Author Topic: Voltage / Coil /  (Read 2095 times)

boomer632

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Voltage / Coil /
« on: April 22, 2023, 11:03:31 PM »
Im going through the car since I bought it. Specs of car are below in signature.

No resistance wire being used here and battery is brand new.

So heres what I have going on. Car is kind of hard to start when cold so I started going through the ignition that was previously installed and doing some testing. Car came with Pertronix Flamethrower distributor. Its not the ignitor 2 or 3. Flamethrower 2 coil that says 0.6 ohms on the label (more on that later). 

Here is the good.

I checked the vacuum canister on distributor and it holds vacuum well. I could see the advance plate move as I applied and released vacuum. The counterweights and springs are not rusted and move freely as the should. I removed the coil to test primary and secondary windings. I got .08 on the primary and 8.07K on the secondary (perhaps low?)
Here is the bad

I then removed the coil to distributor plug to keep motor from starting. I hooked up the meter for 12V and attached leads to + and - side of coil to check cranking volts. When I cranked over, the meter numbers jumped all over the place quickly up and down as seen in video.

It was wired up like this. Red wire from distributor goes to + side of coil. Black wire from distributor goes to - side of coil.

So do I have the wrong coil for this car? It looks like this coil may be for a 6V system after looking it up on Pertronix site. Why is my voltage going wonky like that during startup?
06A 711 57 57 X66 L78 M22 BU

David K

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Re: Voltage / Coil /
« Reply #1 on: April 25, 2023, 06:17:10 PM »
Define kind of hard to start when cold? What procedure do you use? Details are important.

boomer632

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Re: Voltage / Coil /
« Reply #2 on: April 25, 2023, 07:35:20 PM »
Pump accelerator 2 times then crank engine. Takes three or four 5 second bursts to get it to start
06A 711 57 57 X66 L78 M22 BU

David K

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Re: Voltage / Coil /
« Reply #3 on: April 25, 2023, 11:16:36 PM »
What carburetor?

boomer632

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Re: Voltage / Coil /
« Reply #4 on: April 25, 2023, 11:29:39 PM »
Holley 4346.. stock 1969 L78 carb
06A 711 57 57 X66 L78 M22 BU

RichSS2006

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Re: Voltage / Coil /
« Reply #5 on: April 26, 2023, 06:42:53 PM »
Have you considered fuel evaporation? I recently tested this and found that today's fuels evaporate from the fuel bowl nearly 50% overnight. This is enough to cause starting issues if left even overnight. I have this issue with my L48 Quadrajet and L78 Holley. I can post the results later of my test if anyone is interested.
Rich
69 X22 L78 M21 10-10
69 Z11 L48 M20 50A

boomer632

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Re: Voltage / Coil /
« Reply #6 on: April 26, 2023, 08:08:35 PM »
I have considered that. Im going through and checking my float level and needle / seats
06A 711 57 57 X66 L78 M22 BU

boomer632

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Re: Voltage / Coil /
« Reply #7 on: April 29, 2023, 01:51:11 PM »
Ok so heres todays latest on being unable to time the engine with light because the mark is so erratic on indicator. While waiting for parts to arrive, I pulled all the plugs and did compression check. All cylinders between 190-200 psi. Plugs looked good, nice tan insulators. Re gapped them (AC Delco Rapid Fire 4) to .040 Today, put in new P3 ignitor distributor and Flamethrower 3 coil. Went right in where the old one was.. no issues there. I used black mechanical advance springs with no advance limiters. Set the internal rev limiter to 6200 rpm. 110 octane fuel in tank. Checked real good for vacuum leaks. None found. Only vacuum sources being used is the large one from rear of manifold to brake booster, pass side base plate port that goes to vacuum advance, and the front base plate port that goes to the choke diaphragm. Motor fired right up. Let it get up to temp and hooked the timing light up to external car battery and #1 wire. Again timing mark was bouncing everywhere but the engine idled smoothly and revd fine just as before. It did respond to turning the distributor as expected but I could not get a read on timing no matter where I put distributor. I then tested vacuum by connecting vacuum gauge to the booster vacuum port. Needle read 16Hg of vacuum at idle. Needle stayed put and did not move at all. I checked the idle mixture screws on Holley and they were both turned out 1.5 turns.

So no what? Could this be a valve lash issue? Im stumped at this point.. Stock L78 solid lifter motor with less than 5k on the rebuild.
06A 711 57 57 X66 L78 M22 BU

rich69rs

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Re: Voltage / Coil /
« Reply #8 on: April 29, 2023, 03:00:17 PM »
Have you tried a different timing light?

Are you sure your harmonic balancer is sound and not partially broken?

Richard
Richard Thomas
1969 RS

boomer632

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Re: Voltage / Coil /
« Reply #9 on: April 29, 2023, 04:00:58 PM »
That is next on list today
06A 711 57 57 X66 L78 M22 BU

169INDY

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Re: Voltage / Coil /
« Reply #10 on: April 29, 2023, 05:44:45 PM »
Your Mechanical Advance could be (*could be attempting to)  "Coming-In" at a to Low of a RPM as in: near or around your idle speed which is generally higher on these solid lifter motors, this instability can make the appearance of a instable "INITIAL" advance setting.

ask my why,

I am having this problem RIGHT now with my CE L78 motor!
Jim
68 SS/RS L35 Th-400 LOS
69 Pace Car L48 Th-350 LOS
68 Z28 M21 LOS

boomer632

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Re: Voltage / Coil /
« Reply #11 on: April 30, 2023, 01:39:00 AM »
Well good news.. my timing light was bad. Weird.. was an Actron light that I bought 2 years ago. Anyways so on to setting timing. As stated... 110 race fuel. Heres where Im at..

1) unplugged vacuum advance and plugged it. Set timing to 12 degrees

What are my next step exactly with setting timing? I get confused about when VA should be plugged after the "initial" timing is set to 12 degrees.

Is it:

1) Plug VA advance back in and see what indicator reads at idle? Should it change or should it still read 12?
2) Unplug VA and read timing marks at 3000 rpm to check the mechanical "all in"
06A 711 57 57 X66 L78 M22 BU

boomer632

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Re: Voltage / Coil /
« Reply #12 on: May 03, 2023, 11:06:11 PM »
So heres what I did. I unplugged VA line and capped it off. Set timing at 12 at 850 rpm. Mechanical advance was about 36 all in around 3300-3500 rpm. Just to check, hooked VA back up and was about 34 at idle. I then adjusted my idle mixture screws using vacuum gauge and re -set idle to about 850. All this seem right?
06A 711 57 57 X66 L78 M22 BU

 

anything