DYNA III ignition: why a 'F' in the timing hole at idle?

[Rohls]

Whelp, got a new condenser and going to try that this morning. Appreciate this forums help as usual. To be continued...

[PITAPan]

Whelp, got a new condenser and going to try that this morning. Appreciate this forums help as usual. To be continued...

The points gap is critical*. But just going for spark and basic debugging, ballpark will do. You use a dwell meter to completely nail it later.

With points you set the timing with a static light (always carry one anyway). You only use the strobe for checking the operation of the advance unit. So you can put it away until last thing on the final tune.






*kinda. Lot more to this as far as what matters, what you can get away with and do just fine, and why you want, or don't, a lot of accuracy.

[Kurt in S.A.]

The condenser uses it's case as it's reference plane---ground. There is only one wire. it's important to know it must be grounded to work---clean mounjting and all that. The diagram establishes a convention for this with the ground symbol at the plugs. But you don't want someone going and looking for the other wire

Guess there are dozens of pictures of the Kettering ignition system on the web that are wrong, too. Some of the diagrams simply show connections, some show actual wiring. Certainly there's nothing technically wrong with Duane's diagram...maybe the reader assumes since he's shown actual components, such as plugs, coils, etc., the extension is that all of the connections shown are also physical items, ie wire, as opposed to a path. You said "functionally" wrong...maybe that's your point. But really, it doesn't matter does it?

Edit: Duane didn't actually draw a condenser...he drew an electrical diagram representation of a condenser. Therefore, he's going to have to have "lines" attached to the item. He also doesn't physically show the points either, but more a wiring diagram notation.

If someone takes that diagram and begins looking for the other wire, they better step back from the voltmeter and wrenches and call a guru!

Kurt in S.A.

[PITAPan]

The condenser uses it's case as it's reference plane---ground. There is only one wire. it's important to know it must be grounded to work---clean mounjting and all that. The diagram establishes a convention for this with the ground symbol at the plugs. But you don't want someone going and looking for the other wire

Guess there are dozens of pictures of the Kettering ignition system on the web that are wrong, too. Some of the diagrams simply show connections, some show actual wiring. Certainly there's nothing technically wrong with Duane's diagram...maybe the reader assumes since he's shown actual components, such as plugs, coils, etc., the extension is that all of the connections shown are also physical items, ie wire, as opposed to a path. You said "functionally" wrong...maybe that's your point. But really, it doesn't matter does it?

If someone takes that diagram and begins looking for the other wire, they better step back from the voltmeter and wrenches and call a guru!

Kurt in S.A.

Who is looking at that diagram, and why?

[Kurt in S.A.]

The points gap is critical*. But just going for spark and basic debugging, ballpark will do. You use a dwell meter to completely nail it later.

I'd like to expand on critical* as I see it. I see people get so hung up on setting the gap and then never coming back to reconsider that setting. Duane's said it before...he might have it on his site. Gap is only critical on a more than 2-cylinder engine. For our boxer engines, I've come to understand that the only thing you need "some" gap. Too much and you get a weak spark because the coils don't have time to saturate with the flowing current. Too little and the coils can begin to heat up because there's no balance between saturated and unsaturated. But just right...is just right!

I suggest the following:

- set gap to the nominal value
- set the points backing plate in the middle of it's rotation
- check timing
- if off, see if rotating the backing plate will fix it
- if not, reset the backing plate to the middle and change the gap
- a small gap change makes a huge change in timing
- go back to rotating the plate

Don't think you have to hog out the holes in the backing plate...not the right thing to do. You have two degrees of freedom and they need to be worked together to get there.

Kurt in S.A.

[Kurt in S.A.]

Who is looking at that diagram, and why?

I'm not sure...you said "But you don't want someone going and looking for the other wire." The only reason someone would be looking for a wire is if they looked at a diagram. That's what I got of your statement. If they were looking at a condenser and had never seen the diagram, they wouldn't be looking for a wire.

As to why...you got me there.

Kurt in S.A.

[PITAPan]

Who is looking at that diagram, and why?

I'm not sure...you said "But you don't want someone going and looking for the other wire." The only reason someone would be looking for a wire is if they looked at a diagram. That's what I got of your statement. If they were looking at a condenser and had never seen the diagram, they wouldn't be looking for a wire.

As to why...you got me there.

Kurt in S.A.

if you don't know why someone is looking at the diagram, how do you know who they are (in terms of what they know), what they are looking for and what they are likely to get out of what they see? You can make a diagram many different ways. What you chose to do depends on what you perceive as your audience and their needs.

[Kurt in S.A.]

if you don't know why someone is looking at the diagram, how do you know who they are (in terms of what they know), what they are looking for and what they are likely to get out of what they see? You can make a diagram many different ways. What you chose to do depends on what you perceive as your audience and their needs.

So how do you go about making diagrams on websites for the interweb traffic? The audience is all over the map and so are their needs. If you're writing a physics text book or preparing notes for EE 101, you have a much better perception of the audience and needs. The internet is both a curse and a blessing, depending on where you stand.

Kurt in S.A.

[PITAPan]

The points gap is critical*. But just going for spark and basic debugging, ballpark will do. You use a dwell meter to completely nail it later.

I'd like to expand on critical* as I see it. I see people get so hung up on setting the gap and then never coming back to reconsider that setting. Duane's said it before...he might have it on his site. Gap is only critical on a more than 2-cylinder engine. For our boxer engines, I've come to understand that the only thing you need "some" gap. Too much and you get a weak spark because the coils don't have time to saturate with the flowing current. Too little and the coils can begin to heat up because there's no balance between saturated and unsaturated. But just right...is just right!

I suggest the following:

- set gap to the nominal value
- set the points backing plate in the middle of it's rotation
- check timing
- if off, see if rotating the backing plate will fix it
- if not, reset the backing plate to the middle and change the gap
- a small gap change makes a huge change in timing
- go back to rotating the plate

Don't think you have to hog out the holes in the backing plate...not the right thing to do. You have two degrees of freedom and they need to be worked together to get there.

Kurt in S.A.

You have gotten into massive fussing and fooling around and going back and forth looking for where it is right. The idea is NOT to do all this.

try this:

-Set the points gap to the exact value, per specification.

-rotate the points plate so the static timing is on the correct flywheel mark.

-walk away.


Yes, there is plenty of leeway in the points gap. This is good to know if you have to do a roadside repair. But it's not something you want to invoke during a regular tune-up in the driveway.

Going dead on spec. with a dwell meter doesn't serve this tuneup as much as your next one. You don't have to keep track of what the gap was set to, you know what it was because it was on spec and that is marked on the face of your dwell meter. A sliver of electrical tape works well. You could record a given previous setting in your log and look it up come tune-up day and then reproduce it---but you are back to fussing.

On tuneup day you check your timing with the static light. If it's right you are done and move on with your under-the-cover lubrications and inspections. If it is not right it is because your points faces and/or rubbing block has worn. This changes the gap and thus the timing. If visual inspection of the points faces indicates they have life left, you clip on your dwell meter and reset the gap to the line on the meter face. You don't even have to remember what that value is. Check the timing again and you will find it is correct. The points plate doesn't tend to move---if it does you will know all about it long before tune-up day!.

You are after speed and simplicity and clipping on a dwell meter and test light is as quick and simple as it gets. You use feeler gauges or a setting tool once (and the cleaning routine they demand) when you replace the points, and not again until you replace them again. No fiddling.

I might check the advance operation with a strobe once a year. But if it's running well I often won't bother at all. Advance problems will announce themselves and can be corrected then. It's not something that creeps up and hoses mileage and performance gradually like your timing getting off from points wear or your air filter clogging up.

Lubing the points cam and advance happens always at tune-up as well as inspecting the alternator commutator and brushes and sometimes cleaning them. Then you button it up and move on to the carbs if they have been telling you that they want adjustment. Otherwise tune-up is done and you go off for a ride or do scheduled inspections and maintenance per mileage/time. There can be a lot to do and most of it is very quick if you work from an organized checklist.

[PITAPan]

if you don't know why someone is looking at the diagram, how do you know who they are (in terms of what they know), what they are looking for and what they are likely to get out of what they see? You can make a diagram many different ways. What you chose to do depends on what you perceive as your audience and their needs.

So how do you go about making diagrams on websites for the interweb traffic? The audience is all over the map and so are their needs. If you're writing a physics text book or preparing notes for EE 101, you have a much better perception of the audience and needs. The internet is both a curse and a blessing, depending on where you stand.

Kurt in S.A.

The interwebs might contain almost everybody but the diagram itself serves as a filter. Some will glance at it and move on quickly while others will print it out and head out to the shop. You design the thing with your user in mind. Do they need to know what's where? What connects to what? What's happening inside the Black Box? What things are called?

The diagram contains different kinds of information--connectivity information (schematic) and layout information (what's where). And then for each you might have varying levels of detail. Duanes diagram shows the wiring and connectivity inside the coil. It lacks the coil terminal numbers. Another diagram might only show the coil as a cylinder with wires coming in and out. Some diagram may have all the inline connections, wire colors, relative position and shapes of components, indications of protective sleeving, wire looms, places where wires pass through casings or are bundled, etc. Yet another diagram might be a pure schematic with no indication of even the physical boundaries of components.

A diagram that is heavy on layout information can form a cognitive bridge, as it were, between the abstraction of the pure schematic and the concreteness of the mess in front of you. But it can also be overly detailed and confusing. Using linked sub diagrams can resolve this.

In all cases you begin with your user in mind--and you decide who that is going to be. Then you just try to deliver. You also shoot for consistency in the level of detail and abstraction---just good practice.