I know at the end of a long restoration, we say "Its done!" only to drive around the block and experience the car quitting from a bad condenser. Our regular readers know that when we finished the restoration/preservation on my 1951 Packard Mayfair (see southernwheels.com, archives, December 2021) I drove it on the first drive, which was fine, but the second drive started out okay, then I lost power and black smoke was coming out of the tail pipe. I knew it must be a stuck automatic choke. What the what?!!!? When I got it back to the shop and removed the oil bath air cleaner, I could see the choke flap was only half opened and the tail pipe was sooty. The carburetor was rebuilt several years ago and during the restoration, I would start it regularly and kept fresh non-ethanol gas in it, but there was always an issue with the choke. To get it to where it would fully open when hot, I would have to set it where it didnt quite close when cold. I had replaced the choke spring with a fast-opening one, but didnt make much difference. I let it go to focus on finishing the car. Now I would have to find the problem. I removed the spark plugs. They were carboned up. I checked the points and they were .016 correct for a 1951 Packard Delco distributor. The plug wires were new (stranded type). Then I checked for vacuum leaks. The car has a vacuum/fuel pump with vacuum wipers (no leaks). I replaced the spark plugs with Autolite 295 plugs (non-resistor) and gapped them at .028: I felt that the carburetor was working well and that the trouble was in the choke. Carburetion on the 1951 Packard models 200 and 250 is a Carter WGD dual downdraft climate control No. 7845. What is unusual to me about these carburetors is the way the Fast Idleadjustment is set. With the thermostat coil housing gasket and baffle plate removed (this is a paper gasket that covers the coil mechanism inside the cap) crack throttle valve and hold choke valve closed, then close throttle. There should be .026clearance between throttle valve and bore of carburetor (see opposite idle port). Adjust by bending the choke connector at a lower angle (G).
The choke on these Carters is a hot airchoke. A metal tube connects the carburetor choke to the exhaust manifold. When the engine is cold, a spring inside the choke housing retracts and closes the choke. When hot air reaches the spring, it uncoils and opens the choke. So, making sure that the spring is good, choke cap is not broken and is sealed and the heat pipe (tube) is not restricted are all important.
My heat pipe had a step down (reducer on the end going into the exhaust manifold. I am not sure why. When I removed it, the pipe pushed snug into the tube in the exhaust manifold, so I eliminated it, sleeved the heat pipe with insulation and checked the choke assembly before hooking up the pipe. My cap looked good. I put the spring in a pan of water heating on the stove and it opened up, but the gasket was missing.
Have you tried to find carburetor parts lately? Kits are no problem, but springs, gaskets, etc., are a big problem. When I looked up 1951 Packard choke spring, there were none listed. A group of springs to fit a 2cap, 2 1/4cap, etc., are the way you buy them. I like things a little more precise, and I kept looking until I found a NOS in the box Carter cap with spring for $50. I bought the cap, but no gasket. Good friend restorer/writer Ron Carpenter had a good used one on the shelf. I soaked it overnight to swell it up a big, put in the new cap/spring gasket. There is also another paper gasket that covers everything under the cap called a coil housing gasket. I put it on and adjusted my choke. I held the carburetor linkage back so as to relieve all pressure on the choke mechanism and rotated the cap to just close the choke flap cold, then tightened down the three screws on the cap, then hand-throttled the linkage. It felt good and smooth. To start these cars and Buicks
of the period, (on a cold start) you push the accelerator to the floor (key off) then key on, push the accelerator down. This sets off the vacuum/electric starter switch on the carburetor (see southernwheels.com Archives April 2021) and the car starts. It was a Winters day when I did this, and the straight 8 started quickly. I let it warm up, went out for a drive, and it ran smoothly with plenty of power. When I got back to the shop I removed the air cleaner, saw the choke flap fully opened. After letting it sit overnight, the choke flap cold was closed and no soot in the tail pipe. I think the problems were a constricted heat pipe and no cap gasket. I have found two more problems: 1, no brake lights (bad wiring and switch) and 2, a dim right front headlight and bad dimmer switch. These parts are an easy find, and I now have them both. We will cover these repairs in a future article, but first I need to get my lift back. Our 67 Jaguar Mk 2 has been sitting on the lift with a sticky brake pedal for more than a year while we work on the concrete floor with floor jacks. Does that sound like a Jag? Anyway, most everything else on the Jag is done. We just finished up putting the door panels back on. They were removed when I had all of the chrome done. We had to remove them to remove the outside door handles. They are back on now, and look great and work smoothly. While the door panels were off, we vacuumed down inside the doors, sprayed in rubberized insulation, then cut 14square pieces of heavy insulation and glued them to the inner side of the doors, giving the doors a nice, solid sound when they are closed. All of the doorslinkages were greased and the window tracks sprayed with track lubricant. The openers/rollers were tested and then the door panels were installed. They appear to be original vinyl and match the Dark Red color of the seats and carpet. Jaguar changed from leather to a tough vinyl in 67. Its sort of like Mercedesuse of M-B tex. They wear well and look very English when capped with the two-piece solid, burled walnut moldings, combined with the solid walnut dash, it would rival a Rolls of the period. Here is the way we removed and installed the panels:
With the door panels on and everything working, we only have to cut some carpet pieces to go on the floor. Floor insulation out of the same door insulation has already been made. We are now simultaneously working on the brakes. Watch for this and also updates on our 48 Packard Custom Club Sedan and 53 Buick Roadmaster 2-Door Hardtop restoration projects.
Keep em driving! . . .and, Never Give Up