oscilloscope hookup? ?

I

Ivan Vegvary

Guest
Trying to find hookup instructions for using an older oscilloscope (heathkit) to do auto ignition analysis. (1948 Pontiac, 8cyl).
Searched the web to no avail. All advice appreciated.
Ivan Vegvary
 
On Mon, 30 Mar 2015 07:12:52 -0700, Ivan Vegvary wrote:

Trying to find hookup instructions for using an older oscilloscope
(heathkit) to do auto ignition analysis. (1948 Pontiac, 8cyl). Searched
the web to no avail. All advice appreciated. Ivan Vegvary
Click to expand...

I was given an old Champion scope to 'look at'. Trigger the scope with
an inductive pickup on #1 plug lead, and observe the coil output (center
distributor) through an El Hugeo (big-ass) resistor. You should see a
string of 8 pulses, and you can compare the shapes to evaluate each cyl.
Search the Champion spark-plug info for pulse shapes etc.
This is all I know about that!
 
On Monday, March 30, 2015 at 8:58:27 AM UTC-7, Wond wrote:
On Mon, 30 Mar 2015 07:12:52 -0700, Ivan Vegvary wrote:

Trying to find hookup instructions for using an older oscilloscope
(heathkit) to do auto ignition analysis. (1948 Pontiac, 8cyl). Searched
the web to no avail. All advice appreciated. Ivan Vegvary

... Trigger the scope with
an inductive pickup on #1 plug lead, and observe the coil output (center
distributor) through an El Hugeo (big-ass) resistor.
Click to expand...

NO! That 'center distributor' is tens of kilovolts, rather probe the primary
(low voltage) side of the coil (it'll be a few hundred volts, might be wise
to plan for +12V... -500V and use a resistive voltage divider). The 'inductive pickup'
is a very sloppy current transformer, you want a small-value burden resistor
on its secondary (and the primary is just a #1 plug wire threaded through
the open center of the C-I transformer core).
 
I would pick it up capacitively. No tampering with the system and it will protect the scope.

Actually the main thing that type of scope shows you is cylinder balance when it comes to compression ratio. If you are at the coil wire, the higher spikes indicate higher cylinder pressure at the time of firing.
 
On Mon, 30 Mar 2015 15:41:11 -0700 (PDT), jurb6006@gmail.com wrote:

>I would pick it up capacitively. No tampering with the system and it will protect the scope.

roger that . If the probe is near the wires you'll have plenty of
signal. I'd wrap a few turns of insulated wire on the insulated HT
lead and use a times ten probe.
Actually the main thing that type of scope shows you is cylinder balance when it comes to compression ratio. If you are at the coil wire, the higher spikes indicate higher cylinder pressure at the time of firing.
Click to expand...
 
On Mon, 30 Mar 2015 07:12:52 -0700 (PDT), Ivan Vegvary
<ivanvegvary@gmail.com> wrote:

Trying to find hookup instructions for using an older oscilloscope (heathkit) to do auto ignition analysis. (1948 Pontiac, 8cyl).
Searched the web to no avail. All advice appreciated.
Ivan Vegvary
Click to expand...

You don't say which scope you have. The heath CO-1015 Ignition
analyzer? The manual is on ebay, http://tinyurl.com/o7qxc2f

I'd guess you just aren't looking very hard, because I've managed to
find a lot of old Heathkit manuals on line. I'm generally just
looking for schematics, but sometimes the whole manual is there.

AND utoob has the heath ignition analyzer and shows something about
the setup.

But do tell the model number of the scope.
I did see a reference to an inductive pickup (not capacitive like I
suggested and like I've been using with my cheap Elenco scope)
 
On Tuesday, March 31, 2015 at 6:23:13 AM UTC-7, default wrote:
On Mon, 30 Mar 2015 07:12:52 -0700 (PDT), Ivan Vegvary
ivanvegvary@gmail.com> wrote:

Trying to find hookup instructions for using an older oscilloscope (heathkit) to do auto ignition analysis. (1948 Pontiac, 8cyl).
Searched the web to no avail. All advice appreciated.
Ivan Vegvary

You don't say which scope you have. The heath CO-1015 Ignition
analyzer? The manual is on ebay, http://tinyurl.com/o7qxc2f

I'd guess you just aren't looking very hard, because I've managed to
find a lot of old Heathkit manuals on line. I'm generally just
looking for schematics, but sometimes the whole manual is there.

AND utoob has the heath ignition analyzer and shows something about
the setup.

But do tell the model number of the scope.
I did see a reference to an inductive pickup (not capacitive like I
suggested and like I've been using with my cheap Elenco scope)
Click to expand...

Thank you, Default
The scope is a Heathkit Model 10-18. I do have the manual, it is not an automotive scope.
Please clarify. Wrap a wirt around the hight tension lead from coil to distributer, and, from that wire make a connection to the scope input. Ground the other scope input to chassis ground?
I also have an 'inductive' clip on that I can borrow from my timing light. Would that be better?

Thank you very much for your comments.

Ivan Vegvary
 
Default, thank you for the time you have invested in this. Will try your suggestions as soon as it stops raining. (Northwest ).
BTW I am working on an 8 cylinder 1948 Pontiac, however, it is good to know that your technique also applies to my vintage 1964 BMW cycle.
Thanks again.
 
Moved from CA to Portland, OR 10+ years ago. Sure miss seeing all the various bikes. All you see up here is Harleys. Sadly, you hear them before you see them.
 
On Tue, 31 Mar 2015 19:03:26 -0700 (PDT), Ivan Vegvary
<ivanvegvary@gmail.com> wrote:

On Tuesday, March 31, 2015 at 6:23:13 AM UTC-7, default wrote:
On Mon, 30 Mar 2015 07:12:52 -0700 (PDT), Ivan Vegvary
ivanvegvary@gmail.com> wrote:

Trying to find hookup instructions for using an older oscilloscope (heathkit) to do auto ignition analysis. (1948 Pontiac, 8cyl).
Searched the web to no avail. All advice appreciated.
Ivan Vegvary

You don't say which scope you have. The heath CO-1015 Ignition
analyzer? The manual is on ebay, http://tinyurl.com/o7qxc2f

I'd guess you just aren't looking very hard, because I've managed to
find a lot of old Heathkit manuals on line. I'm generally just
looking for schematics, but sometimes the whole manual is there.

AND utoob has the heath ignition analyzer and shows something about
the setup.

But do tell the model number of the scope.
I did see a reference to an inductive pickup (not capacitive like I
suggested and like I've been using with my cheap Elenco scope)

Thank you, Default
The scope is a Heathkit Model 10-18. I do have the manual, it is not an automotive scope.
Please clarify. Wrap a wirt around the hight tension lead from coil to distributer, and, from that wire make a connection to the scope input. Ground the other scope input to chassis ground?
I also have an 'inductive' clip on that I can borrow from my timing light. Would that be better?

Thank you very much for your comments.
Click to expand...

You probably mean your scope is an IO18 (India Oscar -not 10) a tube
type scope? http://www.vintage-radio.info/download.php?id=722

Looking up the Heath ignition analyzer
http://www.vintage-radio.info/download.php?id=537
They show an inductive pickup, feeding a transistor type vertical amp.

I can't say if the inductive pickup on your timing light will work but
if you don't mind the effort of trying it, it should (may) produce
better results since it is a low impendence source, the signal should
reflect the actual wave form closer than a high Z capacitive pickup.

I generally wrap some 22 gauge insulated solid hookup wire around the
coil lead for 1/2" wide, and twist the ends so it stays tight without
moving then connect one stripped end to the scope and leave the other
floating. Scope gets grounded to the motorcycle chassis. My bike has
two coils and four high tension spark plug wires - so there's no
syncing involved, but my scope has two channels and I can compare two
ignition wire signals.

You might want to sync on one HT (#1 cyl) lead, then put the vertical
input on the coil wire, which would require two pickups. (distributor
ignition and multiple cylinders) The schematic for the CO-1015 shows
one inductive pickup then a wire running off to a "secondary pickup
clamp" (presumably another pickup for syncing)

It will probably take some tinkering before you have what you want.

My problem is working outdoors and scope brightness becomes another
issue. A heavy dark cloth like the old view cameras used to focus on
ground glass works.

The signal on the primary of the coil may be up to ~400 volts with the
inductive kick and the ringing with the condenser in the kilo-hertz
range.

Good luck.
 
On Wed, 1 Apr 2015 07:03:45 -0700 (PDT), Ivan Vegvary
<ivanvegvary@gmail.com> wrote:

Default, thank you for the time you have invested in this. Will try your suggestions as soon as it stops raining. (Northwest ).
BTW I am working on an 8 cylinder 1948 Pontiac, however, it is good to know that your technique also applies to my vintage 1964 BMW cycle.
Thanks again.
Click to expand...

I covered most of the country on a 71 Triumph and bought a 72 BMW in
73, when I got to California. The bmw bike transited the country a
few times.
 
On Wed, 1 Apr 2015 10:23:48 -0700 (PDT), Ivan Vegvary
<ivanvegvary@gmail.com> wrote:

>Moved from CA to Portland, OR 10+ years ago. Sure miss seeing all the various bikes. All you see up here is Harleys. Sadly, you hear them before you see them.

Know what you mean. I used to love running up to Griffith Observatory
on a Sunday to check out the bikes. Old Indians, Vincents, WWII
service bikes, even a Cushman scooter, Munch Mammoth Turbo, VW BMW
engine swaps, and Ariel Square Four!

I lived in San Diego for 5 years and had a girlfriend who ostensibly
lived in Oxnard, but we spent most of our time in an apartment with a
perfect view of the Hollywood sign, Tower Record Building, etc..

Some great memories there.

Did you ever participate in the California 1,000? and that 64 BMW
that was after the Earles fork version wasn't it? I rode the CA 1,000
in 73 on the BMW, started in the bottom 10% and finished in the top
10% without any effort.
 
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