The Stovebolt.com Forums Home | FAQ | Forum | Swap Meet | Gallery | Tech Tips | Events | Features | Search | Hoo-Ya Shop
Remember old days

Remember
The old Bulletin Board?

click to enter

The old Bulletin Board has been removed from the server. And with recent "spring" cleaning, we are removing links back to it. The BB is still out in cyber space (to some extent) thanks to
The Wayback Machine.
Stovebolt Site Search
'
Oh Lord, I just gotta find it....

A pdf guide to help you search the Site


Old Truck Calendars
Months of truck photos!
Nothing like an old truck calendar

Stovebolt Calendars

Check for details!


Who's Online Now
15 members (3B, DaveV, GIJOE298, Flatblu4748, FinnBolt, 1951chevy3100AD, 2 invisible), 99 guests, and 3 robots.
Key: Admin, Global Mod, Mod
Forum Statistics
Forums59
Topics128,093
Posts1,037,196
Members45,931
Most Online1,229
Jan 21st, 2020
Step-by-step instructions for pictures in the forums
Previous Thread
Next Thread
Print Thread
Page 1 of 2 1 2
#1441093 Sun Feb 13 2022 11:05 PM
Joined: Jun 2008
Posts: 1,716
S
'Bolter
The 235 I recently purchased came with a NAPA Ichlin IC-12 coil. Says "12v use with external resistor" and “use external resistor” on the side. The PO had converted his truck to 12V and I will do the same. I just want to confirm this is the correct coil to be using. If not, what should I purchase?

Thanks


Chuck
1950 Chevy 1/2 ton (all original)
1951 Chevy 1/2 ton (future streetrod)
1941 Chevy coupe
1938 Chevy coupe streetrod
Joined: May 2005
Posts: 8,824
B
Sir Searchalot
Yes, correct. To be used with a ballast Resistor.


Watch out for careful drivers!!!
I'm away on an ego trip. Will be back on Feb 30.
I'm not an Auto Mechanic, but I play one on TV.
I charge $0.02 for every opinion and I take Paypal.
Plan B is always better than plan A, by definition.
"We have no time for comment, every man will make his own. LET IT BE MADE WITH POWDER AND BALL!!!"
I recommend invoking MIL-T-FP41c when machining and fabricating
I used to think beer was bad for me, so I gave up thinking.
Sometimes no nonsense makes sense, in a sense.
You can't teach a new dog old tricks.
Honk if you're Amish


Joined: Feb 2004
Posts: 24,563
H
Kettle Custodian (pot stirrer)
Here's a selection of the correct resistors from Rock Auto:

https://www.rockauto.com/en/catalog/chevrolet,1960,c10+pickup,3.8l+235cid+l6,1489472,ignition,ballast+resistor,7052

Jerry


"Freedom's just another word for nothing left to lose"
Kris Kristofferson

Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!

WAG MORE- - - - - -BARK LESS!
Joined: Jun 2008
Posts: 1,716
S
'Bolter
Thanks Bartamos and Jerry. All 4 of those resistors look alike to me. Thanks for the link Jerry.


Chuck
1950 Chevy 1/2 ton (all original)
1951 Chevy 1/2 ton (future streetrod)
1941 Chevy coupe
1938 Chevy coupe streetrod
Joined: Feb 2004
Posts: 24,563
H
Kettle Custodian (pot stirrer)
You'll also need the 12 volt type foot start switch with the small side terminal for the resistor bypass wire. Rock also shows a listing for that item. Search their website for the 1957 C-10 with a 235 for a "starter solenoid". That's not the correct name, but that's how it's listed.


I lied- - - - -they corrected the listing!

https://www.rockauto.com/en/catalog/chevrolet,1957,truck,3.8l+235cid+l6,1326091,electrical-switch+&+relay,ignition+starter+switch,4700

Jerry


"Freedom's just another word for nothing left to lose"
Kris Kristofferson

Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!

WAG MORE- - - - - -BARK LESS!
Joined: Jan 2014
Posts: 2,075
J
'Bolter
I’d see about finding an NOS Delco Remy on eBay. I had a go around with the modern replacements having higher resistance than the stock one.

Joined: Feb 2004
Posts: 24,563
H
Kettle Custodian (pot stirrer)
If the ballast has the right resistance, the "Ignition on- - -points closed- - - -engine not running" voltage at the coil + terminal will be approximately 9.5 volts.
Jerry


"Freedom's just another word for nothing left to lose"
Kris Kristofferson

Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!

WAG MORE- - - - - -BARK LESS!
Joined: Feb 2000
Posts: 101
T
'Bolter
Anyone know what the correct Ohm value should be? I always thought that was one of the most important aspects of choosing the correct coil.

Joined: Feb 2004
Posts: 24,563
H
Kettle Custodian (pot stirrer)
The resistance of the coil primary winding will be a factor in how much voltage the resistor drops, since the resistor and the primary winding are in series with each other. Half an ohm difference in the coil winding resistance will make a big difference in the voltage drop you can measure with the circuit conducting. Measure what the circuit is actually doing- - - -don't rely on some chat room "expert's" pontificating- - - - -including mine. If you don't know enough about DC resistive circuits to understand the readings you're getting, find someone who does.

Terry- - - -I'm 60 miles south of you down I-65- - - -drop in sometime and I'll show you exactly what I'm talking about with a multimeter.
Jerry


"Freedom's just another word for nothing left to lose"
Kris Kristofferson

Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!

WAG MORE- - - - - -BARK LESS!
Joined: Jun 2012
Posts: 1,748
S
'Bolter
This is one of those, "it never goes away" questions. Hotrod has the practical solution. He always does. If you want the more "technical" solution, then this is for you. The points are a switch. There is a limit to the current that switch can take. Some Engineer figured out how much current those points would take and still live. His or Her math was based on 6 volts. "Cause that was what they worked with at the time. Simple IRV equation. I(current) R(resistance) and, V(voltage). Ohms law. Add the coil, and you get a new set of numbers. Reactance. That is AC resistance. The coil is an Inductor. 6 Volts becomes 20,000 Volts and you get a spark. For those who like math, Voltage equals Current times Resistance. V=I(R). If you measure the coil resistance, multiply that by the Voltage, you will get the current through the points. Kinda. Sorta. Cause the D.C. resistance is close, not correct. So what to do? Relax. This is car and truck stuff. No rockets here. So we then(around 1954) go to 12 Volts. No one is gonna pay an Engineer to recalculate because, that takes money. Same switch, and same coil, add a cheap resistor. Problem solved. That is the "Ballast" resistor. Back to our kinda/sorta problem. Coil D.C. resistance is matched to the ballast resistor. Problem solved. Then sometime around 1967 those sneaky makers hid the "ballast" resistor inside the coil. The true 12 volt coil was invented. Sorta. But, no "ballast" resistor is needed, "cause it is built in. Same switch, same coil, same resistor, new can. Some where the hotrod guys got in the mix. Bigger spark for higher compression. They wanted more power. Use more current. That worked, and burned up points. Change the number of turns inside the coil. That worked, and messed up the current. Burned up the points. So, you now have to match the coil to the resistor. Or, use a "12 volt" coil. Are we having fun yet? Hotrod and his practical solution. Winner.


Steve H
Page 1 of 2 1 2

Moderated by  Rusty Rod 

Link Copied to Clipboard
Home | FAQ | Forum | Swap Meet | Gallery | Tech Tips | Events | Features | Search | Hoo-Ya Shop
Powered by UBB.threads™ PHP Forum Software 7.7.5