47 V8 ignition mystery

[FlatheadTed]

I was thinking the same thing ,give it the old hevHo ,I set my cars up so service ablty is top .Machine the caps on the diver so they pull off join the Vac pipe with rubber ,,never run the Generator or ING wire through the pipes .ect I use just black rubber copper core .,I think I would be investing in a crab cap .Can you try someone elses Carb ,

[BoGu]

You mentioned in post #67 that it ran fine without the gen.
What charging voltage do you have when the problem shows up?

Can you just disconnect the generator electrically and see if this make difference (i.e. running on the battery only)?

[Old Henry]

Originally Posted by BoGu

You mentioned in post #67 that it ran fine without the gen.
What charging voltage do you have when the problem shows up?

Can you just disconnect the generator electrically and see if this make difference (i.e. running on the battery only)?

I'll check the charging voltage and let you know.
I will start with disconnecting the generator and see if that makes a difference before disconnecting the belts to stop the pulleys from turning.
I can't imagine any reason there would be a connection but I'm desperate to try anything right now (short of replacing my stock sparkplug wiring and distributor caps with something else.)

[Mart]

Craig, crab distributors are great bits of kit. My personal recommendation would be as already mentioned by others above.
Buy a crab cap.
Buy the conversion clip kit to hold the cap on.
Run the wires without the conduit. I bundle the wires for convenience using cable ties.
I had a set of custom wires made to my own specified lengths unfortunately I have no record of the lengths.

Lots of people use this setup and it works well for me at least, across 4 different vehicles.

As stated above ease of maintenance is the key.

If it completely cures your problem then maybe you could try running in conduit to see if it reverts to previous behaviour.

Mart.

[tubman]

It's always been amazing to me that the early V8's don't have more cross-fire problems with the metal spark plug conduits. As I've said before, I'm an "8BA guy" and I won't even run the early plug wire guides, only the later "clover leafs". Because of this, I agree with "Mart" on trying it without the conduit.

[1942deluxe]

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Craig, a couple of random thoughts. On my 48 this past spring it would idle fantastic but almost immediately bog down and run rough on throttle. Changed distributor, new wires, plugs, rotor. Thought perhaps fuel problem so changed carb, fuel pump, and fuel line. No difference. Running a NAPA coil. Replaced that and problem solved. Good readings on the old one but apparently once it heated up it started failing. P/N on that is a IC7 and you bypass the resistor as it has an internal one. Understand # 3 and 6 are the cylinders with the misfire? I'm sure you already have checked but recheck they are in the right holes on the cap. I almost did that on one of mine. I have a Charlie NY fully rebuilt distributor and a Skip rebuilt coil I could lend you if you wanted to try them.

[FlatheadTed]

Lending is a good option ,he changed the coil but was it new ?
I have been running the tubes for years , you get a little Neon affect ., I saw the current offering of HT wires ,nothing soldered ect ?

[WBrown]

Originally Posted by Mart

Craig, crab distributors are great bits of kit. My personal recommendation would be as already mentioned by others above.
Buy a crab cap.
Buy the conversion clip kit to hold the cap on.
Run the wires without the conduit. I bundle the wires for convenience using cable ties.
I had a set of custom wires made to my own specified lengths unfortunately I have no record of the lengths.

Lots of people use this setup and it works well for me at least, across 4 different vehicles.

As stated above ease of maintenance is the key.

If it completely cures your problem then maybe you could try running in conduit to see if it reverts to previous behaviour.

Mart.

IF, you change to a crab cap configuration, be sure and use the correct rotor. The "rabbit ear" rotor is not compatible with a crab cap.

[1942deluxe]

On the crab (42) you will also need different length wires to my knowledge.

[Old Henry]

Originally Posted by 1939mars

You mention the generator and fan going on and off a few times in all of this and once that it ran fine before they went on. No idea how that could cause what you are seeing, but does taking that equipment off fix the problem?

Originally Posted by BoGu

You mentioned in post #67 that it ran fine without the gen.

Can you just disconnect the generator electrically and see if this make difference (i.e. running on the battery only)?

I disconnected the generator but it didn't help any.

[Old Henry]

Originally Posted by BoGu

What charging voltage do you have when the problem shows up?

The charging voltage is 6.8 volts.

[Old Henry]

Originally Posted by FlatheadTed

. . . he changed the coil but was it new ?

I put in a new 6 volt coil. It didn't help.

[Old Henry]

Today I thought I'd try a different rotor. It's cheap and easy to swap out.
When I took the new one out that I just put in I noticed that the brass contact that transfers the spark to the distributor terminals was loose on the rivet that connected it to the stainless steel part that ran on the center distributor post. I was so excited that such was the problem and quickly installed the new one bought from NAPA just today. Nothing any better.

[Old Henry]

I've responded before to suggestions to scrap the stock cap and wire conduits. That certainly sounds like a probable fix to my problem. The reasons I'm hesitant are several:
1) This car has run reliably 76 years and 311,000 miles on the original stock system.
2) I take great pride whenever anyone wants to see under the hood to be able to tell them that everything under there is exactly like it was when the car was new - everything.

I admit that it seems that every possible cause of my problem has been eliminated except the brand new spark plug wires that I just installed and I'm focusing again on them as well. I have considered all suggestions. Whatever I do next regarding them is going to be very difficult and time consuming but not impossible. So, I will do something. I'm not giving up yet.

[Old Henry]

Originally Posted by 1942deluxe

Craig, a couple of random thoughts. On my 48 this past spring it would idle fantastic but almost immediately bog down and run rough on throttle. Changed distributor, new wires, plugs, rotor. Thought perhaps fuel problem so changed carb, fuel pump, and fuel line. No difference. Running a NAPA coil. Replaced that and problem solved. Good readings on the old one but apparently once it heated up it started failing.

My problem is the same right from a cold start to warmed up.

[Lawrie]

Craig , I eagerly await your post when you have found the problem , Keep at it.
Lawrie

[40 Deluxe]

Could the replacement distributor have the rotor out of time? That is, could the rotor tip be in between the contacts in the cap when the coil fires? This could cause the spark to jump to ground or to the wrong cylinder. Who knows what that poor distributor has undergone in its life!

[Old Henry]

Originally Posted by 40 Deluxe

Could the replacement distributor have the rotor out of time? That is, could the rotor tip be in between the contacts in the cap when the coil fires? This could cause the spark to jump to ground or to the wrong cylinder. Who knows what that poor distributor has undergone in its life!

I don't know how the rotor could be that far off. It is attached to the end of the cam shaft. If it was, all cylinders would misfire, not just the same one or two consistently.

There are a lot of things that could cause sparks to fly willy nilly all over the place but 6-7 of my cylinders fire perfectly every time. It is mostly #6 that misfires consistently and sometimes #3. Whatever the poor distributor has undergone in its life was fixed by Ford when they rebuilt it. Then Michael set the dwell and timing and replaced the condenser. The distributor shaft has no play in it either side to side nor in and out (both of which I've suffered before).

[Mart]

While respecting your desire to keep all original, the overriding aim is to fix the problem. If you try the crab type cap and rotor and no conduits and it is then perfectly ok, you can then have more confidence when troubleshooting. You can then try and reintroduce the original parts step by step until the problem comes back. the last thing you replaced will be the problem item.

Changing the cap and leads to the crab type will be a valuable troubleshooting tool.

Borrowing a good running distributor from someone will also prove something.

Could you be suffering from burned valves on the cylinders concerned? How about a bad condenser? (not cylinder specific, I guess).

Temporarily changing away from stock as a diagnostic tool is not a bad thing.

I await with interest what you find.

Mart.

[Terry,OH]

suggest you charge your battery then take it one of the local auto parts stores and have it load checked to eliminate a possible problem there.
IMO The way Ford made the car it should run properly. Keep the rabbit ear cap and plug wire conduits.