Background info: '75, L48, original engine, original style everything.

Car had been running ok, but I recently replaced plugs and wires for maintenance reasons. Engine ran even smoother after replacement.
I checked the base timing and found it way off. Mark on the balencer is about 5 inches counter clockwise from where it should be. It's so far off, that the distributor doesn't have enough adjustment range to even get it close. It seems like I'm on the wrong spark plug wire but I'm on number 1 (drivers side front).
Just for the hell of it I tried putting the timing light on different wires and if it's on 8, the mark on the balencer is lined up around TDC of index plate.

I've tried 2 timing lights and results were the same.

Next I removed the distributor cap and cranked the engine manually with a ratched until the mark on balencer was lined up with TDC of the index plate. The rotor points directly to number 8 plug wire.

This is the first time I've checked the timing on this car so it could of been like this a while.
How could the engine even start with the timing that far off?
I would appreciate any advice on what to do about this.

Thanks,
Tim

 

i would suspect the outer ring on the balancer may have slipped, its mounted on a rubber ring, age and deterioation may have taken its toll, since its the original balancer and the car runs fine, i would look at that first. its happened to several people.
good luck.

 

Try bringing #1 cylinder around to TDC on the compression stroke and look to see where the timing mark is. A thumb or finger over the plug hole will test for the compression stroke.

 

Very common problem with late C3s, the ring has slipped.

 

 

I just confirmed that the balencer ring has slipped. I had no idea such a thing could happen.
Thanks everyone that responded.

Tim