The 240 in our 66 just quit on me the other day. It was running fine, did a four hour round trip in it at highway speeds on Friday, no issues at all, and then went to go start in on Saturday and it just cranks but doesn’t start. It cranks strong.

Its a stock 240, the only things that have been changed is the distributor is an aftermarket GM style HEI, and the carb is a Carter YF clone.

Its getting gas, but for the hell of it I put a capful in the carb and still won’t start.

Things I have checked so far:
Replaced the ignition control module with a new unit from Napa.
Replaced the rotor with one from Napa.
Checked all of the plugs (Autolite 45), they were all dry and crusty black, I cleaned them all up on the wire wheel and checked the gap, all around 35.

Any suggestions on what I should check next? I’ve heard these HEI coils rarely go bad.

thanks!

 

Is the "ignition control module" just a basic 4 pin GM style module?
Have you checked the power input to the distributor? 12 volts?
You could run a temporary wire from the battery positive to the distributor, to rule out power supply issues.
Make sure the rotor is still going around while you crank it over.

On a side note, 035 is a point ingition gap, with HEI you can increase the gap to around 44 -50.
Jim

 

Jim has covered everything I would check.
Yes check that the rotor spins when the motor is spinning.
I would also pull the coil out of the top and check that little "button" and spring and any spark tracing / burn through.
If the plug wires have a high resistance and cant make it to the plugs it has to go somewhere and can burn through the cap to ground.
Just because you replaced the module does not mean it is good. Todays parts a crap out of the box so it could be bad.
If you do a Google search you should be able to find how to test them but power to it is a first.
Dave ----

 

I'll second the cap/rotor check, if'n you're getting fuel, then the spark ain't happenin... I would start there, I still have points in my old 66 F100, was a 240, swapped it to a 300, put the old dist. out of the 240 in it, it NEVER fails to fire up, ever, if it takes a bit longer to start, then it's time for cap/rotor/points/plugs and a timing check, but even then (hope I'm not jinxing him) he starts. He has sat for 3+mos in the winter when I haven't driven him or started him, with a pull of the choke and a spin he fires, so I would be sus on the distributor.