Re: Vacuum Advance unit

Posted by Bowman Davis On 2009/10/26 18:35:12

Jack Vines, The Distributor is OEM Packard per STB 56T-14, when they went to the Delco p/n 6489847 (Delco 1110880) to correct a reported problem of detonation due to poor quality of gasoline being suppplied at that time. The vacuum unit is also OEM. But one thing I noticed when I pulled it out of the engine, there was no gasket on the shaft or hole in the block. The manual idicates there should be gasket there, which means the distributor was removed previuosly for some reason.
I did test the distributor on the car using engine vac, timing light and dwell/tach meter. The cap, point set were all in great shape, although the gap was too wide @.019, rather than .016.
At 500 RPM (the lowest the engine would idle) the dwell was 26 degress with the timing set @ 10 degrees BTDC, (spec requires 26 to 33 degrees), I also checked the centrifigal advance and it worked when engine speed was increased. I did not do extensive testing and did not record any of the readings because I had decided to pull the distributor but first I wanted to know if everything was working. I also checked the ignition coil, plug wires, plugs, engine vacuum and compression. All tested okay and within specs.
I also made a trip to NAPA and was told theyy do not have a Delco vacuum unit and have no way to cross reference the Packard or Delco p/n's to another vendor for a replacement.