8N front mount distributor replacement

[Ron Petterson]

Over the past 2-3 years, I have had discussions here about points failing and it is now where the tractor only has to run for a short period of time before the distributor (points fail again). So I have followed the advice I have received here checking different components and have decided that there is something in the distributor itself causing this failure, either with points just cleaned and reset, or with new point/condenser. (And yes, I know just enough to be dangerous when it comes to electrical systems) I have checked the current situation and have no spark (inline spark lite) from distributor to plug. Have traced ohms and power all the way through system and through coil itself. Everything seem to read within specs. The only significant play in the distributor I can find is about 1/8" movement in and out on the main shaft when pushing or pulling on the rotor cap.(No the rotor cap itself is not moving on and off the shaft). So I am going to replace the distributor and want some advice. Has anyone had any feedback on the distributors sold by Yesterdays Tractors? I ask that because so many of the after market parts, (if not all), are Chinese produced and many are failures before they are even installed or last 91 days if the guarantee is 90 days. I have never had problems before with anything from Yesterdays Tractors, but just need some feedback if anyone could provide that. Your assistance is appreciated!!!!
 

[JMOR]

you say points fail. How are they failing? What is not right after "fail"?
 

[Bruce (VA)]

" So I am going to replace the distributor "

You're going to replace the entire distributor because the points are failing?

Where are you getting the points? As JMOR asked, what do they look like when they fail?

Are you setting the gap at .015 on the high side of the cam?


No spark has lots of causes. Seems like it would be a wise move to actually find the problem before you start replacing parts.

If you want to rule out the distributor itself as being defective, measure the component parts.

Here are the factory specs for a FM distributor:

Front Bushing ID .437

Rear Bushing ID .863

Front Shaft .436

Rear Shaft .863

Cam Flats .790

Cam Lobes .870
75 Tips

 

[Ron Petterson]

It will run after removing distributor and resetting points and then when it is turned off, it will not restart, either hot, cold, hours or days later. The last time I
was returning it to the shed and backing it in, the tractor was moving over a small stump in the ground, bogged down because I was almost at an idle and shut off. Tied
restarting, no go, and that was just after running for an hour or so. I have checked the resistor, the coil etc and if I remember correctly I was getting 6.25 volts
anywhere i checked and 1.0 to 1.5 reading on the ohm meter with the settings at the smallest setting 200ohms, (my meter has multiple settings from 2M down through
multiple K's to 200). And that went through the coil to the connection that comes in contact with the distributor. So is there something else I should be checking. Right
now its cheaper to replace parts than to have someone come out and work on it for me. (That knows what they are doing!)
 

[Ron Petterson]

OK you are addressing someone that has no idea what you are suggesting. I have been here asking questions previously and have been directed to check the system which I did the best I could. Most of the time when I check the points, they are burned with a raised buildup on one side and the burned indentation on the other. I have used NAPA, New Holland tractor dealer brand and a brand that someone here suggested, about $18.00-$23.00. can't remeber the name but was told they were the best. Other times there does not appear to be any residue on the points, but if I barely move a piece of fine emory cloth over them, reset at 15/1000ths, it fires up. So do I need to take the distributor apart that to measure the reading you gave me? I am about ready to sell the dang tractor because something with a system as simple as that 8N should not be that difficult to trace why it will not run and restart. Many have said in earlier discussions the front mount distributors were noted for wearing out, so that is why I said I was going to replace it
 

[Jim L WA]

Ron, you say it's cheaper to replace parts than to have someone that knows what they are doing to work on it. Okay, replace the coil and see what happens.
 

[lha]

Rock auto has Standard brand points,condenser,rotor and cap. I don't know about now,but I have a set in mine that's been in and working fine for about 6-7 years. The points now days are not what they used to be and need to aligned and squared up before set. Some brands are good,but I've seen some expensive ones that weren't aligned when installed. If the bushings are sloppy[loose],the gap will vary when run. I bought some bushings from YT and they've been good for 10-12 years now. It takes time and patience to work with the low quality stuff that's sold these days. Good luck!
 

[Bruce (VA)]

" Most of the time when I check the points, they are burned with a raised buildup on one side and the burned indentation on the other. "

That is a text-book example of a failed condenser.

And a new distributor will not fix that.

Are you replacing condensers every time you replace the points? Do you know how to check a condenser?
75 Tips

 

[Ron Petterson]

So if I am getting 6.25 volts and 1 to 1.5 ohms through the coil, it could still be bad?
 

[Ron Petterson]

Yes, but I will try that again before replacing distributor.
 

[Ron Petterson]

Thanks, will try that again. And I guess I could try working on the distributor and see if I can do something with it before buying another. I don't even know it the one on there is the original or has been replaced in the 75+ years various people have owned this tractor.
 

[JMOR]

[Bruce (VA)]

Those tests tell you the coil is not bad.

The results do not mean that the coil is good.

There are a few ways to see if a coil is bad, but it’s not possible to determine if a coil is good w/o some expensive ( or old) testing equipment. If you detect a dead short or high resistance in the coil w/ an ohm meter, it’s bad. If it’s cracked, it’s bad. If a sidemount coil w/ battery voltage to the primary will not jump a ¼” gap from the secondary wire to the block, it’s bad. But, here is the hard part: even if you do not detect a short, even if it will produce a spark, even if it’s not cracked, that doesn’t mean the coil will work when it’s hot & under a load. So, it’s a process of elimination. If the tractor starts & runs fine for 30 minutes or an hour then cuts off & refuses to re-start, and you checked for spark at the plugs & it had no spark at all, AND you have the correct voltage at the coil that’s a good sign that you have a bad coil. Let it cool off, restart it & if you have a good spark, odds are it’s a bad coil. But, even then, you might end up w/ a spare coil on the shelf!

Bottom line.......coils do go bad, but I'll venture a guess that 75% of new N coils sold today are sold to folks who do not understand how to diagnose a poor spark problem or how a coil works. So, for those who don’t know any better, in a no spark situation the first suspect is usually the coil……and, more often than not, it isn’t the problem.
75 Tips

 

[Ron Petterson]

Bruce, thanks. Much more complicated for a non mechanic than I would have thought, given this was 1940 technology. But I was aware of coils failing when hot given cars that had that problem. But once it stops running, it wont restart at all. Its been 6 weeks since it stopped and no spark. So thats why I thought it in distributor. So based on previous comment here, I will check condenser. Now, if you would comment, should there be any vertical movement in the shaft? I open points and wiggle shaft and the points dont move, so that indicated to me the bushings are ok, but I dont understand the horizontal movement.
 

[hunkydory]

FYI, I heeded Bruce's advise when going through my front-mount distributor. I figured after 70 years there would be some perceptible wear and was correct. I replaced the bushings with new ones from our host. The play is gone.

My $.02: If you're going to pull it take care of all of it. Once & done.