Here is how I modified my crank trigger so I could adjust ignition timing. This is for the 8-plug engines. I've been running this for some time now, waiting for the pictures to be developed. Probably close to 3,000 miles on it now. Thanks to everyone over the years for the chats that provided the inspiration to try it.
http://home.earthlink.net/~touring23/DIStriggerDWG.jpg
Here's how I did it:
1. Remove crank trigger (duh).
2. Weld the 2 trigger rings together, taking care not to weld to the cast iron hub nor the rivets. Just a dab or two should do as the rings aren't under any load.
3. Etch/engrave an alignment index mark on both the cast iron hub and the outer PIP ring (see photo). It doesn't matter where. Once the rings are moved this will be the only means of getting back to "zero" so be precise. I ALSO notched mine in a second spot just as a backup.
4. Drill out the two rivets.
5. This was the tough part. Separate the rings from the hub. I had to use a variety of tools and still managed to bend the rings into a taco shape. This, obviously, was not good. Leading to step 6.
6. Restore/flatten/round the rings. The outer ring should have a nominal outer diameter of 3.660 inches by my measurements.
7. Slot the rivet holes of the rings using a drill and dremel. I went ~0.25" either side, not particularly precise, enough for ~8* advance or retard.
8. Next to the alignment index on the outer ring, engrave additional timing marks. The circumference is 3.660"xpi=11.50", divide by 360* to get one degree of timing is 0.032". I couldn't be that precise, so I marked mine for two-degree increments (=0.064"). See photo.
9. Drill and tap the hub at the rivet holes for retaining screws. I chose M5x10mm fine thread screws, and was lucky enough to find a short panhead allen-key style that won't hit the crank sensor.
10. Dress the hub and the ring ID with emory paper to make adjustment easier.
11. Bolt the ring to the hub, obviously with attention to the timing marks.
12. Reinstall trigger assembly on engine, but not the serpentine pulley&belt.
13. Rotate the crank by wrench, checking for adequate clearance between the crank pickup and the crank sensor. My shop manual says the air gap should be 0.018"-0.039". Adjust as necessary.
14. When you're satisfied that there are no intereference problems with the crank sensor, go ahead and reinstall the serpentine pulley ad nauseum.
15. Remove SPOUT connector and confirm base timing.
16. Reinstall SPOUT connector.
Cheers y'all
http://home.earthlink.net/~touring23/DIStriggerDWG.jpg
Here's how I did it:
1. Remove crank trigger (duh).
2. Weld the 2 trigger rings together, taking care not to weld to the cast iron hub nor the rivets. Just a dab or two should do as the rings aren't under any load.
3. Etch/engrave an alignment index mark on both the cast iron hub and the outer PIP ring (see photo). It doesn't matter where. Once the rings are moved this will be the only means of getting back to "zero" so be precise. I ALSO notched mine in a second spot just as a backup.
4. Drill out the two rivets.
5. This was the tough part. Separate the rings from the hub. I had to use a variety of tools and still managed to bend the rings into a taco shape. This, obviously, was not good. Leading to step 6.
6. Restore/flatten/round the rings. The outer ring should have a nominal outer diameter of 3.660 inches by my measurements.
7. Slot the rivet holes of the rings using a drill and dremel. I went ~0.25" either side, not particularly precise, enough for ~8* advance or retard.
8. Next to the alignment index on the outer ring, engrave additional timing marks. The circumference is 3.660"xpi=11.50", divide by 360* to get one degree of timing is 0.032". I couldn't be that precise, so I marked mine for two-degree increments (=0.064"). See photo.
9. Drill and tap the hub at the rivet holes for retaining screws. I chose M5x10mm fine thread screws, and was lucky enough to find a short panhead allen-key style that won't hit the crank sensor.
10. Dress the hub and the ring ID with emory paper to make adjustment easier.
11. Bolt the ring to the hub, obviously with attention to the timing marks.
12. Reinstall trigger assembly on engine, but not the serpentine pulley&belt.
13. Rotate the crank by wrench, checking for adequate clearance between the crank pickup and the crank sensor. My shop manual says the air gap should be 0.018"-0.039". Adjust as necessary.
14. When you're satisfied that there are no intereference problems with the crank sensor, go ahead and reinstall the serpentine pulley ad nauseum.
15. Remove SPOUT connector and confirm base timing.
16. Reinstall SPOUT connector.
Cheers y'all