2.5 ohm ignition resistor
 

Like a dummy I’ve lost my cheat sheet that listed a part# for a 2.5 ohm ignition resistor. Would anyone on here know it? MSD and Standard has/had one.

Re: 2.5 ohm ignition resistor
 

That's pretty high. You may have to add 2 resistors in series to get 2.5 ohms.

I just searched and could only find aluminum cased ones like this:

https://www.ebay.com/itm/Dale-RH-ser...cAAOSw3Z9atYF5


Glenn

Re: 2.5 ohm ignition resistor
 

JSeery posted this a short time ago.


https://www.fordbarn.com/forum/showp...0&postcount=15

Re: 2.5 ohm ignition resistor
 

I'm running the ICR35 on a 12 volt conversion. If I remember correctly, I have about 4 volts at the coil with this resistor.

Re: 2.5 ohm ignition resistor
 

is this used on original coil for 12 v battery ?

Re: 2.5 ohm ignition resistor
 

Yes. I'm running 12 volts and a skip rebuilt original coil.

Re: 2.5 ohm ignition resistor
 

MSD has discontinued apparently the one I was hunting. A 1.8 ohm will work just fine.

However for the particular car a certain distributor and coil I am working on for a customer I had hoped for 2.5 ohms, to get the primary to 3.2 with a skip coil 12V. This car is going on a 14,000 mile essentially non stop trip next year and I was hoping to get "picky" on the primary resistance to ensure point life. I may just stack resistors.

Re: 2.5 ohm ignition resistor
 

. I may just stack resistors.[/QUOTE]



If you stack two 1.25 ohm resistors is the end result 2.5 ohms resistance?

Re: 2.5 ohm ignition resistor
 

They have to be wired in series, end to end in a line, to get 2.5 ohms.

Re: 2.5 ohm ignition resistor
 

I feel like this trip has the potential for a lot of fun. Wish it were me.

Re: 2.5 ohm ignition resistor
 

I did cross check in my old napa buyers guide but nothing above 2.0 ohms ?????

Re: 2.5 ohm ignition resistor
 

Jim,
I was a MSD I had been using. The standard number was for a 1.8. MSD had at one time a 2.5 which I bought a handful of from a going out of business speed shop. Ran out and it appears they no longer exist. Typical me I am over thinking this.

Re: 2.5 ohm ignition resistor
 

The resister is used to cut the 6.3 volts from the battery down
to minimum of 3.5 and max of 4.0 volts. This reduces the arc
at the points. The higher the voltage the bigger the arc. If you
get below 3.0 volts when you push the starter button the amp
draw from the starter pulls the coil voltage to low to make a
strong enough spark to fire. It will be a fuzzy little yellow ball.
G.M.

Re: 2.5 ohm ignition resistor
 

Check the voltage when cranking. If it is greater than 4 volts calculate what you need for a resistor to get you just under 4 volts. V = IR

Either a direct wire with or without this resistor will be wired directly from the starter to the + coil terminal. Once started the other wire to the + coil provides a reduced voltage for running.

Glenn

Re: 2.5 ohm ignition resistor
 

I dont know the ohms I just add a 65 mustang (ford ) resistor to the original 1933-34 ford resistor . The one on the inside of firewall ( the one next to fuse ) I have been doing this ( 12 volt battery ) - ground for over 40 years. same dist never a point problem. I do think a skip rebuilt original coil made to 12 volt is better.
What do you think.

Re: 2.5 ohm ignition resistor
 

That is a 1.4 ohm and stacked with a .8-1.0 ohm original equates to pretty much what my math concludes is perfect for a 12V skip coil. (skips coils tend to be .7-.8 ohms whether 6 or 12 V)

Most people aren't driving these cars enough to even really matter by I am being nit picky..

Re: 2.5 ohm ignition resistor
 

If running 12v on a 6v coil you could just stack a 50's ceramic voltage resistor first then run it through the stock resistor to coil. Early y blocks dizzys were 6 volts at 12v battery. The secondary stock resistor will knock it down to the comfortable 4v as designed. Just a thought anyway.


If you have a skip 12v coil, I don't see the problem.

Re: 2.5 ohm ignition resistor
 

guess I missed all your travel postings.