.
Also, JMG2's steel tube needs a dog knot added to the end of it if it doesn't already have one to give the clamp a swelled place to grip.
Just wonder if the old man (I'm an old man) in the video gave any thought to the requirements of different carburetors, Holley, AFB, WCFB, Quadra-Jet, the rpm range of the engine and cubic inches, needle seat restriction and other factors related to fuel pressure before he (and others) made a blanket statment on how much fuel pressure and engine is supposed to have?
Not only pressure at idle speed but wide open throttle under load?
Yes. I am throttling back on my posts and have started baiting people as above which is not my style and I'm slightly ashamed of (but only slightly). I need an intervention.
Nothing personal. Simply monitoring for bad information.
You still didn't explain your statement about leaded fuel pressure supposedly needing to be different from unleaded fuel pressure.
Please explain why almost every car manufacturer, before using EFI which needs much higher fuel pressure, used rubber fuel line at some point between the mechanical pump and the carb inlet.
It has been stated above more than once that reinforced fuel line hose must be used. If you use windshield washer fluid or radiator overflow hose, then you're in trouble.
Last edited by 65tripleblack; Jun 17, 2014 at 10:04 AM.
I more than agree that maximal care should be taken to have safe fuel lines. On the other hand I am not sure I would thrust those old carbs - even when redone with new parts - for leaks more than I would trust good quality SAE rubber fuel lines. But that's just me I have certainly read more about leaking carbs on this forum than about leaking fuel lines...rubber ones included.
I more than agree that maximal care should be taken to have safe fuel lines. On the other hand I am not sure I would thrust those old carbs - even when redone with new parts - for leaks more than I would trust good quality SAE rubber fuel lines. But that's just me I have certainly read more about leaking carbs on this forum than about leaking fuel lines...rubber ones included.
I'm going to replace it this weekend...
1) what kind of hose should I but and
2) I have no idea when the carb was added, or even what kind it is (other than a holly). If I were to go with a new carb, anyone have any suggestions? I kinda like hollys, but not married to them. What cfm were stock carbs? I assume I'd gain nothing by going higher cfm other than even worse gas mileage?
Yeah - I know the GM fuel pressure specs with the old leaded gas...they're high nowadays. All the pumps have to do is keep your bowls full with a slight reserve capacity. They're pushing alcohol now (ethanol really) and not lead.
I run a Holley 12-804 1-4psi regulator on my Carter 3721SB and its happy as a clam at a smidge over 3psi. Not going to get in a big debate about old leaded vs new gas and psi settings; see for yourself at 1:20 seconds into the video: .
This person has about 20 AFBs that he has rebuilt for individuals and posted their performance on running engines at 3psi with modern fuel. That's all you need. I run my WCFBs at 4 to 4-1/2 psi with modern gas. (I've had eight of them over the years and all running at this pressure).
Originally Posted by 65tripleblack
Lead free gas has no bearing on fuel pressure. Maybe I'm missing something so you can explain it to me. If I know you, you're thimking that the old gas with LEAD in it would be HEAVIER and thus have more INERTIA (according to that genius in the video @ 1:20 in).
If you get yourself a fuel pump that's set up properly you wouldn't need no stinking pressure regulator. Totally unnecessary, and just one more thing that can fail, or leak.
I doubt Frank was inferring that the lead in leaded gas made it "heavier" than unleaded gas (ie higher specific gravity), although I suppose if you want to be critical of him one could choose to interpret what he wrote that way.
It seems to me is that his point is pretty clear from his reference to ethanol in most modern unleaded gas. Ethanol/alcohol has a lower specific gravity than gasoline, so the modern mix would be slightly "lighter" than the old gas.
it's simple, really. No need for acrimony............
I know what works for me...others can do as they like
