HCCT questions - every other spark stronger

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namdc3
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HCCT questions - every other spark stronger

Post by namdc3 » Thu May 23, 2019 12:23 am

First off, I'm a newbie to using an HCCT and fully understand that I understand very little. I have a professional rebuild my coils, but I happened into the opportunity to buy this HCCT and like to fiddle with it. (Read as please refrain from suggestions to have a professional do my coils or to try xyz type of tester). My HCCT is a Service Station Equipment Company unit. I was supposedly rebuilt quite some time ago. I was putting 8-10 coils across it this evening, basically experimenting without actually doing any coil adjustments. Before I started, I thoroughly cleaned the ID of the brass ring and the pointer and set the point gap to a smidgen under 1/4". In testing the coils, it seemed like, generally speaking, every other spark on the ring tended to be stronger. In other words, every other spark location on the ring tended to look weaker when it did jump, didn't jump as often, and for some coils didn't seem to want to jump at all. For some coils, all 16 locations seemed to work fine, but for coils that weren't perfect, the "good" and "bad locations were always the same. After finishing, I noticed that my observations seemed to be confirmed, as every other location had a small brown spot where the spark jumped. The locations with the brown spot are the "strong, easy spark" locations. To be clear, it's not the brown spot that I see as the problem or that some coils didn't behave right, it's the "every other location" aspect that seems wrong/odd to me. What's going on? Field coil or magnets? Why is it such a clear pattern?

I took photos of the spots to show how they are on every other location. Sorry about craning your neck - the iphone thinks it knows which side is up.
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Matt in California
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Re: HCCT questions - every other spark stronger

Post by Matt in California » Thu May 23, 2019 2:10 am

Martin,
It sounds like the HCCT is bad. Please PM me and I will give you my address. You can send it to me and I will keep it:) I don't have a HCCT, so I can't give you any other advice:)

Matthew

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Re: HCCT questions - every other spark stronger

Post by jmc » Thu May 23, 2019 6:47 am

Could you try to post a picture of the spark pattern? If the room is dark, the sparks will show up in a picture pretty well.


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Re: HCCT questions - every other spark stronger

Post by Hal » Thu May 23, 2019 7:30 am

I don't know that Ron Patterson frequents the forum very often anymore, but I'll bet he could answer your question. If he doesn't respond here, you might try looking him up and e-mailing or calling. He has posted his phone number on the forum many times over the years, I'm sure a search would turn it up.


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Re: HCCT questions - every other spark stronger

Post by TheMoneyPit » Thu May 23, 2019 7:50 am

You might have one dead coil on the mag ring, something tells me this came up with mine and I had to rebuild the ring.... that was 35 years ago, and a bit shaky on reflection so let’s wait for the gurus to chime in.
There is no such thing as a “free” lunch... :D

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Re: HCCT questions - every other spark stronger

Post by namdc3 » Thu May 23, 2019 8:35 am

Good thoughts. I have to go to the four letter w word, but will check back later. I haven't seen any instructions on how to ensure your HCCT is good (other than a pro rebuild). I wish I knew who rebuilt it, but the gentleman I bought it from passed away recently. I do know the ring standoff insulator issue was fixed with blind-hole standoffs.

Matt, you may be right. I just checked, and S&H to CA was $10,000. Drop a check in the mail, and you can take this junky thing off my hands. ;) I might wait until the check clears...


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Re: HCCT questions - every other spark stronger

Post by Kevin Casey » Thu May 23, 2019 12:16 pm

Just a thought, your HCCT puts out AC current.Therefore it may be that the spark is jumping more easily from the sharp point when the polarity is that way. If some coils are putting out more energy you would not notice this. Try dropping the spark gap to 3/16" and see what happens.Regards Kevin.

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Re: HCCT questions - every other spark stronger

Post by namdc3 » Thu May 23, 2019 8:23 pm

Kevin, that's an interesting thought. If the ring and pointer are switching between being the cathode and anode, perhaps that would also explain the alternating brown spot. I hesitate to even comment for fear of further revealing my complete lack of understanding of what is going on. I would think one way would cause a brown spot on the pointer and the other would cause the brown spot on the ring, hence the every other location. As to the visual "weak spark, strong spark", it's not intuitive to me why one way would jump easier than the other unless maybe it jumps easier when it's concentrated electrons leaving the pointer.

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Re: HCCT questions - every other spark stronger

Post by namdc3 » Thu May 23, 2019 11:59 pm

I played with it some more this evening. I was not successful at taking good pictures, but I observed the same thing. Interestingly, there is a coil that has nice fat blue sparks at all 16 locations gapped to 1/4". When I changed the pointer to 3/16", this coil had fat blue sparks on the previously mentioned "good" locations and thinner, more reddish sparks on the previously mentioned "bad" locations. Going back to 1/4" gap made 16 fat, blue sparks again. I think Kevin must be on to something with respect to 8 of them jumping one way, 8 of them jumping the other way, and one way being easier than the other way. I don't know that that's actually how it works, but it would maybe also explain why only every other spot has deposits.

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Re: HCCT questions - every other spark stronger

Post by Mark Nunn » Fri May 24, 2019 8:21 am

If Kevin is correct you may be able to verify that using the point of a pencil in the spark path. It is the same principle as checking modern coil polarity. Put the "lead" in the spark and see which way the spark goes. I would guess the brown spots have the flash going toward the ring and the other location going toward the pointer.

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Re: HCCT questions - every other spark stronger

Post by namdc3 » Fri May 24, 2019 10:23 am

In the pencil test, a flare on the ring side would correspond to the pointer being negative, which would also correspond to the easy direction for the spark to jump (electron concentration on sharp point) and also the brown spot on the ring. All of this makes perfect sense if indeed the sparks alternate direction (8 one way and 8 the other way).

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Re: HCCT questions - every other spark stronger

Post by namdc3 » Fri May 24, 2019 2:17 pm


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Re: HCCT questions - every other spark stronger

Post by namdc3 » Sat May 25, 2019 9:36 am

I'll restate the bottom line clearer in hopes of an answer. Does the model t magneto generate sparks jumping in alternating directions when used on an HCCT without a timer due to the magneto's A/C?

The answer to the above question hinges on whether polarity of the induced current in the coil's secondary is dependent on the polarity of the collapsing field in the primary/electromagnet. I assume yes, but really don't know and am hoping that's an easy electrical question.

In HCCT use, every peak of the current (8 positive and 8 negative) are creating sparks, whereas in a car with a timer, every fifth peak (either all positive or all negative) create a first spark to fire a cylinder. If all four coils are wired the same internally, each cylinder would have the same polarity of spark.

Further, that's why questionable, unadjusted coils on my HCCT start dropping a particular 8 sparks first because those 8 locations have spark polarity such that it is harder to jump a given gap in the HCCT, namely when the ring is negative and the pointer is positive. A good, properly adjusted coil has no problem jumping with either polarity.

Right??

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Re: HCCT questions - every other spark stronger

Post by Mark Gregush » Sat May 25, 2019 10:50 am

Somewhere in the back of my memory, the alternating sparks rings true. I read somewhere, when the coils are fired on DC only one side of the points gets pitted/worn and I remember reading it was good practice to swap the leads every so often so there was even point wear because the current was only flowing in one direction, unlike AC that flowed both ways. (this would be for cars without starter/generator) I have weak magnets on my HCCT so have to spin it fast to check for double sparks, no time to really tell what direction they are coming from.
I know the voices aren't real but damn they have some good ideas! :shock:

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Re: HCCT questions - every other spark stronger

Post by MKossor » Sat May 25, 2019 11:06 am

Nikolaus asked:

"Does the model t magneto generate sparks jumping in alternating directions when used on an HCCT without a timer due to the magneto's A/C?"
MK> Yes

"In HCCT use, every peak of the current (8 positive and 8 negative) are creating sparks, whereas in a car with a timer, every fifth peak (either all positive or all negative) create a first spark to fire a cylinder. If all four coils are wired the same internally, each cylinder would have the same polarity of spark."
MK> Correct, however, it depends upon spark lever position. Typically, there are 4 magneto polarities: Starting, fully retarded, advanced to the next magneto pulse (still too retarded), advanced to the 3rd magneto pulse (Typically optimal) and advanced to the 4th magneto pulse (typically too advanced, knock etc.)

Further, that's why questionable, unadjusted coils on my HCCT start dropping a particular 8 sparks first because those 8 locations have spark polarity such that it is harder to jump a given gap in the HCCT, namely when the ring is negative and the pointer is positive. A good, properly adjusted coil has no problem jumping with either polarity.
MK> IDK, Spark plug theory is predicated on the center conductor operating at elevated temperature that facilitates electron emission. The HCCT pointer is essentially at room temperature. Considering my experience with an Allen HCCT where missing sparks occurred due to oxidation on the spark ring, varying distance between the electrode and spark ring as it turns, and the nuances of interpreting the ever fluctuating current readings, it's an absolute wonder the HCCT coil adjustment method works as well as it does. You obviously have done some homework on HCCT operation since you said you cleaned the electrode and spark ring and applaud your efforts to learn. Given the end objective is to set the coils for equal and consistent firing TIME by measuring average coil CURRENT as in indirect approximation. The periodicity and amplitude of the HCCT magneto output must remain constant (same hand cranking speed) from coil to coil AND each coil must have very similar electrical characteristics (mainly the primary coil inductance) and use of the proper (RMS reading) Ammeter for the method to work well
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Re: HCCT questions - every other spark stronger

Post by namdc3 » Sat May 25, 2019 11:25 am

Thanks, Mike. On the second point, I should have stated "for a given spark lever setting", as yes, all four would switch if the lever was adjusted to the next 22.5 degree timing position.

On the last point, I agree that the actual spark plug theory is driven by the center electrode being hotter and thus it is desirable to have the center electrode be negative. On the HCCT, temperature is not a driver, but I think shape of the electrode does matter. The pointer comes to a sharp point, and the ring doesn't. I think it has something to do with the field or elections being concentrated in that point that makes jumping from pointer to ring easier than from ring to pointer.


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Re: HCCT questions - every other spark stronger

Post by Moxie26 » Sat May 25, 2019 2:12 pm

Nikolaus:

What did you use to clean the brass ring and pointer ???

I use a crocus cloth or fine steel wool to clean and brighten both metal parts before using my tester. Oxidation and corrosion, however slight, will insulate spark points on the HCCT. I learned that from a great friend.

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Re: HCCT questions - every other spark stronger

Post by namdc3 » Sat May 25, 2019 3:27 pm

Green scotchbrite and some fine sandpaper - 400 or 600 grit I think. Then I checked continuity everywhere.


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Re: HCCT questions - every other spark stronger

Post by Moxie26 » Sat May 25, 2019 6:31 pm

Does the pointer run concentric within the spark ring ??? Spark ring , to me, does not shine like it should, can't see the pointer. Unequal pointer/ring distance will cause visual differences in spark. When testing coil, is the meter needle steady at 60 rpm's ??

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Re: HCCT questions - every other spark stronger

Post by namdc3 » Sat May 25, 2019 7:24 pm

Yes, I painstakingly centered the ring, and the ring is round. I think it's working okay based on a good coil doing what it's supposed to. The "every other location" was what seemed odd, but I think we got it figured out based on the A/C sparks. I think things make sense now. Those are good ideas, though. Thanks; I'll check them again next time.

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