gmc 353 to 12Volts

[Tony B]

I've one of Frank Jolleys electronic whiz boxes in both the 6 volt and 12 volt Dodges. Pull choke, bit of throttle, press pedal! Brilliant bits of kit.

[Lauren Child]

Hi all I've got a gmc 353 very slow in starting getting worried as it is going to be used a lot in the winter.and won't start can I convert just the starter to 12v???

 

Check the size of the cabling to the starter. 6v draws a lot more current than 12v so if the cables aren't up to it they restrict the flow of electricity and drop the voltage. I changed mine out with 70mm2 flexible welding cable and some properly double-crimped terminations and it doubled the cranking speed on a charged battery. No need to change to 12v.

 

That was on a CMP instead of a GMC, but there shouldn't be much difference in electrical terms.

 

At the end of the day, the beasts were used in far harsher conditions when they were new. If it's not working properly I'd try and find out why before risking complicating it further with higher voltage and re-engineering.

[John Comber]

When I put the GMC through my workshop last winter she span slowly on cranking, on inspection of the starter and discussion with Rex Ward, an inexpensive starter brush kit made a huge difference along with refreshing the bright work tarnished in the starter, I also note some of the 6 volt batteries people use are not large enough, Lincoln batteries do a 21 plate 6 volt, and that is well worth inverting in.