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Subject: Problems with Points

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K.LaRue-VA    Posted 05-20-2019 at 11:06:21 [URL] [DELETE]        [Reply] [Email]  
  • Problems with Points
  • My 6 volt 8N has never been a problem until recently. In the past few months I've had three separate occasions where it wouldn't start due to some sort of build-up on the points. The points look fine. There is no measurable change to the gap, but something on the surfaces prevents them from carrying current when closed. Run a file thru there and burnish them to a high polish and the engine fires right up.

    Saturday was the first time this happened while the engine was running. We were digging a ditch with the backhoe and the engine suddenly just quit (like the key was turned off or ran out of gas). Checked fuel, plenty in the tank and the fuel bowl. Noticed a few rust flakes, probably be needing a new fuel tank at some point. Checked for spark, nothing. Wander back to the shop for a handful of tools and parts. Filed and polished the points, checked the gap, put the cap back on, and it fired right up.

    I've tried two different sets of points and swapped the condenser out with another one. No change. Voltages are fine. Terminals are all clean. The ignition switch is good. This late 8N tractor does not use an ignition resistor. The weather has been far wetter than normal for the last couple years. Maybe I should try putting a thin bead of Permatex to seal the distributor cap? The next step may be to try a much older set of used points rather than new. The 12 volt 2N has continued to operate fine thru this entire time and the distributor hasn't been off in over a year. The front distributor does have gaskets, making me think that may be the problem with the side distributor engine. Anybody having a similar problem?

    Mike W    Posted 05-26-2019 at 17:09:58 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Problems with Points
  • It has happened to some of mine as well, and when the new points were not made right, I polished the old ones gently with a very fine whet stone. Restored the smooth appearance and the tractor runs perfectly. They will say that cleaning the points is no good, but it seems more than a few of the new ones are not good either.

    steveVa    Posted 05-22-2019 at 20:07:15 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Problems with Points
  • The last time I had troubles like that with 5he points, it turned out to be a bad coil...

    Farmer Dan    Posted 05-22-2019 at 07:55:59 [URL] [DELETE]        [Reply] [Email]  
  • Re: Problems with Points
  • I think you have a bad distributor cap, have you looked down that avenue yet?

    Tim Daley(MI)    Posted 05-23-2019 at 04:28:09 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Problems with Points
  • I also think the root cause is something other than points. I don't know about tungsten, will look at drawing spec, or about a thin film of other metal, but Bruce would know. I never owned, never used a point file or any other abrasive item on points. At completion of a rebuild, I used a piece of brown paper grocery sack, dabbed in mineral spirits to pull through the points a few times then a few more with a dry piece to get any oil or cam lube removed. I just took a set of points out of a an OEM cast iron front mount and they have the FoMoCo logo stamped on them. The contact points are not metallic so may be tungsten. Anytime you file, sand, or grate something you create a porous surface which opens it up to greater oxidation. Tungsten is very tough, but not very magnetic which means it is not ferrous, depending on what is it alloyed with. I'll look at some of the other used sets I have around. One other thing not mentioned is, if the radiator is leaking and water gets blowing around via the fan, it is possible to be getting water on the distributor.

    Tim Daley(MI)

    K.LaRue-VA    Posted 05-22-2019 at 09:33:44 [URL] [DELETE]        [Reply] [Email]  
  • Re: Problems with Points
  • A bad cap usually causes misfire rather than no spark at all, but I have a few spares, so next time I play with it I'll swap caps and see if it makes a difference. I'm beginning to believe it's just been so wet for so long here that nothing ever has a chance to completely dry out. The side distributor 8N may just be having more trouble with the moisture than my 2N.

    Bruce (VA)    Posted 05-20-2019 at 17:53:34 [URL] [DELETE]        [Reply] [Email]  
  • Re: Problems with Points
  • Once you file them, they're done. You will always be filing them because that thin metallic coating gets filed away and they will corrode in a week.

    K.LaRue-VA    Posted 05-21-2019 at 10:08:26 [URL] [DELETE]        [Reply] [Email]  
  • Re: Problems with Points
  • Are they now making point contacts out of something other than tungsten alloy? Tungsten contacts did not rely on any thin metallic coating and they did not corrode. Back in the bad old days we could try to file a set of points down to the rivet and it would be the same tungsten alloy that was at the surface. Later bonded points appeared that had a small bit of tungsten material welded to a cheaper base material. We still filed those with no problems because the rubbing blocks would wear down long before we could file completely thru the contact material. I have a nice set of point files and polishers that have probably been around since the Model T and have always been the right tool for the job. Are the replacement points different these days?

    duey    Posted 05-20-2019 at 17:12:52 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Problems with Points
  • It would be fun to know what the amp gauge does when trying to start it after it dies.. do you get the normal discharge cycling indication... does it show a steady discharge with no fluctuation....

    The wiring does get disturbed a minor amount when fiddling with the points... also the condenser wire... as well as where the power comes IN to the distributor...

    Keep a broad view of things..Good Luck solving your mystery :-)

    Bruce Dorsi    Posted 05-20-2019 at 11:56:56 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Problems with Points
  • Side-mount distributor?

    Possibly oil vapors coming up from the crankcase through the distributor housing and insulating point contact surfaces.

    If it's condensation from ambient air, maybe the NAA distributor dust cap w/gasket will help, if you don't already use one.

    K.LaRue-VA    Posted 05-20-2019 at 12:26:38 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Problems with Points
  • My side distributor has the 8N dust cap. The NAA dust cap does not fit right in the 8N distributor. It jacks the distributor cap up so the tang is no longer engaged to the distributor body. The only thing keeping the distributor cap in the right location is the spring clips. The 8N dust cap is smaller and fits down inside the distributor body so the cap fits normally. Seems like if it was oil deposits, the inside of the distributor would be oily.

    Bruce Dorsi    Posted 05-21-2019 at 08:34:45 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Problems with Points
  • I was not aware there were two different dust covers for the side-mount distributors.

    I was under the impression the dust cap was introduced with the NAA, but could be retro-fitted on the late 8N's.

    Do you have a part number for the 8N dust cap?

    All of the dust caps I have seen advertised say for 1950-1964.

    JMOR    Posted 05-21-2019 at 08:58:09 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Problems with Points



  • Comments welcome.

    K.LaRue-VA    Posted 05-21-2019 at 10:01:16 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Problems with Points
  • I bought a replacement NAA dust shield that was advertised to fit the late 8N and NAA tractors. It looked like the first photo JMOR provided. It did physically fit, but then the tang on the cap only engaged the slot in the flange of the dust shield. The only thing keeping the distributor cap from turning side to side is the two spring clamps. The distributor cap can shift. I doubt this is bad enough that it would keep the spark from jumping to the correct terminal. Another minor issue was less spring tension between the rotor button and the center terminal in the cap. The cap is raised by the thickness of the flange on the dust shield. This is probably also not enough to cause a problem, and that spring terminal can be bent up a little if necessary. I was mostly bothered because it obviously wasn't the right part. Later, the ad for that replacement dust shield was changed to say NAA only.

    My original 8N dust shield looks like the second and third photos JMOR provided. The flange is a lot smaller and fits down inside the distributor body. It has a slot that aligns with the slot in the distributor body so when the cap goes on the tang in the cap engages both the distributor body and the dust shield. I have never seen a new replacement for the 8N dust shield offered by anyone. Just for grins I used a cracked but mostly whole 8N dust shield to make a mold, then made several replacement dust shields with a two-part Urethane plastic. They turned out fine but are tan color rather than black. My distributor didn't seem insulted by the change in color.



    JMOR    Posted 05-21-2019 at 12:38:58 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Problems with Points
  • Nice job on those! On the shield I pictured with distributor, the 3 slots in bottom of shield index with 2 breaker plate & condenser mounting screws & then cap indexes to shield slot.

    JMOR    Posted 05-20-2019 at 11:36:20 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Problems with Points
  • I have experienced this same thing (while running) on my '62 PU, Farmall SMTA, and 8N side mount. Scrape with pocket knife and back in business. Much easier to lay on corrosion when sits days and then no start than to just stop while running. :^(
    I have no explanation.

    K.LaRue-VA    Posted 05-20-2019 at 12:28:22 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Problems with Points
  • This makes me wonder if they have come up with a cheap substitute for the tungsten breaker point material.

    JMOR    Posted 05-20-2019 at 13:11:34 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Problems with Points
  • Don't know, but doubt the points in the '62 have been changed since mid '80 and the Farmall since about 1998. 8N last points were 2010.

    Dn-N-Tn    Posted 05-22-2019 at 10:36:04 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Problems with Points
  • About 30 years ago, a neighbor was having trouble with dust in the Distributor and premature point failure on his 52 8N. If memory is correct, I cut the bottom out of a plastic, gear oil squeeze bottle, about 1/2-5/8" from the bottom--cut a hole for the shaft and made sure it cleared the rotor button, and covered the points and condenser in the distributor. After that, we'd replace the points about every five years. This was a cheap fix, but it worked, Dennis

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