Advance Setback...

The wife and I drove Nell to a meeting at church this evening.  I knew something was wrong as I pulled out of the driveway.  There just didn't seem to be much power!  During the entire 5 miles to church, I kept thinking "something just isn't right!"  It was bogging and lagging, and I couldn't go much over 50 on the freeway.  The car ran great yesterday... what could be wrong now?

By the time we got to church, I could smell burning plastic.  Nell was idling too low, and seemed ready to stall.  I pulled into a parking lot and opened the hood... the tach cable casing had melted where it goes over the battery heat shield.  This has never happened before... the heat shield was HOT... so were the exhaust manifolds... really hot!

Well, we went to the church meeting, figuring that Nell could probably get us home again.  She did, but it wasn't a fun ride.  The engine bogged terribly, and backfired under load if I gave it more than half-throttle.  I was grateful to get home without incident, and back Nell into the garage to cool down.

I suspect that the advance mechanism on the mechanical advance Mallory Unilite distributor has somehow failed.  It is a racing model with no vacuum advance, so it may not be advancing at all.  All the symptoms point to this.  I will check on repairing the distributor, but I may also be interested in replacing it with a '57 vintage Ford/Mercury tach drive distributor.  Having a vacuum advance will make the engine run cooler at idle, and will improve fuel economy a little.  Unfortunately, these distributors are rare and expensive... I've been looking for a good deal on one for almost two years!

I'll give the Mallory another chance... tomorrow I'll check the advance with a timing light.  If so, I'll pull the rotor and see if there is anything obviously wrong with the advance mechanism, like a broken spring or something.  If not, I may be going shopping.

Update 9/30: I checked the timing with a timing light, and it was all over the place.  I pulled the cap and rotor off the distributor, and found that the backing plate (underneath the advance mechanism) could be moved back and forth about 10 degrees!  This is not good, and indicates to me that something important has come loose inside the distributor.  I'm hoping that the pin holding the drive gear to the shaft didn't shear off, because that means there is probably a little piece of metal rattling around inside the engine! 

I plan on pulling the distributor weekend after next... this weekend I am taking a group of Boy Scouts on an Astronomy campout.  In the mean time, I'm looking for a '57 tach drive distributor!