Model A Ignition Newbie Question

[mgambuzza]

Recently I started to notice an increase in backfiring - initially thought was because the nicer weather and driving with windows open, but now noticing definite lack of performance, almost like the motor is missing a cylinder. I at a minimum pulled all the plugs and they do look a little like heavier carbon - cleaned up, but same symptoms. I went online and ordered plugs, wires (strips) cap, rotor, body with brass pins, new coil to cap wire, and condenser- all to arrive tomorrow. Then I notice a couple items - my current coil doesn' t seem a standard, and was wondering if it was original or some older OEM - pictures included. The wire seems embedded in the coil and connected to the cap (and the electrode inside doesn't look too good). I'll probably have to order a new Coil as well now that I see that issue. Also I didn't see the capacitor unless it is below the plate where I show the pictures? Any advice would be greatly appreciated.

 

[J Franklin]

Before you change parts check the point gap and see that it is correct. The condenser is the silver colored cylinder under the main distributor body as seen in picture 4. Only change one thing at a time to find the trouble, and remember it could be the fuel system.

 

[Patrick L.]

Yep, what J said.

Try not to throw parts at it.

One thing though about coils. Our monsters do not like oil filled coils. Those coils don't like to be tipped upside down, neither do I.

 

[nkaminar]

It is good that you are doing a tuneup of your electrical system. As others have said, do one thing at a time and try cleaning and adjusting the points before throwing money at it. But, plugs that have carbon on them indicates a rich fuel/air ratio so look at your carburetor too. Have you tried adjusting the GAV?

 

[mgambuzza]

Thanks - I'll try cleaning the points first. The GAV was set VERY rich when I bought it. It wasn't until I did some research that I did start thinning it out making it run better and definitely could smell it in the quality of the exhaust.

 

[old31]

Do what the others have said. I would start the gav at 1/2 a turn and see what happens. So, turn in the gave until it stops, then back it out 1/2 a turn and play with it at that stage.

Also, it is hard to see. Is that a crack on your dist cap on picture 2 at the 1 o'clock position?

 

[Conaway2]

In addition to what’s already been said, be sure you have a solid-core (ie - not carbon-core) high tension wire from coil to distributor. The points spring contact is pretty rusty; perhaps not making consistently good contact. I can’t tell what plugs you’re using. Champion 3X - although pricey - were designed for the Model A engine. Champion 16Y’s work well, too.

 

[frank55a]

Another thing to check. It has been quite a few years but depending how old your distributor body is (may be 20 + years old), some of the older repo bodies were poor quality and did not have sufficient insulation or would crack between the #3 & #4 plug connections. The spark would jump from the #4 to the #3 spark plug lead thru the body. The arcing could be seen if the engine was idling in the dark and you look where the #3 lead comes close to the body. At one tune up clinic our club had perhaps 20 years ago we had 5 or 6 cars that were running poorly and it seemed nothing could fix the problem. Sure enough we found 3 that had bad repo bodies that was causing this problem. When the bodies were change the problem went away.

 

[Kurt in NJ]

from looking at the pictures it looks that the rotor spring is not touching the carbon button, this causes a spark that eats the carbon button

i used to have condenser problems, since i got the A&L burnout proof one it's been over 35 years trouble free, all i do is adjust point gap occasionally and lube cam

 

[daren007]

You are chasing the wrong problem. It is not your ignition but either a leaking intake valve or overly lean mixture.

 

[J Franklin]

You are chasing the wrong problem. It is not your ignition but either a leaking intake valve or overly lean mixture.

I think a too lean mix or leaking manifold would give a different indication on the spark plugs, less carbon and burnt electrode are common. Let him check the ignition first.

 

[Ernie Vitucci]

Good afternoon...The key is to make a list of all the good suggestions above. Test them one at a time...if no change put the old parts back on and move to the next possible problem. A couple of comments...coils and condensers are known to begin to fail when they are hot, but continue to work when they are cold. Keep this in mind. Also your intake and exhaust manafold combination might be loose if it has not been tightened in a long time...40 to 45 pounds feet on the torque wrench...Ernie in Arizona

 

[J Franklin]

Don't over tighten and bust the manifold, 35-40# is plenty of torque

 

[mgambuzza]

one question I have on the coil. From picture when measuring voltage to ground the left wire has voltage. The old coil in picture 2 has Bat and Dist posts on it. The old coil was wired Dist to the hot (left wire) and Power to the left (no power on it). The new coil- Picture 4 has Positive and Negative terminals. Which of these for my positive ground should I connect to the hot lead - I'm presuming the Negative terminal, and the Positive to the right lead that is not hot.

 

[Patrick L.]

Wire the primary coil leads the same as the battery. If car is + grd then the + lead from the coil goes thru the switch to the points.

 

[mgambuzza]

OK, got the coil figured out and wired. Next I thought before I started I take a look at the condenser. When I unscrewed the plate the screw came up but the mounting bracket fell off showing that it wasn’t even attached to the condenser. I pulled the condenser out and as you’ll see it seems that the tip of the condenser is in the distributor. My question is do I have to completely disassemble distributor in order to get that last tip/piece out of the distributor or would I be able to pull it out with a needle nose? I wasn’t sure whether the tip is fastened with a screw or by pressure from the plate when the condenser is screwed into-the distributor body? Pictures of the comparable sizes are attached.

 

[mgambuzza]

OK, got the coil figured out and wired. Next I thought before I started I take a look at the condenser. When I unscrewed the plate the screw came up but the mounting bracket fell off showing that it wasn’t even attached to the condenser. I pulled the condenser out and as you’ll see it seems that the tip of the condenser is in the distributor. My question is do I have to completely disassemble distributor in order to get that last tip/piece out of the distributor or would I be able to pull it out with a needle nose? I wasn’t sure whether the tip is fastened with a screw or by pressure from the plate when the condenser is screwed into-the distributor body? Pictures of the comparable sizes are attached.

OK, “I can hear the chuckles". I found where I bought the farm on this one. Great learning experience. I’ll save the real questions for the real experts. Didn’t realize there was a screw on the other end of the distributor. I guess that’s why sometimes it’s easier to have both sides of the hood open if you can.

 

[wwirz]

I would strongly suggest two things which will help you quite a bit:
1. Join your local Model A club. There are people in the club that grew up with Model As and they can help you in real time.
2. Purchase the Les Andrews "RED" book. This is the bible to maintaining a Model A

I have had my Model A for 1 year. I am still learning. What is excellent is that you are jumping into this great hobby and you are learning too by doing. Do you think you will forget the second screw that holds the condenser again?

Best of luck. This is a great forum.

 

[mgambuzza]

I would strongly suggest two things which will help you quite a bit:
1. Join your local Model A club. There are people in the club that grew up with Model As and they can help you in real time.
2. Purchase the Les Andrews "RED" book. This is the bible to maintaining a Model A

I have had my Model A for 1 year. I am still learning. What is excellent is that you are jumping into this great hobby and you are learning too by doing.Do you think you will forget the second screw that holds the condenser again?

Best of luck. This is a great forum.

I did join a local club, but unfortunately they are a bit away from me. In agreement from past experiences from other car clubs there are always good members willing to help.


I did purchase the Red book. Sometimes it doesn't have the detail I need, and sometimes I need to rewire myself to going back to basics. These are great cars that are truly serviceable - I just need to readjust my troubleshooting techniques (the last problem child I had was a 1973 450SL with multiple sets of "control points"- my first real experience with troubleshooting vehicles with points and system issues).


Complete agreement - a great forum. It shows how participants are so engaged with assisting with troubleshooting.

 

[mgambuzza]

Last update for the evening. Replaced the coil, wire, cap, distributor body, sanded the points, condenser, and although the quality of the sound of the engine improved, I still had some backfire as well as hesitation and light skipping. I then replaced the spark plugs and wire strips. This time it seemed much better. The backfiring disappeared, and I could actually accelerate beyond 20MPH without straining. I'm calling it a night, but I am crossing my fingers that this may have done it. I did purchase a new screen and gasket for my filter that I'll replace next, but it does seem like I'm on the right path. Thanks to all for advice, and posting some pics of the parts that were replaced (condenser was probably not making good contact as it fell apart on disassembly, and coil wire was not in the greatest shape).