Hi guys.

I have a 57 bird with a 312 & Fordomatic. My temp gauge seems to run at about half way between the C and H, the needle straight up most of the time. I find the car seems to run way better when it gets hotter.

The acceleration from a standing stop seems much crisper and cleaner when it runs hot. No problem, just curious.



Thanks

To a point, yes.


Lawrenceville, GA

Cold gasoline doesn’t ignite well so anything that can heat it up to aid vaporization before combustion takes place will be a big help.  A warm engine is obviously at the top of the vaporization list.  Lots of other factors are also involved such as the quality of fuel, the air/fuel ratio, atomization, compression ratio, etc.  And as Charlie says, “to a point”.  I’ve seen engines hot "to the point" that combustion is spontaneous even after the igntion is turned off.

Lorena, Texas (South of Waco)

Y-Guys Ted & Charlie:     Why then, do "We" block off the heat passages, in the

                              intake, for better performance, and some racers still use

                              "cool cans" for their fuel lines? I'm not argueing(sp?)

                              I'm just trying to learn from the "master's"of Y-Block....  

                                                            Bill

Bill

Pelham,Al

Bill,

      The intake air wants to be cool to cold because heavier air is denser, has more oxegyn. More O2 will allow more fuel to be burned, making more power. Clear as Mud?

Frank/Rebop

Bristol, In ( by Elkhart) 

Ted will explain it better but here you go.

There are some parts of the engine where cooler is better, but again to a point. A cool intake charge, relative to the heat of the rest of the engine is good because cooler air/fuel is more dense so you can get more into the cylinder. If it's too cold, there is the potential for the fuel to condense and fall out of the air stream and then you can loose power or worse.



I'm sure we've all experienced one effect of an intake charge which is too cold at one time or another, under the right conditions. Carb icing, anyone? - runs like crap, if it runs at all.


Lawrenceville, GA

Not sure I can explain it better but let’s try this.

 

Cool fuel is obviously denser but cool fuel is also less prone to other problems such as premature vaporization as a result of pressure changes both within the carb and at its base.  This is where atomization comes into play and making the fuel droplets as small as possible is the goal.  Essentially only the surface area of the droplets burns so the smaller the droplets, the greater the surface area and in turn, the more fuel that’s in a position to be burned.  The smaller sized droplets also tend to travel more freely and not drop out as easily while traveling through the intake runners.  This all equals the potential for more power with less harmful emissions.

 

The new cars with the plastic intakes are also going for a cooler air charge as the aluminum intake manifolds tends to heat up that same air more but remember these setups are not carburetted and the fuel is being injected either at the head or directly into the combustion chamber.  Cool air and cool fuel at this point.  As Frank mentions, cool air carries with it a higher concentration of oxygen and that in itself is more power when coupled with the correct ratio of fuel.  But higher temperature thermostats has the cylinder heads hotter which then aids in the final combustion process.

 

Blocking the exhaust crossover ports on our carburetted engines does make for some cranky cold engine starts but as both the engine and the intake manifold warms up to operating temperatures, then that heat alone is enough to aid in the heating of the fuel mixture.  Hope that helps.

Lorena, Texas (South of Waco)

You didn't learn that in Georgia! This is why aircraft (carburated) run Carb heat. It gets worse with altitude or in humid conditions and can actually stop an engine completely. Also explains the hot intake air hose from the exhaust manifold of the last cars with carbs.

   The other reason that they were used is what Ted mentioned, Vaporization. This got critical with the Emissions Laws. You don't want excess fuel in the exhaust, Hot intake surfaces and air vaporize the fuel better. This allows a leaner mixture because you are utilizing the fuel more completely. Eureka, less emissions. Also less horsepower, throttle response etc. etc. 

Frank/Rebop

Bristol, In ( by Elkhart) 

I sure did. It was when I was running a 1" aluminum carb spacer. Every morning in the winter, I'd get a mile down the road before it wouldn't idle. And if I didn't pull off somewhere, it would eventually die all together. After letting it sit for 5 or 10 minutes, the heat thaws everything and I could make it to work just fine. I switched to a 3/8" spacer made of some kind of laminated composite looking stuff and never had the problem again.

I don't and wasn't running with the manifold heat completely blocked off either. I think it gets too cold in Georgia to block it off for a vehicle in use all year round - and so I'm kinda on the fence about a particular new manifold.


Lawrenceville, GA

Since that "new manifold" with no heat riser is still bolted up against the exhaust source, I wonder how hot it actually gets using the standard gasket?

6 VOLTS/POS. GRD. NW INDIANA