intake manifold sweating

[tx-19]

what does it mean when your manifold is sweating for the first 5 inches from the carbs?to fat to lean or perfect?

[Gearhead]

The swetting does not particularly have a direct relation to rich or lean. It does have more of a relation to ambient weather and velocity within the intake.
When the velocity and atomization is high in the intake, it lowers the temperature of the incoming charge. When the charge in the ports is a lower temperature than the DEW POINT of the external (ambient) temperature it then forms moisture. Moisture or condensation from the high humidity ambient air forms on the intake. Much like taking your favorite cold soda out on a warm summer day. Cold on the inside and condensation forming on the outside.
All in all I think it is a good thing...

[Sleeper CP]

All in all I think it is a good thing...
All in all it is. At 3,800 rpm's on long cruise ours would frost over on the upper part of the manifold.
Sleeper CP
565" Ford Lover

[tx-19]

that is what mine does even after a couple of hard runs

[lifter]

Latent heat of vaporization
The heat of vaporization is a natural process that takes place when a liquid changes to a gas. Deceiving at first, by definition, it would be assumed that the transformation of liquid to a gas is creating heat. But quite the contrary. While the composition of the liquid is being changed to a gas energy is consumed in the form of heat. The area where the transformation takes place gives up heat to the transformation process and this heat is carried away by the newly formed gas. This is the law of physics that creates cooler charge air temperatures in carbureted engines when compared to dry-flow port fuel-injection systems. The conversion of the liquid fuel to a gas in the carburetor and intake manifold plenum pulls the heat from the manifold runners, effectively creating a substantial drop in charge temperatures.
Bob
Credit: evans

[SmokinLowriderSS]

what does it mean when your manifold is sweating for the first 5 inches from the carbs?to fat to lean or perfect?
It doesn't mean anything of the sort about mixtures per se.
It means the fuel mixture atomizing is lowering the temperature of the metal manifold arround it to below the dew point of the given day you are out in faster than the contact with the engine can warm it. Thus, the cooler metal draws moisture from the air as condensation.
If the humidity falls enough, it will stop, because the dew point lowers in response, requiring a COLDER surface to condense on.
If the daytime temp rises enough, it will stop, as the temp drop required to reach dew point may become more than the chilling factor of the fuel vaporizing.
It is a very comon phenomenon while engines inhale carb-plate injected Nitrous as the chilling effect of a nearly cryogenic liquid is HUGE as it vaporizes.
It is also much more comon on tall manifolds like tunnel rams and rather rare on short single or dual plane manifolds.
Almost impossible in a manifold with functioning exhaust crossover heat enabled.

[Cheyenne580]

what does it mean when your manifold is sweating for the first 5 inches from the carbs?to fat to lean or perfect?
tx-19 that is normal with all the humidity we have this time of year.My blower will do the samething if the humidity is high.No problem!!!!
How did it work out for you last weekend?
Jim

[tx-19]

it worked great,but now i have condinsation in my valve covers.

[Blown 472]

It doesn't mean anything of the sort about mixtures per se.
It means the fuel mixture atomizing is lowering the temperature of the metal manifold arround it to below the dew point of the given day you are out in faster than the contact with the engine can warm it. Thus, the cooler metal draws moisture from the air as condensation.
If the humidity falls enough, it will stop, because the dew point lowers in response, requiring a COLDER surface to condense on.
If the daytime temp rises enough, it will stop, as the temp drop required to reach dew point may become more than the chilling factor of the fuel vaporizing.
It is a very comon phenomenon while engines inhale carb-plate injected Nitrous as the chilling effect of a nearly cryogenic liquid is HUGE as it vaporizes.
It is also much more comon on tall manifolds like tunnel rams and rather rare on short single or dual plane manifolds.
Almost impossible in a manifold with functioning exhaust crossover heat enabled.
Wow, you sure am a smart one.

[GofastRacer]

Want to see sweat on a manifold, just run Alky!.. Maybe a little ice also!..:D

[Beer-30]

it worked great,but now i have condinsation in my valve covers.
Unless you either:
A - go on longer cruises
OR
B - raise your oil temperature
OR
C - Both A and B,
You will have condensation in your oil. Part of the reason for todays 195* thermostats is to keep the oil warm enough to "boil out" the contaminants. Short-trips and low oil temps cause oil yogurt.

[DUCKY]

Burnuli's Principle..."A column of air moving through a restriction increases in velocity and drops in pressure"
The drop in pressure (intake vacuum) and the latent heat of evaporation (liquid fuel atomizing) decreases the surface temp on the intake manifold below the dew point and causes the moisture in the air to condense. Same reasons carburetors "ice up" on small aircraft and cars in very cold temps, just in a different location.

[SmokinLowriderSS]

it worked great,but now i have condinsation in my valve covers.
What engine temp are you running?
Too cold of oil/engine temperature causes this one, and this one is NOT really a good thing.
As ultra said, longer cruises to raise the oil temp above boiling, engine temps arround 140/150 running, 170+ idling help.
This happens to a lot of guys I hear when they are running too cold/arround 100 degrees.