Gunfreak25

I have a 455 Olds in my M211 Military 6x6. The truck is entirely 24V but the 455 ignition obviously needs to see 12V to work properly. I did not want to change anything on the truck for my own reasons, so I bought a 24V to 12V converter to supply 12V for my ignition. I need to finish getting it wired in, but in the mean time I had another idea.

Would anyone know if the ignition could be made to work on 24V? Military 24V ignition coils are readily available for the old GM gas engine Military trucks and it seems like the 455's points ignition and plug wires would handle the extra voltage just fine.

Can anyone comment on this? It would be double the voltage but only half the amperage of a 12V system.

J-(Chicago)

GM points can barely hold 12v. They disintegrate in no time flat.
If you're going to be running 12v, I'd convert it to a pertronix system.

MDchanic

Why not use a military coil and change the condenser to whatever is usually used in the military ignitions? You might be able to get away with the same condenser - values are not super exact - but if you use a military one, you know it's right for the voltage and the (military) coil.

And as for a converter, a resistor of the right resistance and power handling would work fine.

- Eric

Gunfreak25

Exactly! NOS coils/condensers for all M series Military Vehicles are still readily available and about the same price as any other commercial coil. My main concern is the increase in voltage. How will the engine run on it? Will I need 24V Military spark plugs too?

I'd like to get more input on this from you guys here before I even try doing anything. If it looks like it will work without too much trouble I think i'll save the converter box for running 12V creature comfort accessories instead of relying on it to run my ignition. I know 12V starters work just fine on 24V but I can also throw a 24V starter solenoid on there too.

Lady72nRob71

Do you have some pictures of this beast? I admire those old military workhorses...
Nice to hear it has an Olds heart in it!

joe_padavano

The plugs see coil secondary voltage (on the order of 20,000 volts) so there's no need to change them. Just get a 24v coil and condenser. This is not a big deal.

oldcutlass

To get to 24v what kind of battery setup is it. Most of the deisel duece and 1/2 were a multiple batteries hooked up of 2 or more batteries in parrallel and series to arrive at 24v. I've tapped into 1 set to arrive at 12v for accessories through a relay, why not do the same for an ignition setup??

Gunfreak25

Thanks for the input guys!

I'm going to go ahead with it then, this sounds more feasible than I thought. Maybe with half the amperage going through everything it will be easier on things too. I can pickup an M series 24V coil/condenser on ebay right now for about $35 and it looks exactly the same as any other old Delco Remy 12V coil so it should bolt right on.

I'll save the converter box for my 12V accessories I'll add later. Somehow, however functional it might be It just doesn't seem right to rely on it for my vehicles ignition.

I do not like tapping off one battery for a 12V power source as it irreparably damages both batteries in time. As for the battery setup it's just two 12V wired in a series. It was the 5 tons and shop van trucks that used a larger battery setup. EXPENSIVE.