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32 intake throttle valve rust problem


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Looking for ways to fix the throttle vale section of the intake on my 32   66s intake, developed a major vacuum leak, pulled it apart to find a rust hole from inside the heat riser section. It about quarter inch wide and three quarter inch long.

thinking of filling it with epoxy after sand blasting inside. Or building a new piece out of plate and pipe, have never used it to heat carb here in California.

any other ideas? 

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This is a common problem on Buicks with the Marvel intake heat system. The only way to properly repair it is to remove the sleeves and replace them. We have done a bunch of these. New sleeves used to be available but now I turn out custom ones for every job, as there are variations in the size of the jacket castings. Don’t try to press or hammer the old ones out. I slit them and carefully peel them inward to reduce the diameter. Then they can be safely removed. Repair with epoxy has been done but only if the exhaust has been blocked off from the jacket which should be done anyway since it is not necessary with modern gas, especially here in California.

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Treat the heat riser with care!!!  They are prone to crack from stresses on the casting.  Replacements are extremely rare.  Roger is correct on the removal process.  Some people go to a custom exhaust shop and get them to fabricate tubes to fit in the casting.  The heat controls were necessary on the low octane fuels available in 1932.  With ethanol fuels and almost double the octane rating, the heat control is unnecessary if not detrimental to good good operation.  I put freeze plugs in the bores of the exhaust side of the het riser and the exhaust bypass valve on the end of the exhaust manifold.  Most people remove the exhaust diverter valves  in the units so they do not have any chance of diverting the exhaust  to the carb.

 

Bob .Engle

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Had the same issues, I replaced the inner tubes with some exhaust pipe that needed shaved by about .010. then carefully pressed them in. It's not difficult to get the tubes out, I chiseled them while twisted inboard making sure not to catch the manifold. Take your time don't crack the manifold!! Message me if you have questions or want me to talk you through it. 

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