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I just completed a valve adjustment on my '53 Clipper but #3 exhaust valve was still clicking a little too loudly. While I was adjusting it the second time, I noticed about 3/8" length of 5/16" tubing protruding out of the #3 exhaust manifold port roughly an inch back from the head. The hole that the tubing is in is open all the way into the manifold port and I'm quite sure that exhaust leaking out of it is magnifying the "normal" lfter to valve tapping sound. I'm thinking that the tubing was longer at one time and just broke off but regardless, I don't know where or what it would have connected to so I'm hoping somone else can enlighten me. The heat riser to choke tube is still intact on the engine so I'm clueless as to what this one would be for.

I am a little confused. On an original 53 manifold the heat riser for the choke is cast on the surface of the exhaust manifold, rearward of the carb and is covered with a flat plate retained by two screws. In prior years the heat riser was a 5/16 tube that passes clean through the manifold on a diagonal by the #3 exhaust port. The tube is warmed by exhaust gas but is not open to it. A 1/4" tube is inserted in the top of the diagonal tube and runs up to the carb.

I have not yet seen one of those breached in 20 years of servicing Packards, but anything is possible. Put your hand near it while running and you will know the tale.

Valves that won't run quietly even when set properly usually have loose valve guides.

THe tube should pass THRU the manifold but not be OPEN to the INside of the manifold. If it is burned thru then check the carb choke for carbon build up. Note that usualy the choke tubes are stainless steel (cheap magnetic grade from production)to keep them from burning.

I'm not real familiar with the Packard set up. But the tube u describe is typical among many makes up thru about 1965. Chevy V8 used a similar set up as well as Packard V8.

I would replace it with an SS tube not just plain steel. Be sure to check the choke housing on carb that tube is connected to.

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I need to clarify my post but I also need clarifcation. The car is equipped with the original '53 engine and currently has the setup for heating the choke at the rear of the carburetor just as you described Ross. Obviously, this manifold was cast to also accomodate prior years since it also has the short 5/16" stainless tube installed diagonally into #3 exhaust port and extending roughly 3/8" outside of the manifold. It is also open clean through and into the port just as you stated but then you also stated that you had not seen one breached before. Did you mean that Packard chose to cast the exhaust manifolds to accomodate both early and later versions but did not open the hole all the way through on the later models? I didn't have time to check it yesterday but I suspect that some exhaust gas has to be escaping out of the hole since it is open all the way through. Regardless, I need to plug the unused hole with something but in the meantime, I'll attempt to wiggle #3 exhaust valve and distinguish if the guide is worn too.

Believe there was at least one other with a manifold tube open to exhaust situation. Check out Carl Madsens project blog and also this threadhttps://packardinfo.com/xoops/html/modules/newbb/viewtopic.php?post_id=27993#forumpost27993 and see if anything looks the same or a similar fix would work.

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Geez HH, I'm embarrased...twice! One for not performing a search as I usually do before posting and second for not seeing the picture that Ross was painting! It never dawned on me that the tube was supposed to extend all the way thru the port and that Ross's statement about never seeing one "breached" meant that he had never seen a hole burned all the way through it! Good grief, now I know why he said to hold a finger over it to see if I felt exhaust coming out of the end. Even though my car uses the later set-up, I assume the 5" tube had to be installed on all of the manifolds in order to seal the opening...I was hoping that the refusal of the valve to quieten down after adjusting was somehow linked to the tube being open but now thinking it must be a worn exhaust valve guide...dang it! Oh well, I'll check it when I get home.

Not to worry about the search. I just happened to remember someone else had the problem. The way our topics change & float from one thread to another, it's a wonder any search is successful so hats off for even trying.