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Packard 8 Timing

Posted: Tue Feb 02, 2021 10:22 am
by Dwight Bedsole
I have a 1937 120C with a 1946 282 engine and I am trying to determine the correct ignition timing (vibration damper). Any help would be appreciated.

The !941-48 Packard Engine manual says:
1951 Clipper 7 * BTDC
20th & 21 series 7* BTDC
22 nd series 6* BTDC

The AEA Tune-Up System says:
Packard Eight 1946 2101, 2111, 5* BTDC
Packard Super 8 2103, 2106, 4* BTDC

I have included the Super 8 because I have the Super 8 distributor - Auto-Lite IGT 4203 12A8. My draft tube discharges from the crank case and not the valve cover so the engine is not a Super 8.

Thanks
Dwight

Re: Packard 8 Timing

Posted: Tue Feb 02, 2021 3:00 pm
by Dave Czirr
Honestly, I think you'd be hard-pressed to detect the difference between 5 and 7 degrees BTDC. And with the changes in gasoline since then any any changes in your compression ratio (cylinder head servicing during past years), I'd rather see you just time it for optimum performance rather than to a specification that may no longer be optimal.

I'd time it to give just the faintest, barely audible hint of spark ping on a hard pull with heavy throttle in high gear at 30_45 mph. Open the passenger window to help you hear the sound, and try to find a stretch of road with a wall or berm in the right side to help amplify the sound. And when you've found the optimim timing, put a timing light on it and record your result.

Re: Packard 8 Timing

Posted: Tue Feb 02, 2021 4:07 pm
by Dwight Bedsole
Dave, what you say makes sense to me. The fuels today have significantly different vapor pressure than the fuels that were formulated for carbureted systems. Today the fuels are made for fuel injection systems where the fuel is injected into the chamber under pressue as opposed to carbureted systems where the fuel finds it's way into the cylinder under vaccum.

Thanks
Dwight