[SWHEATON]

Hi guy's i am sure this will be an easy one for one of you out there.

My friend is restoring a 70ss 396 which he wants to keep the stock points ignition for shows etc which is where the problem is so lets not get into the electronic conversion for now wasting your time suggesting it because he is a purist and would like to stick with it for now.

The problem is that 9 times of ten you go to start the car there is little or no power to the coil/ign so of course it wont fire.

There is little or no voltage at the coil when chekced with ign switch on or when cranking the motor,coil is new too.

But if i hit the coil with 12 volts from the battery the car will fire up just fine and runs decent but the motor does drop a few hundred rpm when the 12 volts is removed from the coil after it fires up and runs a little shabby too untill you get it off idle so i think it's runnig off the alt which has lower power at idle.

Now all the other eletrical items work fine in the car so what i am hoping to do is just replace the primary ignition resistance wire and not waste tons of time trying to hunt down the problem/s with the original wire,kind of a bypass thing.

So my questions are as follows:

1)Could a bad ignition switch cause this problem?

If yes how can i test for thie without buying a new ignition first?

2) Am i coerrect that the stock points ignitionr runs on approx 9-9.5 volts at the coil?

3) Where should i hook the new primary resistance wire for power,from the fuse box or where?

4) Where can i get a new length or primary resistance wire to do this with or if it's not available then could you give me a brand & pt# for a resistor that would drop 12 volts to the 9volts needed for ignition when the ignition switch is turned on the then twisted to the cranking position to start the motor too.

5) It did Does this with the old and new starter so i dont think its an issue with the wires at the starter solenoid.

The bottom line is we just want to get the correct amount of pwr( 9 volts?) to power the ignition when cranking the motor,also to be there after you release the ign switch after the motor fires,and then turns off when the ign swithch is shut off to stop the car the easiest way possible so where should i get my power from to do this? And where do i get the primary resistance wire i need or which resistor pt # will drop 12volts to 9 volts for the coil?

Thanks....Scott

 

[Herb]

Some things can't/shouldn't be jury rigged. Why not fix it right. Why not get a wiring diagram for that car and find / replace the bad part. 15 mins with a volt meter will tell you what's bad. If you can't do it, find a friend or garage that can. It's not that hard.

You spent more time and effort writing that question than it would take to isolate the problem and replace the bad part.

 

[SWHEATON]

Hi Herb,well that would be nice if it turns out to be that easy to fix,you know how wiring can be a problem on 34 yr old cars that have been through many hackers hands in those yrs.

I am not looking to cobb job/jury rig it,i am really looking to just bypass the bad wiring for now so we can get it running correctly as it's due to go into the body shop in a few wks and we can do a better fix later on as time allows.
If its easy to fix exisiting wires i will do so but sometimes it faster to bypass old wires just so we can get it running right so it can be run to the shop,at the shop,and back home to avoid $200-300 in flat bed towing fee's.

I am planning on checking with a volt meter to see if the r term on the starter solenoid gives 12 volts at startup and to also see if the wires for the coil power for startup are on the correct starter terminals and are not broken. I am slo going to chk to see why there is not 9 volts at the coild when the starter sw is realeased after the motor is started and going from there.

I see from the tone of your note you were bothered by my questions,sorry about that,i was just trying to get some help from the guys that know. By the way it took me 3 mins to write the note and there is no way anyone could could diagnose and fix/rewire both the starting 12 volts circut and running 9 volts needed after startup in 3 mins it took me to write the note. So lets be real here,i am sorry it bothered you that much to read my lengthy questions/note as I always try to give as much info as possible when asking questions so the people advizing can better answer them.

Anybody else have any good advice for my questions?

Thanks...Scott

 

[Dean]

Hmm, strange because the coil is powered from two different sources, one from the resistive wire coming from the bulk head connector which comes from the ignition switch and provides 9 volts (so I'm told) and one from the start yellow bypass wire from the starter's "R" terminal which provides a full 12 volts from starter during cranking.

I would maybe suspect a poor connection at the bulk head connector contacts but you need to check and see if there is 12 volts coming from the ignition to the "inside the car" side of it also.

Assuming the resistive wire is bad, you could use a ballast resister and a new primary wire coming from the ignition.

I think you could find a terminal on the fuse block that has 12 volts both during ignition switch "Run" position and "Starting" positions to feed the "add on" ballast resister.

I would check the yellow bypass wire from the starter's "R" terminal and find out why it's not sending 12 volts to the coil during "start/cranking"

You can get 14 ga. stranded flexible wire from any auto parts store.

 

[SWHEATON]

Dean,thanks a lot for taking the time to answer my question. The info you gave me has verified what i had suspected and will help send me in the right direction to get this problem squared away.

Anytime i have had something i needed help with on my chevelle or a friends i am working on as in this case you guy's alway's come through.

Last time it was a stuck pilot bushing that the removal tool or a dowell & grease force out method would not budge.

Someone suggested threading a 5/8 inch cap bolt into the pilot bushing untill it bottomed out in the crank to force it out. I tried it and it came out in 1 minute flat after speding mult hrs on it,who knew?,the T/C guy's knew,that's who.

Thanks....Scott

 

[Herb]

Scott,
Sorry if I sounded sarcastic or bothered. Thought you were looking at a jury rig rather than an end solution. You obviously have done some serious analysis of the issues. Would not want to leave a serious enthusiast hanging if I could help.

You can install a ballast resistor rather than a resitive link in the line from the solenoid to the coil. NAPA should have one.

For a quick run to the body shop, you might consider just hot-wiring it with a wire and alligator clips from the positive of the battery to the distributor side of the coil, then hit the key to urn the engine over and start it. 12 volts on points and the condensor for short periods of time won't blow them or the coil. That's how cars are hot wired when they are stolen. Done it many times.

Again, sorry if I seemed bothered. Long day.

 

[Dean]

Originally posted by Herb:
Scott,
Sorry if I sounded sarcastic or bothered. Thought you were looking at a jury rig rather than an end solution. You obviously have done some serious analysis of the issues. Would not want to leave a serious enthusiast hanging if I could help.

You can install a ballast resistor rather than a resitive link in the line from the solenoid to the coil. NAPA should have one.

For a quick run to the body shop, you might consider just hot-wiring it with a wire and alligator clips from the positive of the battery to the distributor side of the coil, then hit the key to urn the engine over and start it. 12 volts on points and the condensor for short periods of time won't blow them or the coil. That's how cars are hot wired when they are stolen. Done it many times.

Again, sorry if I seemed bothered. Long day.

"Done it many times"
Just how many have you stolen Herb?
j/k, I know what you meant

There shouldn't be any resistive link in the line from the solenoid, it sends full 12 volts to the coil.

 

[SWHEATON]

Thanks Herb & Dean for all the good info you guy's gave me,i will surely be able to get this fixed with no problems now.

Herb,no problem,i can get a little bothered too when i see real cobb jobs out there and i see how it may have seemed i was headed that way from the info i 1st gave.

Scott

 

[Herb]

Good catch Dean!!!

Must have been a longer day than I realized.

 

[ASB]

Hi All. You might check the Ign sw. Some ign sw ground the coil wire in the off position. if the car has been hot wired in the past that dead shorts the ign sw. causes it to go bad.

 

[Herb]

You'd know that in hurry. In fact, as soon as you connected the battery end of the hot wire. Easy to check, just disconnect the ignition side of the coil, use an ohm meter on the lead with the switch off. Should be open to ground.