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1967 Fastback converting to Electric Fans / Carburetor fuel boiling

67stang

Active Member
1967 fb 351w 5speed 650 quickfuel no electric chok

Well summer is here in FL. I have been running the beast several times a week(when it’s not raining or course). However if I run my car from about 30 min or more and let it sit for 30 min or so the fuel seems to vaporize in the bowls. So when I start it up again I press half way down on the gas and start her up. It takes a few seconds before it will light and I have to keep my foot on the gas 2.5k tach for about 5 seconds to get the fuel flowing. After that it runs perfect.

So my question is (for the first step without going crazy), is to either get a 1 inch phenolic spacer, or the quick fuel cool plate. Anyone have any thoughts on which one is better.

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My impression is that a cooler plate won't do the job cause it also sits on top of the engine. So I would go for the phenolic spacer.
On the other hand I would check engine cooling system/coolant temperature ,spark timing and fuel mixture.
Maybe your engine is running on the hot/very hot side.
Or maybe you can opt for an electric fan , wired that it even runs with the ignition off , so it cool down the engine when its shut down.
Just some thoughts from across the big pont.
 
The science of the cooler plate is solid and if hood clearance is an issue doesn't raise the carb as much. Either option will make a difference so personally I'd go with a spacer first and if it is not enough spend the money and try the plate.

Bruno's idea about the fan is good too. I built a circuit into my fan control to allow it to run when the engine is off to help cool things off more quickly.
 
I have an old style gauge for temp (no numbers). It’s does seem to work. And if I’m idling it never has reached the middle. At most maybe 40%, but normal around 30% then when I start driving it will go down near C. During cruise (as expected) always at c.


If I did the spacer and still wanted an electric fan, is it dumb to have a pusher electric and keep the manual puller fan too?




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same problem here years ago.
I did the phenolic spacer
Changed the metal tube fuel line to a steel braided line away from the block. STock has metal line attached directly against the block
and the final real solution....
check the routing of the fuel line under your car. Mine was down the drive shaft area. There it came within an inch of the down exhaust from the manifold. It also ran alongside the exhaust almost the complete length of the car. Pre-heating the fuel.

I moved it to the side rocker area and now it is fine.
 
I have an old style gauge for temp (no numbers). It’s does seem to work. And if I’m idling it never has reached the middle. At most maybe 40%, but normal around 30% then when I start driving it will go down near C. During cruise (as expected) always at c.
If I did the spacer and still wanted an electric fan, is it dumb to have a pusher electric and keep the manual puller fan too?
As I always suggest, getting a "real" gauge that shows an actual numeric value is a good idea. Even if it is mounted elsewhere and just serves to give a reference to the stock dash gauge it certainly helps to know what is going on.

Adding an electric as a secondary system is an acceptable option. Mounted as a pusher it will not adversely affect the stock mechanical fan performance.
 
same problem here years ago.
I did the phenolic spacer
Changed the metal tube fuel line to a steel braided line away from the block. STock has metal line attached directly against the block
and the final real solution....
check the routing of the fuel line under your car. Mine was down the drive shaft area. There it came within an inch of the down exhaust from the manifold. It also ran alongside the exhaust almost the complete length of the car. Pre-heating the fuel.

I moved it to the side rocker area and now it is fine.
As long as the car is moving the underside routing close to the exhaust shouldn't be too much of an issue. If you spend a good deal of time in traffic or slowly cruising around would be a different story. Up front under the hood where the air doesn't flow through freely is where most of the heat transference would likely take place. Isolating the fuel line away from the hot engine makes great sense.
 
what intake are you using? Is it possible to block off the crossover? If you live in Florida you shouldn't need it and it is heating up the intake. Aluminum is a good heat conductor so if you have an aluminum intake and the crossover is open you could be heating the intake a lot.
All the other suggestions are good too, just thought I'd throw that crossover thing out there to think about also
 
Could I just replace the old temp gauge with one with numbers? If so is it difficult?


Crossover?? Sorry for my ignorance, but what do you mean by crossover?

I have an Edelbrock Performance intake.

Here are a few pics.

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The crossover is located in the center (as judged by the side length) of the intake. It is a port that allows heated air from the cylinder heads to migrate up into the intake to warm it. Pictures online indicate that a 351 Performer does have this provision. It will look like a shallower runner on either side between the center two fuel runners. You can remove the intake to install pieces to block it off.
 
Changing out the gauge is possible. You can find plenty of info on the Web on how to do it. Thing is your dash will look funny as it wouldn't match the rest of the gauges. Like we always say, one thing leads to another and then another and then...

You could always just hook an inexpensive gauge up under the hood just for comparison to your stock gauge so you could "assign" a numeric value temp to various points on the stock scale from C to H. So when it is at your normal running temp at say half scale this other gauge could be read to show that point is actually 195 degrees, for example. Once known the other gauge isn't really needed and you can keep the stock dash look.
 
Good idea. I think I will do that unless if anyone knows: how accurate of a reading Is a temperature gun hitting the same location and the temperature sensor? Obviously it’s on the outside but if it’s within 5 degrees I could borrow one and use that as a reference, even though I think getting a real gauge would be more accurate.

I think I will try the QFT cool insulator as it’s 1/2 compared to a 1 inch phenolic spacer. 1 inch I think I will hit the hood. I will let you guys know how it works out.




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You could use such a tool instead of a gauge. It would be easier but also more expensive. Accuracy is not that critical. If you're off by 5-10 degrees it won't matter for your purpose.
 
The crossover is located in the center (as judged by the side length) of the intake. It is a port that allows heated air from the cylinder heads to migrate up into the intake to warm it. Pictures online indicate that a 351 Performer does have this provision. It will look like a shallower runner on either side between the center two fuel runners. You can remove the intake to install pieces to block it off.
yeah, what he said! oh and looks like a nice ride! we need more pics
 
So I’m still waiting for the cool plate to show up, but I was thinking about everyone’s suggestions. I will check the temp on my car soon and that will help me decide what to do next.

Question: Is it a fact that electric fans(pullers) keep the coolant/engine cooler compared to a mechanical puller?

If so I’m currently running the 3 row 20 inch aluminum rad that I purchased through CJ, and they do have an electric fan to go with it, see photo below. I assume it’s pretty easy to install with the wiring kit?

Visually it looks pretty nice.

Off the wall question:
Has anyone ever kept the mechanical fan puller and place a pusher fan in front of the evaporator? Would that help at all? Just curious?

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It makes no difference whether the fan is mechanical or electric in terms of cooling efficiency. Its all about air flow. One advantage an electric fan offers (be it push or pull) is that it draws all its air from in front of the radiator where it should be cooler. A really good stock mechanical fan with a proper shroud can do the same but in most cases people simply do not set them up right. The shroud needs to be sized to the fan blade diameter and the fan sitting at the correct depth into the shroud, etc.

The other really big advantage of an electric is that it runs at the required RPM all the time. Always moving the same volume of air. A mechanical fan is dependent on engine RPM to get the volume cranked up. This is why you always hear about cars overheating when stuck in traffic but "OK" when moving. A good electric setup allows you to use a couple speed settings on the fan so it can run faster (move more air) at idle or in traffic than it does on the open road when natural air flow aids in cooling.
 
Well here is my current set up using a 5 bladed fan. Fan sits about 2.5 inches from the rad, and maybe 1/3 of the blade is out of the back side of the shroud.

Would a six blade make a difference?


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That looks like a pretty good setup. I would first get a gauge hooked up so you know the operating temps of the engine in all circumstances before I invested in making any changes to the cooling system. You need to know what you are dealing with to approach it properly. Last thing you want to do is get the operating temp too low as that can create a whole other set of issues.
 
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