How do I make an ignition advance guage ?

[Danielson]

Any ideas on this or can I buy one ? I have been also pondering over the idea of optimising the advance curve and it makes sense to me to have inboard advance and vacuum guages so you can see what the optimum advance would be for a given RPM/Load. By applying more or less vacuum via the vacuum advance unit you could then plot your optmum advance curve. Would this work?
I was thinking along the lines of using a pulse generator hooked up in conjunction with the dizzy and balancer and then sending the signal to a calbrated guage but just don't have the knowledge.. Let me know what you think and your formula if you have one..
Cheers Dan

 

[xctasy]

Easy.


Old Ford 105E and Vauxhall service tools used to run little timing lights which ran off the generator or flywheel witness marks. From there, you could set the timing from witness marks on the fan belt, fan blade, pully, whatever with just a lamp.

In your case, all you do is index one part of the alternator pully or bottom half of the transmisison dust cover to TDC. And mark off 0 to 48 degrees before top dead centre at 2 deg intervals.

Then grab a black and white closed circuit TV monitor used for closed circuit cameras, and back light the white marks with a timing light off plug no 1.

There is another much easier way of doing it via electronics. The movement of the plate in the distributor is turned into an potentiometer voltage. So static may be 9 btdc, and then a voltage from 0 to , say 1 volt could be anyhwere from 18 to 48 degrees. Then you could datalog it on a mutimeter against manifold vaccum, or throttle position. I'd grab three multimeters, and log advance, manifold pressure via an XF Falcons Bosch manifold sensor, and use a TPS from an EA CFI Falcon. Add a forth multimeter, and an EF knocksensor, and you could run the engine to within an inch of knocking. Run a bowden cable off the stricker plate, and you can optimise ignition while you cruise

Then get a camcorder, and go have some fun in realtime. A quick 10 minute blatt around the block could yield a a stack of four voltages on the multimeter, from which you can determine the onset of knock, the vaccum at which knock sets in, the behavaiour under 100% load, 80% load, 60% load, 40% etc.

What you alimately need is a 3D advance verses manifold pressure, verses throttle postion verses knock, just like Ford does when mapping the EFI unit. This allows you to trim the advance curve without a dyno.

 

[Lazy JW]

I have thought of this as well but had a simpler plan. Never did it though

First, mark the crank pulley in degrees up to at least 50º. Unplug the vacuum advance, then start at 10º initial advance and use a timing light and tachometer to plot the advance curve until it stops advancing.

Then, temporarily lock the mechanical advance mechanism to prevent it interfering with the next test.

Use a small vacuum pump to apply vacuum directly to the vacuum advance. With the engine idling and 10º initial advance, gradually increase vacuum and check the degrees with the timing light until it no longer advances.

Unlock the mechanical advance and hook a T into the vacuum line that goes to the disributor.

Using the plotted curve from the mechanical advance test you know how much advance you are getting at any given rpm.

Reading the vacuum gauge you can know how much advance is occuring there.

Now, you can unhook the vacuum advance and use the manual vacuum pump to add advance under load to test the optimum advance.

Clear as mud, eh?
Joe