Irregular miss under load😫

[AnthonyG]

Thx Bubba's, the module was getting full 12V from in front of the resistor. it was the ballast R. Last test drive before connecting direct to coil was running as indicated at beginning of thread. Went back to set up direct and as the meter was there checked for voltage one more time and the circuit was open. Checked again no reading. Must have been on its last leg. Coil is a Petronix 1.5 ohm and hooked up direct and engine ran great. Pulling like a champ again. No missing no hesitation.
OK question is if Mallory calls for a 1.5 ohm ballast resistor why do I need it if the ohms on the coil is 1.5 ohms? Do I really need the resistor?
Thx to you all for all the help and thinking out loud with me.

[G.M.]

Originally Posted by AnthonyG

GM engine has under 2500 mile, what do you think would cause sticking valves? Can't ever hear at idle or revving up while sitting no load. If it were valves wouldn't it happen then as well as on the road. That's why I was leaning towards something electrical. Timing / distributor maybe? Ran fine for a couple thousand miles? No pinging and seems like plenty of power up to that breakup point?

Valves can stick in a few hundred miles from a residue from gas on
on the stems. G.M.

[JSeery]

12 volts / 1.5 ohms = 8 amps, that is too high, should be in the 3.5A to 4.5A range which would be around 3.0 ohms (12/3 = 4). A 1.5 ohm coil coupled with a 1.5 ohm ballast resister would work for a points distributor, no idea with the electronic one, but appears to be what was recommended. Something is not correct somewhere, 3.0 ohms of total resistance in a 12 volt system would not give you 3.5 volts at the coil, should be more in the 6.5 to 7.5 volt range.

At 13.5 volts the current through the points (in a points system of course) would be around 13.5/3.0 = 4.5 amps and the voltage at the coil should be around 4.5 X 1.5 = 6.75 volts.

[AnthonyG]

Checked Mallory distributor data and instructions delivered with otherengine paper, also checked on line at Speedway and no Ballast resistor required when using a 1.5 Ohm coil per:
http://www.speedwaymotors.com/Mallor...utor,7965.html

[BUBBAS IGNITION]

Originally Posted by AnthonyG

Checked Mallory distributor data and instructions delivered with otherengine paper, also checked on line at Speedway and no Ballast resistor required when using a 1.5 Ohm coil per:
http://www.speedwaymotors.com/Mallor...utor,7965.html

You got it per Mallory instructions.........1.5 is fine , these are designed to handle 8-9 amps of current.

Note: This distributor requires 1.4 ohms of coil resistance. If you are using a coil with less than 1.4 ohms, you must use a ballast resistor that will achieve the required 1.4 ohm total resistance. If you are using coil #447-45001, no resistor will be required.

[AnthonyG]

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happy camper again!!!
Thx for the great help

[wbedwards]

ok, what was it??? =]

[BUBBAS IGNITION]

Originally Posted by wbedwards

ok, what was it??? =]

Too much resistance lowering the voltage below the range of the ignition module operation......

[wbedwards]

I just came off of a similar problem with my 59 but it was a bad ground giving the coil 5.5 volts instead of 8.5

[JSeery]

It's always (almost) the grounds!