#1
IP: 69.143.44.113
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Ignition confusion
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 |
#2
IP: 32.211.28.40
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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!
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ernst (08-08-2020) |
#3
IP: 69.143.44.113
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Quote:
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'). |
#4
IP: 137.103.82.227
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Quote:
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The Following User Says Thank You to joe_db For This Useful Post: | ||
ernst (08-08-2020) |
#5
IP: 24.152.132.140
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There are only two possibilities for your test result:
__________________
Neil 1977 Catalina 30 San Pedro, California prior boats 1987 Westsail 32, 1970 Catalina 22 Had my hands in a few others |
#6
IP: 69.143.44.113
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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. Last edited by ernst; 08-06-2020 at 06:38 PM. |
#7
IP: 69.143.44.113
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Quote:
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.... |
#8
IP: 47.142.134.119
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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 |
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ernst (08-08-2020) |
#9
IP: 69.143.44.113
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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... |
#10
IP: 73.209.130.249
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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.
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ernst (08-08-2020) |
#11
IP: 71.208.58.235
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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. |
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Dave Neptune (08-08-2020), Sam (08-08-2020) |
#12
IP: 69.143.44.113
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Quote:
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! |
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Administrator (08-08-2020), sastanley (09-09-2020) |
#13
IP: 47.142.134.119
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Quote:
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 |
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ernst (08-10-2020) |
#14
IP: 67.176.203.192
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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.
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ernst (08-10-2020) |
#15
IP: 69.143.44.113
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Quote:
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! |
#16
IP: 69.143.44.113
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Thank you, good to know. This was the very first time I used a points file and I did not know when to stop. Will keep that in mind for next year!
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#17
IP: 137.103.82.227
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My engine has been a bit hard to start lately.
1. File points and clean them. Result - engine runs worse. 2. Replace points and condenser. Result - no spark at all. 3. New points have about 800K resistance when closed 4. File new points and clean them. Twice. 5. Resistance now about 0 ohms closed. 6. Put new rotor on just because it is sitting there. 7. Test new condenser and old one - both meter at about 220 pF. 8. Find other old condenser in drawer and that one is 220 pF too. 9. Put distributor back together with new cleaned points and new condenser. 10. Test spark with wire from coil - nice long blue spark. 11. Engine still won't start 12. Put wire back on distributor 13. Engine fires right up |
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Sam (09-08-2020) |
#18
IP: 47.142.133.234
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How worn was the rubbing block on the old points? Did you take a dwell reading before or after replacing the points?
ex TRUE GRIT |
#19
IP: 137.103.82.227
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Not sure and not yet - the dwell meter is in the shed someplace.
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#20
IP: 155.186.124.219
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Cleaning points
I had a good deal of experience with "clean or new" points in the "transistorized" style ignition systems before the newer electronic triggered stuff. Those systems ran a very low voltage through the points for the spark triggering signal", amplify and signal the coil. The purpose was to make the points last longer.
One of the problems was the points getting dirty and not conducting!!! These point systems often needed cleaning ESPECIALLY IF A POINT FILE WAS USED!! Sometimes even a fresh set was non conductive. To clean the points on these systems we would use a piece of smooth card stock like a 3x5 cut into a small strip. Then we would dip in acetone or lacquer thinner and pull the paper between the closed contacts to remove any debris and the oils than made them cling. I never had a failure of new points, but many sets that needed the cleaning before they would work. Fresh non filed points will last longer. A filed set will work just fine but the wear of the points is considerably faster. Filing an old set is fine but not as good as a fresh shinny set that is "clean". They will just plain ole last longer which means more run time to get sailing. In these old engines with well worn cams in the distributor it is very necessary to set the gap by dwell and not by a physical measurement like a feeler gauge!!! The engine will run much happier as only then will it have "proper coil saturation" for a good spark. Dave Neptune |
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Sam (09-08-2020) |
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