Guest Posted December 10, 2001 Share Posted December 10, 2001 I HAVE A REBUILT 401 IN MY 65 RIV AND EVERYTHING IS TOGETHER & NEW.I NOTICED THIS NEW RATTLE NOISE COMING FROM THE MANIFOLD. I THOUGHT AND IT SOUNDED LIKE THE CARB BAFFLE PLATE BETWEEN MANIFOLD & CARB.I REMOVED IT & NOISE IS STILL THERE. I NOTICED THAT CARS INC. SELLS AN INTAKE MANIFOLD PLUG FOR 63-66 RIVI'S. I HEARD THAT THESE THINGS RUST OUT AFTER A WHILE AND CAN CAUSE POOR CARBURETION.I DONT KNOW WHERE THIS THING IS LOCATED.ON THE BOTTOM, I GUESS THE SERVICE MANUAL LEFT THIS PART OUT.LONG STORY SHORT,DOES THIS SOUND FAMILIAR? AND IF YES PLEEEEEEASE HELLPP ???? Link to comment Share on other sites More sharing options...
The Old Guy Posted December 11, 2001 Share Posted December 11, 2001 The plug you are refering to is under the manifold. the hole it plugs was probably used to clear away the core sand when the manifold was cast. If it goes bad ,you will have a HUGE vacuum leak and the car won't idle or perform well Link to comment Share on other sites More sharing options...
Guest Posted December 11, 2001 Share Posted December 11, 2001 I think that the first part of what old guy had to say is right on, but also think that if the plug does rust out, you get an exhaust leak. It's in the exhaust crossover/ heat riser circuit. Link to comment Share on other sites More sharing options...
Reatta Man Posted December 11, 2001 Share Posted December 11, 2001 I remember replacing one on a '66 Wildcat with the 401. The earlier posts are correct; it is under the intake manifold, and is only visible when you remove the manifold and turn it over. It was easy to find a replacement steel plug once I had the intake manifold off. Take the intake manifold with you to a good parts store when you do yours. <P>When mine went bad, I don't remember if I heard an exhaust sound, or if I could hear the vacuum leaking. Either way, when I replaced it, the difference was awesome. <P>Joe<p>[ 12-11-2001: Message edited by: Reatta Man ] Link to comment Share on other sites More sharing options...
The Old Guy Posted December 12, 2001 Share Posted December 12, 2001 When you get old ,it is easy to forget. You are right !! It is in the exhaust passage Link to comment Share on other sites More sharing options...
JUSTIN Posted December 12, 2001 Share Posted December 12, 2001 How do you tell if you have this? What are the symptoms? Link to comment Share on other sites More sharing options...
capgage Posted December 12, 2001 Share Posted December 12, 2001 what - getting old, or having the leak??? Link to comment Share on other sites More sharing options...
Guest Posted December 12, 2001 Share Posted December 12, 2001 WOW !! THAT WAS QUICK AND ACCURATE. I DID FORGET TO TELL YOU I LIVE IN CALIFORNIA & I WAS TOLD THAT I DIDNT NEED THE HEAT RISER VALVE BEACUSE THE CLIMATE CONDITIONS HERE ARE GREAT FOR COLD STARTS.MY VALVE WEIGHT WAS BROKEN & I CALLED EVERY PARTS HOUSE LOOKING FOR A REPLACEMENT & FAILED.FINALLY I JUST DID WHAT EVERY DOES IN CALI.I CUT OUT THE BUTTERFLY VALVE & WELDED UP THE SHAFT HOLES . THE CAR RAN BETTER BUT I DID NOTICE A LITTLE RATTLE FROM THE BOTTOM OF MANIFOLD. I TRACED THE NOISE BACK TO THE EXHAUST MANIFOLD AND AT THE FRONT OF EXHAUST PIPE. THANX I KNOW WHERE TO START NOW THANX AGAIN. Link to comment Share on other sites More sharing options...
Guest Posted December 14, 2001 Share Posted December 14, 2001 I live in AZ and was told I didn't need to use the heat riser valve either. I cut out the butterfly as you did, but I also plugged the heat riser circuit with set screws and went with an electric choke. Link to comment Share on other sites More sharing options...
Guest wildcat65401 Posted January 29, 2002 Share Posted January 29, 2002 i know what you mean , this site is the answer to my prayers . i've been trying to make my '65 401 wildcat behave again ,these people have really helped me.<BR> THANKYOU ALL Link to comment Share on other sites More sharing options...
Guest Posted January 30, 2002 Share Posted January 30, 2002 I LOVE THIS SITE I DONT HAVE TO LISTEN TO ANY MORE FAKE MECHANICS THAT DONT KNOW A THING ABOUT BUICKS.I DONT HAVE TO HEAR BUICK,CHEVY,CADILLAC,PONITIAC ALL GM ALL THE SAME.THATS WHY I WORK ON MY CAR MYSELF.PLENTY OF HELP FROM THIS SITE, LARRY D. & MARTYS AUTOMOTIVE WORLD. THANX, THANX EVERYONE Link to comment Share on other sites More sharing options...
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