off a tooth on dizzy

[fdbdw]

Anyone know an easy way to tell if your dizzy is off a tooth, I can only get about 8 BTDC then the vac can runs into the manifold, that plus some other little qurks that Im not sure are related but I have a feeling its off a little, Is there a way to tell without re-stabbing it

[STOCKISH]

Roll the engine to TDC on #1 cyl. LIne up your balancer and timing pointer. Then take the cap off and see where she points. #1 cyl on the cap should be pointing torwards the drivers side rear corner of your carb. Good luck

[fdbdw]

at numer one using the finger over the plug hole method the rotor points front left about the 4 o-clock postition I now its close just mabe off a tooth or two I dont mind pulling it, turning the oil pump a hair and restabbing it, just didnt know if there was a way to tell for sure when its lined up right

[fdbdw]

sorry read it fast and thouth it said rear corner of the cab, Ya its not anywhere close to pointing at the carb

[Gary 70 Jimmy]

Just move every spark plug wire back one on your cap this will give you more room to turn it.

[monte0185]

Rule of thumb is usually point it to the #1 cylinder. If its off turn it counter clockwise one tooth and drop it back in. I need to do this myself. Mine is times correctly but I like the distributor to be sitting as close to even across as I can get. Just picky that way.

[americanmusc1e]

Originally Posted by fdbdw

sorry read it fast and thouth it said rear corner of the cab, Ya its not anywhere close to pointing at the carb

WATCH OUT, Remember a 4-stroke engine has 2 Top dead centers, One between the compression and power stroke(the correct one) and another between the exhaust and intake strokes. watch the valves and make sure your on the right stroke. the camshaft (and the dizzy) turn at 1/2 the rate of the crankshaft so when the crankshaft goes around twice, the camshaft only goes around once. If your rotor is waaay off, you are on the wrong TDC and the rotor is pointing 180 degrees from where it will be on the correct TDC

the 4 strokes of a 4-cycle engine
Intake down, compression up, power down, and exhaust up

if your already aware of this, I'm sorry, but I figured I'd remind you, in case you didn't know or forgot

[LONGHAIR]

Where the rotor is pointed only matters to the wire terminals on the distributor cap......Where it points, relative to anything else is completely irrelevant. Any terminal can be number one on the cap, and go clockwise from there. 18436572.
For some unknown reason, many guys think that the number one cylinder on the cap has to be the one that would make the rotor itself point toward the left front corner of the engine..."literally" at the number one cylinder. Totally not necessary. It can be anywhere

BTW, if you really just need more travel to get the timing right, it is easier to just move the wires over one space on the cap.....as previously suggested by Gary 70 Jimmy

[WorkinLonghorn]

I guess it doesn't matter much but on point ignition era Chevys I have #1 pointing at the passenger side rear carb corner as illistrated here in a Haynes manual;
Well it doesn't want to upload. But trust me,it's passenger side.

[monte0185]

Your right it realy does not matter but its what all the manuals have it as. Hence the rule of thumb. Dosent mean you have to its just the preferred method.

[STOCKISH]

I agree. You can put # 1 anywhere you like as long as you go 18436572 clockwise from there. BUT, to put it as the factory did in these v8s it should be as described above.

[D.PASSMORE]

Two correct opinions, you can put the #1 wire in any one of the terminal/holes on the dizzy as long as the engine is a TDC and the rotor lines up with the newly determined #1 terminal/hole. In the 67-72 tech manuals it shows the #1 terminal/hole as being on pass. side facing #2 cylinder.

Let me ask this, what are some of the know symptoms of the distributer being one tooth off?

[Green Machine]

In reality there are no "symptoms" of being a tooth off, in fact it does not matter what tooth is where as long as there is enough room to turn the distributor to get the timing set. Any terminal can be #1, plug wires just fit better with certain locations.

[LONGHAIR]

Yeah ^^^, the only "symptom" would be that you cannot turn the distributor body far enough in the direction you need.


As a side note: If you have the "factory" plug wire retaining ring for an HEI distributor, it does have the cylinder numbers moulded into the plastic. It puts the no.1 cylinder as the first one clockwise after the wire connection terminals.......it still doesn't matter though.

[D.PASSMORE]

Originally Posted by Green Machine

In reality there are no "symptoms" of being a tooth off, in fact it does not matter what tooth is where as long as there is enough room to turn the distributor to get the timing set. Any terminal can be #1, plug wires just fit better with certain locations.

I wonder if it would change the readings that you would see on a timing light flashing on the timing marks? That is with the distributer being one tooth off.

I had a motor that I put a new petronix fitted distributer into the hole. I couldn't get it to fire. Started to play with the timing and got it to fire and run decent, but anything over 8* BTDC the valves cattered when you put your foot into it. Set it again the TDC, set distributer, timed to 8*BTC and it ran fine. Maybe, it was something else, but I always thought it was a tooth off.
Bottom line is that its got work like you want it to when your driving it! Not sitting in the garage!

[LONGHAIR]

Originally Posted by D.PASSMORE

I wonder if it would change the readings that you would see on a timing light flashing on the timing marks? That is with the distributer being one tooth off.

No it wouldn't. The light "fires" when the sparkplug does, which is in relation to the crankshaft's rotation. Turning the distributor is how you change this relationship. The "one tooth off" thing is just a stopping point to your ability to turn the distributor. If the vacuum advance cannister didn't "hit" anything, which would limit it's rotation, then you could never be a "tooth off"

[D.PASSMORE]

Makes sense, thanks.

[PanelDeland]

I would imagine there is a reason for the "rule of thumb".The first thing that comes to mind is that the factory set the engines up that way to facilitate dropping distributors in engines on the assembly line.

[LONGHAIR]

I'm sure that you are right PanelDeland. I would bet that the factory did it the same way all of the time, if for no other reason then speed and repeatibility. I would think that they dropped in the distributor with the rotor pointed toward #6, because that is where it needs to be when the dots of the cam gear and crank gear are aligned.

[MT1972cheyenne]

If the factory wanted to do something for simplicity & repeatability, why didn't they just make it so that the rotor pointed straight back when it was at #1 TDC?
I'm kind-of being a smart**s, but really, wouldn't that make the most sense, then build the distributor cap accordingly?

[fdbdw]

took it out and moved it clockwise a tooth, vac can clears manifold, looks better, runs great, thanks