Simple Remedies for Vapor lock and hard starting.

[The Going Thing]

I know many who drive their cars have issues with hard starts when the engine is at operating temperature.
I was working with another member here and suggested not only using the 3/8" Canton Phenolic Carburetor Spacers but insulating the fuel line from the apron to the pump but about a foot and a half on pump to carburetor and the phenolic fuel pump spacer.  The changes lowered the fuel temperature almost 10 degrees. For those who have never seen the pump spacer I posted it below.

[Bob Gaines]

I know many who drive their cars have issues with hard starts when the engine is at operating temperature.
I was working with another member here and suggested not only using the 3/8" Canton Phenolic Carburetor Spacers but insulating the fuel line from the apron to the pump but about a foot and a half on pump to carburetor and the phenolic fuel pump spacer.  The changes lowered the fuel temperature almost 10 degrees. For those who have never seen the pump spacer I posted it below.

Another problem area is the fuel log. Keep in mind that on a 67 GT500 the fuel log bolted to the intake will be heated by the intake and rest of the engine . It can boil the gas. On one of my pleasure driven cars I eliminated the bolt down tabs on the fuel log . I let the fuel log be held by the rubber outlet hoses to the carbs and the steel fuel line on the other end going down to the fuel pump . It is still very stable even without the bolt down tabs. Modify a repro fuel log and not a genuine one.

[2112]

The pump spacer doesn't affect the lever arm to cam contact in any deleterious way?

[shelbydoug]

I think that the 67 GT500 fuel log could be replaced with 1" od Delrin tubing and painted carb gold. As it is, it is just a heat convector.

You could probably put a tea kettle whistle on it now and listen to it whistle?


The connection tabs are only part of the issue with the log. The material it is constructed of will transfer heat calories almost as well as a copper tube baseboard heater.

The fuel temperature in the log will adjust to the temperature in the engine compartment as a result. Because of those properties it is just a natural place for vapor lock to occur. Any metal log at some point will just boil any fuel in the log in a 67 GT500.

Delrin is self insulating, very stable and virtually immune to heat transfer. It will always be cool to the touch regardless of how hot it's environment is. It also machines like a soft metal would so it can be drilled, and threaded very easily and is impervious to fuels.

[2112]

Couldn't a phenolic spacer/mount be fabricated to mount the log?

Assuming one didn't want to leave it supported by the connections as Bob shared.

[427heaven]

Anything that will give some form of heat isolation/insolation will keep heat down. A phenolic washer, spacer between the intake manifold and fuel log works fantastic same between the fuel pump body and engine block, then lastly moving up the line to phenolic 1/4 spacers under the carbs. My heavily messaged 427 that has a tendency to run angry hot in the summer time... runs the carb, and fuel log spacers, to keeps things cool and happy. Good Luck keeping things looking factory but with a little extra engineering under the hood.

[Greg]

I fought this for a few summers before eliminating the problem.
* Run a 160 deg thermostat to keep block temp down.
* Disable choke if summer only.
* Block off intake exhaust gas crossover.
* Disable heat riser.
* Use 1/2" canvas, phenolic carb spacers.
* Consider for a performance coil and wires for best spark energy.  I use an MSD Blaster and Ford Racing wires.
* Lower fuel bowl level slightly below lowest normal setting.
* Use a fixed pitch, race fan typical of short track, modifieds.  Need to be moving a LOT of air to keep under hood temps tolerable.
* Never shut down engine immediately after running at highway speed.  Let it idle with hood open for a minute if possible.
* Open hood when parked.

That sounds like a flight plan... LOL. 

In regards to the 160deg thermostat it doesn't work like that.  A 160 thermostat makes the block hotter, you want a 180 deg thermostat. 

Before you disagree, think about it this way.  In the system, the radiator is the cooling device, so a 180 deg thermostat stays closed longer and doesn't allow water in the block but it keeps the water in the radiator longer, to be cooled until the temperature of the water reaches 180, then it opens allowing water to flow into the block.  So it stay in the radiator longer to get cooled.  A 160 deg thermostat opens at a lower temperature thus allowing the water to get hotter in the block.

Greg

[Bob Gaines]

Couldn't a phenolic spacer/mount be fabricated to mount the log?

Assuming one didn't want to leave it supported by the connections as Bob shared.

The spacer would have to isolate the bolt so it does not touch the metal sides of the tab it going through otherwise it will transfer heat to the tube filled with fuel. Part of the problem is for the forward bolt that holds the fuel log is that it can not be much longer then stock otherwise it will not clear the intake runner when installing the bolt. A spacer would seem to require a longer bolt . There does not seem to be enough thread to run the stock bolt and a spacer IMO.

[The Going Thing]

Yes, I have phenolic washers on both sides of the fuel log flanges that mount it to the intake as well as about 16" of insulation on the heater hoses where they travel from the firewall down the fuel log.  I added the fuel pump spacer and the insulation on the fuel feed and up the metal pump to carb line just to about the top of the power steering pump.  I was pleased with the outcome.  There is a tremendous amount of heat that gets trapped back in at the firewall around the booster. It actually makes it's way up the column. The engine is within operating temperature 185-195 even in 100 degree weather with a Stewart EMP thermostat.

[2112]

Before you disagree, think about it this way.  In the system, the radiator is the cooling device, so a 180 deg thermostat stays closed longer and doesn't allow water in the block but it keeps the water in the radiator longer, to be cooled until the temperature of the water reaches 180, then it opens allowing water to flow into the block.  So it stay in the radiator longer to get cooled.  A 160 deg thermostat opens at a lower temperature thus allowing the water to get hotter in the block.

Greg

excellent post

[2112]

Couldn't a phenolic spacer/mount be fabricated to mount the log?

Assuming one didn't want to leave it supported by the connections as Bob shared.

The spacer would have to isolate the bolt so it does not touch the metal sides of the tab it going through otherwise it will transfer heat to the tube filled with fuel. Part of the problem is for the forward bolt that holds the fuel log is that it can not be much longer then stock otherwise it will not clear the intake runner when installing the bolt. A spacer would seem to require a longer bolt . There does not seem to be enough thread to run the stock bolt and a spacer IMO.

Ah, got it. Thank you

[The Going Thing]

You don't need to change the Ford Fan. As long as your thermostatic fan clutch is functioning correctly it works perfectly. The C7ZX intake doesn't have a crossover and most performance intake gaskets block them anyway.

[FL SAAC]

Insulate the fuel line, add lead and octane booster

[The Going Thing]

Exactly what I did, Tony. I didn't want it to be too obvious. The fuel pump line under the power steering has a slide on insulation as well as as about a food that runs next to the power steering pump. The 427 canister filter doesn't seem to create an issue.

[JWH]

Heater Hoses - It seems like a common routing for the heater hoses is to have them run right alongside or right over the top of the fuel log. I have tied the heater hoses to the Export Brace with black zip ties to lift the hoses up away from the fuel log as much as possible.

A solution on the spacers between the fuel log and the intake -- I removed the two intake manifold bolts that secure the fuel log and installed studs. I tightened the studs using the "double nut" method.  I then installed a spacer, the fuel log and a nut to secure. As Bob pointed out, if you try longer intake manifold bolts, they do not clear the intake manifold where the carbs sit and will not install.

Another step that is admittedly drastic is to install a louvered hood. I have no scientific data, but seems those louvers would really help get hot air out of the engine compartment.

This is a great thread.
Jeff