"Working on a Straight 8" - Part 8
After buying our'36 Packard Standard 8 Rumble Seat Coupe in June of this year (see issue #8), there have been other projects that have kept us from getting the old straight 8 on the road. The engine had a broken exhaust manifold (a common problem on these 320 ci engines), a worn distributor, a gear driven generator that wasn't charging, vacuum leak, weak starter, and a bad miss. Other than that, the car ran fine.
Obtaining parts for these cars takes patience and a lot of phone calling. Also, I have found that having part numbers and photos can save a lot of wasted time and money. I drove this car before buying it, and even with all its ills, it ran at 65 mph and was great fun to drive! So, we reluctantly started repairs, knowing it would be months before it could go back together.
Before we started, I wanted to know more about these engines. This is the same engine that is in our '37 Super 8. In 1936, Packard called the 320 ci engine its Standard 8 and its 384 ci the Super 8. In 1937, the 384 was dropped and the 320 was then called the Super --same engine, different name. The 320 is a 3-piece engine consisting of a cast iron block, aluminum crank case, and a cast iron head for low compression and aluminum head for high compression. The high compression head has "HC" stamped on it. It is a 9 main bearing engine with 16 valves and a 2 bbl downdraft carburetor (type EE-23). In 1935, Packard began using the new insert bearings, replacing the babbit type. In November of that year, they made an endurance run of 15,432 1/2 miles at the Packard Proving Grounds-the most severe test ever put on a car to that date. The engine held up beautifully, showing almost no wear to any moving part! With that kind of reputation, we wanted to get our old Packard back into condition, so the work began.
The dash had been pulled for new woodgraining, so the gauges had been rebuilt and rewired. The problem with the charging system was in the generator. To compound the problem, the voltage regulator was mounted on the firewall instead of being correctly mounted on top of the generator. We shipped the generator off for repair, where three new brushes were fit, the armature turned, field re-wired and a generator top-mounted voltage regulator installed. This took 6 weeks, in the middle of the UPS strike, during which time the package disappeared for several weeks!! It was finally found, but what a nightmare!
The starter was turning slowly, so it was rebuilt. The vacuum leak was caused by the ball-valve on the drip tube on the intake manifold. This is a tube that allows excess gas to drain off and exit at the end of the tube through a ball valve when the engine is off. With the engine on, vacuum pulls the ball bearing into its seal. Our problem was that after 60 years, it didn't seal. A new one had to be fabricated. The carburetor was rebuilt and the choke (mounted into the exhaust manifold) calibrated. Our distributor is a single-point Delco, replacing the original dual-point Autolite. It was rebuilt as was the vacuum advance.
The exhaust manifold had 4 ears broken off and had to be repaired or replaced. Since a new one must be custom made at a cost of $1350, and takes several months to complete, we decided to repair ours. It was sandblasted, powder welded and re-surfaced. The re-surfacing was done carefully, taking off only enough for a good, straight surface. Too much would create mis-alignment with the intake manifold which bolts to the top of it. With all these external parts repaired, we removed the head for a valve job.
After removing the 27 stud nuts, the head was ready to come off. We carefully tapped it was a rubber hammer, it came loose and was removed, then all the studs were pulled.
When the head was removed, we used a valve spring lifter for L-heads (ours is a K-D Tools, part #700 for L-head engines, available through most parts stores). We were careful not to let the valve keepers fall down inside the engine. Then we removed the valves and inspected the seats. Two had hairline cracks and had to be replaced. The good news is that Chevy V-8 seats will fit! To test the valves for seating, we put a couple of dabs of "blueing" around the seat part of the valve, put it in the valve guide and spun it around. Pull it out and wipe off the blueing, then put it back in and the blueing on the valve will show where it is seating. Ours were not seating, so all had to be ground at 45 degrees to match the new valves.
With the valves out, we checked the valve springs for correct spring pressure, We found a tool for this at our local parts store, Closed pressure is 68-78 lbs. @ 3-1/16", and open pressure is 154-164 lbs. @ 2-9/32". We also magnafluxed between each valve port and found no cracks. All surfaces were cleaned using Scotch Brite pads and wiped with mineral spirits. WE are now ready to start putting everything back together. Next month, we will let you know how it went. See you then.