Ignition Wiring 1948 - The 1947 - Present Chevrolet & GMC Truck Message Board Network

cobraffr · 09-06-2015, 03:28 PM

I am trying to wire up a simple ignition system to test run the engine in the chassis. The previous owner had run the engine in the frame, but removed the coil and some of the wiring. I don't plan on using the chassis in my build, but I wanted to get it running for fun and to verify its condition.

I hooked up a 12 volt battery and the engine turns over fine. I bought a generic 12 volt coil and wired it up like the diagram below indicated, but I get no spark. I pulled the cap on the distributor and the the rotor is present and the points open and close.

I have attached a couple pictures of my temporary wiring. BTW my "ignition" switch is to unplug the coil if the engine ever runs.

Any suggestions to trouble shoot this? If I can get spark, I will move on to the carb and fuel system.

Torres 1948 Chevy Truck Build

**mr48chev** · 09-06-2015, 05:02 PM

I wouldn't hook it up any different if I was doing it.

I am assuming that you have the point gap right or very close to right.

Plus the gap was set with the rubbing block on the tip of one of the lobes of the distributor cam.

If that is right I'd take my ohm meter and check the continuity between the points and the connection at the coil. I've seen the lead from the condenser or points put on the wrong side of the insulator for the screw that goes through the housing before and even did it myself when I was 16 and had a no fire condition.

mog797 · 09-06-2015, 10:35 PM

I am having same problem let me know if u get it started and what u did I will do the same

cobraffr · 09-08-2015, 11:16 PM

Thanks Mr48chev, Apparently at 46 I made the same mistake as a 16 year old. I had attached the black wire between the coil and the points to on the wrong side of the connection. I put it under the nut rather than the metal tab on the side of the distributor. I have confirmed the engine has spark with timing light. Thanks for your suggestion.

I will roll it out of the garage and try to start it next weekend!

Donny

**mr48chev** · 09-09-2015, 11:08 AM

I think the list of those who haven't done that is shorter than the list that did make that mistake.

From the time I was a student in high school auto shop I seemed to end up troubleshooting vehicles that others had worked on and couldn't get to run so I have seen about everything that usually happens when someone worked on a rig and now it doesn't run.

OrrieG · 09-09-2015, 12:28 PM

I have also twisted the connectors just enough that it grounded out on the base plate or external housing too, especially on the older SBC distributors.

cobraffr · 09-12-2015, 02:35 PM

Success!

https://youtu.be/0Ra6GVySkVY

Needs the fuel system cleaned out and the carb rebuilt, but not bad for being dormant about 6 years.

09-06-2015, 03:28 PM	#1
cobraffr Registered User Join Date: May 2011 Location: Houston Texas Posts: 24	Ignition Wiring 1948 I am trying to wire up a simple ignition system to test run the engine in the chassis. The previous owner had run the engine in the frame, but removed the coil and some of the wiring. I don't plan on using the chassis in my build, but I wanted to get it running for fun and to verify its condition. I hooked up a 12 volt battery and the engine turns over fine. I bought a generic 12 volt coil and wired it up like the diagram below indicated, but I get no spark. I pulled the cap on the distributor and the the rotor is present and the points open and close. I have attached a couple pictures of my temporary wiring. BTW my "ignition" switch is to unplug the coil if the engine ever runs. Any suggestions to trouble shoot this? If I can get spark, I will move on to the carb and fuel system. Torres 1948 Chevy Truck Build

09-06-2015, 05:02 PM	#2
mr48chev Registered User Join Date: Jul 2007 Location: Toppenish, WA Posts: 15,718	Re: Ignition Wiring 1948 I wouldn't hook it up any different if I was doing it. I am assuming that you have the point gap right or very close to right. Plus the gap was set with the rubbing block on the tip of one of the lobes of the distributor cam. If that is right I'd take my ohm meter and check the continuity between the points and the connection at the coil. I've seen the lead from the condenser or points put on the wrong side of the insulator for the screw that goes through the housing before and even did it myself when I was 16 and had a no fire condition. __________________ Founding member of the too many projects, too little time and money club. My ongoing truck projects: 48 Chev 3100 that will run a 292 Six. 71 GMC 2500 that is getting a Cad 500 transplant. 77 C 30 dualie, 454, 4 speed with a 10 foot flatbed and hoist. It does the heavy work and hauls the projects around.

09-06-2015, 10:35 PM	#3
mog797 Registered User Join Date: Nov 2012 Location: Fountain, CO Posts: 40	Re: Ignition Wiring 1948 I am having same problem let me know if u get it started and what u did I will do the same

09-08-2015, 11:16 PM	#4
cobraffr Registered User Join Date: May 2011 Location: Houston Texas Posts: 24	Re: Ignition Wiring 1948 Thanks Mr48chev, Apparently at 46 I made the same mistake as a 16 year old. I had attached the black wire between the coil and the points to on the wrong side of the connection. I put it under the nut rather than the metal tab on the side of the distributor. I have confirmed the engine has spark with timing light. Thanks for your suggestion. I will roll it out of the garage and try to start it next weekend! Donny

09-09-2015, 11:08 AM	#5
mr48chev Registered User Join Date: Jul 2007 Location: Toppenish, WA Posts: 15,718	Re: Ignition Wiring 1948 I think the list of those who haven't done that is shorter than the list that did make that mistake. From the time I was a student in high school auto shop I seemed to end up troubleshooting vehicles that others had worked on and couldn't get to run so I have seen about everything that usually happens when someone worked on a rig and now it doesn't run. __________________ Founding member of the too many projects, too little time and money club. My ongoing truck projects: 48 Chev 3100 that will run a 292 Six. 71 GMC 2500 that is getting a Cad 500 transplant. 77 C 30 dualie, 454, 4 speed with a 10 foot flatbed and hoist. It does the heavy work and hauls the projects around. Last edited by mr48chev; 09-09-2015 at 11:16 AM.

09-09-2015, 12:28 PM	#6
OrrieG Registered User Join Date: Jun 2006 Location: Idaho Posts: 8,800	Re: Ignition Wiring 1948 I have also twisted the connectors just enough that it grounded out on the base plate or external housing too, especially on the older SBC distributors. __________________ 1959 Chevy Short Fleetside w/ 74 4WD drive train (current project) OrrieG Build Thread 1964 Chevelle Malibu w/ 355-350TH (daily driver) Helpful AD and TF Manual Site Old Car Manual Project

09-12-2015, 02:35 PM	#7
cobraffr Registered User Join Date: May 2011 Location: Houston Texas Posts: 24	Re: Ignition Wiring 1948 Success! https://youtu.be/0Ra6GVySkVY Needs the fuel system cleaned out and the carb rebuilt, but not bad for being dormant about 6 years.



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