 |
PM |  | |
Quote | | |
Reply | | |
Full Topic | |
| Joined: | 05-01-2005 |
| Location: | Minneapolis, Minnesota USA |
| Posts: | 575 |
| Status: |
Offline
|
Either will allow you to adjust the static timing, one just allows more change than the other.
The slotted screw head loosens/ tighten's the clamp's grip on the distributor. Loosen it, and you can spin the distributor in circles... ignoring details like the vacuum capsule (when fitted) and the cap's spring clips interfering with things.
The Nyloc nut on the stud allows something like (?) 10 degrees of adjustment. The mating hole in the distributor clamp is a slot that allows a limited range of motion. If the timing is basically right, and you just want to make a small tweak, loosen the Nyloc nut.
If you're starting the timing process from scratch, loosen the Nyloc nut and set the clamp's position so that the stud is roughly centered in the slotted hole's width. Tighten the Nyloc nut. Then do your timing by using the slotted screw to loosen the clamp's grip on the distributor. When you're done, the slotted hole/ Nyloc nut will allow a small plus or minus tweak of the timing without loosening the clamp's grip via the slotted screw.
Before loosening the slotted screw, remember that the distributor is spring-loaded outward. Grasp the end of the distributor cap in the palm of your left hand, and apply inward pressure to the distributor before loosening the clamp. Maintain that inward pressure until you're done adjusting the timing and have re-tightened the slotted screw/ clamp.
When you loosen the Nyloc nut on the stud, the distributor clamp maintains it's grip on the distributor... it doesn't let go, and the spring doesn't pop the distributor out of the oil pump housing. The slot only allows small adjustments, but it's the easy, convenient way to go. For larger adjustments, or initial set-up where more movement will probably be required, you will probably need more than the small bit of movement allowed by the slotted hole, so apply inward pressure and resort to loosening the clamp via the slotted screw.
Back when my 907s had to pass an annual emissions test, I'd set the stud to the far left end of the slotted hole... which means turn the distributor & clamp clockwise (advance) until the slot bottoms out against the stud, then tighten the Nyloc nut. Then I'd loosen the clamp and adjust the timing to exactly what I wanted.
That way, when it was time to go in for an emissions test, I'd loosen the Nyloc nut, rotate the distributor counter-clockwise until it clunked to a stop when the stud hit the right end of the slot. That retarded the timing by about (?... faulty memory) 10 degrees. After the test, I'd loosen the Nyloc nut, rotate the distributor back clockwise until it clunked to a stop when the stud hit the left end of the slot, and tighten the nut. Easy. I could do it in the dark.
The slot width gave a convenient two-position setting...
1) Counter-clockwise to the stop = emissions test, and...
2) Clockwise to the stop = normal driving. The timing was carefully set in this position, and was what I wanted. Then the slot width gave me whatever it gave me for the emissions test, it was enough, and I wasn't too fussy.
If you don't have to pass an emissions test, then center the stud in the slot before you time via the screw & clamp. Then the slot will facillitate any small plus or minus timing tweaks you may wish to make later on.
Make sense?
Regards,
Tim Engel
Last edited on 07-05-2019 09:05 pm by Esprit2