Ignition confusion

[ernst]

Due to Covid-19, I have sailed zero days (minutes) this year. The boat is in the water (necessary for anti-fouling) but it hasn't moved out of the slip.

Today I wanted to start the Atomic 4 to move the prop a little, and perhaps even the boat and go swimming or something. To my surprise, for the first time since I have the boat (19 years), it did not start! Starter fluid did not help, I have no reason to assume anything is wrong with compression, so I suspected ignition. Indeed, no spark at the plugs and, as I then found, at the coil when I turn over the motor.

To check the coil, I shorted the negative side of the coil to ground with the ignition on and got a beautiful spark at the HV cable. So, coil is fine, looks like either condenser or points. I suspected the condenser but it measured at 220nF, same as the brand new one in my spares collection.

So it must be the points. Hard to see how they can go wrong but there must be a reason. So I measured resistance between the cable and ground and get infinity when they are open, as expected. So far so expected.

Now it gets weird. I had by now taken the plate with the points out (to check on the flyweights since I hadn't done that in years; they are fine) so it was easy to open and close the points. To my surprise, I am getting infinity also when they are closed!

Hmm. Maybe some corrosion? I wiped some fine sandpaper between them. No change. Hmmmm. Something fundamentally wrong with the old points that I somehow cannot see?

So I break out the brand new spare points, still sealed in their packaging. Just to make sure, I measure resistance when open (infinite, good) and when closed (infinite!!! WTH???).

What is going on? It is not my VOM; when I measure from the cable to the 'near' part of the points (the one connected to it) I get 0 Ohm, of course. But on the other side it is infinite.

Is there some insulator between the two contacts? But how can the whole thing then work? It needs to establish a low-resistance connection when closed to generated the magnetic field in the coil.

Again, what is going on??? Utterly confused

[Al Schober]

Ran into the same issue with my first engine job (Triumph TR-3). Had an ignition lead on the wrong side of an insulating washer in the distributor. You'll find it!

[ernst]

Ran into the same issue with my first engine job (Triumph TR-3). Had an ignition lead on the wrong side of an insulating washer in the distributor. You'll find it!

Hmm, maybe I don't understand. But the ignition lead is not even connected in the case of the new points. They are straight out of the box, never being installed.

And it does not matter whether I measure the resistance between the ground plate of the points (where they will be screwed to the distributor) and the electrical connector (where the lead will go after installation), or between the ground plate of the points and the body of the points (anywhere on the moving 'arm').

[joe_db]

Hmm, maybe I don't understand. But the ignition lead is not even connected in the case of the new points. They are straight out of the box, never being installed.

And it does not matter whether I measure the resistance between the ground plate of the points (where they will be screwed to the distributor) and the electrical connector (where the lead will go after installation), or between the ground plate of the points and the body of the points (anywhere on the moving 'arm').

Thick layer of grease?

[ndutton]

There are only two possibilities for your test result:

1. Defective points
2. Testing technique

Be certain the pointed test probes are making good contact with the conducting metals by rotating them or "drilling" them through whatever might be on the surface into the metal.

[ernst]

Thick layer of grease?

Well, not on the old points, they were in there for many years and always worked. Perhaps some oxidation which is why I tried to sand them. Maybe I should be more aggressive about that but I read somewhere that there is some coating on the contact surfaces and filing it off dramatically reduces the life expectancy of the points. But I guess I have not much to lose with the old ones...

I thought of some protective coating for the new ones but I have never heard of having to clean points before installing them. I guess I could wipe them with some solvent, this should do any harm.

[ernst]

There are only two possibilities for your test result:

1. Defective points
2. Testing technique

Be certain the pointed test probes are making good contact with the conducting metals by rotating them or "drilling" them through whatever might be on the surface into the metal.

First of all, I am grateful to everybody that replied so far, confirming that I am not completely crazy and overlooked something really stupid! When this happened on two completely unrelated sets of points, one having been used for years and the other brand new, I started to doubt my sanity

To your two (ehm) points : what would be a failure mode of two touching metal surfaces? I suppose there could be a layer of grease on the new ones, as Joe suggested, and oxidation on the old ones? This is why I sanded the old ones, without success. I did nothing to the new ones. Perhaps I should invest in a points file?

Testing: sure, that is always possible but it seems pretty unlikely. I scraped the metal surface pretty good, and I had immediate contact on one side but nothing on the other. But you are right, stuff happens. Now that I think of it, one way to make absolutely sure is to measure resistance between two locations on the ground side, confirm that it is ~ zero there, keep one of them where it is without moving, move the other one to the 'hot' side. If I get ~zero, the problem was with my measuring technique. If I do NOT get that, move the first point to the 'hot' side. If now get ~zero, I know that there really IS no conductivity across the points.

I am 99.9% sure that it is not measuring technique. Have done this MANY times....

[JOHN COOKSON]

This is why I sanded the old ones, without success. I did nothing to the new ones. Perhaps I should invest in a points file?
...

YES.

If you have points you should buy a points file. It is the correct tool. Then you can file the points without taking away excess material. I always file any and all points before I install them. It cuts down on the "drama".

ex TRUE GRIT

[ernst]

YES.

If you have points you should buy a points file. It is the correct tool. Then you can file the points without taking away excess material. I always file any and all points before I install them. It cuts down on the "drama".

ex TRUE GRIT

You got the drama part right

OK, will make a trip to the nearest car parts place. Hope they know what I am talking about, and won't have to fetch 'the old guy from the back'

Will let y'all know...

[Sam]

I got my "points tool kit" - file, small thin wrenches, feeler gauge and some emory cloth at a flea market a few decades ago. Not sure a branded auto parts store would carry this today. You might find one in a basemen/garage of an old estate sale etc. Covid probably limits the opportunity now.

[romantic comedy]

Have points hooked up, gap set as usual.
Have cap off
rotate motor so the points are closed

Take the coil high tension wire out of cap and hold it 1/8 off the block to test for spark

turn ignition on

open and close the points with something that does not conduct.

Each time you open and close the points there should be a spark from the coil.

[ernst]

You got the drama part right

OK, will make a trip to the nearest car parts place. Hope they know what I am talking about, and won't have to fetch 'the old guy from the back'

Will let y'all know...

Wow, that was impressive!

I procured a points file, NAPA Auto parts even had it in stock for a meager $2.49 plus tax. Took out the base plate with contacts and condenser and went to town with the new file. Gave is approx. 20 strokes.

After that, put everything together and tried to get a spark from the coil to ground by cranking the motor. Yes, there was spark!! I was first a bit concerned because it seemed yellow at short distance but when I increased the distance a bit (1/2"?) it turned purple.

Then the real test: connecting everything and actually trying to start the motor. This was the impressive part: The motor started IMMEDIATELY!! By this I mean within much less than a second, it felt like on the very first revolution!!

Mind you, the motor had not run since last November when I winterized the boat. And there was still the MMO in the cyclinders from the winterizing (so there was some white smoke out the exhaust, and of course anti-freeze).

So, what have I learned:

First, I have not gone crazy, the laws of nature still apply and I do actually understand the basics of ignition.

Second, coincidences happen: Completely independently, there was no conductance between the contacts of the old points and those of the brand-new points.

Third, the right tools matter. As I had reported earlier, I had used some emory cloth to sand the contacts but either I did not do enough of it, or it just does not work well enough. The file really did the trick.

As an additional benefit, since I had the base plate off I had a good look at the advancement weights (whatever their real name is). They seem to move freely and the springs are intact but there was a little surface rust. So I brushed them with MMO (that's the only light oil I had on hand) and I expect them to be good until 'next time.'

Again, many thanks to all who responded and confirmed that I had the basics right. In particular John Cookson who reinforced the notion of using the right tool for the job.

This is a great community!

[JOHN COOKSON]

I do actually understand the basics of ignition.
This is a great community!

Congrats on getting 'er running. Feels good doesn't it?

It would seem that you are ready to move to the next level. Do you have a dwell meter? It is a good idea to check the dwell after working on or gapping the points.

ex TRUE GRIT

[Sam]

Glad it all worked out. Just a brief note - Twenty strokes w/point file seems too much for regular yearly maintenance and point life. After 6-7 months winter layup with a fogged engine 2 or 3 strokes w/file seems to work fine.

[ernst]

Congrats on getting 'er running. Feels good doesn't it?

It would seem that you are ready to move to the next level. Do you have a dwell meter? It is a good idea to check the dwell after working on or gapping the points.

ex TRUE GRIT

Yes, feels good

No, I don't have a dwell meter. Honestly, I think I will leave it at that. I find it, on the one hand, fascinating that this 100 year old method of running a motor works, and it is a quite ingenious system! On the other hand it is a sailboat, and as much as I love my A-4, it is still an auxiliary (maybe this is heresy on this forum? ). So since it now 'purrs like a kitten' I think I will good let be good enough, and go sailing .

Again, thanks a lot for getting me up and running again!