Vapor Locker shoes

[jeffbcn]

Vapor lock issues
I'm at my Wit's End trying to figure this out I have a 1947 thriftmaster with a 235 from 1962 and it has some serious vapor lock issues.
I have a new carburetor a new Edelbrock electric fuel pump as well as a new mechanical fuel pump and I continue to have these problems I thought that it might have been the heat Riser stuck and so I had the heat Riser completely removed and I'm still having the issues I'm at my Wit's End and would appreciate any ideas.

[Getter-Done]

Are your fuel lines close to your exhaust system?







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[The Rocknrod]

I had a big block in a 56 big window once and ran into that. I used silicon heat shield on the fuel line, fabricated a shield for the fuel pump (exhaust heat) and used a phenolic spacer on the carb. That put that issue to bed.
Depending where your pump is mounted a simple bent piece of sheet metal will work for the shield.

[jeffbcn]

Fuel line and both fuel pumps are on the opposite side of the motor from the exhaust.
Mechanical pump of course mounted on the Block electric pump about a foot behind it on the frame

[geezer#99]

you Might try building a heat shield to isolate the carb from the intake/exhaust manifolds.
Sandwich between the carb and intake.
This type can be made from sheet aluminum.
Just an example made for a Holley but easy to make.

https://www.holley.com/products/fuel...s/parts/108-70

Your timing can effect engine heat which causes vapour lock.
Do you have lots of initial timing?

[Getter-Done]

What the condition of your fuel tank?
Is tank rusty causing a restricted flow?
How is the tank vented?
If it is vented by the cap is the vent still working?








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[jeffbcn]

Tank was painted nice and black when I bought the truck three and a half years ago either a repop or if the original that has been I would assume cleaned out because why would you paint it if you didn't clean it out
I'm pretty sure it's a non-vented system I do have a vented cap and I actually took the cap off and got vapor lock issues with the cap completely off .

[BigBird05]

Just a thought, Is the strainer (sock ) in the tank collapsing and shutting off the fuel flow? I have that happen to me.You run out of fuel but it's not vapor lock.

[jeffbcn]

Interesting thought do I have to pull the tank?

[BigBird05]

The strainer is at the end of the pickup tube inside the tank.

[jeffbcn]

I live in Las Vegas so of course summers are very hot and most of the issues that I have had is when it is hot yesterday it was only about 85 I took it on a 5-mile run part of it on the freeway at 22 to 2500 rpm and I had no issues at all the truck ran about a hundred and sixty 165 degrees and again no issues it was later on when I was driving it and stop and go when it hit about 200 that the vapor lock issues really started to show. So I'm thinking it's more heat-related then it is the strainer although that's a possibility

[geezer#99]

What do you have for a fan?
How many tubes and what style radiator?

FWIW electric pumps push better than pull. They need to be as close to the tank as possible.

[The Rocknrod]

Ya, there's something wrong there. I had a mechanical pump, only on dual Rochester's on my six banger and never had a problem. It was a Vegas truck to begin with also. Sounds like your clogged up somewhere.

[jeffbcn]

I know that part of my overheat problems are my fan and radiator setup I have a aluminum High Performance Radiator I put a 6 blade flex fan on it but didn't realize that if put it further away from the radiator right now it's about 2 and 3/8 inch away from the radiator and I have an inch and 1/2 spacer to put in haven't done it yet I know that's something I still have to do

[geezer#99]

You need a shroud more than you need your fan closer to the rad.

[jeffbcn]

Any suggestions I don't see anything on the internet.

[AcampoDave]

A failing ignition coil will start cutting out under higher temperatures. Just an FYI in case you're barking up the wrong tree.

[jeffbcn]

Thanks for the reply but it's electronic distributor

[geezer#99]

Originally Posted by jeffbcn

Any suggestions I don't see anything on the internet.

Search with ‘google images’ shows lots for fabricated fan shroud.
I’ve had them custom built by a sheetmetal shop.
I had them not cut the hole for the fan opening.
Cut it myself once I was satisfied with the fit.

https://www.google.com/search?tbm=is....5.7-SqAih_4B4

[geezer#99]

Originally Posted by jeffbcn

Thanks for the reply but it's electronic distributor

Electronic or not it still has a coil.

[AcampoDave]

Originally Posted by jeffbcn

Fuel line and both fuel pumps are on the opposite side of the motor from the exhaust.
Mechanical pump of course mounted on the Block electric pump about a foot behind it on the frame

Im curious, why do you have the electric pump if you already have a functioning mechanical pump?

[jeffbcn]

my mechanic did that as an effort to fix the vapor lock issue I understand is not an uncommon practice.

[The Rocknrod]

If you can do some fabing these kits from speedway would work - https://www.speedwaymotors.com/shop/...m_content=Shop
I like them because the fan isnt always where they put the hole.

[MySons68C20]

Run a fuel flow test and see if the volume and pressure is sufficient.

[garyd1961]

I would get rid of the flex fan especially if it's one of the skinny blade models. The more air moving under the hood the less chance of vapor locking.