9n distributor to rotor gap

just did an ignition tuneup on my 6V 9n.when the distributor cap was mounted the rotor tip was hitting 2 of the distributor terminals.I was rotating the assembled distributor by hand and noticed this issue. I filed the rotor terminal a little to stop the interference.When I mounted the distributor on the tractor , it runs, but not real clean.Starting is a bit slow also. I read some stuff on the internet about that gap and it seems to show .015 to .025 is a desired gap. They say too small a gap or almost no gap is a bad thing.Any ideas here.I don't know where I got the parts I used, they were in a drawer of reserve parts.The bearing in the distributor seems OK.
 

" I read some stuff on the internet about that gap and it seems to show .015 to .025 is a desired gap. "

On the front distributor, the gap is .015.

" when the distributor cap was mounted the rotor tip was hitting 2 of the distributor terminals."

Time for a new rotor & cap.

" The bearing in the distributor seems OK. "

It doesn't have a bearing. It has 2 bushings. You can guess all day or you can measure it & know for sure.

Make sure your distributor isn?t worn out; check the wear parts with a micrometer and compare what you have to the factory specs (below).

Factory Specs:

Shaft top .4367 / .4370

Shaft Bottom .8625 / .8630

Cam Flats .789 / .791

Cam Lobes .869 / .871

Base Tang .177 / .178
75 Tips
 

[b:d308754c8f]"He is not asking about point gap. Never seen a spec on rotor to cap towers."[/b:d308754c8f]

does "as close as possible without hitting" qualify as a spec?

[b:d308754c8f]"Time for a new rotor & cap."[/b:d308754c8f]

and unless your distributor IS wobbling around, i'd suggest u get that new cap and rotor from a different source than the last set.
 
(quoted from post at 00:38:22 01/28/17)
[b:5285a87c54]"He is not asking about point gap. Never seen a spec on rotor to cap towers."[/b:5285a87c54]

does "as close as possible without hitting" qualify as a spec?

[b:5285a87c54]"Time for a new rotor & cap."[/b:5285a87c54]

and unless your distributor IS wobbling around, i'd suggest u get that new cap and rotor from a different source than the last set.
o, it does not qualify.
 
I changed all distributor parts including rotor and cap. I used Napa parts per recommendations this forum. I decided to change all because it sits outside with a tarp cover and would not start after periods of rain. After a couple of dry days it would start fine. Once it started it ran fine that's why I am hoping there is not wobble in the distributor bushings. I have read in this forum about the random quality of a lot of offshore parts for our tractors. Just inquiring if anyone has had trouble with rotors and caps being inconsistent.
 

wait, that makes sense.

i was thinking "tiny alien with tiny gauges installed inside cap" :oops:
 
(quoted from post at 20:53:04 01/28/17)
wait, that makes sense.

i was thinking "tiny alien with tiny gauges installed inside cap" :oops:
measured and can say Bruces model a is closer to right tha 6 to 8 thousandths. That is simply too tight for those parts.
 
(quoted from post at 18:46:38 01/27/17) just did an ignition tuneup on my 6V 9n.when the distributor cap was mounted the rotor tip was hitting 2 of the distributor terminals.I was rotating the assembled distributor by hand and noticed this issue. I filed the rotor terminal a little to stop the interference.When I mounted the distributor on the tractor , it runs, but not real clean.Starting is a bit slow also. I read some stuff on the internet about that gap and it seems to show .015 to .025 is a desired gap. They say too small a gap or almost no gap is a bad thing.Any ideas here.I don't know where I got the parts I used, they were in a drawer of reserve parts.The bearing in the distributor seems OK.

David,

I've said this before cause it happened to me with the Jubilee.

I installed a new correct part# rotor but left the old blue FoMoCo Dist cap that was on the tractor, after chipping off the buildup on cap poles and steel-wooling inside the towers.

The tractor started right up but I heart a cacking sound that I could tell was coming from the rotor and so I quickly shut it down.

Immediately I put the new distributor cap on that I already had and that ended that problem.

So . . .
if a rotor has too much reach that it clips the flat parts of the poles then it's the wrong rotor for that cap.
if a new rotor is touching the poles higher up then that rotor might be too tall for the old cap style
OR conversely the old cap is too shallow for that rotor (poles sit too low for the rotor tip to clear.

I can't remember now if I did a side-by-side of rotor and cap heights; I probably did.
I remember comparing the out-reaches of old and new rotor tips and they were the same.

Anyway, regardless of my feeble memory, my new rotor clicked quite loudly under the old blue FoMoCo cap. Had me worried for a sec but no damage done cause I shut it down fast.

Imagine being so cheap you try to keep on using an old cap when you already have a new replacement on the shelf.

So now my emerg. spares are the old blue Ford cap and it's matching rotor.
 
Jmor,I'm just going by what the specs show,.006 - .008,Rotor center of shaft to end of electrode (new 1.275) (wear limit 1.272).
9ndistspecs3.jpg
 
6 to 8 thousands has got to be wrong; that's just too damn close. Here is .025 on the Model A (not .020 as I thought; pays to check the specs!)
A%20rotor_zpsnvixqyeh.jpg
 
6 to 8 thousands has got to be wrong; that's just too damn close.So Bruce your sayin that Mr.Fords distributor specifications are incorrect and wrong? Well that might be hard to prove since finding a original 9N 2N 8N unused distributor cap and rotor to measure with inside micrometers and dial calipers would be almost impossible.
 

Hey, I'm just presenting alternative facts! ;)

Seriously, get out your feeler gauge & look at .007. I got out the digital calipers; the paper cover of a shop manual is .008.

Jesse, how did you measure it?

I tried, but my calipers won't fit in the cap.
 
(quoted from post at 16:01:21 01/29/17)
Hey, I'm just presenting alternative facts! ;)

Seriously, get out your feeler gauge & look at .007. I got out the digital calipers; the paper cover of a shop manual is .008.

Jesse, how did you measure it?

I tried, but my calipers won't fit in the cap.
ell, it certainly wouldn't be Fords first publication error. I have found numerous errors in them over the years.
How measured?
The rotor is easy, just measure tip to edge of shaft hole, then measure shaft diameter and add shaft radius to the to hole-to-tip measurement. Then grind down a no good drill bit until it just fits between cap posts & measure it. Subtract the quantity (hole-to-tip+shaft radius) from the distance between posts divided by 2. Result is gap.
.
 
(quoted from post at 23:30:39 01/29/17)
The rotor is easy, just measure tip to edge of shaft hole, then measure shaft diameter and add shaft radius to the to hole-to-tip measurement. Then grind down a no good drill bit until it just fits between cap posts & measure it. Subtract the quantity (hole-to-tip+shaft radius) from the distance between posts divided by 2. Result is gap.

hey now! i was not told there would be a test :shock:
 

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