Bah...almost the perfect weekend - but the engine quit

[ndutton]

Yeah Jay, I think that's where we're headed.

I'm not so sure the points test will be all that helpful now that I think about it. If the points are reinstalled without replacing the already stressed coil, the result may well be a repeat of the coil failure. If the coil is replaced, it might tolerate whatever conditions damaged the previous one giving the illusion of a solution whether it's connected to the points or a damaged EI. It could be months before the new coil is damaged to the point of failure.

Assuming upon shut down the coil spark test condemns the coil, was it the coil itself or a faulty EI that damaged it, or something else like low voltage to the coil primary? I think Shawn's headed for simultaneous replacement of both as well as resolution of any uncovered low voltage condition.

Sorry Shawn.

[sastanley]

67 -
Had we been even 1/2 mile farther to the East, we would have been pummeled by the storm..as it was, we got lucky and it built & swirled above us & headed east, just making it difficult to have steady breeze to sail in a confined space...one big reason to have a reliable engine is to NOT have to sail in thunderstorms. - I agree 100% on your assessment. Cruising is no fun if you can't trust every system on the boat.

I have a voltmeter in the engine panel..it is simply tied to the purple wire in the engine's ignition system. I am ALWAYS staring at the gauges, probably to the point of being anal, & the readings seem steady. However, I may need to tweak my alternator output, as sometimes I think I am running close to 15v. Even though I haven't changed it, it is possible the lower resistance and larger gauge (4#) cable in the charging circuit is the reason for raised voltage compared to last year when I was pumping about 14.2v into the batteries, but using smaller cable & 'not new' terminals, etc..

I also have a "battery check" analog gauge in the new electrical panel, it says 14.8-14.9v with the engine running. I don't think I've put a hand held meter on the batteries yet with all the new wiring to compare them to the readings on the other instruments I now have.

Is 14.9-15.0v too much?

Should we also expect that the normal resistance (3.0 ohms) on a good coil would be raised on a failed one...to the point that it stops working? Am I incorrect in thinking the heat is a byproduct of the increased resistance inside the coil? The coil/EI relationship is still a little foggy to me...I am not sure how this little shiny can takes 12volts from a 14# wire and turns it into 40,000v and sends it thru the big secondary wire for the spark plugs.

[ndutton]

This is a guess Shawn but recently we had a discussion of allowable alternator operating temps. The caution from the alternator shop was beyond 200 degrees the insulation on the windings breaks down damaging the alternator internally.

With your report of excessive coil temperature and knowing it too has insulated internal windings I'm thinking a similar breakdown is likely, regardless of what caused the heating in the first place. The Cliff Notes version is I think your coil is toast. My guess is the resistance is lower than the rated 3 ohms, perhaps not so when it's cold but more when it heats up with use.

This fits with my caution that replacing the coil may give you the illusion of resolution for a while. Why it failed is the bigger question.

[roadnsky]

Hey Shawn-
You may have missed it, but I had an alternate possibility.
Check POST #7 and see what you think...

[hanleyclifford]

All of this points to the conclusion that too much voltage is being supplied to the coil. A resistor or rheostat should be installed ahead of the coil. 14.9-15.0 volts output at the alternator is definitely too much. Yes, 67, is on the right track.

[ndutton]

Shawn,

Your voltage has to be way out of whack for it to be the problem. Pertronix' own literature specifies the Ignitor system is suitable for 8 - 16 VDC. I know you never would but if you tweaked your external regulator that high you've hurt the batteries too.

Reference:

http://www.pertronix.com/prod/ig/ignitor/default.aspx

first specification on the page.

Jerry,
Shawn's a manual pumper, no OPSS for him.

[hanleyclifford]

Neil - I had a look at that link. Just because the coil will operate at 8-16 volts doesn't mean it should especially for prolonged periods. Remember these are hot rod folks working with race cars and high compressions. IMO a 40,000 volt coil is a waste of rations on an engine with 6:1 compression. The elevated dwell of an electronic ignition system only exacerbates the issue. I think spark voltage only has to be sufficient to ignite the mixture - anything in excess of that is just making heat in the transformer/capacitor to no purpose. I think Shawn should tone the system down by providing some resistance ahead of that coil.

[ndutton]

I'm just reporting their specs for the Ignitor electronic ignition system, figured it was best to go to the source.

[hanleyclifford]

Nevertheless it is a fact that many A4 owners are having success with the ignitor coils and electronic ignitions - without shutdowns. Apart from voltage supplied to the coil is there any other variable over which we have any control? It would be interesting to hear from some owners who use the system; what voltage do you read at the coil+ at cruising rpm?

[ndutton]

I think until Shawn reports back with an errant voltage measurement we're trying to lasso a cloud. I'll lay back and wait to hear his findings before too much speculation gets the better of us.

[Carl-T705]

Not many coils are going to survive at 13 + volts, for hours of running. In the day GM cars had a special Ballast resistor wire to drop the volts to 9 when running. They had a wire from the starter to the positive side of the coil that sent 12 volts when the starter was engaged , then when the starter kick off the volts drop to 9. Chrysler and Ford had a ceramic type resistor mounted on the firewall that dropped the voltage. You may want to check with manufactor about voltage for the coil your using.

[jpian0923]

Don't forget i=v/r. (i is amp/current, v=volts, r= resistance.)

The lower the resistance, the greater the amps...which = heat through the coil. Hot coil = shutdown.

Increase the resistance.

[ndutton]

Since the general consensus seems to be excessive voltage to the coil it also seems the preferred remedy is to add additional resistance to the coil circuit. I'd like to know where this excessive voltage is coming from.

How 'bout Shawn's relatively new external regulator that's manually adjustable? If so, I can see a scenario where in a desire to have more control over charging voltage than an internal factory set regulator, there's now a need to protect other components downstream from the perceived optimal voltage output. Today it's the coil, maybe tomorrow it's the GPS or the auto pilot. Where does it end?

And as Hanley suggested, how do the rest of us with trouble free EI systems compare?

Shawn, if it were me I'd give Pertronix a call to get their opinion. In a few minutes on the phone with them you'll get the best advice possible.

[Dave Neptune]

Reminder

This is an interesting thread to say the least. Don't forget that the coils on most old systems that used a resistor also used an 8~10 volt coil with the ballast resistor, however full battery voltage was supplied only during start. As soon as the key/start button was released the ballast resistor was switched active, to supply the voltage the coil required for opperation. The hotter "start spark" was just for faster starts!
I have run performance motors with ignitions that would burn a hole through your thumb if you got bit by one, those operated in the 100,000 + volts range and ran for years.
When I set my EI up some 25 years ago with a system I adapted I changed to a stock 12 volt coil (nothing special and the stock 8 volt would not work) I had laying around, no idea of resistance. When I decided to replace with the Indigo set up I stuck with the same coil as I figured something like the "flame thrower" was a waste of money for the A-4.
Shawn you may indeed have a voltage issue but I wouldn't try making it work I'd just get a less aggresive coil and open the spark gap a bit like I've done and be done with it.

Dave Neptune

[zellerj]

At least Shawn will post the cure

The silver lining of Shawn's issue is that we will learn from it. Many post symptoms, and the Afourians post possible diagnoses, but few report the cure. So sorry Shawn that you have had issues with your little beastie, but at least we will all learn from it.

Best,
Jim
1982 Catalina 30
Kelleys Island, Ohio