Another Front Mount Distributor Question

[RWS904]

Hello Everyone,

I have a 1949 8N that is giving me fits. Change the points and it runs great for a few hours and then it starts running rough again. Is this something that could be due to a worn bushing in the rear of the distributor housing? With just the rotor assembly installed in the housing, there is a slight amount of slop between the shaft and the bushing, just enough to make a faint “click” when wiggling the shaft from side to side.

I pulled it tonight to check the points, gap was a little loose on a .015” feeler gauge. Carburetor was rebuilt recently, fresh fuel in the tank, no debris in the bowl. 12 volt conversion was installed when I bought it. Thanks in advance for thoughts and suggestions.

 

[HCooke]

1s this something that could be due to a worn bushing in the rear of the distributor housing?

It is a common problem.

 

[old]

Hello Everyone,

I have a 1949 8N that is giving me fits. Change the points and it runs great for a few hours and then it starts running rough again. Is this something that could be due to a worn bushing in the rear of the distributor housing? With just the rotor assembly installed in the housing, there is a slight amount of slop between the shaft and the bushing, just enough to make a faint “click” when wiggling the shaft from side to side.

I pulled it tonight to check the points, gap was a little loose on a .015” feeler gauge. Carburetor was rebuilt recently, fresh fuel in the tank, no debris in the bowl. 12 volt conversion was installed when I bought it. Thanks in advance for thoughts and suggestions.

View attachment 123738

Check the point gap on all 4 lobs of the distributor to make sure all 4 are at 0,015 if they aren't then good chance that is the problem and it needs to be rebuilt

 

[flembo]

I replaced the bushings in my 8n a while ago { not a hard job }and it made a huge difference. Your problem sounds like you have more going on due to running for a few hours before acting up, it doesn't sound like a bushing problem. I would change the bushings to eliminate the slop you speak of. Just my 2 cents.

 

[Jim in LA]

Don’t forget there is a centrifugal advance in the back that can wear out.

 

[Mad Farmer]

My 9N (still 6V+ grd) started doing that, at first only when very hot weather, eventually started to die and not start, until it cooled off. Winter seemed fine.

Got to the point would only run ~1/2 hour. Coil was going bad. Before fixing it to get back to the barn, I ran a jumper around the resistor so coil got full voltage. Still had to cool down, but then started and ran good into the barn.

Might try that sort of jumper when it starts running rough, see if it cleans it up? Might indicate coil (or resistor/bad connections from key to coil).

One more thing is key switch going bad. Again can jumper around that and see how it runs.

 

[HarryVanderpool]

I recommend compression checks, hot & cold.

 

[Jim L WA]

I'm with Mad Farmer, the coil is breaking down, by the time you put a new condenser in, the coil has cooled down and it runs good for awhile longer.

 

[RWS904]

Gents,

Thank you all for your replies and insight.

I looked at the points while still installed on the breaker plate under a microscope this morning. What I thought were properly aligned to the naked eye, were not. I bent the tab until it looked like proper contact was being made and re-timed it on the bench. I found a set of Jonard point files and cleaned up the same points and reinstalled the distributor this afternoon.

Here’s what happened on a cold start:

1) Fired right up, nice idle like before. Let it warm up a few minutes in 90 degree Florida heat.
2) Ran the throttle up and down with no misses, hiccups or lags.
3) Took it for about a 10 minute ride in third gear, varying speed up and down.
4) Starts sputtering and struggling at about 3/4 throttle (no backfiring). Ran (mostly) ok at 1/4 throttle and below.
5) Parked it and left it running at idle. Jumpered the resistor, no change from #4. Jumpered the ignition switch, no change from #4.

I forgot to mention, the coil was replaced a month or so ago. Bought from Y-T.

I haven’t checked compression yet.

The plugs are about three years old. This thing has always burned oil, I will check the plugs tomorrow morning when it’s cooler.

Plug wires are of unknown age but appear to be in good condition.

I will keep you all posted with progress or lack thereof.

Thanks again!

 

[RWS904]

Two things I forgot to mention. I did order new bushing from Y-T and will install them next week. Second, I had to replace the coil because I left the ignition switch ON for days and ruined the previous one. The current problem I have was still going on then.

 

[old]

Two things I forgot to mention. I did order new bushing from Y-T and will install them next week. Second, I had to replace the coil because I left the ignition switch ON for days and ruined the previous one. The current problem I have was still going on then.

Good chance you need new points due to leaving the switch on which smoke test points

 

[RWS904]

Good chance you need new points due to leaving the switch on which smoke test points

Yes Sir, they smoked and burned the bakelight to a crisp! New points are currently installed.

 

[Mad Farmer]

Two things I forgot to mention. I did order new bushing from Y-T and will install them next week. Second, I had to replace the coil because I left the ignition switch ON for days and ruined the previous one. The current problem I have was still going on then.

Sometimes you get lucky when you leave the key on and the points are open.

 

[Non-farmer]

Sometimes you get lucky when you leave the key on and the points are open.

I've only done it twice. With my WD, I got lucky. With my N, the more expensive EI from Pertronix had my back.

 

[Btzj02]

During your next test run have your spark gap tester ready at step #4 when, (if), it starts to sputter. If the spark is jumping 1/4" I would think your problem is not a spark problem but a restricted fuel flow problem. Assuming all four cylinders are firing.

 

[RWS904]

Saturday morning update…

Changed the plugs and tried starting her, weak battery. Unusual, normally starts right up…

Put a battery charger on it for a few minutes, fired right up, but wouldn’t run well past about 1/4 throttle.

As it turns out, I have a bad 12V Delco Remy alternator (90-01-3125 on the faded tag), only putting out .7 volts at low RPM, just over 1 volt at high RPM (had to put the Charger on “boost”).

 

[Jim L WA]

Saturday morning update…

Changed the plugs and tried starting her, weak battery. Unusual, normally starts right up…

Put a battery charger on it for a few minutes, fired right up, but wouldn’t run well past about 1/4 throttle.

As it turns out, I have a bad 12V Delco Remy alternator (90-01-3125 on the faded tag), only putting out .7 volts at low RPM, just over 1 volt at high RPM (had to put the Charger on “boost”).

Wow, none of us thought about a weak battery causing your problem.
I Hope your new or rebuilt alternator fixes all your problems.

 

[wore out]

Saturday morning update…

Changed the plugs and tried starting her, weak battery. Unusual, normally starts right up…

Put a battery charger on it for a few minutes, fired right up, but wouldn’t run well past about 1/4 throttle.

As it turns out, I have a bad 12V Delco Remy alternator (90-01-3125 on the faded tag), only putting out .7 volts at low RPM, just over 1 volt at high RPM (had to put the Charger on “boost”).

"I have a bad 12V Delco Remy alternator (90-01-3125 on the faded tag), only putting out .7 volts at low RPM, just over 1 volt at high RPM"

How are you measuring that voltage, do you have the alternator disconnected from the battery?

 

[Mad Farmer]

Saturday morning update…

Changed the plugs and tried starting her, weak battery. Unusual, normally starts right up…

Put a battery charger on it for a few minutes, fired right up, but wouldn’t run well past about 1/4 throttle.

As it turns out, I have a bad 12V Delco Remy alternator (90-01-3125 on the faded tag), only putting out .7 volts at low RPM, just over 1 volt at high RPM (had to put the Charger on “boost”).

If you don't have the excite wire wired in correct it won't charge.

 

[RWS904]

Latest update in the saga.

Bought an alternator from O’Reilly Auto parts. Had the battery load tested while I was there, all good. Had to swap pulleys as the new alternator‘s pulley was too narrow for the v-belt. Alternator is now outputting 14+ volts, still runs rough over 1/4 throttle. Keeping the old alternator since the core charge was only $12.

Put a battery tender on it and leaving it alone for the evening. I found a new set of plug wires in a box I forgot the previous owner included. If nothing changes when I start it in the morning, I’ll try installing the new wires tomorrow. The only other thing that I know isn’t working at the moment is the ammeter, which hasn’t worked in years. Tractor Supply is 3 miles away and has them in stock for $14, just in case…