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Re: What to use? Close to finishing.
Post by jeepistdougiowa on Aug 8, 2006, 11:12am
Walcks has a 24V firewall mounted coil... used in the M38s/M151s etc. $32.
Sotck military looking and is in a neat square box with mounting tabs (firewall or fender well)
I "believe" the Part Number is 118712 . Search for it + coil and you will find a ton of sources. I can't seem to find one with a pic though.
Re: What to use? Close to finishing.
Post by porkchop on Aug 8, 2006, 11:13am
Really? I figured it would fry the system. So your saying that all the stock chevy parts will run on 24 volts just fine?
Re: What to use? Close to finishing.
Post by jeepistdougiowa on Aug 8, 2006, 11:23am
I had trouble getting my M38 to run...PO had been running the 24V coil on 12V and it worked for them that way for years. I was getting poor spark so I swapped it to a 12V coil.
I wouldn't recommend it, but I won't say it doesn't work. (12V to a 6 V coil is different...surplus power vs not enough in my case)
Re: What to use? Close to finishing.
Post by jeepistdougiowa on Aug 8, 2006, 11:24am
Porky, output of the coils (24v and 12v) is going to be close to the same, you're just deciding what input you want....no big deal at all.
Re: What to use? Close to finishing.
Post by barrman on Aug 8, 2006, 11:25am
Think about Ohms law. E=mcsquared, no no no no no no. E=I/R or R=IxE. R is resistance, I is amps and E is volts. Resistance is what makes heat which is what burns stuff up. Since resistance equals volts time amps, doubling the volts which cuts the amps in half doesn't affect your resistance one bit.
Get a 24 volt coil and run it is what I am trying to say.
My 1947 Ford 8n tractor was meant to be a 6 volt vehicle that I switched over to 12 volt. I burned up 6 volt coils about every 30-40 hours of running time. Putting a 12v coil in solved that problem. The starter, points and condensor are still 6 volt parts and don't really show any undue wear. I would recommend not using the starter for more than 5-8 seconds at a time though. But, you probably do that with the stock volage anyway.
Re: What to use? Close to finishing.
Post by porkchop on Aug 8, 2006, 11:33am
Ok so what about getting a 3.0 ohm coil and using a 3.0 ohm resistor, would this be the same as using a 24 volt coil? I cannot seem to find a coil and I have been searching all morning. Haven't made any calls yet. Just don't want to get a coil and have it look like the one for the M715 and not be able to use it.
Oh yeah, Tim, you made my head hurt, LOL!
Re: What to use? Close to finishing.
Post by jeepistdougiowa on Aug 8, 2006, 11:36am
The one for the M38 is a firewall mounted unit seperate from the distributor, the "stock" wire for it is a mil type wire so you WILL have to alter it to accept a typical spark plug wire to feed the center of you points style distributor cap.
Check your local CAT and John Deere dealer, they probably have one on the shelf that uses standard plug wires.
Re: What to use? Close to finishing.
Post by porkchop on Aug 8, 2006, 11:38am
I will look into that, thanks.
Re: What to use? Close to finishing.
Post by 40grit on Aug 8, 2006, 12:09pm
you can feed 24V into a 12V ignition coil, ignition coil is merely a small transformer taking 12V and turning it into 10KV, so feed it twice it's voltage and it'll take half the "normal 12V current"... so points shouldn't matter, difference between 12V and 24V DC self-arc distance is very small,
as for the starter, it should work great on 24V as long as you don't crank for long extended periods of time( think minutes), think of the low rider crowd, they use 12V starter motors to run the hydraulic pumps, usually up to 72V, it shortens the life of the motor, but for quick starts, I don't think you'll see the difference in life...
the ballast resistor in the old 12V systems was to limit current thru the points when cranking, the resistor is basically a throttling orifice for the current and limits how much can flow in a given period of time, as the 12V is bogged down by the starter turning, the current rises to make up for the voltage drop since the resistance remains unchanged...( see Barrman's Ohm's law above)
or, if it worries you, patch the ignition off only one battery and run it 12V, the small amount of drain won't adversely affect the batteries
Re: What to use? Close to finishing.
Post by tacomainoh on Aug 8, 2006, 12:14pm
Good info, Mark.
I was going to suggest the one battery thing.