Hot Intake Manifold

[Colonel]

Ran the 'A' today in place for about 15 minutes. The engine seemed ok but when I shut it off the intake manifold was red hot. I pulled the vac plug and smoke came out the hole. What is likely going on?

[WHN]

Were you sitting there idling with the spark retarded for 15 minutes?

What was the air temperature?

[Colonel]

Spark about half retarded. 88F outside.

[redmodelt]

Generally if the engine is running too lean and late timing the exhaust manifold will glow. You would have to been running very hot to get the intake to glow! Not enough fuel (open the GVA) and advance the timing some more. How hot was the radiator?

[WHN]

I would check you radiator just to make sure you have coolant. Than take the old girl for a short ride.

If you were not having any problems before today. I think you let it idle to long.

Parade mod over heating. I look for simple answers, it's really a very simple car. Enjoy.

[eagle]

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If the timing is correct and not running lean, you should be able to idle all day without the manifold getting red hot. I would say most likely timing is off.

[Drive Shaft Dave]

Originally Posted by eagle

if the timing is correct and not running lean, you should be able to idle all day without the manifold getting red hot. I would say most likely timing is off.

x2.

[WHN]

Originally Posted by WHN

I would check you radiator just to make sure you have coolant. Than take the old girl for a short ride.

If you were not having any problems before today. I think you let it idle to long.

Parade mod over heating. I look for simple answers, it's really a very simple car. Enjoy.

Do you have engine side pans?

With what you have written I still believe your problem is poor air flow around engine at idle, and 88 degree day, compounded by letting car idle to long.

Model A's have been known to get hot and over heat when driven in summer parades. Enjoy.

[Jacksonlll]

There is no way the intake manifold could be glowing red without the exhaust manifold damn near melting??? There must be quite a fire going on in there, fed by fuel.

[pgerhardt]

I could be wrong, but I think the Colonel was just using the expression "red hot" meaning too hot to touch. Like the others, I can't see how you could get the intake manifold to actually glow red and still have a running engine.

[Marshall V. Daut]

Can you duplicate the red hot intake condition and photograph it for those of us who have never see this? A red hot exhaust manifold, yes. But I am stumped how an intake manifold can get red hot, but not the exhaust manifold. I'm not doubting you. I'd just like to see a photo of a glowing intake manifold. That may help diagnose problems down the road.
Marshall

[WHN]

Originally Posted by WHN

Do you have engine side pans?

With what you have written I still believe your problem is poor air flow around engine at idle, and 88 degree day, compounded by letting car idle to long.

Model A's have been known to get hot and over heat when driven in summer parades. Enjoy.

The fan on a Model A is only needed when the car is at idle or moving along slowly. Once up to 15 or 20 mph it is really not doing anything. The movement of the car is forcing air flow through the radiator and around the engine. The engine pans help in directing that air flow whether at idle or underway. They are an important part of your car. Also a car that is idling with retarded spark for any length of time has a good chance of over heating. Especially on a hot day. 15 minutes, I would think, is a long time to leave a car at idle. Enjoy.

[BILL WILLIAMSON]

REMEMBER, the intake WAS designed to be HEATED by the EXHAUST manifold! I "think" he over used the term "RED HOT"???
Bill Simple

[Colonel]

The manifold's were not glowing red.... but the intake was way way too hot to touch.

[Marshall V. Daut]

Any metal like a manifold that's next to the engine (even with gaskets in between) will get too hot to touch, even after a few minutes' running time. If the w/s wiper line vacuum fitting is removed from the intake manifold immediately after shutting down, you will get some smoke/vapor coming from the hole as the fresh air meets the hot air inside the manifold. The closest place for it to exit is through that manifold fitting hole. Normal. It should dissipate quickly, however.
Marshall

[Patrick L.]

The intake will get too hot to touch. After all, its bolted to the exhaust and the two of them live together.

[jhowes]

I thought that some of you may find this interesting. I have a Willys Knight with a vacuum fuel pump. The intake manifold was sucking raw gas through the vacuum line for the fuel pump. The intake manifold got so cold that water condensed on it It was really cold to the touch.. Good for beer but not much else. Jack

[Patrick L.]

Willys-Knight ! The Knight engine is one great engine.

[FRANK PKNY]

Pagerheart was thinking same as me. They do get hot I think that's what colonel meant. Take it for a good ride blow out the carbon make sure the timing is set correctly, don't run to lean or rich.

[Fullraceflathead]

Roughly at 110 degrees or higher you will feel the burning sensation on your skin.