Good afternoon folks I’ve been getting a slight misfire at idle and at constant engine running speeds so today I decided to go ahead and pull the plugs and look under the rotor and see what was going on. The spark plugs all look about the same I’m posting a picture (#1 is on the right, #6 left) so any spark plug gurus can tell me if they look right or not, from what I can find online this seems to be a proper color. These plugs having about 400 miles on them total. When I pulled the cap, there is some arcing evidence near the five and three cylinder terminals, I’m wondering if whatever is causing this could be the reason for my misfire. I have ordered plug wires, and new plugs, just to remove those as a possibility of being an issue.

While looking for spark plugs, however I did observe that they make an HEI distributor that fits the engine, I am wondering if that would give me smoother ignition then I’m currently experiencing with the stock distributor, with an electronic module installed. 

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IMO the plugs are good.

But the distributor cap is saying there is a problem. The arc tracing on 3 of 6 plug terminals, 2 being not good at all indicate there is a problem. It could be the cap, but first guess since they are all one side is the distributor shaft or gear may be worn.

A coil/points/condenser will usually have indications on all plug terminals.

The other possibility is 3 bad wires and if those worst arc lines are cylinders 5 + 3 then I'd start there and replace the rotor/cap.

I’ll pick up a new cap and rotor today and try that first.  

Thoughts on something like this?

https://www.jegs.com/i/JEGS/555/40021/10002/-1" rel="nofollow - https://www.jegs.com/i/JEGS/555/40021/10002/-1

With that output voltage jump it would be well advised to ask others that have that distributor what spark plugs they are running as the heat range will likely need to change for optimum performance/longevity.

Points, rotors, and caps are old technology. The ability to score good products has vastly reduced in the last couple of decades. Your problem may be as simple as a bad cap casting. Then again, it may not. Replacing the the cap and rotor may not help. Then again, it may. Do you see a theme developing?

Electronic ignition should not improve the running characteristics of a street driven points/condenser ignition. However, if the product quality is better, then it just might. There are good good conversion distributors and bad ones. To be honest, I don't know the status of the one in your link.

If you do go electronic, don't forget about the resistance wire which drops voltage to the coil. Electronic systems may require full 12V.

You might investigate Trader's suggestion of worn distributor bushings before dropping coin on electronic ignition. If you do the fix yourself, it will be cheaper.

The first car I ever drove had a 199 in it. It may not have an overabundance of power, but it took abuse from three teenagers and lived to tell the tale. Good solid engine IMO.

The HEI distributor does intrigue me, although I don’t know if there would really be any advantage to a vehicle like mine, other than reducing the amount of installed parts.

The ignition timing could be wrong as well. Over-advanced timing can cause an engine to stumble in a way that feels like a misfire. People often crank up the timing thinking more is better (not the case), so if you do not know what the timing is set at currently, I suggest checking it. 

I am running a perteonix currently, the miss at speed is gone but the idle is still “lumpy”.  Timing is at around 9 btdc hot with vac advance disconnected. I was running 6 BTDC before but a friend of mine that’s an old school mechanic said that wasn’t enough and might be the cause of my miss. 

I don’t have the manual for this engine as it’s not the original, it’s out of a 69. I will adjust to 10 degrees and see how it does. 

Anything from 5* to 10* BTDC at 500 RPM with the vacuum hose disconnected will make a 199 or 232 idle happily. 

Setting the timing with the hose connected or with the engine idling faster than 600 RPM will cause you problems. 

Correct, it is a 199 with about 450 miles since rebuild.  

Fine tune it with a vacuum gauge if you really want to know what the engine likes.

That is a tool I actually don’t have, I guess I need to get one.

So I got a vac gauge and following procedure I found online I still ended up at about 10 degrees, it’s running pretty well now. 

Don't sweat over factory specifications like this that are decades old with much different fuel.

I'm not sure which springs you're referencing? 

Also, I'm still getting a little bumpy idle, its not bad but I feel like it should be smoother.  

I'm starting to think this engine might have a weak or dead cylinder. 

Have you done a power balance test on it yet? That is where you disconnect (or short) each spark plug wire one by one and note how much the engine slows down when you kill that cylinder. Any cylinder that causes less reaction than the others or no reaction at all is weak or dead.

I am not familiar with that test, but I’ll give it a shot. Is there anyway to do that without getting zapped by the ignition coil?

That would make sense, I ended up using plastic fishing pliers to pull the boots one at a time and this is what I got. 

Base idle warm with 85 degree ambient was 525rpm, drops are as below.

Cyl 1-475 rpm

cyl 2-470 rpm

cyl 3-480 rpm

cyl 4-475 rpm

cyl 5-455 rpm

cyl 6-455 rpm

So since there is some variance, what could this mean for this engine? 

If ignition is better now, then it's likely fuel causing your stumbling.

Don't know if this is the same tank of gas or what grade your running. Some stabilizer like Seafoam in the tank will help clean the system and you may consider a different fuel supplier or one grade higher octane.

You could wind in your idle screws counting the turns to gently bottom, pull them, clean and reinstall to the same setting.

525 RPM idle is still low IMO, especially since you like heavy oil, and it would definitely stumble at those numbers less then 500 RPM for this test.

Bump the idle up to at least 550 and drive the car with the can of Seafoam or equivalent in the tank. Fill it with some fresh fuel and then see how it runs.

Nick

I don’t believe there is any adjustment in the 199 valve train. 

I’ve run only ethanol free fuel with startron and MMO, I took your advice and cleaned the idle screw/needle as it did have some buildup.  The car seems to be idling much better now.

Also I’m running 10/30 oil now and have idle about 600. 

We keep forgetting you're running a 69 199 and not the original 196!! I was about to say something but read through the entire thread before typing and got the reminder!

Why don't you change your signature to "1963 Classic 550 w/1969 199"? you can leave "Rambler" in if you want, but on this board we would all know or assume that part. Or remember to note it's a 69 199 when you ask engine related questions. Otherwise we assume you're talking about the original engine...

Good point, I will do that.