Ignition Timing - Lets get technical

[Schmieder]

http://www.diy-efi.org/gmecm/papers/plug_cuts.html

That is very interesting, thanks. I know how to read plugs but I still referrence a chart. But I never thought of pulling a WOT high load run and then immediately turning off engine to preserve material on the plug. For later inspection when cool to see piston material on the plug.

Thats a neat trick I won't forget, thanks.

One thing you may be able to help with, I have a noticable pink burn on the ground electrodes (old plugs) and it doesn't seem to match anything in my plug reading chart. It is a very distinctive pink and appears to be burned into the electrode rather then stuck onto the surface.

edit: Does this mean my timing is too advanced if there is burnt pink on the ground electrode? Most timing I have is 38 at the peak of the map, 12-8 under boost.

[robertisaar]

"Manganese leavs a pink residue which can be a ground path and cause misfires"

ideally, you'll use new/cleaned plugs every time you do a plug cut.

and bruce plecan was the man... he has done more for the DIY EFI community than anyone else ever will.

[pocket-rocket]

There is one cut I have that isn't on that chart. What does it mean when you pull a plug and the center electrode is missing?

[robertisaar]

missing as in fell out or blown out? blown out would say detonation, and fell out would say either a factory defect, or the metal/porcelin got so hot it unbonded and fell out... that could be caused by a few things though.

[pocket-rocket]

I've no idea where it went, so I have no clue if it fell out or was blown out. If I had to guess since the car sounded like a hat full of buttholes when it ran, it was detonation because it for sure wasn't running on all 6 cylinders. This being the same car that looked like someone baked about 1/4" layer of oil on the insides when I went to do a LIM gasket job... No, this car is no longer around either. I dunno why...

[Schmieder]

"Manganese leavs a pink residue which can be a ground path and cause misfires"

ideally, you'll use new/cleaned plugs every time you do a plug cut.

and bruce plecan was the man... he has done more for the DIY EFI community than anyone else ever will.

Manganese is in or on piston rings, correct? Where else could manganese be entering my cylinder chambers?

Is it common to have a little bit of pink on the tip of the ground electrode? Or is it a sign of something I need to take care of?

I read a lot about reading spark plugs. Even how the brown ring on the porcelin can indicate timing being too much, too little or just right.

A lot of questions, I know. This is all very educational for me. I'm sucking all this info up like a sponge. Thanks guys.

edit: I decided to gap my plugs to 0.045" and the misfires at 6-8psi are gone. No more false knock either, so that is a relief.

Would there be any benfit from an aftermarket, more powerful ignition system? Or is the GM HEI strong enough as I know they are the more powerful ignition systems on the market today.


On another note, I have an idea I would like to try out on a test engine. The idea is to construct a tesla coil spark plug. Instead of requiring a ground electrode, the arc would travel out in all directions. Igniting the air/fuel mix in all areas of the combustion chamber instead of at the ground electrode. The difference, in theory, would be a faster and more complete burn.

I'm sure you guys seen a Tesla Coil in action. Imagine that action inside the combustion chamber. I can not see how it would not work wonders for power, emissions and economy.

Opinions, advise, ideas....discussions

[pocket-rocket]

Manganese is in or on piston rings, correct? Where else could manganese be entering my cylinder chambers?

Is it common to have a little bit of pink on the tip of the ground electrode? Or is it a sign of something I need to take care of?

I read a lot about reading spark plugs. Even how the brown ring on the porcelin can indicate timing being too much, too little or just right.

A lot of questions, I know. This is all very educational for me. I'm sucking all this info up like a sponge. Thanks guys.

edit: I decided to gap my plugs to 0.045" and the misfires at 6-8psi are gone. No more false knock either, so that is a relief.

Would there be any benfit from an aftermarket, more powerful ignition system? Or is the GM HEI strong enough as I know they are the more powerful ignition systems on the market today.


On another note, I have an idea I would like to try out on a test engine. The idea is to construct a tesla coil spark plug. Instead of requiring a ground electrode, the arc would travel out in all directions. Igniting the air/fuel mix in all areas of the combustion chamber instead of at the ground electrode. The difference, in theory, would be a faster and more complete burn.

I'm sure you guys seen a Tesla Coil in action. Imagine that action inside the combustion chamber. I can not see how it would not work wonders for power, emissions and economy.

Opinions, advise, ideas....discussions

Multiple points of air/fuel ignition would probably be a bad thing. Besides, then you would need 6 of them to run each plug individually because a distributor won't work in that kind of application, unless you tried to get an ICM to run 3 of them and still ran it like the DIS.

[Schmieder]

Multiple points of air/fuel ignition would probably be a bad thing. Besides, then you would need 6 of them to run each plug individually because a distributor won't work in that kind of application, unless you tried to get an ICM to run 3 of them and still ran it like the DIS.

I think you may be misunderstaning what I am saying.

A tesla Coil arcs all over the place from one source dome. It's basically an ultra high voltage that disperses towards anything in its radius of reach. In the cylinders perspective, that would include the cylinder walls, piston, valves, head, ect.

It would fill the entire chamber with millions of arcing voltage like a dense 3d spider web. Igniting the fuel at every location which would create a much stronger pressure in relation to fuel used. The timing would also need to be much closer to TDC.

All that is needed is one tesla coil device, a spark plug modified to have a dome emitter like a regular Tesla Coil and a distributor capable of isolating the ultra high voltages to each spark plug commanded. Insulating the spark plug wires would require serious insulation and I believe the electronics would need curcuit protection from such high voltage spikes and other electromagnetic effects.

But it is just an idea so far. Building a home made Tesla Coil isn't too hard. I may try experimenting on a lawn mower engine.

[robertisaar]

the manganese quote was from the bruce plecan doc, classified as an additive.

[pocket-rocket]

I think you may be misunderstaning what I am saying.

A tesla Coil arcs all over the place from one source dome. It's basically an ultra high voltage that disperses towards anything in its radius of reach. In the cylinders perspective, that would include the cylinder walls, piston, valves, head, ect.

It would fill the entire chamber with millions of arcing voltage like a dense 3d spider web. Igniting the fuel at every location which would create a much stronger pressure in relation to fuel used. The timing would also need to be much closer to TDC.

All that is needed is one tesla coil device, a spark plug modified to have a dome emitter like a regular Tesla Coil and a distributor capable of isolating the ultra high voltages to each spark plug commanded. Insulating the spark plug wires would require serious insulation and I believe the electronics would need curcuit protection from such high voltage spikes and other electromagnetic effects.

But it is just an idea so far. Building a home made Tesla Coil isn't too hard. I may try experimenting on a lawn mower engine.

I don't think you quite get what I meant with the first line of my response. Think of it like preignition from hot spots. Multiple flame fronts colliding with each other probably wouldn't be the best thing for parts like pistons. Besides, trying to run a 1 million volt spark through something like a distributor just isn't going to happen reliably unless the rotor were about 1 foot in diameter. I know how Tesla coils react and how they work. I've researched them for some time now and want to build one of my own. I'm not trying to be mean, but I don't think they really belong in an automotive environment.

[Schmieder]

I don't think you quite get what I meant with the first line of my response. Think of it like preignition from hot spots. Multiple flame fronts colliding with each other probably wouldn't be the best thing for parts like pistons. Besides, trying to run a 1 million volt spark through something like a distributor just isn't going to happen reliably unless the rotor were about 1 foot in diameter. I know how Tesla coils react and how they work. I've researched them for some time now and want to build one of my own. I'm not trying to be mean, but I don't think they really belong in an automotive environment.

Ah, you aren't being mean, no worries. Just tossing a thought out there. I see what you mean now about multiple flame fronts impacting each other.

It gave me an idea, a what if so-to-say. What if we were able to have the fuel ignite in a disc like fashion instead of a single point. The flame front, in perfect conditions, would push down evenly across all areas of the piston. Versus the flame front spreading in all directions.

But how could we ignite fuel in such a way?

I like invetive theories...

[robertisaar]

I see what you mean now about multiple flame fronts impacting each other.

i believe that's the exact definition of pre-ignition actually...

[Schmieder]

i believe that's the exact definition of pre-ignition actually...

Hmmm, I conjured a device to create controlled pre-ignition. Never will be used in a casual car but it may be a good device to have when researching materials, engine construction, piston strengths, tolerances, ect.

Now back to the disc ignition. That may actually work well if we could just find a way to ignite the fuel evenly at the top of the chamber. Imagine if there were thousands of miniature spark plugs that lined the cylinder head inside the combustion chamber. All the power generated from the combustion would push down more evenly across the piston top, instead of more force towards the center of the piston?

I like thinking out of the box.