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Re: [oletrucks] To heat the intake or not to heat the intake

To: Oletrucks Board <oletrucks@autox.team.net>
Subject: Re: [oletrucks] To heat the intake or not to heat the intake
From: B&A Kettunen <bekett@uslink.net>
Date: Sat, 25 Dec 1999 19:13:27 -0600 (CST)
>
>Hi Bruce,
>
>Your informative message seems to have come only to me.  I think others on
>the list would also find it interesting.
>
>Even here in So Cal, carburetor icing is a problem at about 3,000 feet.
>
>Thanks,
>
>Grant S. gls@4link.net
>
>
>
>
>-----Original Message-----
>From: B&A Kettunen <bekett@uslink.net>
>To: G. Simmons <gls@4link.net>
>Date: Friday, December 24, 1999 8:53 PM
>Subject: Re: [oletrucks] To heat the intake or not to heat the intake
>
>
>>>>OK everyone, i need some advice.  I am to the point of installing the
>offy
>>>>intake (1x2) and the fenton headers on my 235.  Question, do i need to
>heat
>>>>the intake, if so how.  I know there are holes in the exhaust manifold
>that
>>>i
>>>>have been told i need to link together.  Is this true?
>>
>>Just a quick word on why that heat is there.  In high humidity when the air
>>pressure drops going through the carb and the gasoline evaporates the air
>>going through the carb cools and water condenses out inside the carburator.
>>This can upset the running of the engine or keep it from starting.  In
>>cooler weather, (say below 40) this condensed water can actually freeze,
>>causing carburator icing which will really ruin your day until you stop and
>>let it thaw out and dry out.
>>
>>The symptoms of icing are that the engine will start cutting out or loosing
>>power at higher speeds or RPM's.  The RPM point gets lower as ice builds up
>>further, and it goes away when the truck sits hot a while and thaws the
>ice.
>>
>>On most old GM V8's there is a heat riser valve in the manifold that's
>>always stuck and is supposed to send some exhaust through some passages in
>>the intake manifold to heat the bottom of the carb.  On the stock sixes,
>>the intake manifold is mounted so that the exhaust manifold heats it up.
>>This puts heat in the carb too.
>>
>>The newer cars pick up carb air directly from around the manifold  for the
>>same reason.
>>
>>In short, heat the carb or the incoming air unless you run it in only hot,
>>dry weather.
>>
>>Bruce Kettunen
>>'57 3100
>>Minnesota (We definitely need carb heat)
>>
>>
>


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