I want to get a coil and spark plug tester for my own use. Where can I find one?
Ron's Machine Shop in Shandon,Oh. has 2 coil testers for sale in the new Model T Times.
... Or to save $$ and avoid a hernia, look at the Strobospark.
Find the Strobo-Spark here:
I was repairing coils for some time, just replacing the points, before I ever learned the capacitors were always bad. The StroboSpark also checks the capacitor value and leakage.
It is a good idea to check for bad capacitors but they are not always bad. In the interest of long term reliability it may be reasonable to just replace them because they are old even though some old ones will work just fine. Of course you could say the same thing about a Model T.
I just love my StroboSpark, saves lots of time when working on coils, and the performance difference will be noticeable. Money well spent and recouped in better fuel economy and performance.
In regard to capacitors failing in coils, I think they occasionally failed "back in the day" of the T. I base that on the fact that I have a jar of NOS coil capacitors I acquired with a lot of NOS parts decades ago. I think replacing with the correct new capacitor is the only reliable way to go. Anything less is just throwing new points at a bad or potentially bad coil. Just my 2 cents.
Another vote here for the StroboSpark. Great machine.
Straight "Buzz Box" type testers like your looking for will turn up on e-bay occasionally. It will only tell you if the coil operates and they will still have to be HCCT'd or Strobo Sparked for optimum operation. It's worth doing as the performance/power of the engine is greatly inhanced. (you'll never know until you have a set of coils properly calibrated on one of these machines). On capacitors: it's a no brainer here. I replace them with modern stuff. Some work involved but worth the effort I think.
Ditto, strobospark, love it. Permits testing the capacitor value, leakage, and adjust the points very precisely. A buzz box can never show you if the points are making a double spark. If they are, they are not functioning well and performance will suffer. Shocking (ha) how a small adjustment to parts of the points can make all the difference in correct performance of this vital component. I do use my HCCT to check spark plugs though.
A buzz box is a tool that will not tell me enough good information so why waist my money and time with it?
Unless you cannot live with the Bench Art get a Strobo Spark for your coil testing. You can loan it to your friends too.
Proper spark plug testing requires some specialized tools that operate and test the plug under compression like it is used in a engine cylinder. Using a HCCT to check spark plugs is not a comprehensive test.
Ron the Coilman
That Buzz box will tell you the coil is bad, if there are no sparks at all, but it cannot tell you the coil is good.
The HCCT will display all the sparks and tell you if the coil has random misfires, which you can not see with the buzz box and which causes a rough running engine with reduced power.
Setting up coils based on current measurement was the only viable method back in the day but it virtually guarantees cylinder to cylinder timing variation because coil inductance can vary considerably coil to coil.
Engine performance depends on ignition TIMING not ignition Currenting! There are better methods today to actually measure coil dwell time to fire thanks to modern technology. Coils set up for the same dwell time to fire result in a remarkably well performing engine.
How does one set up coils to have identical dwell times? (and ultimately have even cylinder-to-cylinder firing)
Mike, do you have the ECCT ready and available for accurate testing and adjusting of our coils yet?
Folks with access to an oscilloscope and knowledgeable in its use can and have been using this method to set up their coils with great success; especially for performance intensive events like race competitions. I have been working on the Electrically Cranked Coil Tester (ECCT) which will allow anyone do the same thing without special technical knowledge and a fraction of the cost. The project is still in Beta test but making good progress.
Of course, ignition timing depends on many variables. Setting up your coils for identical dwell time to fire does not in itself guarantee even cylinder to cylinder firing but does eliminate timing variation associated with the coils from degrading engine performance.
Mike, has there been a paper or post showing how to use a scope?
I believe that a Model T running on magnet with coils properly adjusted on a HCCT or Strobospark to give just 1 spark per period (of which there are 16 per revolution) does pretty well when it comes to dwell angels.
That is a significant reason why a model T runs better on magnets than on 6V battery.
Mike sums it up perfectly. I built a CRO based tester a couple of years ago primarily to set coils to all the same dwell time, but it was only once I'd completed it I realised it could perform all the other tests required for correct adjustment. http://members.iinet.net.au/~cool386/tester/tester.html
While I've never had the experience of using a mechanical type of coil tester, I'm not sure how it could display actual dwell or firing time.
I easily get a smooth 70+ km/h speed running on 6V battery on a flat road, and this has recently been helped further with the installation of a TW timer.
Ben, Here is a link that describes how I measured coil dwell time to fire: http://www.modeltecct.com/uploads/ECCT_Intro.pdf
Anticipating the ire this newfangled method of coil adjustment would raise, a lot of time was also spent on designing, building and testing with the Model T Data Acquisition System (TDAS) to measure and compare various methods of coil point adjustment. You can read how this was done at this link: http://www.modeltecct.com/uploads/TDAS_V4.pdf