[wbnapier]

Attached photos:

1) Spark plug #1

2) Ported vacuum source from the rear carb, drivers side.

3) Brake vacuum from the front carb. For your interest.

No picture of vacuum source at the rear of the center throttle body, no room to take a photo.

[wbnapier]

What is this black cap / vent for on the dizzy cap?

[HWYSTR455]

That plug looks OK, maybe a little too much advance, but looks OK. I don't think it's lean, but maybe a little.

Brake booster connection looks fine, but no, I don't believe that's a vacuum port that you are pointing to, it should be at the base of the carb.

I will look it up, give me a few.

Do you know your initial timing, and your total timing?


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[HWYSTR455]

Originally Posted by wbnapier

What is this black cap / vent for on the dizzy cap?

Yes, that's supposed to vent the cap and prevent moisture build up in the cap/dizzy.

That's the new cap I would guess? And your old one didn't have it, correct?


.

[Bill Hanlon]

Originally Posted by wbnapier

Attached photos:

1) Spark plug #1

2) Ported vacuum source from the rear carb, drivers side.

3) Brake vacuum from the front carb. For your interest.

No picture of vacuum source at the rear of the center throttle body, no room to take a photo.

Either I'm mixed up (happens a lot, especially on Monday mornings) or you have pictures 2 and 3 reversed. Looks to me like #2 is brake vacuum.

[HWYSTR455]

Originally Posted by Bill Hanlon

Either I'm mixed up (happens a lot, especially on Monday mornings) or you have pictures 2 and 3 reversed. Looks to me like #2 is brake vacuum.

Yes, but the pics have text in them that clarify that.


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[wbnapier]

The old cap had the black cap on the vent, so it was not vented. I had no idea it was there. I will pull the vent cap off of my new dizzy cap to minimize corrosion.

The timing is 12 initial, 32 total.

The passenger side plugs are actually dark. I leaned out the idle mixture screw a little on that side to see if it helps. On the driver side, I have an O2 sensor, so I have it dialled in nicely.

[HWYSTR455]

Hm. I dont think removing the cap is needed, it vents the way it is, but see what happens when you pull it, dont think it will harm anything. Maybe pull it off the old one 1st, see if it was vented. If so, it wasnt vented enough, or itsnot going to make enough of a difference.

I suspect you have avacuum leak on the drivers side, probably where the intake meets the head. With it running, spray some carb cleaner around the edges, if idle speed changes, you have a leak.

Be careful with o2 sensors, each engine needs a diff range, and what many say is the baseline may not work on your combo. What are your readings?

Timing sounds about right for an iron head engine.

Start with that and post back.

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[wbnapier]

When I phoned MSD this morning, they told me to drill 2 x 5/32" holes in the dizzy cap to vent and thus, prevent corrosion.

I was unaware, so didn't discuss with them, the black cap on a hole on the top of the dizzy cap. Anyhow, no big deal either way. What's more corrosion at this point?


HWYSTR455, do you think I have a vacuum leak based on the #1 cylinder temp being 100 degrees cooler?

Understood on O2 sensors. I am aware that they are just an indicator and I shouldn't fixate on specific target AFRs.

I tore into the old wiring today and found all sorts of nastiness. Such as:

1) The heavy red wire from the MSD 6AL box was wired directly to my 150amp alternator. The MSD installation instructions specifically say to do not do this.

2) One or both of my electric fans were spliced directly into the red/keyed 12v wire on the MSD 6AL box.

3) The black/negative coil wire was spliced with a failed butt joint and fell apart as I touched it.

4) The wires were overloaded and melted (likely from the alternator and fan wiring) and destroyed. See the attached photos.

I will call MSD in the morning for replacement wires, so I can keep the same colors. I'm really happy I'm doing this. It was a miracle the car started and ran at all.

[Geoff]

Never understood the vented cap theory. Nothing inside the dist to cause moisture/rust, so no moisture to escape via a vent. Venting the cap will let moisture IN.
Factory dists do not have vented caps..........

[HWYSTR455]

Wow, that's not good. Yeah, good thing you tore into it. Make sure you use quality wire too, GXL is what you need. This place is fast, and inexpensive:

https://www.wirebarn.com/GXL-TXL-Wire-_c_530.html

Use quality non-insulated butt connectors, and heat shrink tubing, as well as a quality crimper. My go-to crimper is the Klein 1006, many places carry it, even Home Depot usually has some in stock:

https://www.summitracing.com/parts/kle-1006/

Yes, the temp, and the plug. Check carb base gaskets too. Older intakes may also not be 100% true, might have to run a thicker intake gasket, or have the intake machined.

What kind of fans do you have? Hopefully they are run at least using a relay setup, and 10 or 8ga wire, depending on the load. Really, you should use a PWM controller, for a number of reasons.

Run the alt charge wire using 6-8ga. You can run one in parallel to the existing one if you want.

If you use quality crimpers, connectors, and wire, you can make the MSD wires yourself. The newer boxes use metripack connectors, you can buy a set of crimpers and terminals, and even replace the wires in the original MSD harness. WaytekWire.com carries that stuff, but you can probably get the crimpers somewhere else cheaper. Or, just butt connector slice into the harness.

Geoff - I feel the same way, moisture really shouldn't get up in there, but believe it comes from the engine, past the shaft bearings/seals, as well as under the cap lip. The OE points dizzys had a dwell door, those would allow moisture in/out.

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[wbnapier]

HWYSTR455,

Yes, it is actually much worse than what the photos show.

Thanks to your previous replies, I have 12, 14, & 16 AWG GLX from wire barn, the Waytek connectors, and the Klein 1006 tool.

I am still going to get replacement wire harness from MSD, as I need orange, which wasn't in my assortment kit. I assume they use good wire. I'll also get some SPAL wiring harness, so my colors match up.

Once the cars running again, I will spray some carb cleaner around. I am doubtful I have a vacuum leak as it idles so well and I have 12+ inches of vacuum.

Maybe my spark to #1 was bad with my ignition wiring being bad?

I have dual 12" Spal fans. I have the fan relay kit on order from Mad Electric. Waiting on that still. It's been 7 days and we are both in California. I will phone to check this morning. I also have a headlight relay kit and something alternator related.

I will be wiring the alternator directly to the + battery terminal with a 6 gauge wire, per Powermaster's instruction.

The fans will run off relays direct to the alternator post per Mad Electrics recommendation.

For the MSD wires, I will butt connect them I think using my Waytek butt connectors. Maybe a metri pack.

Off to work, I will have to pause on the car till Friday evening probably.

[Scott65]

Originally Posted by Geoff

Never understood the vented cap theory. Nothing inside the dist to cause moisture/rust, so no moisture to escape via a vent. Venting the cap will let moisture IN.
Factory dists do not have vented caps..........

I was told years ago, that venting is not for moisture, but to release ozone buildup, that could enable the atmosphere inside the cap to be more conducive to cross firing. Specifically related to using MSD boxes. I've drilled holes, in the cap, or in the points window, ever since. No ignition problems for me. FWIW

[AG]

Originally Posted by Geoff

Never understood the vented cap theory. Nothing inside the dist to cause moisture/rust, so no moisture to escape via a vent. Venting the cap will let moisture IN.
Factory dists do not have vented caps..........

The point of the vent cap is to allow ozone (which is generated inside the cap from the extra high voltage ionizing the air) to escape. It is the ozone that oxidizes the inside of MSD distributors, not ambient moisture.

[wbnapier]

I received my package from Mad Electric today.

I will use the electric fan relays and run them to the junction hardware they supplied. I am unsure about the keyed 12v wire for that. With the M&H engine harness, I replaced the resistor wire with a HEI keyed 12v wire, and I was going to run that to the MSD 6AL small keyed 12v wire. Unsure if I join all 3.

The alternator kit, I am unsure about as I have a one-wire alternator. And the instructions are specific to 3-wire alternators.

The headlight relay kit seems complicated to install and I need to take apart / remove some wires from my new harness. The instructions aren't clear there.

They recommend running the starter to a relay and using their wires and wire per their instructions. I have the new engine harness, which is a clear install, and now I have to wrap my head around something different.

Lots of documentation included. Pages and pages to go throw...

I will receive my new 6AL box Monday. Lots to think about.

[wbnapier]

I installed my 6AL today on the driver's side inner fender after hours of contemplation about where the best place would be. I decided serviceability is the priority compared to aesthetics.

I installed the new headlight harness (no relays yet), and began routing wires.

Question:

I have 3 grounds in the engine bay. Battery to the engine, MSD 6AL heavy black wire, and my AutoMeter tachometer.

I am thinking to combine them all at the engine ground. Is there any issue with that? What size ring terminal do I need there?

[HWYSTR455]

I originally used a 3/8 fame bolt to go from the battery to the frame, then from the frame to the engine. Then I grounded a bunch at the frame bolt. The brake/fuel line bolts work well. You still need to ground the body to the frame, which you can do from the battery to the fender, and the firewall to the engine.

There should be one ground in the rear from the body to frame as well.

Battery to engine should be same size as POS cable, all others can be 10/12ga.

So the eye terminals should be 5/16 and 3/8.

This time around I used Thread-serts on the frame & body, and made grounds along the driver's side frame rail. That ensures full contact at the ground points, but isn't required, it's basically overkill.

I still recommend a PWM fan controller, the on/off shock of the fans is hard on the electrical system, you will see lights dimming when they kick on, and could possibly reduce the life of the alt regulator.

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[wbnapier]

HWYSTR455,

My negative battery cable currently runs to the purpose-built stud on the driver's side head. Is there any reason to not use that stud to also ground my tach and MSD 6AL? I would need to find some really large eyelet terminals, but the location is good and all the grounds would be in the same place for easy serviceability. Or, I could just ground them at the battery negative terminal? Is that acceptable too?

I have a chassis ground strap on one of the bell housing bolts. I'm leaving it be.

My battery positive goes to a large junction block on the frame rail, then off to the starter.

[george kujanski]

The MSD box connection to the engine bolt is a good idea. The tach could go to a smaller bolt, firewall, whatever, as long as that surface is well connected to the engine block or batt negative.

George

[HWYSTR455]

Just make sure you have a body to ground is what I was saying.

When I did mine, I basically made the junction on the frame a ground point, between the battery and engine, so it's basically both.

I always do ignition boxes and EFI ECUs directly to the battery, in the event I need support. That's one thing that is strongly pointed out on all instructions.

The key really is to have a common positive point, as MAD states in the PowerUp!/Chevy Main Electrical Power System and Remote Voltage Sensing tech papers.

http://www.madelectrical.com/electrical-tech.shtml

Minor variations to those papers are acceptable. What I do is use a Ford solenoid as the main power distribution point, except for the MSD and EFI ECU, which I put right to the battery. As long as everything else is on the power point, it's fine.

To keep wires as short as possible, I have a couple runs to both the POS and NEG battery posts. Again, as long as most is to the common power point, you're good. I would do all the accessories to the common point, and electronics to the battery.

Spikes is what kills parts, so you have to manage loads too. The biggest spikes come from fans and stereo amps. I used to eat alts, and oddly, against popular belief, once I added a stereo capacitor, I stopped eating alts. I then added a PWM controller for my fans and it decrease the load spikes almost entirely.

Sensor grounds, for engine sensors (oil psi, water temp, etc) I always ground to the engine. And that's why grounding the engine to the frame, frame to the body, and engine to the body are important.

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