The Stovebolt Site Forums The Shop Area Engine Shop Intake Manifold Heat

Putting on Fenton headers and two carb Fenton intake on my 61' 235. What's the concensus on intake heat.
Not required?
Exhaust manifold heat?
Hot water heat?

This is discussed at least twice a week.

Concensus?

Not required?
Yes, Required

Exhaust manifold heat?
Works fine

Hot water heat?
Works fine

Some intakes allow "flow" of heated water (Offenhauser) and some do not (Fenton). If no true flow, you simple get contact heat transfer (which is good enough).

I have used both methods. I now use heat tubes from the Fenton headers to a plate on the bottom of the intake manifold.

Absolutely essential, Tom Langdon, former General Motors 6 cylinder engineer, has been preaching manifold heat for 50 years.

Manifold Heat, Tom Langdon, author

Thanks tclederman and Cosmo.

Do both systems(exhaust vs water) produce the same results? Or in your opinion, is one better than the other? Pros/Cons?

Both techniques provide the same results in providing adequate heat.

according to some tech bulletin from chevy someone here posted not so long ago. The corvettes came with out manifold heat and wasn't actually recommended except for extreme cold weather. I haven't had heat on mine for 3 years and it has never ran better. Even when it is below freezing. (not much below, as I don't live in Minnesota or wherever it gets really cold) So I wouldn't say it was essential. Unless of course you live where it is very cold and actually drive your truck in the winter weather.

The Corvette's used a different style intake and carb, that maybe why heat wasn't needed on them. On the dual intakes where the fuel hits the intake floor, heat is essential to atomize the pooling fuel. Heat turns the fuel back to vapors as soon as it hits it.

Mine would run great without heat once warmed up and the outside temp is warm to hot. On cool or damp days, it was a bear to start and keep running. Once I added exhaust heat, it acted just fine no matter what the weather was.

Joe

Very interesting comparing the 235 Corvette's needs to the needs of the conventional use of the engine.

I wonder why GM wasted money on the heat riser if it is not needed?

I don't know, it was just what was in an official Chevrolet tech bulletin. Probably they never figured anyone to be taking their corvette out in the snow (?) Also probably they were pretty sure the trucks were going to be used in any and all conditions. However I do know even when it is cold enough for snow, I haven't missed it, it actually runs the best it has in many years. But then again I keep my truck in an attached garage in the seattle area, (unheated). I also try not to take it out in bad weather (doesn't always work that way though) So my experiences may not be so relative to someone who keeps theirs outside at 10 below.

I don't know, it was just what was in an official Chevrolet tech bulletin. But there is precious little difference between the 2 engines, all of about what 15 horsepower? Probably they never figured anyone to be taking their corvette out in the snow (?) Also probably they were pretty sure the trucks were going to be used in any and all conditions. However I do know even when it is cold enough for snow, I haven't missed it, it actually runs the best it has in many years. But then again I keep my truck in an attached garage in the seattle area, (unheated). I also try not to take it out in bad weather (doesn't always work that way though) So my experiences may not be so relative to someone who keeps theirs outside at 10 below.

I have just been looking at the '54 Corvette intake manifold, thinking about using one.
The car didn't have a heat riser but the intake manifold had the same square heat sink on the bottom and it bolted to the matching cast dual exhaust manifold. There was direct heat transfer between the 2 manifolds. The 3 side draft carbs had a shorter and straighter mixture flow path and wouldn't have required as much heat.

Discussion of Corvette Carter YH carbs, etc

Tom Langdon's words of wisdom.

yes I know all the common discussions, but the one I am talking about was a GM tech bulletin. (people talking about something in a forum doesn't quite hold as much water as an official tech bulletin, or a scientific treatise) I do know that I have no problems with fouling plugs or sluggish acceleration, or any of the ailments usually attributed to a non heated installation. In my particular case it happens to be a fact, your experiences may vary. I have planned to put heat on it for quite some time now, But it runs so good, I see no reason to fester with it. However once I put the aluminum dual intake on that may change.