Can a distributor REALLY be one tooth off? lets discuss this...

Discussion in '1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-' started by 99FiveOh, Apr 13, 2009.

  1. Yeah, I'm sorry, you are correct, I would use my left nose picking finger. The last time I put a distributer in was on a Chevy, which requires your right nose picking finger.

  2. with ours i dont see how you could be a tooth off because if you go to time it with your light and put it to w/e u set it at be it 10* for example. There its on time. However thats not the case with all cars. I know when I built the motor on my jeep in project 4liter I got everything put together and did stab the dizzy a tooth off and took me a bit to figure it out though because timing isnt adjustable and when I started it it would start up but backfire like hell through the exhaust. Again with our cars since the dizzy can rotate 360 we can get away with it but others are different.

  3. :rlaugh:
  4. back from the dead! sorry, but i have a question about this ...

    my understanding was that the pip sent a signal to the computer, sort of like (or maybe just like?) a crank position sensor would. i imagined that this was a (if you will) "significant" event, in that it was used to know what the current crank degree is, which is involved in other calculations .... things like the TFI and how it knows when to send the spark signal based on the commanded advance, and when the computer decides to open and close the injectors based on the tables it uses after determining load and rpm and what not.

    so i would guess that if the distributor was a tooth off, the the pip signal would be sent to the computer at the "wrong" time, and the computer would do incorrect things like pulse the injectors at the wrong time, and other calculations it makes based on where it thinks the crank is.

    so are you all saying that the pip signal from the distributor does not indicate to the computer the position of the crank?

    please educate me, thanks
  5. It does, but the pip sensor vanes spin with the rotor and the sensor is stationary with the housing, so as long as its timed correctly there isn't a problem
  6. Exactly. If the car runs and is at it's correct timing then it cannot be a tooth off. If it's not timed and is not running... it isn't a tooth off either, the dizzy housing is simply turned too far out in one direction or the other or the firing order is fubared!

    Now it can be a tooth off in relation to the exact spot the dizzy housing was stabbed from the factory, usually noted by a notch in the dizzy and the block. If you want these two spots to line up again you have to play with it for a while until it's right on.
  7. Actually the dizzy can be off and the timing be right. The computer uses the dizzy to determine when #1 cylinder injector is ready to be fired. Look at the stator inside the distributor and notice one of the tabs of the stator is wider than the others. Otherwise how would the computer know which injector to fire in relationship to the cam position.

    It's really easy to determine if it is right or not though. If #1 spark plug wire is located on the distributor cap in the stock location (you know where the 1 is on top of the cap) and the timing where you want it. It is right!!!

    I didn't know this when I rebuilt the engine in my car and I moved the #1 plug wire to a different location on the cap and my car idled rough. I pulled the moved it back and it instantly idled smoother. btw I know I had the firing order right just in the wrong orientation related to the distributor housing and cap.
  8. why the heck would you ever put #1 plug on any other terminal? Every single dizzy cap I've ever seen has #1 stamped on it. Unless you're a complete moron, there's no way the dizzy can be a tooth off. If the situation is as you stated, then it wasn't a tooth off, you just had the plug wires off.

    And for the record, there is only one reluctor wheel in the dizzy, the it stands to reason that the computer uses that ONE wheel to work both spark plugs and injectors. So if spark timing is on the money then so must injector pulse timing as well. /thread lol
  9. As stated in post 10.
  10. It's not that it's a dumb move - people in the old days with carbs did it often. Old habits carry over sometimes and people don't realize the injector timing would be affected.
  11. Exactly I didn't think twice when I did it due to the fact I have done it several times on carbed cars without any problems.

    When I stabbed the distributor I couldn't get the timing set right. So I just moved #1 so that I could get my timing set without having to pull the distributor again. The car run fine other than at idle when it ran rough. I read this thread the first time around pulled the distributor and fixed it.
  12. that is the sort of thing i think i was referring to.

    so the rule is, so long as you keep the wires on the correct terminals, and you can turn the distributor far enough to get the base timing to 10, then you are golden

    obviously, if you are more than a couple teeth off, you probably won't be able to turn it enough to keep the wires on the correct terminals, at which time you need to re-stab the distributor

    either that, or it's time to get dentures! :rofl:

    now i'm on board with this, thanks
  13. That's it!!:nice:
  14. This is actually a philosophical discussion.

    Do not try to adjust the distributor gear, instead realize the truth. There is no distributor gear. Then you will see, that it is not the gear that turns, but only yourself.

  15. The distributor gear has 15 teeth so one tooth equals 24 degrees of rotation, which is quite a bit for the timing to be off.
  16. Yeah, however, you can simply turn the dizzy housing which is independent of the shaft to compensate. So it can't be a tooth off.
  17. You can, but the tfi cars it limits the swing if your running AC, and I think it would would interfere with the plenum as well. I recall the service manual calls out for the angle of the tfi. I think it was 30 degrees either from block widthwise as centerline, or lengthwise as centerline? I can't remember for sure.

    You are right though as long as it has travel and wire room it can be adjusted.
  18. Words of wisdom here:nice:
  19. Am I the only one that noticed the newcomer's avatar and that this thread is 6 years old? And this is the second time it's been resurrected? :shrug: