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Always wondered if a standard "O" scope could not be setup to see the same thing. Have not tried it, but don't see why not (with an inductive pickup to trigger off of #1 ignition wire, and another off the coil wire to see the individual plug firings).
That and a good manual to tell what the traces should look like, and what a poor trace may indicate.
Plasticman
When I bought my shop it came with an ancient Sun Ignition Analyzer. It was junk but I kept the pickups hoping to use an O Scope someday...have not had time to play but sure it could be done. The trick would be to compare cylinders and look for differences. Kinda like checking compression and finding 1 cyl way off. Maybe we could stop hijacking and start a new thread??
BTW I LOVED building Heathkits, Still have VTVM, Sig Gen, always had highest quality..and tons of Nam vets built the color TV's under the GI bill
When you become proficient at interpreting the patterns here are some of things you can tell:
• lean or rich mixtures
What do the waveforms look like for rich and lean mixtures? It would be very interesting and useful to determine rich/lean on a cylinder by cylinder basis.
I have a nice Tektronix 2225 50 mhz. dual trace scope, but have never tried it as an ignition analyzer. Also have a few "spare" inductive pickups, so be an interesting thing to try.
John, earlier this year I tried doing this with my Heath scope. It sort of worked but needed further development that I didn't have time for.
I used a Radio Shack two piece ferrite choke (two "C" sections held together with a plastic band to form a rectangular toroid, if you will) as the pick up. I wrapped a few turns of wire around the ferrite and then clamped the ferrite around a plug wire. Normal 10X scope probes picked up the signal.
It worked to the extent that I could trigger the scope and get a waveform. I didn't see the classical ringing pattern I expected.
It could be my choice of ferrite material was poor. I dunno. I didn't have the time to think about it much and moved on to other matters.
If you decide to try using your inductive pick ups to do this, how about posting some waveform photos?
What do the waveforms look like for rich and lean mixtures? It would be very interesting and useful to determine rich/lean on a cylinder by cylinder basis.
Jim
There is a part of the pattern called the "spark plug firing line". It is just after the high KV spike. Since the spark across a plug gap is sustained for approx. .8 to 1.5 milliseconds you can tell if the cylinder is lean, rich or if you have turbulence.
On a lean cylinder the KV voltage spike will be higher and the spark line will start higher and slope down. This is because with a leaner mixture there is less conductive fuel so it takes more voltage to cross the gap and to ignite the mixture.
On a rich cylinder just the opposite occurs. The KV voltage spike will be lower and the spark line starts lower on the pattern, usually about 1-2KV.
This is because it has more fuel and it is easier for the spark to cross the gap and ignite the mixture.
If I have time this weekend I will try and take some screen shots of some patterns and post them.
If there is enough of interest I will explain in more detail pattern interpretation.
Joe
If I have time this weekend I will try and take some screen shots of some patterns and post them.
If there is enough of interest I will explain in more detail pattern interpretation.
Joe
Thanks for the explanation and, yes, please do post pictures and more explanations of how to interpret them.
This helps fill a dark band in my knowledge spectrum. I suspect I'm not alone...
This thread really brought back some old memories - I built countless Heathkit amplifiers, preamps, and tuners back in the late 50's (plus huge bass-reflex speaker enclosures in wood shop with the biggest Electro-Voice speakers I could find). Made my share of noise back in those days; haven't used a soldering iron and flux for years (at least since building my own anglewinder slot car frames from brass rod and silver solder in the late 60's)
I have an analyzer like that but cant figure out how to hook it up to a GM HEI ignition.....I thought there was an adapter for it but can't seem to find one..Any help would be appreciated..
I have an analyzer like that but cant figure out how to hook it up to a GM HEI ignition.....I thought there was an adapter for it but can't seem to find one..Any help would be appreciated..
Which analyzer do you have? Heath made a couple of them. Do you have the Heath-supplied cables? If so, one connects to ground, one connects to coil (-), there is a clamp which goes to the coil output, and one other connection to the #1 cylinder. Do you have this?
there is a clamp which goes to the coil output, and one other connection to the #1 cylinder. Do you have this?
With HEI, internal coil with out a coil wire, the coil inductive clip will not work. You need an HEI coil adapter which sits on top of the internal coil such as this one. Sun and Allen have similar ones.
I did a paper on basic scope pattern interpretations, if anyone wants a copy PM me your email address.
Joe
With HEI, internal coil with out a coil wire, the coil inductive clip will not work. You need an HEI coil adapter which sits on top of the internal coil such as this one. Sun and Allen have similar ones.
I did a paper on basic scope pattern interpretations, if anyone wants a copy PM me your email address.
Joe
Had one for many years in the 70s and used it all the time. It finally quit and I couldn't find anyone to fix it. Here it is as part of my engine dynamometer console
Dennis
