sparks around spark plugs...

[robw]

Ok, so last weekend I sprayed some engine degreaser on the engine and cleaned off all the gunk... when I started it up to move it back into the garage... the problems began...

suddenly the engine was running lean... rough running, and it would backfire if I revved the engine. If I covered most of the carb with my hand, it would smooth out and allow me to open the throttle some.

This lead me to believe there was a blockage in the carb, so I pulled it apart, and verified all the jets were open and flowing.

Put it back on... same problems... took it off again and double checked all the jets... put it back on, then double checked the float level... all good.

ran it again... same problems. I took a can of spray carb cleaner and sprayed around all the connections in the intake manifold... to see if there were any leaks... didn't find any at first... but then after a while I found one on the left side underneath, where the intake manifold goes into the head. So I put a little more torque on the manifold bolts... no luck.

I pull the manifold off and it is obvious that the gasket is leaking... end of work... order new gaskets from Snyder's..

new ones came this week. Put them on today. Took a little bit, but eventually got rid of the vacuum leak... hey, I can even adjust the carburetor with the idle mixture needle now...

but... alas... it still isn't running right.. so I go through Les Andrew's step by step trouble shooting... for the 10th time... everything is checking out... I'd previously bought guts for the distributor (original style)... so I put all of them in there and go through Les' trouble shooting again... to include a new cap and rotor.

still no luck... but as it is running this time.. I turned off the lights. Once my eyes adjusted... I could see sparks around the spark plugs... a pretty blue ring around the base of the insulator... right where it goes into the steel part of the plug. It becomes more obvious as I speed the engine up.

I also noticed a bit of sparking from the high tension coil wire to the armored ignition cable... high up, near the junction box. Hmmm... that is a new coil wire too..

so here is my question... these blue rings of sparks around the base of my plugs... does that mean they are probably bad and need to be replaced? Perhaps there are cracks inside the insulator?

Plugs are gapped at about .035.

would bad insulators on the plugs cause the sparks to jump from the coil wire to ground?

hmmm

what do you guys think?

rob

[BILL WILLIAMSON]

Dog here,
Stuff is still WET from hosing the engine. Break out the air hose. (Wait 'til I cover my EARS!) Buster T.

[ford3]

spray the hell out of every thing with wd 40, as bill said blow every thing off

[robw]

Originally Posted by ford3

spray the hell out of every thing with wd 40, as bill said blow every thing off

well, it's been sitting for well over 2 weeks... I'd think it'd be dried out by now... I'll try it, but don't have much faith in that solution...

[BILL WILLIAMSON]

Originally Posted by robw

well, it's been sitting for well over 2 weeks... I'd think it'd be dried out by now... I'll try it, but don't have much faith in that solution...

Well, it's quick, cheap, & easy!!! Can't drive it that way. Dog (Please report back)

[Chuck Sea/Tac]

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You said this weekend in the first post, now you say it's been sitting for two weeks ????
Point is you have contaminated the wire and plugs, if cleaning them doesn't work, the you'll have to replace. I have an electronic ignition as well, and it has a higher intensity spark. I had the same problem with 2 of my 3X plugs, about 10,000 miles, and ended up replacing all four. Plus the higher voltage does eat away at the electrodes.

[Hicktick]

Did you do any painting on the engine ????

[Chuck Sea/Tac]

Oops, sorry about the electronic ignition, I got mixed up with another post. Chuck

[James Rogers]

You can use WD 40 or go to the parts store and get some Wire Drier. It is a silicone spray that will seal the insulators. You have some high resistance somewhere, probably in the plugs. You could try a set of modern style Champions W16Y.

You can also try loosening the plugs and retightening them to get a good ground. On the head and at the nut that holds the insulator.

[QGolden]

Yup, seems your Engine Cleaner left a conductive residue on your plugs. The current is simply finding the easiest path to ground. Pull your plugs an clean them with a solvent. I use Brake Clean. You might as well gap them while you have them out. But clean the seats good as well. If someone painted the head with the plugs out or the have grime under them, your ground is compromise. Good lesson here, when you have a change in the way the engine runs, ALWAYS blame it on the last thing done to it and eliminate that possibility first. Then go back to the next thing you did. Getting into the Carb if you had not been there recently put you on a wrong road.

I sold a bike once to a guy who adjusted the Cam Timing Chain. Afterwards it was slapping the nylon adjuster. Rather than stopping to think about what has changed, he kept digging and tore the top end down, couldn't put it back together, and blamed me for selling him a piece of crap. Last I knew the bike was rotting in a shed.

[tbirdtbird]

Agree whole heartedly withQGolden.

And the reason partially covering the air intake allowed you to give some more throttle is because a rich mixture fires with less voltage...

[Patrick L.]

Yep, what the boys said about the ignition system.
As far as the air leak. Did the new gasket stop that leak ? Was the manifold checked with a straight edge ? If the leak isn't fixed, and, you can fit about a .010" feeler strip between a straight edge then the manifolds should be fixed.

[Tom Wesenberg]

I'd remove the coil wire and spray some WD-40 in the cap and coil towers, then blow dry them. Also spray the coil wire, distributor body, and spark plugs with WD-40 and wipe them dry, then see how it works. Sometimes, once a carbon track is made, it's hard to fix without replacing the part.

BTW, the Model A did NOT come with boots on the ends of the coil wire, and I never use them. I've seen them trap water and cause shorts.

[robw]

New cap, new rotor, new coil wire, no boots.

Cleaned & dried the plugs. Verified the gap on the plugs. ensured plugs had a good ground with the head.

same problem. It may run slightly smoother, but when I go to rev the engine, it bogs down and backfires... if I cover the intake about halfway, the engine will rev without backfiring. Can't tell if the ring of sparks are still there... too much daylight.

double checked the seals around intake manifold... they seem to be working fine. I can spray WD-40 all around them with no change... same for the connection to the carb.

not sure where to go from here... I've done all the troubleshooting the Les' book and it seems to pass all of them.

rob

[V4F]

i use starting fluid for finding intake leaks .you do have a mystery

[robw]

Originally Posted by V4F

i use starting fluid for finding intake leaks .you do have a mystery

starting fluid, carb cleaner, WD 40... they all seem to work... usually.

[Tom Wesenberg]

It sounds like a blocked passage in the carb. With all the jets removed, did you use high pressure compressed air to blow out the passages in the carb body?

[robw]

Originally Posted by Tom Wesenberg

It sounds like a blocked passage in the carb. With all the jets removed, did you use high pressure compressed air to blow out the passages in the carb body?

That was my starting point... I checked each of the passages using a carb cleaner and its straw... everyone checked out as described in: http://modelabasics.com/Carb/ZenithPassageways.pdf

Actually did those tests twice...

[Mitch//pa]

are you running original style lower distributor plate or modern style? what about bad condenser

[P.S.]

It's pretty obvious (to this electrical engineer) that the ground connection is the problem. The blue sparks around the base of the spark plugs and the sparks up the armoured cable were the giveaways. This is NOT a carburetor issue, guys.

[robw]

Originally Posted by Mitch//pa

are you running original style lower distributor plate or modern style? what about bad condenser

original style... the condenser passes Les' test

[robw]

Originally Posted by P.S.

It's pretty obvious (to this electrical engineer) that the ground connection is the problem. The blue sparks around the base of the spark plugs and the sparks up the armoured cable were the giveaways. This is NOT a carburetor issue, guys.

Ground may be an element of this problem... but I've since cleaned the plugs and ensured that where they mate up with the head is good and clean too... I think I've resolved the sparking around the base of the plugs issue...

However, the fact that the engine will only rev when it choked seems to indicate an overly lean condition... I just can't seem to pinpoint the cause of the overly lean...

[P.S.]

It will rev only when choked because a richer mixture will srill explode even with a weak spark.

The grounding issue is somewhere between the coil low end (at the points) and the ground return, through the block to the chassis to the battery terminal. Do you have the pans? Do you have a ground cable between the engine block (or transmission housing) and the frame? What kind of condition is your battery ground strap? Those are the kinds of things I suggest checking.

I'm admittedly very new to this exact type of car, but very experienced with electrical systems. If the model A contains some special kind of electrical science, then please disregard my suggestion.

Oh, FYI: a condenser IS part of the grounding scheme for the HV spark. Its connections and condition shouldn't be overlooked.

[robw]

Originally Posted by P.S.

It will rev only when choked because a richer mixture will srill explode even with a weak spark.

The grounding issue is somewhere between the coil low end (at the points) and the ground return, through the block to the chassis to the battery terminal. Do you have the pans? Do you have a ground cable between the engine block (or transmission housing) and the frame? What kind of condition is your battery ground strap? Those are the kinds of things I suggest checking.

I'm admittedly very new to this exact type of car, but very experienced with electrical systems. If the model A contains some special kind of electrical science, then please disregard my suggestion.

Oh, FYI: a condenser IS part of the grounding scheme for the HV spark. Its connections and condition shouldn't be overlooked.

I've checked the ground strap... cleaned and tightened the connection. Also the whole distributor was cleaned to include the condenser.

There does not appear to be any other ground strap anywhere. I would've thought that if it were a ground strap problem, it would have showed up before now... I'll hook up another ground cable just to check.

[Tom Wesenberg]

Hold the coil wire 1/4" from a head nut and check for a hot blue spark. If that's OK, then I'd rev the motor and slap your hand over the carb intake. Just before the engine dies, remove your hand and let it rev up and do it again. This may pull some junk through the carb and help. I still think it sounds fuel related.

[BILL WILLIAMSON]

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Some moisture "may" be trapped in the distributor itself?? Bill W.

[P.S.]

Ground for the bottom of the coil proceeds as follows:

Through the lead on the + side, down the inside of the armoured cable, through the connection to lower plate, (through condenser for HV) through connection to flexible wire, through flexible wire to points, through the points to points block, through points block to upper plate, through upper plate to distributor housing, through distributor housing to head and block, etc. ALL of those connections have to be clean and tight with no paint, oil, dirt, etc. between them. Points especially have to be clean and touch squarely, not on edge. Clean the points with isopropyl alcohol, not brake cleaner. You don't want any trace of oil between the points or any other electrical connection.

Then lastly, the engine block has to be grounded to frame, etc.

Your HV is finding the return path through armoured cable, etc instead of proper path. I am guessing a problem with grounding based upon that clue.

[robw]

Originally Posted by Tom Wesenberg

Hold the coil wire 1/4" from a head nut and check for a hot blue spark. If that's OK, then I'd rev the motor and slap your hand over the carb intake. Just before the engine dies, remove your hand and let it rev up and do it again. This may pull some junk through the carb and help. I still think it sounds fuel related.

Did the 1/4" check... blue spark. Also did the momentary cover of the carb intake... and disassembled verified all the passage ways clear... I've done the momentary cover of the intake many times...

Originally Posted by BILL WILLIAMSON

Some moisture "may" be trapped in the distributor itself?? Bill W.

I went through it pretty well when I replaced the lower plate and put new points in... they are clean and dry.

Originally Posted by P.S.

Ground for the bottom of the coil proceeds as follows:

Through the lead on the + side, down the inside of the armoured cable, through the connection to lower plate, (through condenser for HV) through connection to flexible wire, through flexible wire to points, through the points to points block, through points block to upper plate, through upper plate to distributor housing, through distributor housing to head and block, etc. ALL of those connections have to be clean and tight with no paint, oil, dirt, etc. between them. Points especially have to be clean and touch squarely, not on edge. Clean the points with isopropyl alcohol, not brake cleaner. You don't want any trace of oil between the points or any other electrical connection.

Then lastly, the engine block has to be grounded to frame, etc.

Your HV is finding the return path through armoured cable, etc instead of proper path. I am guessing a problem with grounding based upon that clue.

I think I've gone through all of that... but I'll go through once again...

[Patrick L.]

I too feel that right now the issue is fuel. That said, an electrical problem could happen if the distributor isn't well grounded to the block, thats thru its contact and the set screw.
Back to fuel, have you removed the line at the carburetor and checked for proper flow ? Does the fuel line extend too far beyond the ferrule into the carburetor ?
What carburetor are you running ? Where are the adjustments set ?

[P.S.]

Originally Posted by robw

I think I've gone through all of that... but I'll go through once again...

OK, sounds good.

As a side note, after gapping points the very first time on the Model A, I had problems. I had used the feeler gauge to set the gap and the barely noticeable oil on the feeler gauge obviously left some behind on the points and was enough to make the points work poorly. After soaking the edge of a thick business card in isopropyl alcohol and cleaning the points, she purred like a kitten.

Also discovered through tiral and error that the points have to close absolutely square for best results. Using a magnifier, you can reposition the points block or bend the points themselves slightly to make them land square.

I started using a scope, power supply, and load resistor, and spinning the distributor with an electric drill to "tune" the distributor while on the bench before installing in the car, and it's amazing how much very small problems can cause the waveform to go scattered and not be perfectly square.

Since adpoting the electronics engineer approach to setting up distributor and points, our car is running better than ever. This last week, the guy who owns the body shop in town (whose dad is an old Model A guy) told me that his dad said our Model A is the best running car he's ever heard in his decades of working on them. Quite a compliment!

The drill/scope method will also uncover a condenser that isn't yet bad, but will be soon. I had to buy 4 different condensers before getting one that works exactly right.

[Tom Wesenberg]

Do you have a known good carb to try on your car? That should let you know if your carb has a problem. As mentioned, you also need to check for good fuel flow to the carb.

[robw]

Originally Posted by Patrick L.

I too feel that right now the issue is fuel. That said, an electrical problem could happen if the distributor isn't well grounded to the block, thats thru its contact and the set screw.
Back to fuel, have you removed the line at the carburetor and checked for proper flow ? Does the fuel line extend too far beyond the ferrule into the carburetor ?
What carburetor are you running ? Where are the adjustments set ?

fuel flow is great... fills a cup up very quickly. No, it doesn't extend too far in...

Originally Posted by P.S.

OK, sounds good.

As a side note, after gapping points the very first time on the Model A, I had problems. I had used the feeler gauge to set the gap and the barely noticeable oil on the feeler gauge obviously left some behind on the points and was enough to make the points work poorly. After soaking the edge of a thick business card in isopropyl alcohol and cleaning the points, she purred like a kitten.

Also discovered through tiral and error that the points have to close absolutely square for best results. Using a magnifier, you can reposition the points block or bend the points themselves slightly to make them land square.

Ok, starting at the coil I went step by step... removed the coil, scuffed up the firewall and the coil mount to make sure there was good metal to metal contact. cleaned out the coil tower... made sure it was good and dry. expanded the contact just a bit so the coil wire would fit in good and snug...
Pulled the distributor... cleaned it, made sure no oil anywhere. scuffed the spot where the condenser screws in. buffed up the metal on the condenser to make sure it had a good ground. buffed the hole in the head to make sure the distributor made a good ground there.

Pulled every plug. gapped at .035. buffed the hole in the head to make sure there was a good ground. cleaned all the plugs.

retimed the distributor. points open on 2d click.

added a ground strap from the transmission to the frame.

no change. I'll check tonight to see if my sparkler show is still there. I think it is gone now.

Originally Posted by Tom Wesenberg

Do you have a known good carb to try on your car? That should let you know if your carb has a problem. As mentioned, you also need to check for good fuel flow to the carb.

Nope, no other carb to use. I'm fairly certain the carb is ok... it was recently rebuilt by a professional... and was working great until the great washing.

It starts very easy. almost as soon as you press the starter button. The engine turns over about a 1/4 turn and is running.

anyway...

[Mitch//pa]

the coil itself does not need to be grounded>>>>>
you can hang it by a rope and it will work

[robw]

Originally Posted by Mitch//pa

the coil itself does not need to be grounded>>>>>
you can hang it by a rope and it will work

well... something is not working...

[Tom Wesenberg]

When it's dark look carefully at the coil tower for any sparks.

I've also seen the distributor body have an internal short (usually between 3 & 4) and this will cause a miss, especially at higher speeds, where more high voltage is required to fire the plugs.

[robw]

Originally Posted by Tom Wesenberg

When it's dark look carefully at the coil tower for any sparks.

I've also seen the distributor body have an internal short (usually between 3 & 4) and this will cause a miss, especially at higher speeds, where more high voltage is required to fire the plugs.

Yep, I checked for that... seems to check out ok on an ohm meter... no continuity between 3&4...

Also did lots of continuity checking between various components looking for other possible shorts besides what Les has you look for in his book... no luck there either.

[Tom Wesenberg]

Originally Posted by robw

Yep, I checked for that... seems to check out ok on an ohm meter... no continuity between 3&4...

Also did lots of continuity checking between various components looking for other possible shorts besides what Les has you look for in his book... no luck there either.

Continuity means nothing when dealing with high voltage that can jump large gaps. Be sure to try a good distributor body and cap.

[robw]

Originally Posted by Tom Wesenberg

Continuity means nothing when dealing with high voltage that can jump large gaps. Be sure to try a good distributor body and cap.

Ok, well, I've tried two different bodies... the one that was working well enough before, and this new one, which fits much tighter. Since I'm using different rotors for each cap... it is easy enough to jump between the two...

other than running them... how else would you test them? Even when running them... how would you test them to know that #3&4 were shorting out?

[Tom Wesenberg]

My friend's was shorting between 3 and 4, even at idle, so I could short the plugs and found the fault to be the distributor body. If it only misses at higher speeds on the road, then changing the part is probably the easiest way to check it.

[robw]

Ran it in the dark again... light show is almost gone... only appears at high revolutions and is not nearly as bright as before. Nothing by the coil. One small blue spark between the armored cable and the retard lever, which is almost impossible to see... but it is there. The other part of the light show is at the spark plugs... very faint, but the spark creates an illusion of the spark plugs being transparent.

At any rate... it is still there, so I've still got something not right. I'm done for this weekend... back on it next weekend.

rob

[Tom Wesenberg]

Try running a ground wire from the condenser ground screw to a good ground on the engine. A good clip lead will do.

[BILL WILLIAMSON]

This is like a "SUSPENSE DRAMA", now we have twiddle our paws for a whole WEEK! You know, to a Dog, that's equal to 56 DAYS! If only Ol' Whatzhis name, (My pet Man) would get that TRAP runnin' maybe I could endure the wait? Buster T.

[P.S.]

Originally Posted by robw

Ran it in the dark again... light show is almost gone... only appears at high revolutions and is not nearly as bright as before. Nothing by the coil. One small blue spark between the armored cable and the retard lever, which is almost impossible to see... but it is there. The other part of the light show is at the spark plugs... very faint, but the spark creates an illusion of the spark plugs being transparent.

At any rate... it is still there, so I've still got something not right. I'm done for this weekend... back on it next weekend.

rob

Wow. Real head scratcher.

OK, a new clue emerged in your last post. You shouldn't see a spark "through" the spark plugs. Since the inside of the plugs is a solid metal conductor, the spark should travel along it and not be illuminating through the ceramic. It sounds like severely corroded plugs now. Since you know how to do conductivity testing, what is the resistance from the top of the plug to the center electrode inside the plug (where the spark jumps while inside the motor)? Should be 0 ohms.

[Mike V. Florida]

How old are the points? I don't mean how long since you installed them but rather do you know when they were bought new?

I ask because a couple of years ago I remember owners complaining of missing at high RPM and the problem turned out to be week spring holding the points to the cam. as the speed increased the points would no longer ride on the cam and bounce so as not to close each time.

A shot in the dark, I know.

[P.S.]

Originally Posted by Mike V. Florida

How old are the points? I don't mean how long since you installed them but rather do you know when they were bought new?

I ask because a couple of years ago I remember owners complaining of missing at high RPM and the problem turned out to be week spring holding the points to the cam. as the speed increased the points would no longer ride on the cam and bounce so as not to close each time.

A shot in the dark, I know.

Yes, that's a real good point. However, that wouldn't explain the "light show" he's experiencing.

[Mike V. Florida]

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Originally Posted by P.S.

Yes, that's a real good point. However, that wouldn't explain the "light show" he's experiencing.

He did say in his original post "suddenly the engine was running lean... rough running, and it would backfire if I revved the engine."
That's why I thought of the points bouncing. Is it the problem? I don't know just trying to help.

[tbirdtbird]

You obv still have HV leaking to ground and you are aware of it. Under the circumstances all your eval must now be done in the dark to truly know what is going on.

You've pulled the plugs and cleaned them incl the porcelain and they still bypass voltage to ground. And the coil wire is "new" but some ignition wire is junk, so beware of that. I've had 'new' ign wire leak spark like crazy. 10,000 volts is a lot to hold back.

Charlie Kettering was a genious when he designed the L-C circuit which we have come to know as a points- based system. He knew what he was doing and how to get the voltages needed to jump a gap, and he put the earlier magneto systems out of business. And he was untouched for nearly 100 yrs until electronic ignition was born. Too bad he worked for GM and not Ford.

Since this started with a cleaning, I am gonna suggest you install a new set of plugs and get a length of ultra modern silicone coil wire at least for the time being.

Porcelain under a microscope looks like cinder block (cement block)...meaning very porous. I think the pores are contaminated beyond cleaning.

The grounding discussion is interesting but 10,000 volts will find its way to ground, never worry about that

Tom is very correct about the formation of carbon tracking on plastic and bakelite (the first plastic) parts such as dizzy caps. Once it forms it will always return to the same place no matter how well you clean it. The part must be replaced. Not sure this is your problem right now, just wanted to second Tom.

[James Rogers]

You need to change the plugs. Don't clean them, change them to new. You shouldn't have sparks around the plugs. Not only is it making your engine run bad but in some cases it is dangerous.

[robw]

Originally Posted by BILL WILLIAMSON

This is like a "SUSPENSE DRAMA", now we have twiddle our paws for a whole WEEK! You know, to a Dog, that's equal to 56 DAYS! If only Ol' Whatzhis name, (My pet Man) would get that TRAP runnin' maybe I could endure the wait? Buster T.

Dang it... I never wanted to be a drama queen!

Originally Posted by P.S.

Wow. Real head scratcher.

OK, a new clue emerged in your last post. You shouldn't see a spark "through" the spark plugs. Since the inside of the plugs is a solid metal conductor, the spark should travel along it and not be illuminating through the ceramic. It sounds like severely corroded plugs now. Since you know how to do conductivity testing, what is the resistance from the top of the plug to the center electrode inside the plug (where the spark jumps while inside the motor)? Should be 0 ohms.

It could be an illusion... with the spark travelling along the outside of the insulator... looks kinda cool actually. I'll check the resistance just to see what I've got.

Originally Posted by Mike V. Florida

How old are the points? I don't mean how long since you installed them but rather do you know when they were bought new?

I ask because a couple of years ago I remember owners complaining of missing at high RPM and the problem turned out to be week spring holding the points to the cam. as the speed increased the points would no longer ride on the cam and bounce so as not to close each time.

A shot in the dark, I know.

Just bought the points last week... spring seems strong enough.

Originally Posted by James Rogers

You need to change the plugs. Don't clean them, change them to new. You shouldn't have sparks around the plugs. Not only is it making your engine run bad but in some cases it is dangerous.

Yeah, I'd come to the same conclusion... just can't run down to Autozone and pick up a set though... will have to order them.

Back at it next week...

rob

[QGolden]

I agree with the plug change. Iff'n yours are old their may be very small porous cracks in the porcelain. When you cleaned them you could have pushed enough material into the cracks to create a path to ground. I do not think this is a fuel issue, unless there is another chapter to the story regarding the carburetor. The problem started when you cleaned the engine. Something changed at that time. Choking the carb to make it run better is a red herring.

Sounds like a good problem to run a contest around....

[James Rogers]

Originally Posted by robw

Dang it... I never wanted to be a drama queen!



It could be an illusion... with the spark travelling along the outside of the insulator... looks kinda cool actually. I'll check the resistance just to see what I've got.



Just bought the points last week... spring seems strong enough.



Yeah, I'd come to the same conclusion... just can't run down to Autozone and pick up a set though... will have to order them.

Back at it next week...

rob

Why? Most auto parts keep W16Y or W18Y on the shelf.

[kwisor]

hello
what is the differance in the w16y and the w18y and what is best to use
kevin
1930 mo9del a tudor
1923 model t roadster p/u

[James Rogers]

Originally Posted by kwisor

hello
what is the differance in the w16y and the w18y and what is best to use
kevin
1930 mo9del a tudor
1923 model t roadster p/u

Temperature range. I use the W18Y because they are a bit hotter.

[Patrick L.]

I agree, I would think the local auto store should have the correct sparklers including 3076 or 3077 Autolite. The 3077 being a tad hotter than the 3076 just like the W18 is hotter than the W16 and I prefer the hotter. I prefer Autolite to Champion in just about any application, but, thats just my opinion. The Champions certainly look better though.

[James Rogers]

Might even find some TT10's.

[robw]

Originally Posted by James Rogers

Why? Most auto parts keep W16Y or W18Y on the shelf.

Hmmm... my local ones (autozone, advance auto) don't for some reason.

[1931 flamingo]

Try NAPA..................
Paul in CT

[James Rogers]

Nobody around there owns an N series tractor? Try a local n on chain auto parts.

[midgetracer]

N series tractor has a plug that is way smaller than a model A. It is the same as a 40 or so flathead Ford.

[robw]

Originally Posted by 1931 flamingo

Try NAPA..................
Paul in CT

Napa it is! Not in stock, but in a warehouse somewhere nearby... Of course I'm in PA this week, which makes it easier... somehow I think there are more uses for this type plug around here compared to Northern VA...

[petew]

Just went through this with my freshly rebuilt A engine . Very similar symptoms to yours . I changed the condenser and it stopped missfiring , smoothed right out .
I originally thought that my problem was fuel mixture but the occasional popping led me to the condenser .
I don't know what test Mr Andrews has for them but I would try a new one anyway.
My second target would be the coil but I believe I read that you have changed that already.

[BILL WILLIAMSON]

I knew 2 guys that fought poor runnin' for weeks! Popped in NEW plugs & VOILLE'! Plugs ARE a wear out/disposable part! When buying a toilet part, buy 2! When buying plugs, buy 2 or 3 sets. Those Autolight plugs are cheap & perform extremely WELL. Once plugs are sandblasted, they're NOT long for this world. Bill W.

[tbirdtbird]

his 'misfiring' is because of visible HV leakage around the plugs to ground.

[robw]

Ok, so... new plugs, new condenser, new coil... this is additive to the new distributor cap & cover and points...

cranked it up... same nonsense...

pulled the carb yet again... blew out all the jets... again... put it back on and try it...

ta da! engine starts and the acceleration problem is gone.. or mostly gone...

still idling a little rough... tightened the manifold bolds a bit more, don't seem to have a vacuum leak any more. adjusted the carb.

still seems to run a little rough. drivable.. but still rough.

after it got dark tonight I checked for the light show... didn't see anything...

closer, not there yet.

rob

[Mike V. Florida]

Originally Posted by robw

Ok, so... new plugs, new condenser, new coil... this is additive to the new distributor cap & cover and points...

cranked it up... same nonsense...

pulled the carb yet again... blew out all the jets... again... put it back on and try it...

ta da! engine starts and the acceleration problem is gone.. or mostly gone...

still idling a little rough... tightened the manifold bolds a bit more, don't seem to have a vacuum leak any more. adjusted the carb.

still seems to run a little rough. drivable.. but still rough.

after it got dark tonight I checked for the light show... didn't see anything...

closer, not there yet.

rob

OK OK one more thing off the list, no light show. If blowing out the carb worked temporarily then you must be getting junk in the carb from the tank along with a possible air leak in the area of the butterfly shaft.

[tbirdtbird]

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OK good going; for the record do not overtighten the manifold nuts, that manifold has to move as it expands and contracts....else it will crack...

Also, be sure your gas line doesn't go too far into the carb and bottom out and thus block fuel flow..

keep us posted...

[noboD]

I had trouble with my neigbor's old car. The top radiator hose dripped and when the car sat it for weeks would miss when started. The front spark plug actually rusted under the washer, no antifreeze, and would not fire. I check for continuity and there was none. Even with the threads the plug was not grounded. Cleaned the area under the washer and it was fixed. Might want to check with an ohm meter?

[robw]

So today, before I left for the week... I had to make a run to the Dump... so I loaded the stuff up in the Model A and headed out to give it a good run... it is about a 7 mile trip each way. Four of those miles each way is good wide open highway.

It is still idling a little rough and the roughness does not really go away at higher speeds.

But it runs... It drove all the way there like a champ. On the highway it easily ran 55 mph without pushing it very hard. Engine temp stayed pretty normal too. The motometer is very active... so I was pleased to see the temp staying put as I cruised at high speed.

Whatever is causing it to idle rough... it is not that serious I suppose. It ran smoother previously... I'll get it that way again eventually.