Coil Testing with HCCT and Strobo-Spark

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Model T Ford Forum: Forum 2012: Coil Testing with HCCT and Strobo-Spark
Top of pagePrevious messageNext messageBottom of page Link to this message  By Arnold Wellens on Thursday, July 05, 2012 - 11:30 pm:

I have recently rebuilt about 12 coils, replaced the capacitors with the new thinner high voltage capacitors, replaced the points and potted the coil with tar. I set them up on the HCCT so I have 16 clear and distinct sparks with no double sparks and set the coil AMPS to a steady 1.3 or 1.4 AMPS.

I then have taken the coils to two Model T owners who have Strobo-Spark testers. The coils do not even come close to giving 3 distinct sparks in the Strobo tester window. The capacitors check fine on the Strobo-Spark and the current draw looks good.

My question is: What do I have to do to get the coils to perform on the Strobo tester? Has anyone had a similar experience? I do not own a Strobo tester so I can't make any trial and error adjustments but what would I adjust?

Thanks for any help that anyone can give me. I am new at this and I am at a loss.


Top of pagePrevious messageNext messageBottom of page Link to this message  By John F. Regan on Friday, July 06, 2012 - 12:19 am:

Arnold:

The difference likely is because the SS is operating the points at engine speed rather than hand crank speed. The hardest part of setting up points is getting the cushion spring tension set correctly since that is what prevents the dreaded "double spark" if that is what you are seeing.


Top of pagePrevious messageNext messageBottom of page Link to this message  By James A. Golden on Friday, July 06, 2012 - 05:43 am:

John, Glenn Blough and I provide the Strobo-Spark tester for Arnold's research. I plan to bring my tester and about 8 of those Arnold rebuilt coils to Vermont next week and hope you will be there for a demonstration on what we are doing wrong.

I only bought my tester, after Arnold ran into problems and I found out that your tester also identified bad capacitors.

The four test coils that Coilman rebuilt for me do work normally, for some strange reason. He has never admitted to owning one of your testers, but one can not help but wonder if that device is the real secret to his success.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Arnold Wellens on Friday, July 06, 2012 - 10:47 am:

John, Could you be a little more specific about what you mean by the Strobo tester operating at engine speed?

The following refers to only one coil and one cylinder.

1. HCCT cranks about 60 rpm

2. HCCT produces 16 sparks per revolution (spr)

3. 16 (spr) X 60(rpm) = 960 sparks per min (spm) produced by HCCT

4. 4 cycle engine fires once every two revolutions
( for every two revolution one spark is produced) (rps)

5. HCCT 960 (spm)X 2 (rps)= 1920 (rpm)-- the HCCT is simulating an engine running at 1920 rpm

If the above is correct what rpm or how many sparks per min is the Strobo tester simulating/producing?

Arnold


Top of pagePrevious messageNext messageBottom of page Link to this message  By John F. Regan on Friday, July 06, 2012 - 11:40 am:

Arnold and others:

The back of your HCCT has a magneto ring and flywheel taken directly from a T engine. The ramp time of your coil firing depends upon the speed with which the magnet passes the coil and it matters not how many sparks ultimately get produced per revolution with regard to coil timing dynamics and coil adjustment. The 16 sparks show up because there is no timer used with an HCCT but the crankshaft speed of your HCCT is firing the coil at 60 RPM engine speed and thus in truth the HCCT is not testing the coil exactly as it is being operated in the T with timer and at higher RPM that the T even just idles at. This is not a big deal since it really doesn't matter how you test your coil or how you get it adjusted correctly. It only matters that you do get it adjusted correctly. The Strobo Spark is testing the coil at an engine RPM of 450 and DOES include a timer function so that you are seeing 3 sparks but they are NOT consecutive as with an HCCT. They are "First Sparks" exactly like you would get from your timer contacting and a mag pulse showing up and being fed to the coil in the coil box. Between sparks on the SS, the coil time is allowed to relax just as in the car where the timer does not contact a coil for a complete revolution of the flywheel. The only real consideration is the single spark that fires the fuel and that is the first spark generated by the magneto pulse when the timer has made contact with the coil and thus provided it with power. The SS provides 3 of those sparks per revolution of the spark display device so that you can see if there is any misfiring or double sparking. It is displaying that at a real engine speed pulse equal to 450 RPM. If it displayed the total sparks that might be generated without a timer in there you would not see anything but a continuous spray of sparks that you could not make sense of since you would have so many sparks that it would be nearly impossible to discern any extra ones caused by double sparking.

I have my family including my grand kids coming with me to the tour and tours get rather hectic with everyone going in different directions and living at different hotels. I don't offer seminars on my one tour of the year typically because my wife gets angry that I don't spend time with the family when we are on vacation and I like to tour too when I can. I will try to help but ultimately you need to know I am NOT a coil rebuilder like you guys are. I build new coils and on those the parts are new or totally checked out and the boxes are new too so I don't have to mess with the anomalies that you guys have to deal with. Ron Patterson is way better at rebuilding original coils. I have no idea where we might all meet up but if it can work, I don't have any problem with answering questions or trying to help at any time that I can. I promised my grand daughter a good time on the tour and for that reason I don't want to promise you something that I cannot deliver. At Chicasha swap meet I "hold court" and bring all my equipment to show and explain whatever questions are asked by all comers for all the time that I am there. In those instances I have everything necessary and can promise my time to you guys. It isn't that I don't want to help, but that I have to manage that to a point that I can deliver what I promise also to my grand kids.

Do read the articles written by Ron Patterson, Steve Coniff, and Trent Boggess on coils and timers and their operation for a better handle on how it all works.

Coil adjustment comprises 3 adjustments. Setting the initial gap of the points, setting the operate current of the coil by adjustment of the vibrator spring tension via a small mallet typically, and adjustment of the cushion spring using either a CPT-1 tool or something similar to add or subtract tension until you get only 1 spark per node on either your HCCT or Strobo Spark. The last 2 adjustments have some interaction so you need to work back and forth to get both to eventually produce a single spark and an operate current of 1.3 amps. Sounds simple but can be the devil at times. The repro points vary from lot to lot but the latest ones seem to be better than in past years but every once in a while, I too have to simply toss a set away and put on a new set to get the adjustment I want. I don't screw with them more than about 5 minutes if that helps but remember my coil boxes, hardware, capacitor, and points are all new and the geometry is perfect mechanically to start with since the coil top in my case is perfectly flat new hard maple.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jim Thode Chehalis Washington on Friday, July 06, 2012 - 12:15 pm:

So, the real question is, would a person expect to see any improvement in engine performance using coils set with a SS as opposed to a HCCT?
Jim


Top of pagePrevious messageNext messageBottom of page Link to this message  By Arnold Wellens on Friday, July 06, 2012 - 12:51 pm:

John, I can understand your circumstances at the show, family should come first. I hope you can bare with me a little longer on my quest to understand the coil.

I think I have read every article written by Ron Patterson, Steve Coniff, and Trent Boggess and you. They are excellent.

If I understand your statement correctly: " It is displaying that at a real engine speed pulse equal to 450 RPM."

Questin#1 Would this statement be correct?

The Strobo tester is pulsing or firing the coil 225 times a minute that would equals an engine running at 450 rpm and the tester is only displaying 3 but in fact if you could count them for a minute you would have a total of 225 sparks.

It appears to me that the 225 would be the number of ,"First Sparks" necessary to run at 450 rpm's.

Question#2 I am having problems understanding just what the Strobo tester is doing. If I had the equivalent of a timer on my HCCT and only looked at the pulses that were generated would I have the equivalent of a Strobo tester?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Arnold Wellens on Friday, July 06, 2012 - 12:58 pm:

John, I should add to question #2 if I only looked at the first spark generated by the timer.


Top of pagePrevious messageNext messageBottom of page Link to this message  By John F. Regan on Friday, July 06, 2012 - 02:27 pm:

Arnold:

You are overthinking it. To answer you question if you had a timer hooked up to your HCCT you would display segments of 4 sparks but on alternating revolutions but the RPM would still be 60 RPM. Forget all the counting of pulses and think about one pulse being connected to the coil. As the current pulse rises the coil eventually fires or misfires. That current pulse has a very slow rise if it is being generated with an HCCT since it has a base "speed" of 60 RPM. The current pulse in the SS has a base speed of 450 RPM hence it is a faster pulse and incidentally exactly the same time as would your magneto produce if your car were running at 450 RPM. Your T will NOT run at 60 RPM. The display doesn't really need to show you more than one pulse now and then to show you if it is double sparking or not except that double sparking is sometimes a random event so the more sparks you display the more likely you are not to miss a double spark if it is happening. The SS display is not operating like a T timer or it would show you 4 pulses at each node but they would be so close together you might not be able to see what is happening. Since with electronics I am not bound by the mechanics of the flywheel magneto pulse and spark display that the HCCT has, I elected to essentially enlarge the spark event by displaying 3 events with time between them that allows the coil to go back to being at rest. The display shows the "first spark" that you would see when a timer lands on a coil and then it disconnects the coil for a time and then repeats the sequence so you can see it in rapid succession. It is then more likely you will see any double sparking but also you get a more accurate current setting since it is also metering the operate current of the coil for its "first spark" operation to thus allow more accurate matching of coils. HCCT uses an average current of all sparks when setting the coil while the SS uses the average current of only the "first sparks" which are the most important ones since they alone determine timing accuracy. The T timer will give you 4 sparks in a row but only the 1st one fires the fuel and the first spark takes a different time to ramp up and fire since the coil was not doing ANYTHING just before that. With an HCCT you cannot measure the first sparks since by the time the meter measures anything, you are operating the coil continuously and it never goes back to idle state during the coil current adjustment setting. If I lost you in this explanation I might be able to do a better job at Chicasha time. Just think about the coil and the spark display and what signal is going to the coil while it is displaying the spark event. To see a double spark you only need to know what it looks like on the display you are using. I choose to make it easier to see and to test the coil at engine speed to aggravate the condition that might make it happen. It is for this same reason that I provide 3 settings for the magneto output so as to aggravate that condition too. None of this technical info will be of any help in adjusting coils so I advise most folks out there to not get lost in this. None of this matters. What matters is how to adjust the coil to make it single spark on the display. I do not want anyone to feel bad but my daughter-in-law Angela has zero electronic background and zero model T background yet she can use the SS and sets up all of the new coils we make and she is way faster at it than I am. She just knows what she is seeing and what she wants it to look like. She knows how to make it happen. That is really all you need to do. The more you think about it the more you will over think it and in the end it doesn't help at all. It just makes your head explode :-) I have tried to make a simple but effective tool to set up your coils very accurately. It is a fussy tester and will not make it easy for you to overlook something wrong in the coil operation or adjustment but the method of adjustment is up to the operator. It is just a tool and with practice you might be able to set up a coil faster than Angela but I sure can't.

I Hope this helps.


Top of pagePrevious messageNext messageBottom of page Link to this message  By arnie johansen on Friday, July 06, 2012 - 03:25 pm:

This is another "Arnold", but with the same question as the first Arnold. If Arnold (first one) changed the capacitors and points on 12 coils and got them to operate properly on the HCCT at about 60rpm should they not show the correct pattern on the SS display.

In other words can coils be set up properly on the HCCT and still show "bad" on the SS display?


Top of pagePrevious messageNext messageBottom of page Link to this message  By arnie johansen on Friday, July 06, 2012 - 03:37 pm:

This is another "Arnold", but with the same question as the first Arnold. If Arnold (first one) changed the capacitors and points on 12 coils and got them to operate properly on the HCCT at about 60rpm should they not show the correct pattern on the SS display.

In other words can coils be set up properly on the HCCT and still show "bad" on the SS display?


Top of pagePrevious messageNext messageBottom of page Link to this message  By arnie johansen on Friday, July 06, 2012 - 03:40 pm:

This second Arnold does not know what he is doing. He just got a double message! Is there a machine to fix the Arnold double message problem!


Top of pagePrevious messageNext messageBottom of page Link to this message  By Arnold Wellens on Friday, July 06, 2012 - 03:52 pm:

John

Again I want to thank you for your explanation and patience. I promise this is my last post on the subject today. Jim Golden will be bringing some of my coils to the tour, you might have time to look at one.

I didn't do a very good job of explaining what i see on the Strobo spark after a coil is set up on the HCCT (16 sparks, no double sparks and a steady 1.4 amps)... On the Strobo spark I do not see double sparking ,but just a random spark and on some setting nothing at all.

From your explanation it appears that the Strobo spark is generating a pulse equivalent to one that would be generated by the magneto had it been turning at 450 rpm's and NOT that is putting out 225 pulses. I do not know why you chose 450 rpm's but is it not true that the ramp up time is shorter at higher voltages but the reactance of the coil will make the time to reach 1.3 amp and fire nearly the same at any RPM. If that was true a pulse at 60 rpm would work the same as one at 450 rpm.

In real life the engine is constantly changing speed with various ramp up times.

John have a great time on the tour and I will dream about Model t coils.

Thanks for your help

Arnold (1st Arnold)


Top of pagePrevious messageNext messageBottom of page Link to this message  By Charlie B actually in Toms River N.J. on Friday, July 06, 2012 - 04:01 pm:

So one coil shows differently on both testers because of the speed difference?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Arnold Wellens on Friday, July 06, 2012 - 04:02 pm:

I would like to add that the "first spark " is certainly the important thing that the Strobo tester tests.

Thanks
Arnold


Top of pagePrevious messageNext messageBottom of page Link to this message  By John F. Regan on Friday, July 06, 2012 - 04:43 pm:

Now that you have explained what the SS display is actually showing then I can probably explain that you have been on a wild goose chase somewhat with all the tech questions. The reason you are not seeing sparking all the time in the SS is likely that the coils are arcing internally. Your HCCT is probably not set to the same spark gap of 1/4" as is the SS. Many old coils have long ago been powered up with no place to spark so have laid down carbon tracks inside the box. When subjected to a lessor gap the coil appears to work OK. A good coil will jump a 1/4" gap without issue which is why Ron Patterson's coils are working. If you reduce the gap on the SS it will appear then to say that the coils you rebuilt are OK but they are marginal if they will not jump 1/4" consistently.

Your statement with regard to the electronics rise time is true but you are disregarding the mechanical delay of the points which becomes more signficant as the engine goes faster and they tend to not follow the magneto pulse as the RPM gets faster.

I will gladly set the strobo-spark to a lessor spark gap if a customer wants to thus forgive marginal coils but as I said before "its a fussy tester". 100% of Fun Projects coils are setup on our strobo-spark and they will easily jump 1/4" without issue.

You cannot test a first spark with an HCCT since you don't even get a reading on the meter until you have given the crank a few turns to get up to speed. The HCCT is a good tester and I am not here to denigrate it but the SS is a tool for coil rebuilders to be able to aggravate the conditions and to test internal components (caps for instance). A first test before spending money on a coil is to make sure it is not arcing internally.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Arnold Wellens on Friday, July 06, 2012 - 05:17 pm:

John I just checked my HCCT, it was NOT set at 1/4 inch. I will start the whole adjustment process over again.

Thanks again

Arnold


Top of pagePrevious messageNext messageBottom of page Link to this message  By John F. Regan on Friday, July 06, 2012 - 05:37 pm:

Sorry that was not asked first since it is a common problem unfortunately. I just assumed you were dealing with double sparking issue or some other abnormality. The strobo-spark is not known for delivering "good news" to coils being tested ha ha. Try to set it exactly to .250 since wider endangers good coils while narrower forgives marginal ones.


Top of pagePrevious messageNext messageBottom of page Link to this message  By James A. Golden on Friday, July 06, 2012 - 07:30 pm:

Well I just checked my HCCT and that gap was .196 and not .25 either, so I must admit to misleading Arnold.

The more I learn, the less I know, especially about those coils.

I will just have to pay better attention.

No wonder my daughter calls me the DAD with ADD.


Top of pagePrevious messageNext messageBottom of page Link to this message  By John F. Regan on Friday, July 06, 2012 - 07:56 pm:

We are all learning. It is rather common error since there is such emphasis on "double sparking" as the main issue with coils. Usually brand new coils can in fact withstand 3/8" but it is very dangerous to ever let them jump a gap that wide since it doesn't prove anything and a single "arc over" internal to the coil can start the carbon tracking problem.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ron Patterson-Nicholasville, Kentucky on Saturday, July 07, 2012 - 04:32 pm:

Just so folks get the wrong impression from some comments posed here as questions or suppositions.

After much observation/experience I found that any coil that would not work in the Strobo Spark would also not work correctly in the HCCT and vice versa.
It is always incorrect point adjustment causing the problems and could be witnessed as intermittent missing sparks on the spark ring of the HCCT.
Ron the Coilman


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