Timing light inductive delay?

[DaveMcLain]

If you think about how slow/low the frequency irregardless of RPM is I find it amazing to see that there is ANY noticeable delay in any of the circuits. Think about it the cylinder fires every other revolution even at 10,000rpm that's only 83hz.

[mk e]

Why I am asking. I have 3 timing lights, and though all 3 show same timing at idle (locked distributor), 2 of them show timing retard slightly, progressively as I slowly bring the revs up.

If you use a distributor with an advance curve your retarded timing will not show up, it only happens with locked distributors.

What's that MadBill likes to say....
"a man with a watch knows the time, a man with 2 is never quite sure"

[Zmechanic]

If you think about how slow/low the frequency irregardless of RPM is I find it amazing to see that there is ANY noticeable delay in any of the circuits. Think about it the cylinder fires every other revolution even at 10,000rpm that's only 83hz.

I was kind of thinking this myself, but oddly enough I've never taken a timing light apart. Controlling timing in the 10's or 100's of nanoseconds (billionths of a second) is pretty routine stuff for modern digital electronic parts. The circuit that fires the tube might be the culprit..

Now I want to rig up a circuit that monitors the coil wire and a fast photodiode to see how long the delay is inside a timing light

[upinthehills]

Think about it the cylinder fires every other revolution even at 10,000rpm that's only 83hz.

I wrote a long reply yesterday but when I started to think about I was surprised at the amount of delay it would take to produce this error. As the original poster said it would be about one half millisecond. That's an eternity in electronics and has been for decades. It would be 10 to a hundred times more delay then the time length of the spark.

I was wondering if they had some filtering on the input but even then it would have to very heavy handed. You could open up the cheaper of the units and see if it would make sense to jumper over resistors and capacitors on the input. Sort of a waste of time though.

The USB scope I bought last year ( Pico 2204 ) was about $150 and would easily make a trace of a timing wheel and a coil wire at the same time. It will show signals at 10 million cycles per second so shouldn't have a problem here. It was plenty good enough to show the movement of the pintle in a fuel injector, so it's a fun tool for the money.

An ECU should be spot on for timing, much better than a millionth of a second... It may be they don't always really try.

That's an old saying " an engineer with 2 clocks never knows what time it is..."

[Tuner]

viewtopic.php?p=152381#p152381

Do the math:

6000RPM / 60 = 100 revolutions per second X 360 degrees = 36,000 degrees per second.

Each degree is 1/36,000th of a second or .00002778 sec.

8000 is 1/48,000th = .00002083 sec.

[statsystems]

Why I am asking. I have 3 timing lights, and though all 3 show same timing at idle (locked distributor), 2 of them show timing retard slightly, progressively as I slowly bring the revs up.

If you use a distributor with an advance curve your retarded timing will not show up, it only happens with locked distributors.

What's that MadBill likes to say....
"a man with a watch knows the time, a man with 2 is never quite sure"

That explains why I'm never on time. Watch on my wrist, clock on my phone,one on the dash, radio telling me the time.

[Tuner]

Does anybody ever use the search function?

No dial back, it's just a simple strobe, the Kowa Seiki KE-50-7 “Synchro Beam” timing light is by far the best I have ever used. Small, pocket sized, two AA batteries, brightest ever, brighter than 12V powered lights. They are the most accurate light I know of because they have the least lag between the spark pulse trigger and light flash.

[MadBill]

Why I am asking. I have 3 timing lights, and though all 3 show same timing at idle (locked distributor), 2 of them show timing retard slightly, progressively as I slowly bring the revs up.

If you use a distributor with an advance curve your retarded timing will not show up, it only happens with locked distributors.

What's that MadBill likes to say....
"a man with a watch knows the time, a man with 2 is never quite sure"

That explains why I'm never on time. Watch on my wrist, clock on my phone,one on the dash, radio telling me the time.

Ironically, I now sport a tricked-out Casio which, among a host of other functions, is auto-synched to an atomic clock in Boulder CO that is accurate to +/- one second every sixty five million years. Close enough for a retired guy..

[66Vette]

Tuner:

The Kowa Seiki are not available as far as I could tell. Lots of people looking for them, but no suppliers. Do you have a recommended alternative?

Thanks, Cris

[Circlotron]

Ironically, I now sport a tricked-out Casio which, among a host of other functions, is auto-synched to an atomic clock in Boulder CO that is accurate to +/- one second every sixty five million years. Close enough for a retired guy..

Trouble is, with timepieces that accurate, whenever you are moving around relativity would have a measurable effect on it from the point of view of a stationary observer. Your watch will only be accurate in your frame of reference, not to someone seeing you go past.

[MadBill]

That's OK; I only care 'bout me..

[upinthehills]

Kowa Seiki KE-50-7 “Synchro Beam” timing light is by far the best I have ever used. Small, pocket sized, two AA batteries, brightest ever, brighter than 12V powered lights. They are the most accurate light I know of because they have the least lag between the spark pulse trigger and light flash.

And so what was the delay?

[upinthehills]

is auto-synched to an atomic clock in Boulder CO

Geez, I don't see how a clock in Boulder is going to work for you Bill, can it automatically add leap femto seconds for you? Or is time slower in Canada?

[MadBill]

No, but it does auto-change time zones, and shows what the tides would be if there was an ocean within a thousand miles...

[upinthehills]

I had to look this up because I didn't know wether altitude made a clock run faster or slower. I thought slower because it would be moving faster, but gravity is more important it seems so it runs faster. These clock are now way more accurate than the crappy old regular atomic clock from the 70's. If you have 2 of these on your lab bench and put one on a stack of books, it will measure that just fine. They are trying to get their next model to be good enough to measure a centimeter of altitude!

Keeping time is an old Navy tradition and this stuff is funded by the US navy at NIST (National Institute of Standards and Technology). I was in Washington DC recently and happened to drive by and they display the time to many decimals on a clock outside the base.

http://www.nist.gov/public_affairs/rele ... 092310.cfm

So does anyone have numbers for timing light delay?

At my last job we had a converted LED flashlight to act as a strobe for medical certification on a device. Let's whip up a circuit to convert Harbor Freight LED flashlights to accurate timing lights by replacing the switch with a trigger. Extra points if we can fit it in the flashlight or make a little replacement cap for the flashlight to provide this function.