Coil input information

[hanleyclifford]

Let's see - To do list for next trip to West Coast - 1) Drag races at Pomona (do they still do it there?) 2) A4 drag race with Dave Neptune 3) flat object skipping contest with Neil and Jerry; (not necessarily in that order).

[jpian0923]

Beat this!

[YOUTUBE]7deV22aWESc[/YOUTUBE]

[ndutton]

Waaay off topic

Pomona hosts the drags twice a year, the first and last races of the Full Throttle season. I don't go as often as I used to since they went to the 'countdown' format. Too contrived for me. I much preferred 'run whatcha brung'.

For those who recognize the name, I spent nearly every Friday night at Lion's Drag Strip in my late teens. Saw most of the pioneers of the sport race in the era of front engine dragsters and the infancy of funny cars, even saw Evel Knievel jump. AA fuel altereds were the rage back then.

Kewl video Jim. I couldn't quite make out the wires hanging off the regulator, maybe he snipped them off for streamlining.

[ILikeRust]

All this talk of skipping stones has dredged up some childhood memories.

When I was a wee lad, my grandparents owned 80+ acres of land with a 5-acre lake in the middle of it, which they operated as a swim club. It's where I learned to swim, jump off a dock, dive, fish, wade in a river, sleep in a teepee (yes, a real, genuine, American plains Indian teepee), paddle a canoe and row a boat.

It's also where I spent an inordinate amount of time finding perfect smooth rocks from the river that fed the lake and skipping them across the lake.

There was a half-acre island in the middle of the lake. My grandfather had made the lake in the 1940s/50s, including the island. I would try to get a rock to make it all the way from the east shore to the island (which was shortest distance from the shore to the island).

I got to the point where I could pretty much get just about any rock to skip at least 15 times. I think my personal record was up near 30. And I did actually get at least one or two rocks to make it all the way to the island. I don't know what the distance was, though - it was a loooong time ago.

I so dearly wish my grandfather had never sold that place. My dad wanted to buy it from him, but you know how wierd sometimes dads and sons are - my grandfather wouldn't sell it to my dad (his youngest son), because he didn't think my dad knew what he would be getting into. My dad begged him to keep it in the family, because it was such a fantastic piece of property, and I and my sister and all our cousins had spent so many wonderful days and nights there and had such great childhood memories of the place.

But I guess, as they say, you really can never go home again.

[roadnsky]

...I couldn't quite make out the wires hanging off the regulator, maybe he snipped them off for streamlining.

Oh man! That made beer come outta my nasal passages!
That was rich...

[hanleyclifford]

Blame Kelly

This whole thing started with Kelly......

[jpian0923]

Obviously, we are getting bored with "coil" stuff!

[Kelly]

Ever farther off topic

Come on now, you're not actually going to blame me for carbonated beverages exiting nasal passages, are you??

Just a comment on the single-wire alternators, of which I have one- I need to run the engine above about 1000rpm in order for it to engage. Just another way of "exciting" it I suppose.

And Shawn: no problems here with hijacking threads. Gave me another chance to see your gorgeous DC distribution panel. What a thing of beauty!

[Marian Claire]

I installed a 1 ohm resistor, it read 1.1 on my meter, in the line from the key switch to the coil. This brought by total resistance to 4.4 ohms. After a 30 min run under load the coil + read 12.90 vdc at 2000 rpm. Coil temp was 95 F. I hope to have a few days at the beginning of Nov to do a short trip around the Pamlico. Will check coil temp on longer runs. But I like the #s I got today. Dan S/V Marian Claire

[sastanley]

ignition/coil update

After Hanley's visit (how he had enough energy to offer to help me troubleshoot after a 45nm run from Naptown I am not sure) I've made a few changes and done a test run. If I remember, we were measuring something in the neighborhood of 10.8v at the coil while running (with a 0.8ohm resistor in front of my 3 ohm coil), and Hanley said, "if it will still fire, I'd go even lower on the input voltage to the coil!" - so I removed the 0.8 resistor and put in a 1.35 instead.

(Bonehead moment coming here..stand-by)
One of the other things I'd noticed a few weeks back when I reviewed my wiring diagram and during the "pertronix recommended" set up (1.5 resistor & 1.5 coil), I had connected the (+) feed for the EI unit directly to the ignition bus (@ 13+ volts) to make sure it was getting 'plenty of juice'. I am realzing now this was probably a mistake, so I have since put the (+) lead for the EI back on the coil terminal, which is where I think it belongs. . I cannot recall if I made this change before or after the 1.5ohm coil failure. At any rate, I think we've all agreed that the 1.5 ohm coil does not have enough internal resistance for our application.

So, here is my current configuration: (like Dan, actual measurements shown below don't match what's on the box)
-- 35amp alt. with adjustable regulator back into the system, set so that I am reading 14.07 volts at the battery posts when charging (turns out it was apparently not over-charging the circuit, my multi-meter was malfunctioning..this was confirmed when Hanley's read 'normally' while mine was jumping around. I have since picked up another multi-meter)
-- 1.6ohm resistor in line between the key (bus bar) & a 3.2ohm Pertronix oil filled coil.
The temp of the coil was not hot, I could hold on to it without any trouble (sorry, no temp gauge handy at the last visit.)
Since I can't focus on one task, I let the engine run for about 45 minutes, and she ran troublefree, while I fiddled with winterizing other boat parts. If I recall, the voltage across the coil with the engine running is somewhere around 9.8 volts.
My next plan when I go to play at the boat again is to measure total resistance across the coil circuit, (including the resistor, which should = 4.8ohms), and then double check all of my readings and have them laid out in a table so I can monitor and have accurate readings rather than my memory.

What does all this mean?
I am still not sure. What I cannot currently explain is how I fried the most recent coil, except possibly by the 'bonehead move' above, especially now that I confirmed my multi-meter was bad and the regulator is OK (that was my 1.5 ohm coil right? )
Quite frankly, I've had the darn ignition circuit in so many different configurations, I cannot keep them all straight, along with the history of each to discern anything.

So, currently I am simplifying things and trying to set a baseline:
14.1v / 4.8 ohms = 2.94 amps. At least my math puts me in the safe range. It would be nice if this coil will last longer than about 3 hours.
Actual measurements forthcoming to set up a nice reference point for myself.

When we get nice fall days, me & the Mrs. (and/or a few friends) like to go creek exploring, so maybe I'll get a chance to see how she holds up as we putz around Solomons.

[Kelly]

Dutton modification

Great update Shawn.

My own efforts parallel yours but I can't report any testing as I'm fighting on two fronts: cooling and ignition circuits. I've currently got my alternator removed in order to get at my solenoid which needed attention. My HX is in the car as I assemble parts for my conversion from single-pass to dual-pass cooling (this one excites me as overheating even pre-dates my ignition woes).

The Pertronix coil will be protected with some extra resistance thanks to my "Dutton modification". I've used his handy calculator and relied on his long-distance help in putting together a -hopefully- sturdy ignition setup. I'm definitely tired of burning up coils and motoring with rosary beads in my hands.

I hope to be back soon with some real world numbers.

[Ball Racing]

So,,,,,
with so many things to test, and finding "just" the right resistor for the coil, and finding the right coil,making sure the alternator puts out the perfect tenth of a volt out....
How now,would you sell the benefiet of the EI to others?

I switched my 68 mustang decades ago to petronix because I was just wearing the follower off the points, and did feel it was a smoother set-up.
I also put a MSD box on there, and all that hot rod stuff...

But now, with my A4 having such low rpms, which is the greater hassle?
points or potentail of burning up coils, and the like?

[sastanley]

Daniel, Exactly!

[ndutton]

If I may . . . .

Daniel et al,

I too was skeptical of EI before I made the switch because I read time and time again on this forum about EI failures only to be rescued by reinstalling the old points plate. There's a post somewhere deep in the archives where I put the same question as you out there to the believers. What convinced me to convert were the favorable reports from many of the most respected players here, the big dawgs so to speak.

First, the advantages:

• No more cam shoe wear as you mentioned. Small or not so small, it affects dwell.
• No more points erosion.
• No moisture related issues.
• Less electronic noise.

The only disadvantage is the EI system's sensitivity to system amperage. With the majority of A-4 EI units being Pertronix, the biggest problem I see is the lack of solid technical information from them. That has been the most frustrating part. Had they been forthcoming with a maximum system amperage figure and not been contradictory with their technical advice I don't think we would have more than maybe a 1 - 2% failure rate, if that. I pulled that number out of my 'hat', an estimated statistical failure rate as with any manufactured product.

If all of us who made the move to EI had only followed Don's advice from February 2005 of a 4 ohm coil, none of this would have happened. None of it.

I used a 3 ohm coil. After all, Pertronix - whose name is on the EI unit - said their coil (3 ohm) was the perfect match to their EI system. Well, it ain't. The math works out at 12 volts but once you consider alternator voltage when the engine is running - somewhere between 13.8 and 14 + volts (less system voltage drop), their math flies out the window.

Using a coil or coil and resistor combination of 4 ohms protects the EI system up to 16 volts. Pertronix won't tell you that (why I don't know) but Don did nearly seven years ago.

The math or alternatively the provided resistor calculator varies because all of us have different voltages at the coil due to differences in wiring systems and their resultant voltage drop and differences in alternator output voltages (the manually adjustable crowd often being the worst offenders). The 4 ohm coil figure works well for those who flunked math.

So, in summary, it isn't the EI that's the problem, it's what we ignorantly connected to it. Don said 4 ohms, many of us connected 3 ohms and failure resulted, simple as that.

[sastanley]

The math or alternatively the provided resistor calculator varies because all of us have different voltages at the coil due to differences in wiring systems and their resultant voltage drop and differences in alternator output voltages (the manually adjustable crowd often being the worst offenders). The 4 ohm coil figure works well for those who flunked math.

- I can take a hint! I am up to 4.8 Ω in the circuit!