Recent content by KitCarlson

The AI numbers seem reasonable, most of that from forum comments. Adding 2 degrees should be OK for a test. See if that helps cool. More than 2 will require adjustment of RPM advance. Adding fuel good too. Small steps, one adjustment at a time, with tests promotes progress.

Do you know what the base timing and full advance is? Have you checked TDC is correct?

Retarded timing burns fuel on exit, heats heads and exhaust.

I'm good. I 3D print, and restore early sewing machines. A down size from working in cars. Not sure can still do electronics. I'm a bit scared to find i can't.

I think in trouble shooting, it will be necessary to separate mechanical issues from electrical issues. It is hard, because variable reluctance sensing is not good for position reference, with trigger variations due to angular velocity, gap, remnant magitizm, and other noise and analog...

Del, Good to hear from you. Radio suppression cap is good idea.

The 10k resistor attenuates tach signal, such that secondary spark triggers are reduced or eliminated. A spark event has initial high voltage peak, followed by decaying oscillating peaks. A tach should just read first peak. Additional peaks add to indicated RPM. Viewing coil primary with scope...

@Mattax About HEI coil current limit. It works by turning off coil drive transistor when current exceeds set limit, and back on when current is under limit. Switching happens in fast repetive manner, such that resulting current is smoothly regulated. It takes only one small transistor, and a low...

If you have a timing light, put it on #1 and view timing when cranking. It does two things, it will indicate plug is firing, and timing. Four volts at run is very low, that may indicate bad bulk head connection for ignition circuit. Run power from battery hookup for test.

Good plan.

IGN1 and IGN2 are at ballast resistor. They come from ignition switch. One powers when cranking, other in run. Just connect together and connect to pin 86. Solenoid has start wire, but it is only powered when cranking. Battery power at large solenoid stud is often electrically noisy when...

Relay pin 86 should go to IGN1 and IGN2.

Resistor adds loss, decrease time delay. Diode provides path for stored coil current to circulate, hence holding relay closed longer. A relay hold current is typically 1/4 normal operating current. A scope can be used to capture hold time, by triggering key switch falling signal, and viewing...

I can see using a diode on relay coil, to slow down relay contact release on start to run transition. Diode polarity is important, it must be reverse biased, cathode at + terminal of relay coil. Addition of diode may provide about 100ms of release delay for transition, for a worn ignition switch.