Lets talk about Y-Block vapor lock, shall we?

50mercfan

50mercfan

Member
I've seen a few post on what seems to be a common problem with Y-Blocks. Vapor lock. Why? why would one engine be more prone than others? It doesn't make sense to me. Heat is heat and an engine is an engine, Right? I recently bought a 55 customline with a 272. It's obvious that the previous owner was having problems.

I recognized all the tell tale problems as soon as he opened the hood, electric fuel pump, fuel pressure regulator, heat wrapped exhaust, foil wrap on the fuel lines. When I asked, "vapor locking, huh?" he said "not since i've had it" . OK.

I've made some changes recently. I put dual exhaust manifolds on it, getting rid of the cross over exhaust pipe that runs over the fuel pump and in front of the carburetor. I'm wanting to ditch the electric pump and put the manual pump back on.

I'm putting before and after pics up for reference. Whats your experience?
 

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I have a 56 Bird in which I experienced some vapor lock but only under very limited conditions. Going up very steep mountains (actually mountain chains in the west coast) on a very hot day. Never stalled but it was touch and go for a while. Popped the hood to get better air flow and the problem pretty much disappeared.

Oddly enough, it was after I replaced the fuel lines with stock lines during restoration.

I had made the same trip about 5 years earlier and went almost the same route and didn't have any problem..
 
I'll go with HRR. Ethanol, stop and go traffic, lower fuel pressure for older carbs, all contribute to vapor lock.
 
I too drive a 55. Mine had dual exhaust from the factory, so a lot of heat went out the back. I have never had a vapor lock problem. My advice is to use two fuel pumps. I use the electric as a booster, when the car hasn't been driven in more than a few days, I run the electric to prime the system. My electric pump is in the back near the tank. Many of us dont have a choice on ethanol laced fuel. If we buy fuel, we get up to 10 % ethanol.
 
paul2748 said:
I have a 56 Bird in which I experienced some vapor lock but only under very limited conditions. Going up very steep mountains (actually mountain chains in the west coast) on a very hot day. Never stalled but it was touch and go for a while. Popped the hood to get better air flow and the problem pretty much disappeared.

Oddly enough, it was after I replaced the fuel lines with stock lines during restoration.

I had made the same trip about 5 years earlier and went almost the same route and didn't have any problem..
Click to expand...
Some folks blame it on the metal fuel line that runs over the front & top of the engine, saying it holds more heat and boils the fuel in that line between the pump and the carb.
If/when it happens to me my first (cheap) try at a fix would be to change that steel fuel line to a rubber one.
 
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Years ago MANY cars/engines vapor locked. It was not uncommon to open a hood and see cloths pins on the steel fuel lines. Some hoods trapped engine heat which compounded vapor lock in stop and go traffic. Many engines as late as the 70s would boil the carb dry after running a long trip and shutting the engine off. We use to remove the steel fuel lines and add fiber spacers under the carb. Seemed to help and was relatively cheap.
 
Older Fords had a vented gas tank. You should check to see if there is any obstruction to free venting by disconnecting the vent tubing on the driver side of the gas tank. Blow compressed air into that end of the line and see if the air comes out of the tubing where it exits adjacent to the gas tank filler cap. Rod the line out if necessary.
 
bjmayberry2 said:
Years ago MANY cars/engines vapor locked. It was not uncommon to open a hood and see cloths pins on the steel fuel lines. Some hoods trapped engine heat which compounded vapor lock in stop and go traffic. Many engines as late as the 70s would boil the carb dry after running a long trip and shutting the engine off. We use to remove the steel fuel lines and add fiber spacers under the carb. Seemed to help and was relatively cheap.
Click to expand...
I remember clothes pins on fuel lines too.
Ford OEM carburetor anti-heat spacer, 1/2inch thick phenolic plastic... approx. 1957
 

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Ole Don said:
I too drive a 55. Mine had dual exhaust from the factory, so a lot of heat went out the back. I have never had a vapor lock problem. My advice is to use two fuel pumps. I use the electric as a booster, when the car hasn't been driven in more than a few days, I run the electric to prime the system. My electric pump is in the back near the tank. Many of us dont have a choice on ethanol laced fuel. If we buy fuel, we get up to 10 % ethanol.
Click to expand...
Ole Don,
Go to www. pure-gas.org for a list of ethanol free gas stations in the US. Something like 80 are listed for Illinois.
Ben Hess
 
Ole Don said:
I too drive a 55. Mine had dual exhaust from the factory, so a lot of heat went out the back. I have never had a vapor lock problem. My advice is to use two fuel pumps. I use the electric as a booster, when the car hasn't been driven in more than a few days, I run the electric to prime the system. My electric pump is in the back near the tank. Many of us dont have a choice on ethanol laced fuel. If we buy fuel, we get up to 10 % ethanol.
Click to expand...


Thats what i was thinking too. I didn't know if the manual pump would pull through the electric pump and pressure regulator.
 
Ole Don said:
I too drive a 55. Mine had dual exhaust from the factory, so a lot of heat went out the back. I have never had a vapor lock problem. My advice is to use two fuel pumps. I use the electric as a booster, when the car hasn't been driven in more than a few days, I run the electric to prime the system. My electric pump is in the back near the tank. Many of us dont have a choice on ethanol laced fuel. If we buy fuel, we get up to 10 % ethanol.
Click to expand...

CrownVic55 said:
Ole Don,
Go to www. pure-gas.org for a list of ethanol free gas stations in the US. Something like 80 are listed for Illinois.
Ben Hess
Click to expand...
thanks for the heads up, i'll check that out too.
 
Daves55Sedan said:
Older Fords had a vented gas tank. You should check to see if there is any obstruction to free venting by disconnecting the vent tubing on the driver side of the gas tank. Blow compressed air into that end of the line and see if the air comes out of the tubing where it exits adjacent to the gas tank filler cap. Rod the line out if necessary.
Click to expand...

good tip.
 
I've been making my own phenolic carb spacers for years, seem to work pretty well. I had a stock car years back that was vapor locking, the clothes pin trick worked on that.
 
Would one of you knowledgeable gentlemen please explain the clothes pin theory to me. I've never heard of this trick. Thanks
 
Here's my 'I don't really have a clue' guess.
They amplify/reduce(?) the vibration of the fuel line and this helps break up/prevent the bubbles in overheated fuel which create a blockage, and return the fuel to a liquid.
 
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