I think I installed my distributor right but after reading all these post about how it can run and seem right one tooth off, but not run great, it's got me curious. How could this be? As long as you can turn the dist. base to far enough to advance the timing to say 8 degs advanced or whatever, how could the computer possibly know that this is one tooth off? Or maybe the base can't turn far enough to advance the timing properly with the distributor being a tooth off? Can you set your timing properly at all if the dist shaft is 'one tooth off'? Am I missing something here? How can you verify that your on the right tooth? For instance, say you rotate your engine to TDC on the compression stroke. Couldn't you then install the distributor shaft to any position, then install the #1 plug wire to the corresponding spot in the cap that the rotor is pointing to, and then set the timing? Would this somehow be wrong? If so, please explain.

Your thinking is entirely correct. The "one tooth off" old mechanics tale is just that, a tale. As long as the timing is set right, does not matter what tooth the distributor is on or not on.

Thanks for your affirmation. Makes absolute sense to me. About once a week, someone on here will say to somebody with running problems, "maybe your distributor is one tooth off". Most of the time, it's after that person has stated what degree advanced their timing is set at. Always made me scratch my head.

And as an aside, is anybody else getting tired of people calling them a "dizzy"?

Snoop-dog called and he wants his lingo from 10 years ago back! lol

It's better than a Dissed Tributor

i like saying dizzy, its faster than typing distributor. And it wouldnt matter if your dizzy is off a tooth, as long as you can get at 6 degree BTDC. But if its hard to advance it, because of the wires clearance, then i may be a tooth off. Its possible to set the dizzy 180*degrees off.

if you stab the dist. one tooth off on a vacuum advance car it is possible to spark the next cylinder. its not bs, its just old school mechanic sh!t. guys with computers typically don't have to worry about this, because to a degree the computer wil compensate.

someone PLEASE help. 85 305 TPI. Just bought ACCEL "dizzy" with cacuum advance (when stock is elec. advance) and I can't edjust it far enough to start it and I know it's at least a tooth off or right at a tooth. it hits the fuel rail. what is this i hear that u can point a dist. in any direction as long as TDC is good and plug wires go in corresponding places on cap? so does that mean that my dis. can point in any direction as long as rotor is toward 1 on cap and wires are good? it don't have to be facing the "factory" direction it does. cause if that's the case than maybe I can make this vacuum ACCEL diz. work. please PM ME IF POSSIBLE. thank u and God BLess All.

What you said is , truth be told.

With a vacuum advance engine, at worst you won't be able to set the timing properly because the advance can is hitting something.

Computers won't compensate for improperly set timing. You still need to set the "base" timing, but with no vacuum can to hit anything, you're only limited by the stretch of the harness to the distributor.

well my stock one is elec. advance and this new on is Accel vacum advance but that shouldn't matter right as long as I find a way to turn it enough to start and tune, right? thank you

You can't use a vacuum advance distributor with TPI.

lmao, can you say EST codes? your computer wont like it at all!

ya dude, it has to be computer dizzy, HAS TO BE. or no go, not even with the best technique. vacuum advance = ghetto

you can stab a distributor one tooth off, been there done that. car ran like sh!t. if you put it one tooth advance then you will spark the next cylinder on the cap while trying to advance your timing. and switching up where the wires are isnt going to help that. like i said its old school sh!t. one tooth off may sound insignificant, but the details will kill you.

No you cant.

it can, been there done that. seen it work. if you don't want to believe it more power to ya, form your own opinions.

Its not an opinion its a fact.

The distributor has 2 parts that move in relation, the shaft (along with the lower gear, reluctor, weights if equipped, and rotor) and the base, along with everything that is attached to it. So if you can explain how moving one instead of the other makes any difference other than "seen it work" I'm sure someone would like to hear why.

now if you put on a cap and have the damn thing one tooth off, what would happen. trying to achieve the proper advance on a vacuum advance dist. would put the rotor sparking on the next cylinder (terminal on the cap). which would cause a misfire. advance the shaft one tooth, and that would put your timing where it needs to be. if you don't believe me go retard or advance your dist. by restabbing it one tooth off, and check it with a timing light. the difference will show up, yet your rotor won't be all the way to the next terminal. i really don't care if you doubt what i have to say, because as i've said i've seen it happen.

All you have to do is turn the cap to where the timing is correct. The distributor does not know and does not care if you turned the top half or the bottom half. It is that simple. If you pull it and move it a tooth and restab it, then turn the cap 28 degrees (360 degrees/13 teeth) and its now fine again.

So if what you're saying here is true, how could you possibly set your timing to the proper advance? Installing a dist one way or the other doesn't make the rotor wider so it wouldn't be able to spark two plug wires at a time. So if your timing light shows 8degs advance (or whatever spec your after) with the timing light on the #1 plug wire, your timing is set. There is no way that your #1 cylinder could be firing at the correct time and would also be "sparking on the next cylinder". For that to happen, the rotor would have to be wider.

No one who has said that the dist CAN be one tooth off has been able to explain how your ignition system, or any other system for that matter, could possibly be able to tell what tooth the dist is set at, if the timing events are allhappening at the correct time.

To put a finer point on what I just said, on a V8, the rotor must turn 45 degrees before it can fire the next cylinder. This event happens 45 degs apart no matter where the base is or what your timing is set to. So if your #1 cyl is firing 8 degs advanced, so is #2, #3, and so on.

i never argued that fact. all that i was saying is that if you are one tooth advanced, it is possible for the spark to jump to the next terminal and not where its supposed to be after you add in the initial timing(ie, supposed to spark on 1, instead spark jumps to cyl. 8). the only way the rotor could be that close is while trying to achieve the correct base timing a tooth off. if you back it off one tooth you get the room and can set the proper base without having this issue.

I'm sorry but that makes absolutely zero sense to me.

There is no more or less room between the contacts in your dist cap no matter where your distributor teeth are. IF your distributor is set so far off that you can't set the timing to spec, then you need to reset your distributor teeth, or move your wires. But as long as you can set base timing properly, by what means does any part of the car, whether in the ignition or computer, know where the timing teeth are? Is there a proper orientation to where the #1 plug wire must be located on the cap? Or must the rotor only be set to point to the spot on the cap where your #1 plug wire is connected and be able to set the proper base timing?

From what you seem to be saying, you can set your base timing to the proper spec, and you computer somehow will say "the wrong teeth on the dist shaft are touching the wrong spot on the cam gear. So I'm going to try to correct that" and this will cause it to spark on the wrong cylinder.

I hope you don't misread my tone as being snide or something. I'm not trying to be that way. But I've never believed that you can be "one tooth off" but I've heard it around here like once a month at least and for years. I'm willing to listen if anyone can tell me how it works and why it would be. I definitely haven't heard it yet. The computer can't even tell where the base timing is set on a TPI (and many others). So how could it know what orientation the dist shaft is? And why would it matter?

*I've already said in 2 posts that i'm talking about vacuum advance distributors.* but even in your post you mention restabbing the distributor. like you said as long as base timing can be set correctly then it doesnt matter, i'm just saying that nothing is out of the realm of possibility. and yes moving the plug wires would help, but wouldn't moving the drive gear/rotor one tooth accomplish the same thing. its just another way to skin a cat.

Perhaps you're trying to say the same thing I said - if off too much, you can't turn the distributor body enough (because the vacuum can hits something) to get the rotor to line up with the proper spark plug terminal. But, all you have to do in that case is move the spark plug wires over to the next terminal.

Regardless, "one tooth off" isn't the issue if the car doesn't run right. Having the rotor line up to the proper spark plug terminal and getting the timing set is all that really matters in the end.

As an "old timer" I can straighten out this "one tooth off" thing, OK?
This is how it got started.
Before you pulled the distributor you would mark the flange at the bottom of the dist. and put a mark on the intake so when you put the dist. back in, you would have it in the same location as when pulled. Some shade tree guy's when they did this wouldn't pay any attn. to where the rotor was pointing by marking on the edge of the dist to get the rotor pointing in the same location as when pulled. Most people make sure that the rotor was pointing at #one tower at TDC before pulling the dist. So, if you pulled the dist. without marking the edge and just tried to get the rotor back where you thought it was pointing and missed, you were "one tooth off"
so now, you know how it started! The moral of the story is, "always get the rotor on #one tower before pulling the dist. even when you mark the base and intake" The only thing that can be one tooth off is a timing chain that has jumped. LOCK THE THREAD! SQZBOX

about damn time some sense came of this!

Sounds right to me.

Thanks everyone!

THIS is what I've always considered 'one tooth off'. It was one tooth off because the distributor couldn't be turned far enough to obtain correct timing.

And, in my opinion, the distributor had to be re-set to 'look' right! Vacuum can or not. Moving the wires was never an option!