fuel line routing pump to carb

[Qbronco]

As many here have experienced several of us have problems with vapor lock. I have taken several measures to minimize it. Currently I am making a few other changes and think it might be worth changing the routing of the hard fuel line as it runs from the pump to the carb. I am not positive, but I think mine is stock and runs directly between the radiator/fan and the front of the motor. It seems like it might get less heat if it was routed in a different manner. Anyone have suggestions or alternative routes they recommend.

Thanks,Q

 

[miesk5]

Yo Obronco,
You are on the right path!
See;
"Several Factors Can Contribute to Vapor Lock:

• High underhood temperatures
• Fuel lines next to or touching hot engine components
• Lose of fuel delivery system pressure or flow (volume); this may be caused by a restricted fuel filter or insufficient voltage to the fuel pump
• Fuel pump next to hot operating engine
• Faulty check valve in an electric fuel pump assembly
• Clogged fuel return system
• Hot summer weather
• Stop-and-go traffic
• Dirty or restricted in-tank filter
• Faulty fuel tank vent
• Ethanol-enhanced gasoline
• Geographical areas with high altitude

The following sections explain why vapor lock occurs and how to test for, fix and prevent vapor lock."
See more @
Several Factors Can Contribute to Vapor Lock:

• High underhood temperatures
• Fuel lines next to or touching hot engine components
• Lose of fuel delivery system pressure or flow (volume); this may be caused by a restricted fuel filter or insufficient voltage to the fuel pump
• Fuel pump next to hot operating engine
• Faulty check valve in an electric fuel pump assembly
• Clogged fuel return system
• Hot summer weather
• Stop-and-go traffic
• Dirty or restricted in-tank filter
• Faulty fuel tank vent
• Ethanol-enhanced gasoline
• Geographical areas with high altitude

The following sections explain why vapor lock occurs and how to test for, fix and prevent vapor lock".

See more @ https://axleaddict.com/auto-repair/What-is-Vapor-Lock-and-How-to-Fix-It

 

[Qbronco]

Thanks, A few of those I can remedy some I can't. I live at 9000ft altitude and the Ethanol gas here is brutal as well. I will try to check or remedy everything else.Do most people here prefer an electric pump to the mechanical? Just curious.

 

[Tiha]

I had a 73 that I drove for a couple years in college. One day it just started vapor locking. No real reason why. I tried everything I could think of. Tried re routing, insulating the line, tried copper line. Even took the eccentric off the cam and re drilled it to get more travel on the pump.

Already had some experience with my camaro but never this bad.

Eventually adding an electric pump back by the fuel tanks was the only solution I could come up with.

Now I don't even bother with mechanical pumps, especially on something you don't drive everyday. Hit the key, let it prime and start it. No pumping the pedal, no extended cranking and best of all no vapor locking. I am putting together a corvette right now and every time I start it up I am happy I added the electric pump.

 

[Qbronco]

what electric pump do you guys suggest? Also is there a specific way to wire it so that if for some reason it dies or there is an accident it stops the pump? I am imagining a scenario where I start it, go in the house or garage, come back and it died and the pump was still running. Maybe I am being paranoid, but thought I would ask.

 

[Tiha]

All depends on how fancy you want to get.

Some guys use a relay and tap into the oil pressure sensor. Not a bad idea but doesn't turn on until you cranked the engine some.

The impact safety switch newer vehicles use. Seen a few guys grab one from a junk yard and add it to their wiring.

I don't run anything. Been lucky so far I guess.

As far as pumps, On my corvette I used a Carter from Oreilly's, Was supposed to be fairly quite. Has more than enough fuel for the HP goal I had.

https://www.oreillyauto.com/detail/...ck-1990-ford-f-350?q=electric+fuel+pump&pos=5


Advance auto has them behind the counter as well, they are rated by cylinders, kind of interesting way to do it. I actually have one on my lawn mower and it has lasted far longer than I expected it to. looks like they changed the way they labeled them a little bit.
I think the important thing is to pick one big enough, but locally available. I haven't had problems with electric pumps but I know a lot of people that have. Something readily available makes a quick easy swap.

https://shop.advanceautoparts.com/p...7301/12257406-P?searchTerm=electric+fuel+pump

 

[Qbronco]

Thanks Tiha, I appreciate the info and links. You are right about the convenience of something local.

 

[chrlsful]

I on the other hand never use them and am alill against for same reason(s) as U. Never hada problem w/mechanical, only need 3-7 lbs psi anyway. More? Here's one:

Classic Inlines - Carter Fuel Pump Modification

 

[johnnyreb]

All depends on how fancy you want to get.

Some guys use a relay and tap into the oil pressure sensor. Not a bad idea but doesn't turn on until you cranked the engine some.

The impact safety switch newer vehicles use. Seen a few guys grab one from a junk yard and add it to their wiring.

I don't run anything. Been lucky so far I guess.

As far as pumps, On my corvette I used a Carter from Oreilly's, Was supposed to be fairly quite. Has more than enough fuel for the HP goal I had.

https://www.oreillyauto.com/detail/...ck-1990-ford-f-350?q=electric+fuel+pump&pos=5


Advance auto has them behind the counter as well, they are rated by cylinders, kind of interesting way to do it. I actually have one on my lawn mower and it has lasted far longer than I expected it to. looks like they changed the way they labeled them a little bit.
I think the important thing is to pick one big enough, but locally available. I haven't had problems with electric pumps but I know a lot of people that have. Something readily available makes a quick easy swap.

https://shop.advanceautoparts.com/p...7301/12257406-P?searchTerm=electric+fuel+pump

I had trouble with the regulaor( Mr Gasket) . No matter what you set it on--it would not stay for some reason. Finally I took the regulator and electric pump back off and put the mechanical one back on.

 

[L\Bronco]

Thanks, A few of those I can remedy some I can't. I live at 9000ft altitude and the Ethanol gas here is brutal as well. I will try to check or remedy everything else.Do most people here prefer an electric pump to the mechanical? Just curious.

Hey Q
An electric pump mounted at the tank will help ton (Pressurizing the fuel raises the boiling point, so the more line you have under pressure, the better.)
Make sure you don't go over 8 psi as most needle and seats can't hold back any more and it will flood.
A bigger mech pump will likely make it worse as the pressure on the feed line from the tank will be lower and more prone to vapor lock.
Keep all the lines away from the exhaust and maybe some small foam pipe insulation on the part that goes over the engine to the carb.
It can be a battle for sure.
Just remember, the enemy is heat and low pressure.
Good luck
Cheers

 

[johnnyreb]

Thanks Tiha, I appreciate the info and links. You are right about the convenience of something local.

I remember we used to use close pins on the gas line along time ago and seemed to work

 

[johnnyreb]

Hey Q
An electric pump mounted at the tank will help ton (Pressurizing the fuel raises the boiling point, so the more line you have under pressure, the better.)
Make sure you don't go over 8 psi as most needle and seats can't hold back any more and it will flood.
A bigger mech pump will likely make it worse as the pressure on the feed line from the tank will be lower and more prone to vapor lock.
Keep all the lines away from the exhaust and maybe some small foam pipe insulation on the part that goes over the engine to the carb.
It can be a battle for sure.
Just remember, the enemy is heat and low pressure.
Good luck
Cheers

Lbronc-question---I wonder if a person used a smaller as line would help any or hurt? I know someone had 2 0r 3 different size line on my 78 and I canged it all out to one size and seemed to help.

 

[L\Bronco]

Lbronc-question---I wonder if a person used a smaller as line would help any or hurt? I know someone had 2 0r 3 different size line on my 78 and I canged it all out to one size and seemed to help.

Hey Johnny
not sure there, its more about the heat boiling the fuel in the line.
A small line will have the fuel going faster, so it might help, but it also might lower the pressure (on the suction side of the pump) which will make it worse, so, sorry man no definite answer there.
Cheers