I finally figured out the problem
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Category: Allis Chalmers
Forum Name: Farm Equipment
Forum Description: everything about Allis-Chalmers farm equipment
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=18943
Printed Date: 07 Feb 2025 at 3:08pm
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Topic: I finally figured out the problem
Posted By: craigreavley
Subject: I finally figured out the problem
Date Posted: 01 Oct 2010 at 12:38pm
| I have been jacking with my 1949 C trying to get it to run better. It has been running rough at full speed. I changed carbs, cleaned fuel, set timing, set point gap, new plugs, new wires and it still ran the same. I dont know why this would matter, but the condensor was very loose inside the loop that holds it in place, I changed loops so that it fit tightly, and suddenly the tractor runs perfect. Does the condensor have to ground through the loop or something. This is the only thing that resolved the rough running.I have been loosing sleep over how poorly this tractor had been running. |
Replies:
Posted By: skipwelte
Date Posted: 01 Oct 2010 at 12:41pm
| Yes the condeser has to be grounded, if not it will run rough and it will quit if the condeser doesnt ground. |
Posted By: Gerald J.
Date Posted: 01 Oct 2010 at 1:27pm
|
The engine will run with an open condenser, but point life is short, spark is thin and yellow, not fat and blue. Gerald J. |
Posted By: LouSWPA
Date Posted: 01 Oct 2010 at 2:49pm
------------- I am still confident of this; I will see the goodness of the Lord in the land of the living. Wait for the Lord; be strong and take heart and wait for the Lord. Ps 27 |
Gerald J. wrote:Posted By: GlenninPA
Date Posted: 01 Oct 2010 at 3:09pm
|
Cheer up Lou, better days are coming....
When that happens, you won't be blue any more, just fat. ROFLMAO!
Your friend Glenn ------------- Good judgment comes from experience. Experience comes from bad judgment. From listening comes wisdom and from speaking comes repentance. Wise men learn more from fools than fools from the wise. |
Posted By: LouSWPA
Date Posted: 01 Oct 2010 at 3:20pm
------------- I am still confident of this; I will see the goodness of the Lord in the land of the living. Wait for the Lord; be strong and take heart and wait for the Lord. Ps 27 |
Posted By: Dave(inMA)
Date Posted: 01 Oct 2010 at 3:27pm
|
To your specific question, Craig, the condenser ground is through its case to the body of the distributer. The "loop" you mention, if loose, means that you will have an intermittent ground at best. When tight, there's a good ground from the condenser case to the distributer body. ------------- WC, CA, D14, WD45 |
Posted By: Bob-Maine
Date Posted: 01 Oct 2010 at 3:39pm
| Another bit of useful info that I did not know but may be glad some day in the future that I learned it here. Now if I can only remember it long enough to make use of it. One more reason why this site is great. Bob@allisdowneast :>) |
Posted By: Dave(inMA)
Date Posted: 01 Oct 2010 at 6:34pm
|
Bob, thought I might be the only one with that issue! Happy to know that I have company. LOL ------------- WC, CA, D14, WD45 |
Posted By: Coke-in-MN
Date Posted: 01 Oct 2010 at 8:03pm
|
OK if the condenser is grounded ? WHY ? it is used to store electric when the points are open and discharges through the coil to ground , least that is my understanding.
If a condencer grounds out (internal leakage or dead short) the coil will not build up voltage to be discharged when points open to collapse the field.
Now i am getting myself confused . LOL
The condenser is a simple capacitor that can store a small amount of current. When the points begin to open, the current flowing through the points looks for an alternative path to ground. If the condenser were not there, it would try to jump across the gap of the points as they begin to open. If this were allowed to happen, the points would quickly burn up and you would hear heavy static on the car radio. To prevent this, the condenser acts like a path to ground. It really is not, but by the time the condenser is saturated, the points are too far apart for the small amount of voltage to jump across the wide point gap. Since the arcing across the opening points is eliminated, the points last longer and there is no static on the radio from point arcing.
http://www.familycar.com/classroom/ignition.htm - http://www.familycar.com/classroom/ignition.htm ------------- Faith isn't a jump in the dark. It is a walk in the light. Faith is not guessing; it is knowing something. "Challenges are what make life interesting; overcoming them is what makes life meaningful." |
Posted By: Bob D. (La)
Date Posted: 02 Oct 2010 at 4:22am
|
Coke, most capacitors have two leads. One is normaly tied to ground. The condensor second lead is the case, thus must be tied to ground to complete the circuit. HTH ------------- When you find yourself in a hole,PUT DOWN THE SHOVEL!!! |
Posted By: jaybmiller
Date Posted: 02 Oct 2010 at 6:20am
|
Also the capacitor( condensor) must be the right value for the ignition circuit to work properly. If you change the coil you might need to change the capacitor as well. They form a 'tuned circuit' to get all the energy to the plugs.NOT super critical and if you have a healthy blue spark ,things are 'matched'. But put the wrong cap on a Kohler K301AS and you'll know right away! BTDT.
------------- 3 D-14s,A-C forklift, B-112 Kubota BX23S lil' TOOT( The Other Orange Tractor) Never burn your bridges, unless you can walk on water |
Posted By: wkpoor
Date Posted: 02 Oct 2010 at 8:14am
|
Coke, clear your mind because I think you are cornfused hehehhehe. First off to understand basic ign you need to understand how a transformer works which is basically what a coil is. In order to induce voltage in the secondary windings (they make the circuit to the plugs) you must first collapse the field in the primary windings. You collapse that field by interrupting the flow of current in the primary winding by the use of breaker points. Now that interuption needs to be quick and clean. Points alone will arc therfore the arc is suppressed by the condenser (which is just a capacitor). Now here is the tricky part........while the points are closed the condenser is shorted out and current is flowing in the primary windings. When the points break current will then try to go to ground through the condenser however the condenser no longer being shorted by the points will begin to charge thus stopping the flow of current in the primary winding. This all happens in a nanosecond. The key here is the condenser is what actually stops the current flow and not the points because of the condenser capacitance time constant. Clear Now! |
Posted By: RichinWis
Date Posted: 02 Oct 2010 at 8:51am
| I do know that a condenser will do that to you, I had a WD45 that was giving me fits like that! Changed the condenser and it ran beautifully. Amazing little thing hiding in there that can cause such a headache! |
Posted By: Coke-in-MN
Date Posted: 02 Oct 2010 at 10:11am
|
Now to throw a wrench in your theory. A capacitor will store voltage and is not grounded internally . To test capacitors we used a Champion sand blast cabinet with plug check system. We charged the capacitor with high voltage from plug lead, then set on metal bench, and shorted the lead to bench with insulated probe, if it arced it was good. If no voltage was stored then it was bad.
In fact some capacitors were known to be left charged along side of tools on the bench and when another mechanic went to get the tool the capacitor would be touched and discharge. like grabbing a plug wire.
As the electrical system is DC and the coil is a transformer, a pulse is needed to create a wave within the transformer to energies the secondary windings, this flow creates the high voltage from the 6 or 12 volts on primary side, that is pulsed by the points and the capacitor. Without the pulse all you have is a magnet, not a transformer (COIL).
I have run into several (NEW) bad condensers over time and also bad points where contact of the tungsten to the point frame or arm was bad. This caused a open so points would not flow out to the coil or would ground out to distributor body.
Also have had quite a few capacitors in older Lucas magnetos go bad as it seems over time the capacitor will short out internally and ground to body of armature in mag. (Lucas K2 mag uses a capacitor embedded in armature ) ------------- Faith isn't a jump in the dark. It is a walk in the light. Faith is not guessing; it is knowing something. "Challenges are what make life interesting; overcoming them is what makes life meaningful." |
Posted By: wkpoor
Date Posted: 02 Oct 2010 at 6:05pm
How is there a wrench in my theory? Yes capacitors store potential. So do condensers. So whats the problem here. I think you too are missing the most basic element to points type ign. 3 things are needed to create electricity. 1. a conductor. the winding of the coil approx 100:1 ratio 2. a magnetic field. provided by the current flowing in primary windings 3. motion between the two. collapsing field when points break. My so called theory satisfies all 3 components. |
Posted By: dadsdozerhd5b
Date Posted: 02 Oct 2010 at 6:54pm
|
the condenser must be like a battery that is charged and discharged in nano seconds. the wire is the + terminal and the loop or holder is the - side, if i got it straight. i really think they are full of smoke, like all electrical devises, it is just a matter of time until they let it out and do not work again. lol. ------------- HD5B, HD5G, (2) FARMALL A's, CUB. DO IT RIGHT THE FIRST TIME, IGNORE THE LAUGHTER. FLANNEL IS ALWAYS IN STYLE. |
Posted By: JohnCO
Date Posted: 02 Oct 2010 at 9:06pm
|
Coke and others, please don't try to confuse us, it's just magic, thats all! LOL
------------- "If at first you don't succeed, get a bigger hammer" Allis Express participant |
Posted By: Gerald J.
Date Posted: 02 Oct 2010 at 9:06pm
|
Coils and capacitors both store energy. A coil resists changing the current, so when the circuit opens the voltage jumps, Electrical engineers call that V = L di/dt, e.g. the voltage is a function of the rate of change of current. A capacitor resists changing the voltage, so the capacitor current I = C dv/dt, the current is highest when the voltage changes most rapidly. When the points open, the voltage at the capacitor is minimum and the current in the coil is maximum. Energy gets swapped between the coil and the capacitor a few times rapidly causing the blue spark. No capacitor the spark is thin and yellow because there's no oscillation and the points burn rapidly from the arcing. Gerald J. |
Posted By: Lonn
Date Posted: 03 Oct 2010 at 7:55am
|
Lou and Glenn, you guys made me laugh this morning. Have a great Sunday guys. ------------- -- --- .... .- -- -- .- -.. / .-- .- ... / .- / -- ..- .-. -.. . .-. .. -. --. / -.-. .... .. .-.. -.. / .-. .- .--. .. ... - Wink I am a Russian Bot |
Posted By: Coke-in-MN
Date Posted: 03 Oct 2010 at 8:19am
|
Magic is right, from the old coil box with constant spark caused by vibrating point on coil. To solid state ignition systems where a magnetic pickup mounted on crank all create a spark. The little capacitor (condenser) is still a marvel.
Ah yes electricity in its own is magic that has changed much within our lives.
And the wrench in thoughts, just a point to think on . ------------- Faith isn't a jump in the dark. It is a walk in the light. Faith is not guessing; it is knowing something. "Challenges are what make life interesting; overcoming them is what makes life meaningful." |