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.
Quote from: The Going Thing on August 04, 2020, 11:26:27 PM
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.
The pump spacer doesn't affect the lever arm to cam contact in any deleterious way?
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.
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.
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. ;)
Quote from: vtgt500 on August 05, 2020, 11:46:07 AM
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
Quote from: 2112 on August 05, 2020, 09:33:11 AM
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.
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.
Quote from: Greg on August 05, 2020, 01:00:26 PM
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
Quote from: Bob Gaines on August 05, 2020, 02:37:16 PM
Quote from: 2112 on August 05, 2020, 09:33:11 AM
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
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.
Insulate the fuel line, add lead and octane booster
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.
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
Hopefully you will comprehend that by using my method will cause an anomaly resulting in spinning heads, foaming at the mouth, eyes rolling, finger pointing, crowd gathering, people speaking under their breathes and a very severe POINTS deduction.
But yes it will stop the fuel from atomizing and percolating. The car will work just fine.
Please don't let the attached picture distract you, its only Silky Johnson, Buc Nasty, Mr Beautiful also known as The Haters...
Quote from: The Going Thing on August 05, 2020, 05:07:03 PM
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.
Quote from: JWH on August 05, 2020, 05:58:17 PM
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
Good thinking with the stud idea. :)
Quote from: JWH on August 05, 2020, 05:58:17 PM
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.
The louvered hood would be ideal. I presumed the hood scoop would help with keeping the heat out from under the hood. There seems to be cavitation at the firewall.
The double nut method would still allow heat transfer to the fuel log. I used the spacer between the ear of the fuel log and intake and on the top between the bolt and washer and the ear of the log. The bolts will also transfer heat if not insulated from the log.
I started off with the simple changes and kept looking for other ways to "beat the heat". I have no hard-start issues anymore or percolation.
I was just posting the newest addition to combat vapor lock. The pump insulator.
An insulated fuel supply and carburetors goes a long way in the battle.
Quote from: The Going Thing on August 05, 2020, 06:43:52 PM
Quote from: JWH on August 05, 2020, 05:58:17 PM
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.
The louvered hood would be ideal. I presumed the hood scoop would help with keeping the heat out from under the hood. There seems to be cavitation at the firewall.
The double nut method would still allow heat transfer to the fuel log. I used the spacer between the ear of the fuel log and intake and on the top between the bolt and washer and the ear of the log. The bolts will also transfer heat if not insulated from the log.
I started off with the simple changes and kept looking for other ways to "beat the heat". I have no hard-start issues anymore or percolation.
I was just posting the newest addition to combat vapor lock. The pump insulator.
An insulated fuel supply and carburetors goes a long way in the battle.
Studs would seem to allow more room for appropriate isolating spacer . ;) You can always eliminate the tabs altogether as I mentioned.
Most of the stuff has been covered....
I wrote this a few years ago for when customers had heat soak issues.
It is certainly not the end all but it was meant to point folks in a direction, so a cut and past from my files.
Starting to get warm out around here. In prep for summer driving, a small primer on how to avoid fuel boiling in the carburetor on shut down. My "fuel percolation issues checklist"
I had this problem a lot in Southern GA. Part of the issue is me running whatever pump gas is available. Most of this is 10% Etoh junk. Sure sure people can say "well just buy pure gasoline." But I want my cars to be real street vehicles, I drive them everywhere. The only vehicles I own are carbureted, so it isn't an option to seek out special fuel, especially on 5-6 hour trips.
-Carb spacers. Edelbrock makes a 1/4inch spacer that is good. If you can go bigger, use the phenolic wood resin types, they are the best.
-exhaust crossover blocking. It isn't hard, just get some steel sheet jb welded in the exhaust crossover.
-try to shield the accelerator pump. If fuel in it expands it will push out the accelerator pump nozzle. I think in the 80's Ford addressed this issue by drilling a tiny tiny hole in the accelerator pump channel in the metering block which pushed the fuel back into the bowls. If you look at the location of the pump, it's pretty much a wide open heat sink on shut down. In my Galaxie, I run 2, 600cfm Holleys.... twice the fun! Would be just as bad with a double pumper.
This is less of an issue with the check ball type of pump and more a problem with the later umbrella seal style.
-Keep your timing as far advanced as feasible. Limit mechanical to your max and push the initial a lil further if you can. I regularly run 18 initial and 38 total on a "stockish" engine, my HP engine runs 22 initial, 32total, and it helps keep it cooler.
-Fuel line insulation and isolation, keep it away from anything hot. Best is for it to enter the engine bay and go directly to the carburetor.
-Electric fuel pumps. Insulating the fuel lines doesn't matter if the fuel goes into an engine mounted fuel pump. Have you ever felt how hot the fuel pump gets while the engine is running? Hot oil is splashing on the inside.... just trust me, it gets hot. This also makes fuel routing easier as you can keep it away from anything hot. I run -8 SS braided hose and it stays decently warm through all scenarios.
-Fuel regulation and control. With modern fuels, the are designed for sealed fuel injection, so being exposed isn't an issue. Of course we run carbs, they are wide open. This fuel expands and contracts, and I do not have the data to back it up, but I think the specific gravity is different than it used to be. On side hung floats I regulate to 4.5psi With center hung floats I regulate to 5.5psi. I have also found that the .097 needle valves are better at keeping control than the .110 that most new carbs come with. Now some folks might say this isn't appropriate for performance usage. Everyone knows fuel in a carb is about flow not pressure. Use a larger pump and hoses than needed and have a good regulator.... no problems. I'm in the under 600hp crowd and the Carter HP 4600 works great as a lift pump, very quiet and seems very sturdy. I use a QFT regulator with an Aeromotive gauge. (30-1803QFT and
Aeromotive Fuel Pressure Gauges 15632).
-Some folks suggest a return line. I have never used one, so I cannot comment. Thus far I haven't required one.
Just to clarify, the "double-nut" method I refer to in post #15 above concerns installing the studs.
> remove the two stock intake manifold bolts that attach the fuel log
> install two studs in their place and finger tighten
> spin a not onto the stud
> spin a second nut onto the stud and with a wrench, tighten top nut clockwise and the lower counter-clockwise so that they "lock" against each other.
> with the nuts "locked," you should be able to exert enough force on the top nut to tighten the stud in place in the head. This is to keep it from backing out over time.
> remove the nuts and install the spacer, fuel log, spacer and nut as recommended
Bob, the tab elimination and getting the hot heater hoses off would be simple. You can find a repo fuel log for about 50.00. Summit has spacers if that's your choice of routes. I did find the Phenolic spacers held up to the 32 Lbs torque spec fine.
Quote from: JWH on August 05, 2020, 07:21:58 PM
Just to clarify, the "double-nut" method I refer to in post #15 above concerns installing the studs.
> remove the two stock intake manifold bolts that attach the fuel log
> install two studs in their place and finger tighten
> spin a not onto the stud
> spin a second nut onto the stud and with a wrench, tighten top nut clockwise and the lower counter-clockwise so that they "lock" against each other.
> with the nuts "locked," you should be able to exert enough force on the top nut to tighten the stud in place in the head. This is to keep it from backing out over time.
> remove the nuts and install the spacer, fuel log, spacer and nut as recommended
I assume you may have bought some of the studded intake bolts that were used for the cars with shaker air cleaners. If you isolated the studs with the phenolic washers on both sides it would be the same situation as the factory longer intake bolts with the wahers.