Still No Spark 1950 8N 12v conversion.

[J_J]

If your points are fully closed, you will not get a spark, as the opening of the points is what completes the spark cycle. If the capacitor is shorted, the same thing.

Did you say you were using a 12 v coil? I believe in the start mode, you apply the full 12 v to the coil and after running the voltage is dropped down via the resistor. Some coils have a built in resistor, and others were external resistor.

 

[2LateIWon]

Cool So I got spark now but still not starting But I'm super happy about that.
Yeah some how the bolt doing through the distributor was grounding out. So I'm getting spark now. Now I need to figure out why it's not running now. I need to check fuel or maybe even make sure I haven't crossed the wires some how


Thanks for all your help

 

[2LateIWon]

So Still getting fire (wooo whoo) but it still wont start and it's back firing sporadically. I didn't mess with timing or anything and the cap will only go on one way

 

[TedLaRue]

So Still getting fire (wooo whoo) but it still wont start and it's back firing sporadically. I didn't mess with timing or anything and the cap will only go on one way

Could you have mixed up the order of the spark plug wires? Firing order is 1-2-4-3. This website has a picture showing the correct connections (second image labeled "Engine Detail - Right Side"). The plug wires must be in the correct order, and also in the correct positions (assuming you haven't pulled the distributor out).

A cracked distributor cap (or one that is really dirty on the inside) could also cause that kind of backfiring behavior.

The point gap also affects timing to some degree, but probably not enough to keep it from starting.

Gotta say, I'm impressed by so many previous posts being right on for a 60 year old ignition system, including J.J.'s clear explanation of the theory, and SoundGuy's super-intuitive suggestion about the through-the-distributor-wall bushing allowing a short (which, if I understand 2LateIWon correctly, was actually a problem).

 

[2LateIWon]

That just goes to show you that you can have all the book smarts in the world but experience is priceless.

I never took the wires off except when I change for a new cap and rotor and I did it one by one. So it is possible I had the cap turned 180*

And I hope you guys know how appreciative I am. I'd work more on this thing more consistently but it's been well over 100* (actually yesterday was a cool 103* compared to the 107* and greater we have been getting. 2 sat ago it was 110*)

 

[Soundguy]

yep, prop the points open and then check continuity.

post back

soundguy

 

[2LateIWon]

I'm stuck here at work but after work I'll run outside and check it. I will say after I loosen up the through bolt it wasn't grounding out. And I was getting spark. woo whoo
It's just trying to back fire everynow and then now. So I'll recheck the spark plugs and firing order to make sure I didn't cross them up.
Thanks again

 

[Soundguy]

1-2-4-3.. #1 is at the front.

make sure poitns gap is .025 on all lobes on the the side mount.

soundguy

 

[2LateIWon]

Ok Firing order is correct. and gap is good...... after about 5-10 seconds trying to start nothing after the 3rd or 4th try I get a back fire. I don't get it.

 

[J_J]

Sticky valves will allow back fire to occur by not closing at the right time.

You might also have some cross firing in the cap. or the spark plug cables are arcing to each other.

Have you done a pressure check on the cyl?