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Coil Resistor?

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Jus*Jack View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Jus*Jack Quote  Post ReplyReply Direct Link To This Post Posted: 06 Mar. 2008 at 3:48pm
Hmmm...and this "anonymous teenager" grew up to be....? <g>

Yep...as you said..."Measure twice...cut once!"
Seeya!

<Jack>

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Post Options Post Options   Thanks (0) Thanks(0)   Quote samcj2a Quote  Post ReplyReply Direct Link To This Post Posted: 06 Mar. 2008 at 3:52pm
Originally posted by Jus*Jack Jus*Jack wrote:

Hmmm...and this "anonymous teenager" grew up to be....? <g>
A 63 year-old teenager - with a fondness of saying, "I did everything twice on that Jeep - once to learn how not to do it, and another time to get it right! "
 
 
Sam

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Post Options Post Options   Thanks (0) Thanks(0)   Quote 46CJ2A Quote  Post ReplyReply Direct Link To This Post Posted: 06 Mar. 2008 at 5:15pm
I did put a socket on the crankshaft nut and turn the engine over a few times.  It turned over okay, but a bit more snug than some of the other types of car/motorcycle engines I've rebuilt over the years. 
 
I'd still like to carefully try the 12 volt coil and battery set up if someone could give me that coil part number.
 
Thanks.
 
Jack
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Post Options Post Options   Thanks (0) Thanks(0)   Quote samcj2a Quote  Post ReplyReply Direct Link To This Post Posted: 06 Mar. 2008 at 5:28pm

I would go to Advance Auto or a similar place and buy the cheapest coil and coil resistor for something like a 1955 Pontiac.  That car and many other of that era had a coil and external resistor combination that will work fine with a 2A and a 12 volt battery.   Looking at their Web site, you should be out of there for around $25.

I know that you wanted a coil with resisitor included, but I think you will find the other combination more commonly available.  Then just wire the resistor in series with the battery connection to the coil.

Sam

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Post Options Post Options   Thanks (0) Thanks(0)   Quote cjric Quote  Post ReplyReply Direct Link To This Post Posted: 06 Mar. 2008 at 6:54pm
did you spin the oil pump and make sure there's oil throughout the engine? I always do that after putting a motor back together, because I was told to. Once though, I forget (on a Ford 300-6), and the starter would only turn once until compression built, then it couldnt turn the motor. Pulled the dist., spun the oil pump w/ a homemade chuck on a drill, put it back together and the starter spun full speed andthe motor fired right up.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote bkreutz Quote  Post ReplyReply Direct Link To This Post Posted: 06 Mar. 2008 at 7:20pm
Unfortunately the spinning up of the oil pump is not possible on these engines, the pump drive is keyed to the camshaft and the distributor plugs into the oil pump, kinda reversed from what most of us are normally used to on more modern engines.
Gale

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Jus*Jack Quote  Post ReplyReply Direct Link To This Post Posted: 06 Mar. 2008 at 8:00pm
There IS a thread around here however, that addresses the PRIMING of the oil pump, I believe...but don't ask me t' find it! <g>

IF the pump was removed, then that would be a necessary step, yes? But this may be something entirely different. Have you pulled the plugs and tried turning it over by hand or starter?
Seeya!

<Jack>

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Post Options Post Options   Thanks (0) Thanks(0)   Quote GaryArf Quote  Post ReplyReply Direct Link To This Post Posted: 06 Mar. 2008 at 8:25pm
This is along way from the original post question, but since you asked and I found it...
CJ2A #10021 #34692 #58500

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Post Options Post Options   Thanks (0) Thanks(0)   Quote samcj2a Quote  Post ReplyReply Direct Link To This Post Posted: 06 Mar. 2008 at 8:33pm
I second Jack's idea of cranking it without the plugs just to be sure that something isn't too tight.  Of course, you know where my bias originated! Tongue
Sam

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Post Options Post Options   Thanks (0) Thanks(0)   Quote 46CJ2A Quote  Post ReplyReply Direct Link To This Post Posted: 06 Mar. 2008 at 9:03pm
In the morning I'll trying turning it over without the plugs.
 
I was still hoping someone might have that 12 volt coil number though.
 
If not, I guess I'll try the '55 Pontiac idea.  Was that a 6 volt coil with a 30 watt, 1.0 - 1.1 ohm resistor?
 
Jack 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote westforkboyd Quote  Post ReplyReply Direct Link To This Post Posted: 06 Mar. 2008 at 9:07pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote rocnroll Quote  Post ReplyReply Direct Link To This Post Posted: 06 Mar. 2008 at 9:11pm
........or just go back and reread page two of this thread.
 
Hey Allen, you know you can go back in and erase that don't you? (click on edit post)
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 46CJ2A Quote  Post ReplyReply Direct Link To This Post Posted: 07 Mar. 2008 at 7:01am
Yah, I did miss it.  I saw the Mallory resistor but not the coil.
 
Thanks.
 
Jack
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Post Options Post Options   Thanks (0) Thanks(0)   Quote sean Quote  Post ReplyReply Direct Link To This Post Posted: 07 Mar. 2008 at 10:50am
Jack:
Quote I was still hoping someone might have that 12 volt coil number though.
There's the rub.  There's no such thing as a 12v CJ2A coil, so most just find a suitable 12v coil that was meant for another vehicle.  There could be dozens of different makes & models of coil that would work.

Simplest might be to use a 12v setup from later model Williys:

Autolite original part numbers (have them cross-referenced):
  • CAF-4003
  • CAG-4002
  • 200562
  • 200574
Or ask for sales part "5-10"
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Post Options Post Options   Thanks (0) Thanks(0)   Quote samcj2a Quote  Post ReplyReply Direct Link To This Post Posted: 07 Mar. 2008 at 11:02am

My opinion is that almost any 12 volt coil with a matched internal resistor or any 6 volt coil with a roughly matched external resistor would work.   If the internal resistance of the 6 volt coil is 1.1 to 1.5 ohms, any resistor with close to the same resistance should work for this purpose as long as the resistor is equal to or slightly less than the coil resistance, right?   You just want to drop the voltage in approximately half so you don't burn up the the coil primary windings.  If these things work with 8 volt batteries, then close is okay as long as you don't have an external resistor with greater resistance than the coil resistance and th voltage at the coil goes below 6 volts.  It probably still works if you are close, but who knows what the lower threshold is get a decent spark.

Is that a reasonable way to look at it, Sean?
Sam

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Post Options Post Options   Thanks (0) Thanks(0)   Quote sean Quote  Post ReplyReply Direct Link To This Post Posted: 07 Mar. 2008 at 11:22am
Originally posted by samcj2a samcj2a wrote:

Is that a reasonable way to look at it, Sean?
That's it.

2 equal resistances will precisely divide the applied voltage. Unequal resistances will divide the voltage in proportion to their resistance ratios.

eg, w/12v applied , a 1.0 ohm resistor will see 5.7v, while the 1.1 ohm coil will see 6.3v

Sean
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Jus*Jack Quote  Post ReplyReply Direct Link To This Post Posted: 07 Mar. 2008 at 11:33am
While we're about it (calculating the resistance), anybody wanna take a shot at the wattage rating that the resistor should have? (That's usually the important issue with low-value resistors) Most that I have seen are the large ceramic "blocks", and are probably good to 5 or 10 watts (never actually looked), but I'm just curious...I happen to have some _very_ "flashy" gold-anodized resistors (with heat-sink fins) that I believe were surplus from some NASA projects in years past. Most are in the <5 ohm category, and I believe some even go as high as 10 watts! Pretty things, and it might be fun t' use one in my driver.

...and I'd bet that one would look really neat in Roc's CJ2APU! <g>
Seeya!

<Jack>

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Post Options Post Options   Thanks (0) Thanks(0)   Quote samcj2a Quote  Post ReplyReply Direct Link To This Post Posted: 07 Mar. 2008 at 11:41am

Well, Jack, here are the formulas for DC applications which we have until the points open after whcih things get messier because the current is changing and, and Geek!

Power = Current squared times Resistance or  (I**2)*R 

Voltage = Current times Resistance or I*R
 
so Current = Voltage/Resistance or I = V/R
 
 
Sam

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