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Spark plugs, misfires, and general ignition system
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FSJunkie View Drop Down
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Points: 4602 		Post Options Post Options   Thanks (0) Thanks(0)   Quote FSJunkie Quote  Post ReplyReply Direct Link To This Post Posted: Apr/04/2023 at 4:05am
Something is wrong with an AMC six if you can feel it idle at all, and usually they idle smoothly over a wide range of base timing settings. They are not usually very picky. 

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.
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mtrosclair View Drop Down
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Originally posted by FSJunkie FSJunkie wrote:

Something is wrong with an AMC six if you can feel it idle at all, and usually they idle smoothly over a wide range of base timing settings. They are not usually very picky. 

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?
1963 Rambler Classic 550
Originally a 196, this one has a 199 from a 69 American.
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Heavy 488 View Drop Down
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Pull the plugs wires from the cap side.
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Originally posted by Heavy 488 Heavy 488 wrote:

Pull the plugs wires from the cap side.

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? 
1963 Rambler Classic 550
Originally a 196, this one has a 199 from a 69 American.
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Trader View Drop Down
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It means at less then 10% variance you don't have a bad cylinder.
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.
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nickleone View Drop Down
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Last thought, have you adjusted the valves on this REBUILT engine?

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mtrosclair View Drop Down
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Points: 363 		Post Options Post Options   Thanks (0) Thanks(0)   Quote mtrosclair Quote  Post ReplyReply Direct Link To This Post Posted: Apr/04/2023 at 6:59pm
Originally posted by nickleone nickleone wrote:

Last thought, have you adjusted the valves on this REBUILT engine?

Nick
I don’t believe there is any adjustment in the 199 valve train. 
1963 Rambler Classic 550
Originally a 196, this one has a 199 from a 69 American.
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mtrosclair View Drop Down
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Points: 363 		Post Options Post Options   Thanks (0) Thanks(0)   Quote mtrosclair Quote  Post ReplyReply Direct Link To This Post Posted: Apr/04/2023 at 7:29pm
Originally posted by Trader Trader wrote:

It means at less then 10% variance you don't have a bad cylinder.
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.

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. 
1963 Rambler Classic 550
Originally a 196, this one has a 199 from a 69 American.
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farna View Drop Down
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Points: 19075 		Post Options Post Options   Thanks (0) Thanks(0)   Quote farna Quote  Post ReplyReply Direct Link To This Post Posted: Apr/11/2023 at 4:29pm
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...
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mtrosclair View Drop Down
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Points: 363 		Post Options Post Options   Thanks (0) Thanks(0)   Quote mtrosclair Quote  Post ReplyReply Direct Link To This Post Posted: Apr/11/2023 at 4:58pm
Originally posted by farna farna wrote:

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. 
1963 Rambler Classic 550
Originally a 196, this one has a 199 from a 69 American.
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