HEI voltage

[DEMON44]

What's the minimum voltage the HEI needs to see to fire? Or there isn't really a number, but the lower the voltage the weaker the spark. Until it just quits firing?


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[Fordum]

Its electronically controlled, so there will be a minimum voltage, but I don't know what it is.
I know that it is not uncommon for battery voltage to go to 9 volts while cranking with a cold engine and so so battery.

Remember the magic number is the voltage getting to it while cranking.

If you are not getting a good solid 11.5 to 12 or better with no load, then it is going way down when you are cranking it.

 

[DEMON44]

yep thats what I'm affraid is happening with my 454 in my camaro. the batt was abused and left for the winter. I need to load test it separately

 

[DEMON44]

And even after the charger has been on it for days. The surface charge settles to around a not healthy 12.3v today. Ah ill just replace it and see if it fires.



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[4X4HIGH]

An HEI distributor will run with as little as 9.5 volts to the BATT terminal but it will not have full potential. This is one of the common mistakes that lots of people make when swapping from a points distributor to the HEI is that they don't change the resistor wire out for a non resistor wire (or eliminate a ballast resistor if used in lieu of the resistor wire) going to the BATT terminal of the distributor.

 

[DEMON44]

Thanks guys. This car is factory HEI. The original small block was HEI. And this engine did run just like 4 Months ago I drove it, but I used a battery now that was sitting in the garage for a long time. And I think not recovering a charge. And dropping way low when cranking. Because of the slow crank and no start. It will crank over ok with the charger on it though.

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[4X4HIGH]

Once you have the battery fully charged you should do a load test using a carbon pile load tester or the like. This will tell you if the battery is any good or not, it can have 12+ volts but not have enough amps to do much of anything.