Topics

vapor lock issue


Brett Wright
 

Like this. Pretty easy to do
image1.jpeg
Brett Wright
CEO
Wright Construction Co., Inc.

On Apr 23, 2020, at 3:33 PM, Dennis Terdy via groups.io <dennis.terdy@...> wrote:

Brett,
RE: Vapor Lock
An older thread ... but I wanted to relay to you what happened to my 47 coupe recently regarding vapor lock - percolating gas. I had a similar problem...never happened before on this car. 

I found that my inline metal gas filter and a long fuel line to the carb inlet, slipped down very close to my exhaust manifold.  The gas was being "pre-cooked" and caused my vapor lock/percolating fuel. Pretty obvious, but the last thing in a string of recommendations. was a very simple...but correct fix.

Dennis

On Mon, Apr 13, 2020 at 2:56 PM Robert Kirk via groups.io <kirkbrit=yahoo.com@groups.io> wrote:
It would be most unusual to vapor lock with fuel running through the lines.  Vapor lock would normally occur when you shut off the motor and allow heat build up beneath the hood.  That heat essentially boils the fuel turning it into vapor.  That would be very difficult with fuel flowing constantly. 



--
Dennis Terdy


Brett Wright
 

Dennis,
I am pretty sure I have my problem fixed with careful routing of the fuel line and removal of an in line non functioning but restrictive electric fuel pump. My take on the the location of the fuel pump directly above the exhaust manifold is that it only takes a minor issue to doom the fuel fuel delivery. I also took a great suggestion and wrapped the exhaust manifold and the first 18 inches of the exhaust pipe with “tungsten wrap”. That should lower the Underwood Temps.

Brett Wright
CEO
Wright Construction Co., Inc.

On Apr 23, 2020, at 3:33 PM, Dennis Terdy via groups.io <dennis.terdy@...> wrote:

Brett,
RE: Vapor Lock
An older thread ... but I wanted to relay to you what happened to my 47 coupe recently regarding vapor lock - percolating gas. I had a similar problem...never happened before on this car. 

I found that my inline metal gas filter and a long fuel line to the carb inlet, slipped down very close to my exhaust manifold.  The gas was being "pre-cooked" and caused my vapor lock/percolating fuel. Pretty obvious, but the last thing in a string of recommendations. was a very simple...but correct fix.

Dennis

On Mon, Apr 13, 2020 at 2:56 PM Robert Kirk via groups.io <kirkbrit=yahoo.com@groups.io> wrote:
It would be most unusual to vapor lock with fuel running through the lines.  Vapor lock would normally occur when you shut off the motor and allow heat build up beneath the hood.  That heat essentially boils the fuel turning it into vapor.  That would be very difficult with fuel flowing constantly. 



--
Dennis Terdy


Dennis Terdy
 

Brett,
RE: Vapor Lock
An older thread ... but I wanted to relay to you what happened to my 47 coupe recently regarding vapor lock - percolating gas. I had a similar problem...never happened before on this car. 

I found that my inline metal gas filter and a long fuel line to the carb inlet, slipped down very close to my exhaust manifold.  The gas was being "pre-cooked" and caused my vapor lock/percolating fuel. Pretty obvious, but the last thing in a string of recommendations. was a very simple...but correct fix.

Dennis

On Mon, Apr 13, 2020 at 2:56 PM Robert Kirk via groups.io <kirkbrit=yahoo.com@groups.io> wrote:
It would be most unusual to vapor lock with fuel running through the lines.  Vapor lock would normally occur when you shut off the motor and allow heat build up beneath the hood.  That heat essentially boils the fuel turning it into vapor.  That would be very difficult with fuel flowing constantly. 



--
Dennis Terdy


Robert Kirk
 

It would be most unusual to vapor lock with fuel running through the lines.  Vapor lock would normally occur when you shut off the motor and allow heat build up beneath the hood.  That heat essentially boils the fuel turning it into vapor.  That would be very difficult with fuel flowing constantly. 


Brett Wright
 

Thanks Jim, I  get what you are saying. I am sure you are right that I have overlooked some difference between my car and others but I feel like I have earned the right to give up, if you know what I mean. I rebuilt the pump with parts from one of those guys just don’t remember which one. Doesn’t mean I didn’t make a mistake but it works great except when it doesn’t. I have double isolation gaskets installed on the pump. The electric pump I ordered is 4 psi but I bet it will lose 1/2 psi from the myriad piping on the way to the carb. It had a good rating from a prewar Crosley guy at Summit racing. I will track down an inertia switch for the circuit.
One note of safety though. If you run an electric pump thru a mechanical pump you better hope the diaphragm never fails with a crack. Has potential to leak fuel in to crankcase.

Brett Wright
CEO
Wright Construction Co., Inc.

On Apr 13, 2020, at 2:46 PM, Jim Bollman via groups.io <Jim@...> wrote:

It sounds like you have a plan that should fix the problem but should not be necessary, as you say most don't have a problem. I was just going to suggest when your  last message came in that it was time to start over because one or more of your steps must be bad. I was going to suggest buying a new fuel pump from Yankee or Service instead of relying on a rebuilt that may have another problem other than what was replaced in the rebuild. Also make sure you had one of the insulating high temperature gaskets behind the fuel pump.

Make sure the electric fuel pump puts out between 1.5 and 3.5 lbs of pressure so you don't over power the float valve. Several members run electric pumps near the tank and push fuel through the mechanical pump. You need to have it hooked up so it turns off when not wanted so in an accident situation that it doesn't keep pumping gas. 

Jim...

On Apr 13, 2020, at 2:08 PM, bwright@... wrote:

here is my plan going forward because I feel like I am chasing a mirage on this issue. I ordered some wrap for the exhaust manifold. I plan to do that and see if it or any other minor changes resolve the issue. I also ordered a high quality 6 volt in line electric pump. If the before mentioned steps don't take care of it, I plan to install the pump near the tank and bypass the mechanical pump and pipe direct to the Carburetor. I am really stumped why I have more issues with this than anyone else but I am also plenty tired of spending too much time and money chasing something I know can be resolved by taking the poorly located mechanical pump out of play


Jim Bollman
 

It sounds like you have a plan that should fix the problem but should not be necessary, as you say most don't have a problem. I was just going to suggest when your  last message came in that it was time to start over because one or more of your steps must be bad. I was going to suggest buying a new fuel pump from Yankee or Service instead of relying on a rebuilt that may have another problem other than what was replaced in the rebuild. Also make sure you had one of the insulating high temperature gaskets behind the fuel pump.

Make sure the electric fuel pump puts out between 1.5 and 3.5 lbs of pressure so you don't over power the float valve. Several members run electric pumps near the tank and push fuel through the mechanical pump. You need to have it hooked up so it turns off when not wanted so in an accident situation that it doesn't keep pumping gas. 

Jim...

On Apr 13, 2020, at 2:08 PM, bwright@... wrote:

here is my plan going forward because I feel like I am chasing a mirage on this issue. I ordered some wrap for the exhaust manifold. I plan to do that and see if it or any other minor changes resolve the issue. I also ordered a high quality 6 volt in line electric pump. If the before mentioned steps don't take care of it, I plan to install the pump near the tank and bypass the mechanical pump and pipe direct to the Carburetor. I am really stumped why I have more issues with this than anyone else but I am also plenty tired of spending too much time and money chasing something I know can be resolved by taking the poorly located mechanical pump out of play


Brett Wright
 

Tilotson carb

Brett Wright
CEO
Wright Construction Co., Inc.

On Apr 13, 2020, at 2:29 PM, Butch via groups.io <butch46988=yahoo.com@groups.io> wrote:

Just remember, you want a LOW pressure pump, 1 1/2 to 3 pounds output.

BTW, if you mentioned it, I missed it. What carb do you have?

Butch

On 4/13/2020 2:08 PM, bwright@... wrote:
here is my plan going forward because I feel like I am chasing a mirage on this issue. I ordered some wrap for the exhaust manifold. I plan to do that and see if it or any other minor changes resolve the issue. I also ordered a high quality 6 volt in line electric pump. If the before mentioned steps don't take care of it, I plan to install the pump near the tank and bypass the mechanical pump and pipe direct to the Carburetor. I am really stumped why I have more issues with this than anyone else but I am also plenty tired of spending too much time and money chasing something I know can be resolved by taking the poorly located mechanical pump out of play

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Butch
 

Just remember, you want a LOW pressure pump, 1 1/2 to 3 pounds output.

BTW, if you mentioned it, I missed it. What carb do you have?

Butch

On 4/13/2020 2:08 PM, bwright@... wrote:
here is my plan going forward because I feel like I am chasing a mirage on this issue. I ordered some wrap for the exhaust manifold. I plan to do that and see if it or any other minor changes resolve the issue. I also ordered a high quality 6 volt in line electric pump. If the before mentioned steps don't take care of it, I plan to install the pump near the tank and bypass the mechanical pump and pipe direct to the Carburetor. I am really stumped why I have more issues with this than anyone else but I am also plenty tired of spending too much time and money chasing something I know can be resolved by taking the poorly located mechanical pump out of play
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Brett Wright
 

here is my plan going forward because I feel like I am chasing a mirage on this issue. I ordered some wrap for the exhaust manifold. I plan to do that and see if it or any other minor changes resolve the issue. I also ordered a high quality 6 volt in line electric pump. If the before mentioned steps don't take care of it, I plan to install the pump near the tank and bypass the mechanical pump and pipe direct to the Carburetor. I am really stumped why I have more issues with this than anyone else but I am also plenty tired of spending too much time and money chasing something I know can be resolved by taking the poorly located mechanical pump out of play


Spock Arnold
 

Tmkldwwj@... 

On Apr 13, 2020 12:23 PM, bwright@... wrote:
Let me describe this because I doin"t have photos of everything along the evolution of what I have tried with fuel lines. The fuel line from the tank to the engine compartment is and has been just as it came from the factory. when I first started dealing with this vapor lock I installed an in line 6 volt electric fuel pump in the engine bay and piped it through the mechanical pump. I used it mostly for self rescue and did not run it full time for fear of flooding the crankcase with fuel. I do suspect if that was piped directly to the carb it would have solved the problem. The electric pump has since failed. I still have that loop for the electric pump in place but I should remove it now since the pump is shot. I have tried the fuel line routing run behind the tower shaft and I have tried the fuel line over the valve cover and there is no difference.The only remaining routing would be in front of the tower shaft assuming it will fit there. Right now the fuel comes in to the engine compartment passes thru a loop the a defunct inline electric fuel pump then over the valve cover and in to the top of mechanical pump. It does not ever come close to the exhaust header and it still vapor locks. I shot the temperatures of various surfaces under the hood last summer. The engine block was about 175 degrees the header was 400 as I recall. Arnold, supply me your email and I will send photos off-line


Brett Wright
 

this is a reply to R Williams. The radiator is freshly recored with a modern more efficient core. The engine cooling passageway around the cylinders are very clean. All of the cardboard panels are in place. You mentioned one below the front of the hood. I have a metal panel there if that is what you mean? The routing of fuel line you described is what I have had for some time and had a number of people tell me to move it which I have done over the valve cover. Both routings vapor lock. The engine water temperature is always within normal ranges when the engine vapor locks. It vapor locks at the mechanical fuel pump and then the carburetor gets starved and I am done. The car does not vapor lock with air moving thru ate speed unless I UNDERTAKE A STEEP AND LONG ASCENT. IT WILL ALWAYS VAPOR LOCK IF I LET IT IDLE IN PLACE WITH THE HOOD DOWN FOR 15 MINUTES


Brett Wright
 

Let me describe this because I doin"t have photos of everything along the evolution of what I have tried with fuel lines. The fuel line from the tank to the engine compartment is and has been just as it came from the factory. when I first started dealing with this vapor lock I installed an in line 6 volt electric fuel pump in the engine bay and piped it through the mechanical pump. I used it mostly for self rescue and did not run it full time for fear of flooding the crankcase with fuel. I do suspect if that was piped directly to the carb it would have solved the problem. The electric pump has since failed. I still have that loop for the electric pump in place but I should remove it now since the pump is shot. I have tried the fuel line routing run behind the tower shaft and I have tried the fuel line over the valve cover and there is no difference.The only remaining routing would be in front of the tower shaft assuming it will fit there. Right now the fuel comes in to the engine compartment passes thru a loop the a defunct inline electric fuel pump then over the valve cover and in to the top of mechanical pump. It does not ever come close to the exhaust header and it still vapor locks. I shot the temperatures of various surfaces under the hood last summer. The engine block was about 175 degrees the header was 400 as I recall. Arnold, supply me your email and I will send photos off-line


Richard Williams
 

I rodded out the radiator first. Make sure that you have the panels in on both sides of the radiator and the small one under the bottom of the hood. The fuel line on all of my cars goes across the front of the engine just behind the shaft housing for the tower shaft. That way it is behind the fan for good cooling. Good luck. Rich W.

On Sunday, April 12, 2020, 08:08:03 PM PDT, Spock Arnold via groups.io <tmkldwwj@...> wrote:


I do it frequently with no problem.  Now could you please take a picture of how your fuel line is run under the hood?  Then please describe in detail the path the fuel line takes from the tank to the beginning of the picture.   I have had this problem in the past and fixed it by rerouting the fuel line. 

On Apr 12, 2020 10:10 PM, bwright@... wrote:
I removed the plate on one side of the block and there was a small amount of debris enough to cover the floor) but nothing alarming. The fuel line is now routed over the top of the valve cover. I think I have covered every possible suggestion. just for the heck of it can one of you guys start your car and let it idle for for 15 minutes or so with the hood down and see if it vapor locks. I really don't get what I am missing. I don't see or feel any leak in the exhaust manifold gasket either.


Spock Arnold
 

I do it frequently with no problem.  Now could you please take a picture of how your fuel line is run under the hood?  Then please describe in detail the path the fuel line takes from the tank to the beginning of the picture.   I have had this problem in the past and fixed it by rerouting the fuel line. 

On Apr 12, 2020 10:10 PM, bwright@... wrote:
I removed the plate on one side of the block and there was a small amount of debris enough to cover the floor) but nothing alarming. The fuel line is now routed over the top of the valve cover. I think I have covered every possible suggestion. just for the heck of it can one of you guys start your car and let it idle for for 15 minutes or so with the hood down and see if it vapor locks. I really don't get what I am missing. I don't see or feel any leak in the exhaust manifold gasket either.


Brett Wright
 

I removed the plate on one side of the block and there was a small amount of debris enough to cover the floor) but nothing alarming. The fuel line is now routed over the top of the valve cover. I think I have covered every possible suggestion. just for the heck of it can one of you guys start your car and let it idle for for 15 minutes or so with the hood down and see if it vapor locks. I really don't get what I am missing. I don't see or feel any leak in the exhaust manifold gasket either.


Brett Wright
 

not a bad idea but I keep thinking I am missing something big because this does not seem to be any where near the problem I have on other folks cars. I plan to attack those plates today if all goes well.


Ron D.
 

Just a thought that I have not seen mentioned is this. What about trying some of that titanium exhaust wrap, like racers or hot rodders wrap on their headers, to keep the exhaust heat out of the engine compartment. A 50' roll is under $20, and may be worth a try to keep the heat off the fuel pump.


Brett Wright
 

one other clue that it is not clogged or kinked fuel line is that it will run all day long at 50mph or more on level at obviously high flow rates. On the other hand, it will not sit in one place with the hood down idling for much over 15minutes without vapor locking. So sitting and idling only the air the less than remarkable fan can drag thru the radiator is in play. So I do know the new cored radiator is more than twice as efficient as the stock cored radiator and the fan is the same everyone else has on their car. I will report on what is behind the plate soon


Brett Wright
 

Sorry I missed that in my list but I did rebuild it with all new parts. 


Jim Bollman
 

I didn't see anything about a rebuilt fuel pump. Several others mentioned fuel pump as possibility.

On Apr 11, 2020, at 9:59 PM, bwright@... wrote:

I am aware that Ethanol fuels vapor lock at lower temperatures than non Ethanol fuels. Last summer I syphoned the tank out and put non ethanol fuel in and guess what? It didn't make a remarkable difference! I am going to remove those plates and eliminate that possible source. If I didn't mention it before the fuel line is steel to the engine compartment. They have always been plenty open when I have blown on them. The tank cap is vented. With so many things eliminated I favor that something is amiss with the cooling system like a weak pump or buildup around the cylinder walls in the block. keep casting ideas though