I HAVE A SET OF 6 COILS FOR MY 26 WHICH I SENT TO HAVE SET UP TO A FELLOW RECOMMENDED BY OUR LOCAL T CLUB. 3 OF THE COILS ARE OLD, THE OTHER THREE I PURCHASED NEW FROM SNYDERS. AS THE ENGINE IS HAVING A MISS FIRE ISSUE I CHECKED THE SPARK AT EACH PLUG BY GROUNDING WITH A SCREW DRIVER. THE THREE NEW COILS HAVE A VERY WEAK SPARK COMPARED TO THE OLD STYLE COILS,..IS THIS CONSIDERED NORMAL ??
You are welcome to call contact me offline. I don't want to comment on your question here. You are welcome to call me as well.614-582-9422. I have rebuilt both types of coils mentioned in your posts. Both can and will work, but each requires a little different process.
The Coil Doctor
Could be just the capacitors or windings that are installed in the coils.
A visual observation is just that and there could be other things coming into play like how far the screw driver is each time from the head or bolt when you check or how clean the spot is.
Your miss could be other things; compression, valves, fuel, timing, where you set the timing lever, carb adjustment.
My old coils with the proper capacitors fire at different intensity's for each one and the car runs fine but they are all set for the same draw.
Dave, who ever makes the new coils for Snyder's does not install the right capictor as the The Coil Dr. or Ron Patterson, do not get me wrong they will work but not as good especially on Mag.
Hope this helps.
If the new coils you bought are like the one shown in this photo do not waste your time.
Years ago I tried to get these coils to work correctly and found it could be done but they they have a very poor reliabilty record and won't last long.
I quit trying and now throw them in the garbage when received.
Ron the Coilman
Ron not having any experience with coils yet what do I look for or what does a good coil like like compared to the above pic?
There is nothing wrong with the new coils. However, most dealers do not pre-adjust them. They just sell them and you are responsible for adjusting them. No, they will not work right as received. You have to adjust them. We pre-adjust every coil before we sell them. Our customers are always satisfied and the coils are reliable and long lasting. This has been our experience. Sometimes the wood boxes are a little undersized but that is the only problem we have experienced and can be fixed with a small shim behind the coil. Otherwise they work very well.
If possible I always like to start with Ford coils. Most of them have Ford in script on the wood cases. Also try the FunProjects built coils. They are every bit as good as original Ford coils.
The Bauer coils shown pictured above (made in Mexico) are poor choice to spend your money on. A little undersized (small shim in your coil box?), many have the wrong type internal capacitors and, in my experience, poor long term reliability of the secondary windings. Otherwise they work very well?
But what do I know?, I have only been rebuilding Model T Coils for 25 years.
Ron the Coilman
Many years ago I bought a new set of coils in wooden cases. They fit well but had poorer spark than the ones I had which were themselves marginal. I sent them back. I then bought a set of Patterson coils from a friend. If I paid good money and the parts didn't work I would return them pronto. I am running also a set of KW coils I bought from Montgomery Ward in 1957. These have always worked well.
Thanks Ron, I do have a spare set of new (unused) ones that I brought in Feb privately as back ups, I've had them tested but haven't picked them up yet. it will be interesting to see what brand if any they have on them.
Ron the Coilman, don't throw them in the garbage...you could try selling them as decorative bookends on ebay.
Hmmm. And that's called a difference of opinion. But then what do I know, I've always had the wrong opinion for the last 65 years. Jab jab
Folks interested in testing and aligning their own coils may find can find more useful information here: www.modeltecct.com
Recently came across one of those coils pictured above that had poor capacitor leakage; about 1.25 Meg Ohms:
Finally identified the root cause for poor capacitor leakage. Interesting enough, it was not the capacitor, tar/pitch, wood, coil windings or points. Anyone care to propose what it was causing poor capacitor leakage?
Might the cause have been the black paint on the top of the coil?
Good call Bill, I was surprised to learn it was in fact the black paint used on top of the coil. Carbon may have been used for pigment which would make it conductive. I don't recall any precautions for black paint selection from the coil experts when rebuilding coils but apparently it can be conductive.
Again the fact is that the best coil you can buy is an original Ford coil. The reproduction coils made in Mexico have incorrectly selected capacitors, and the secondary winding is inferior. Why waste your time and money on substandard junk at a high price.
New is seldom better when it comes to Model T parts. Brent Mize and Ron Patterson are two of the most competent coil rebuilders. You can't disagree with what they are saying if you want to be taken seriously.
I put in my coils after having them rebuilt at Antique Auto Ranch in Spokane. My 1914 has never run so good before. Every cylinder is strong and smooth.
I had the same problem with the paint.
I always do what Ron Patterson says. He knows best.
Is that 1.5 mega-ohms? Does the reading double if you were to double the distance apart of the probes? Does the bare wood show a reading?
1.551M = 1,551,000 Ohms. Yes, the value does vary with the distance between the probes. The probes appear to be sticking down into the wood but I laid the probes down flat (rotated 90 degrees) on the painted surface without sticking into the wood and had a similar result. I also opened up the coil and disconnected the point terminals from the coil and capacitor to isolate the source of leakage.
So, what is the recommendation for coil top paint that won't conduct?
Mike, so with one of those ECCT things that you showed can most of us check and adjust our own coils at home?
Most of us don't live close to the two guys who are the expert coilmen and properly adjusted coils make a world of difference in how the T runs.
Are the coil testers that you have available at any of the vendors?
Gene, Yes! That is the exact goal of the ECCT: Accurately test and adjust Model T coils anytime, anywhere by anyone.
Knowledge of coil point installation and adjustment is still necessary but you don't have to be an ordained coil master able to read the nuances of current meter fluctuations to know what to do.
The ECCT provides immediate, concise test results after each adjustment that specifically guides you to a properly adjusted coil based on ignition timing, not coil current.
Please check the www.modeltecct.com website for information on availability.
Having done some reasonably extensive testing on an ECCT on loan to me, I can vouch for its performance and accuracy. I compared its results with those obtained with various laboratory instruments and an electronic tester of my own operating on similar principles http://members.iinet.net.au/~cool386/tester/tester.html. The ECCT was completely accurate and very user friendly in operation.
The way I see it, the ECCT is the future of Model T coil testing because it allows adjustment of coils with an accuracy not obtainable by mechanical means.
Importantly, coils adjusted using the ECCT have an equal firing time, and are optimally set whether your coils run from 6V, 12V, or magneto.
The best thing about it is that anyone can test and adjust their own coils at home or anywhere else. You don't have to be a coil expert.
I think it's the most brilliant testing tool to have appeared since I've been involved with Model T's.
Thanks for the clarification.
Don't go to any trouble, but next time you have your meter and a coil handy, could you check the resistance of just the wood? I'm just curious.
I put a water based black stain on the tops of my coils. I cannot read any continuity through it, but my meter does not read to such a small resolution. El Cheapo meter. I've never had a problem, but I can see how one could, if there were enough continuity through the paint, or in my case, stain. I could believe stain and paint both use the same pigment agent.
John, Thanks for sharing your experience with the ECCT. Very pleased it received such a complementary review. There simply is no reason to settle for approximate current based adjusting techniques like the HCCT today to test and adjust Model T coils.
Hal, your a royal pain! Actually, your thoroughness is commendable; I have come to expect nothing less from you. Here is the data you requested:
The probes are being pressed into the wood with moderate force. Thanks for motivating me to make that measurement for completeness.
To Glen's point, once properly adjusted, the coil in question sure seems to perform well electrically. Spark energy is good (53.6mJ) and firing consistency was excellent even at firing rates up to 4000 RPM.
Unfortunately, the ECCT does not test long term reliability.
Thanks Mike. I said not to go to any trouble. I really do appreciate it, though.
It sure looks like the screen shot shows a fail on Capacitor value and on Capacitor leakage. Perhaps operator error? That looks like a bad coil to me if the ECCT can be trusted.
The ECCT is running the Multi Spark Test. The Capacitor Test Results section is showing the values for the last time the Capacitor Test was run. As you have noted it does look like the last capacitor tested failed.
I have an ECCT and it does work well. It's probably not your cup of tea but that's ok. Each to his own.
Glad to oblige Hal.
Note that in this unusual coil case, the capacitor test fails for value and leakage because of the conductive paint NOT a defective capacitor and with a value in excess of 1Meg Ohms, it does not adversely impact coil function.
If not for the conductive paint, the capacitor failure shown would indicate need for capacitor replacement even though it is the same value because it indicates the capacitor dielectric has been compromised and could break down and degrade coil operation (spark energy).
The capacitor test is very sensitive and can be skewed by fingers contacting both point elements or contact with the coil core. This is easily avoided by using a plastic sheet or bag to insulate point contacts so the results pertain solely to the capacitor.
Will you be at Hershey? and if so, what location?
I will bring my questions to Hershey if you are going to be there.
As always Mike, thank you for sharing your knowledge with us. Same thank-you's go equally to Ron and Brent.
Those of us who have spent our hard earned money on the Mexican made coils have ended up having to replace them in short order. They don't last but a few hundred miles if you are lucky, then the points are bad because the capacitors are no good.
I replaced the capacitors in a set of them and set them on a hand cranked coil tester, but they still were inferior. After talking with an engineer who specializes in inductors who evaluated these Mexican coils compared to a Ford coil, it became clear why the Mexican coils could never be anything but substandard.
James, Yes! I will be at Hershey this year. Chocolate Field CQ25 See you there.
In a pile of coils I bought on Ebay lately there was one of these coils. I tried to make something out of it but even the wood is bad. I just took out the hardware and the tar, The coils and the wood is in the garbage can.
By the way, I didn't know they are selling Choclate in Hershey!!!
Just enjoy and have a good time there. Once I will come over there and visit the swap meet.
Oh yeah, they sell chocolate.....at inflated prices. My wife HAS to buy chocolate every year. She SWEARS it is fresher and tastes better when you get it there, rather than in a store. A friend who lives there tells me it is all imported from Mexico and is all weeks/months old, same as in the store.
I don't believe it, The bad coils came from Mexico. I doubt the Mexican Chocolate is the best.
The best Chocolate is the Belgian Chocolate.
We don't make coils but We Make Chocolate.
Andre'; you forgot something ;
"The best Chocolate is the Belgian Chocolate"
"We don't make coils but We Make Chocolate "
And We Make good Quality Rebuild Coils.
I am disappointed that those on this forum who frankly have the technical knowledge that should and DO know better have not pointed out that capacitor leakage of as little as 1.5Meg ohms is of no real significance whatsoever in the operation of a T coil. NEW capacitors that Ford used and run just fine in any Ford coil routinely can measure much lower in resistance (thus higher leakage current). Too bad someone scraped the paint off of a coil top since you probably could paint on a few more coats of the same paint and it would not have any notice. Leakage in a T coil capacitor is more an indicator that the capacitor is nearing its end of life than it is anything else when the capacitor's value is still in range.
I have no problem with people accurately measuring anything with regard to a T but I think it is important to the new people for them to not think that something is a problem when in fact it is not a problem at all.
John, I completely agree a leakage resistance in excessive of 1Meg Ohms across the capacitor/points will not adversely affect coil function and stated so earlier in this thread.
I am, however, rather perplexed why you would advocate a Model T capacitor with 1.5Meg Ohms of leakage is of no real significance whatsoever on T coil operation. It has been long standing guidance of prominent coil experts to replace those original wax/paper capacitors as matter of policy regardless of leakage resistance. Rebuilt T coils are abundant with modern foil/film capacitors and polypropylene film dielectric that have typical leakage resistance greater than 1Million Meg Ohms at room temperature as I am sure you are well aware. Capacitor leakage resistance of 1Meg Ohms on such rebuilt coils clearly indicates something is very wrong; the dielectric has been compromised. Of particular concern would be risk of dielectric breakdown as the capacitor is exposed to the high dV/dt pulse when the points open which can reach amplitudes in excess of 250V, which again, I know you are well versed. Spark energy is seriously reduced if that occurs at voltages well below 250V and can result in poor or erratic engine performance. For these reasons, I believe it is reasonable to suggest replacement of T coil capacitors which have less than 5 Meg Ohms of leakage resistance.
I think new people should be nurtured and encouraged to contribute to our hobby so it continues to grow and be enjoyed long into the future. What disappoints me are tight clicks of prominent individuals sustained by doing the opposite.
Encouraged to investigate further the effect of leakage resistance across the coil points of a firing Model T coil. The question has been raised in the past but never really answered. The following is the high voltage output of a Model T coil with in excess of 100Meg Ohms of leakage resistance across the points when open. The peak voltage reaches 12.5kV before the air between the 1/4" gap breaks down and fires a strong spark. I have also confirmed that there is minimal degradation in high voltage performance due to very poor leakage resistance (~1000 Ohms) across the coil points.
Now here is the same coil with simulated defect of the capacitor dielectric breaking down at 65V during the high dV/dt voltage spike of the firing coil. The leakage resistance remains well in excess of 1Meg Ohm until the voltage across the points reaches 65V then drops abruptly.
The spark plug voltage doesn't even reach 9kV, insufficient to jump the 1/4" gap at atmospheric pressure (14.7psi) so would likely result in a miss under operating cylinder pressure.
Failing the capacitor leakage test does not immediately indicate the capacitor is bad as was the case in the conductive paint on the coil in question presented earlier. Another cause of poor ECCT capacitor leakage results is leakage through the coil core; indicating possible primary wire insulation damage. It is very easy to determine if the poor leakage result is through the coil core simply by placing a thin piece of plastic in between the coil core and vibrator spring when pressing the vibrator spring down so it does not contact the coil core while holding the point open for the capacitor test. That is how I determined the leakage through the core was at issue on the coil I tested. If the leakage test did pass, further coil testing of primary winding insulation is advisable using a Megger.
Coils rebuilt using the incorrect type capacitor, metalized film, that have insufficient dV/dt rating typically fail open (low capacitance value) due to the higher contact resistance of the leads which high dV/dt pulses can destroy connection to the capacitor leads internally. A very valid reliability concern that is not indicated by capacitor leakage.
Mike, what is your methodology? How did you simulate a dV/dt breakdown?
Tom, I simulated voltage break down using a Transient Voltage Suppressor which remains high impedance until its breakdown voltage is reached, then conducts until the voltage falls below the breakdown voltage.
Happy Labor day!