1963 L76 Fuel Line Positioning due to a vapor lock

[Gerald C.]

Good morning,

I took this car out for a show in 85 degree temperature. On the way, we ran into a lot of traffic and caught every red light on the way! About 40 minutes into the ride, the car started to sputter and it felt like it wanted to stall. I got to the show and after a couple of hours, we left. The car ran fine on the way home.

Based on my research, it looked like I had a vapor lock. I've driven the car about 250 miles since restoration, so I haven't had much "road testing" on the engine.

The fuel line coming up from the pump is right against the cylinder head. So, I thought I would like to move it out a bit to get it off the head by about 3/4" to 1" off. I have included a couple of pictures of the configuration I came up with. To be honest, I don't like the look of my configuration and before I apply locktite, etc., I would like other opinions on how I can configure this setup where it looks a little more like a factory setup versus a hardware store setup.

Any suggestions will be appreciated.

Thanks
JerryFuel Line-1.jpgFuel Line-3.jpg

[Peter H.]

[Gerald C.]

Re: 1963 L76 Fuel Line Positioning due to a vapor lock

Peter,
I believe the fuel pump is clocked correctly. I think my problem is where the fuel filter doesn't go forward enough to give the fuel line the clearance from the cylinder head.

JerryFuel Line-5.jpg

[Dan H.]

Re: 1963 L76 Fuel Line Positioning due to a vapor lock

Gerald, are you sure that's a 63 line and not a 64/65 line? The fuel pumps are different resulting in two variations of fuel lines.
Dan

[Timothy B.]

Re: 1963 L76 Fuel Line Positioning due to a vapor lock

Gerald,

Loosen and remove the fuel line (from the fuel pump) where it attaches to the fuel filter and from the carburetor at the filter. Loosen the fuel filter clamp and slide the filter forward so the filter flange sits against the bracket. Fit the line from the filter to the carburetor back in place, you can reverse the line as there is a short side and a long side so be aware of that.

Last, massage (bend and adjust) the line from the pump to the filter so it's away from the engine block, lower radiator hose and heater hose. You may have to play with it but you can make it nice with some graceful bends and wire the heat risor open.

[Gerald C.]

Re: 1963 L76 Fuel Line Positioning due to a vapor lock

Tim,

I had to make the tube from the carburetor a little longer than the one that was in there to make it work. I couldn't use the existing chrome tube that was there.

Thanks,

Jerry

[Dan H.]

Re: 1963 L76 Fuel Line Positioning due to a vapor lock

Gerald, looking at your filter to carb pipe, still looks too short, especially on the longer end. Also some of the repro filters are shorter than original AC filters, which all must be considered.
Dan

[Philip A.]

Re: 1963 L76 Fuel Line Positioning due to a vapor lock

[QUOTE=Timothy Barbieri (6542);916865]Gerald,

Loosen and remove the fuel line (from the fuel pump) where it attaches to the fuel filter and from the carburetor at the filter. Loosen the fuel filter clamp and slide the filter forward so the filter flange sits against the bracket. Fit the line from the filter to the carburetor back in place, you can reverse the line as there is a short side and a long side so be aware of that.

Last, massage (bend and adjust) the line from the pump to the filter so it's away from the engine block, lower radiator hose and heater hose. You may have to play with it but you can make it nice with some graceful bends and wire the heat risor open.[/QUOTE

This is what I had to do with my 1965 L76.

[Mark E.]

Re: 1963 L76 Fuel Line Positioning due to a vapor lock

Vapor lock occurs when gasoline boils before or in the fuel pump. As long as it's in a liquid state in the pump, fuel will be pumped to the carburetor. So rerouting or insulating the pump to carb line won't help with vapor lock.

Is this a percolation issue? If yes, try a thicker carb gasket or phenolic spacer.

Does this car have a fuel return line from the pump to the tank? If yes, disconnect it from the pump and test for flow. I've seen a pump flow to the carb but not to the return line. This can cause vapor lock.

Is air entering the fuel line between the tank and pump? Air sucked into the line will cause poor fuel delivery. Permeable hoses and leaky connections are likely culprits.

[Arland D.]

Re: 1963 L76 Fuel Line Positioning due to a vapor lock

It has always seemed odd that the fuel line from the carb to the filter positioned the filter so far forward in the bracket. Seeing your pictures, it seems better to have the filter as far forward as possible to get clearance between the fuel line and the head. Check the fuel line on your car to the one in the attached picture and it seems your line is shorter than usual moving the filter back and the fuel line too close to the head. The fuel line is available from many vendors.

[Thomas S.]

Re: 1963 L76 Fuel Line Positioning due to a vapor lock

The front fitting of the filter on the original post picture, has a brass extension on it. I don’t have that extension 63 L76 and my filter to carb tube is longer. That extra adapter places the fuel line forward an therefore further from the block which if anything would help. I have fuel boiling/evaporation in the bowl (Carter AFB) and if the car sits for any length of time after a drive it’s takes a good cranking before it starts. It’s never stalled on me however, and I attribute the hard starts to ethanol content. In my area it’s 10%. Advanced timing can also raise the block temp so that’s another thing to check.


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[Duke W.]

Re: 1963 L76 Fuel Line Positioning due to a vapor lock

Advanced timing can also raise the block temp so that’s another thing to check.

It's the other way around. High overlap cams need at least 30 degrees total idle advance for the least EGT and least idle fuel consumption.

Start retarding it from this and idle speed drops and EGT goes up. This total idle advance is achieved with the sum of initial advance, full vacuum advance, and 2-3 degrees of centrifugal since mechanical lifter cam engine centrifugal starts at 700, but they need about 900 to idle with acceptable quality.

Emission controlled engines have "ported" vacuum advance, which eliminates vacuum advance at idle, so total idle advance is usually only equal to initial timing. This raises EGT from about 500F with optimum total idle advance to at least 900F in order to promote oxidation reaction of HC and CO in the exhaust system with injected air the AIR system, and this higher EGT raises combustion chamber boundary temperatures and throws more heat into the cooling system.

Duke

[Thomas S.]

Re: 1963 L76 Fuel Line Positioning due to a vapor lock

EGT = Exhaust Gas Temperature. Thanks for that correction. I've never had an issue like the original poster in terms of stalling and we have spoken in the past regarding the 2-inch rule. The car runs great and the idle is pretty steady. They should probably check the timing as per your articles to at least rule that out.