Re: 1948 Packard 22nd Series Six Touring Sedan Backfiring and lack of power

Posted by Fred Puhn On 2012/9/6 11:05:07

I suggest you check the items I listed in order listed.

The ignition timing requires finding the mark on the crank damper and clearly marking it with white paint, chalk, or something with contrast. If you have a timing light you can start the engine and see if the timing is in the ballpark at idle. Check your owners manual or shop manual for specs. It should be a few degrees before top dead center (TDC) If you do not have a timing light just turn the engine with a wrench on the crank damper bolt and with the ignition on and the distributor cap off see when the points break. Look at the timing mark and see if it is close to spec for static timing.

The spark plug wires are easy to check. Note which way the distributor rotor turns when you crank engine. Find the plug wire on the distributor connected to spark plug number one. Then write down the order that the plugs fire at the rotor turns around. Check your owners manual or shop manual for the firing order and see if the car matches that. If not rearrange the plug wires. Usually there are only two wires interchanged because the car would not start if many of them are wrong.

A broken crank or jumped timing chain are a lot less likely than the two ignition issues, so don't worry about that right now.