Team Camaro Tech banner
1 - 12 of 12 Posts

·
Registered
Joined
·
49 Posts
Discussion Starter · #1 ·
I'm not sure if this should go in Engine or Electrical but I'll try it here. I've been trying to get the car up and running after sitting for 25 years. I got the engine running but wanted to check the specs out. While the engine seemed to idle fine and rev fine I wanted to check the dwell and the timing before moving on to some carb adjustments. The dwell meter showed a ridiculously low dwell number so I started and stopped the car several times and made some adjustments to dwell, what I thought were minor adjustments, just to verify the changes moved the dwell meter. However, before I was anywhere close to the correct dwell value smoke started coming out of the coil. I suspect there might be an issue with the dwell meter or my use of it but that's a problem for another day.

I think the braided wire to the positive side of the coil took some burn damage but honestly, it's a little hard to say. I can't see any other burn damage but something was emitting smoke. How can I tell if the coil is damaged? What are other likely candidates to check for damage?
 

·
Registered
Joined
·
398 Posts
Pull the coil off the car, find a parts store with an off vehicle electrical tester, and run the coil. Let it get to its operating temperature, and, standing up, on its bottom, NOT on its side.

The "woven" wire is silver stranded, and, is the ballast resistor for the points system. This wire is 7-1/2 FEET long, carries a spec of 1.80 +/- 1% ohms resistance. It connects to the coil, and the bulkhead fitting on the firewall.

One thing you might do is pull the bulkhead fitting off the fuse box, and check the terminals on the fitting and fuse box. Some times, age can dissipate the grease between the parts, and allow corrosion to the wire terminals, which increases resistance, some times to the level of all sorts of strange conditions..

Also, battery cable from negative post on battery goes to ENGINE, not frame, nor body, ENGINE first.
 

·
Registered
Joined
·
49 Posts
Discussion Starter · #6 ·
Also, battery cable from negative post on battery goes to ENGINE, not frame, nor body, ENGINE first.
Well, that's interesting, I've got an AC car. I've never looked before but the connector to the negative post goes to the body, and then to the AC compressor bracket. And that's it.

Right now I'm most worried that the burning/smoke might have damaged other wires in the wiring harness. And other than cutting everything open I'm not sure how to check.
 

·
Registered
Joined
·
49 Posts
Discussion Starter · #7 ·
Then I believe you can adjust the points while the engine is running with an Allen head wrench through the front window on the cap.
You're right, I could have. I was trying to work slowly and carefully thinking that would have made things go more smoothly.

On the positive side, I've learned quite a bit about that particular wiring harness this afternoon.
 

·
Registered
Joined
·
398 Posts
OK, time to pay attention and figure it out. What is the A/C compressor bolted firmly to? How about...THE ENGINE. Now, the FRAME is NOT grounded to the engine, nor the body, ALL the interfaces between body, frame, battery ground and ENGINE, are RUBBER MOUNTED, which is not an electrical connection.

Grounding connections need to be clean, and grounds connected to brackets, like A/C mounts to heads, need to be clean, clean, CLEAN as well.

YES, the ONLY way to set the points correctly and accurately is with the engine RUNNING. Idle speed, dwell meter connected and set to read 8 cylinders, and the correct dwell is 30 DEGREES.

YES, the ONLY way to check the coil is OFF THE CAR, at operating temperature, and running, on a machine that does that, NOT WITH RESISTANCE CHECKS. The coil will cool off too quickly to read issues like "layer shorting" inside the coil at full operating temperatures. By the time the testing gets done, the coil will be partially cooled back off.
 

·
Registered
Joined
·
398 Posts
Yes, I said that, in the post above the one above this one,

"YES, the ONLY way to set the points correctly and accurately is with the engine RUNNING. Idle speed, dwell meter connected and set to read 8 cylinders, and the correct dwell is 30 DEGREES"
 

·
Registered
Joined
·
49 Posts
Discussion Starter · #12 ·
You probably had the key on with the points closed for too long.
I'm pretty sure that's exactly what happened. Not helped by the fact that I can pull my key out of the ignition and leave the car running. The new ignition and lockset are sitting in the passenger seat waiting to be installed.

My initial confusion was my mid-1980's dwell meter reads in dwell percentage and there's a chart on the back to convert to dwell degrees. However, lacking the instruction manual and given its age I wasn't convinced it was working or I was reading it correctly. Unfortunately, the dwell percentage it read was 30, which converts to somewhere around 12 degrees of dwell. And then the screwing around started. I picked up a new dwell meter, this one with no conversion necessary, and it too read around 12 degrees of dwell.

With two dwell meters giving me the same read out, a new coil and points/condenser set, I'm dialed at 30 degrees and moving on.
 
1 - 12 of 12 Posts
Top