I think I have a fuel vapor lock.

[Cleve]

Well, I got my timing problem fixed with my new distributor. But I think I have a problem with my fuel pump. My car still shuts off shortly after the engine warms up to 180 degrees. After a short while the rpm slowly drops and the engine slowly stops. I have a mechanical fuel pump on my 302 engine. I have PPK headers which are close to my fuel pump. I coved the area close to the pump with some good high temp insulation but my mechanic thinks the reason the engine is coming to a stop is because the fuel pump is getting to hot and creating a vapor lock. He recommended a possible fix was a remote fuel pump away from the engine. I was thinking I could add some additional insulation to what is already there Has anyone else have this problem with their fuel pump over heating and creating a vapor lock?
Any feed back would be greatly appreciated
Cleve

[Railroad]

Leave the gas cap off and see if anything changes,,,,
good luck,

Put your hand on the coil, Lightly.

Feed the carb from a gravity feed line, pinch off the mechanical pump.

[rich grsc]

Do you have a filter BEFORE the fuel pump, or after?

[Jeff Kleiner]

Easy to check for vapor lock. When the engine stops immediately remove the air cleaner and while looking down the carb move the throttle to wide open. If you see a shot of fuel from the accelerator pump it indicates that there is gas in the bowl and you DO NOT have vapor lock.

Jeff

[Mike.Bray]

Easy to check for vapor lock. When the engine stops immediately remove the air cleaner and while looking down the carb move the throttle to wide open. If you see a shot of fuel from the accelerator pump it indicates that there is gas in the bowl and you DO NOT have vapor lock.

Jeff

Don't use a lighter to see;)

[rich grsc]

BUT mike that cures the carburetor blues, just duck quick like

Vapor lock doesn't usually happen on a running engine, it happens after shut down and then restart. Also how do you get vapor lock in such cool weather, its a HIGH heat issue.

[J R Jones]

Vapor lock is fuel boil, ~150F maybe less with ethanol. An infared gun can tell you how hot your fuel parts are. The pump has mass and is bolted to the timing cover, more mass.
A (low mass) fuel line too close to the exhaust is more likely. What is the ambient temperature?
You might have still have ignition issues)
Jeff is right, if the engine dies but the accelerator pump still squirts, you have fuel. Is there a sight glass on the fuel bowl for fuel level?
Railroad has a point, is the fuel tank vented?
jim

[Jim1855]

I had problems years ago. Installed an Aeromotive bypass regulator after the carb with a return line. This gave the excess pressure from the boiling fuel a place to go.

Worked for me.

Jim

[PMD24]

Turn on the data logging on the carb. Sorry, couldn't resist after those carb vs EFI exchanges in the other thread.

Pat

[Mike.Bray]

Turn on the data logging on the carb. Sorry, couldn't resist after those carb vs EFI exchanges in the other thread.

Like this:cool:

225782

[Cleve]

I have a 5/16 rubber fuel hose attached to the frame under the car. It pops up at the 4 in. cross tube under the radiator and straight into the fuel pump. the fuel hoses are not getting hot., accept maybe the one going into the fuel pump. The tank does have a vent hose. but no sight glass. The fuel pump is 2 inches away from the header flange. I am able to insulate the flange with heavy duty insulation. I have some insulation on the flange but not enough. I need Several more layers. I am going to run the car and see if I can touch the insulation without burning my finger. I couldnt the other day. It was to hot to touch.
Thanks for all the info. I am going to try several different things. I am already thinking about plan B if this doesnt work.

[CraigS]

Many, many FFRs including mine run mechanical pumps w/ headers w/o problems. I'd move on to another possible cause besides vapor lock.

[rich grsc]

Where is your fuel filter?

[J R Jones]

Cleve, This is an assumption and a reach, but consider this:
Your comment on fuel hose suggests you are not running steel fuel tube from your tank to the fuel pump. Using all hose makes for easy routing but compromises flow and safety. I minimize hose length and use it for coupling hard lines together.
My theory in this case is the hose gets hot and has bends with restricted diameter. A mechanical pump creates suction to pull the fuel from the tank. Heat may cause the hose to become soft and the pump sucks the hose diameter down restricting flow.
An electric pump at the tank has less dynamic suction and more pressure to push the fuel forward. Soft hose would not be such an issue with a pusher pump.
jim