Re: #3 Exhaust Port Tube
Posted by Gary On 2011/9/26 7:46:09
Quote:
Ross wrote:
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.
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.
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