The Ford Barn

Pat Martone · 08-04-2012, 12:07 PM

Purdy and others,
Thank you for the informative responses!

BILL WILLIAMSON · 08-04-2012, 11:17 PM

Quote:

Originally Posted by Pat Martone

Purdy and others,
Thank you for the informative responses!

Pat,
Just an afterthought, resistor wires causes spark voltage to increase in order to overcome the resitance, which will result in the plugs burning cleaner. This is a PROVEN fact! When modern cars changed to electronic ignition, black, sooty plugs were almost non existant!
Some of my local chaps say a Model A won't run with resistor wires!!! (Poor chaps!)
On my'30, with 6 volt system, stock distributor, I ran it for 2 weeks with NO ground electrodes on the plugs!! I don't know what brand the coil was, but it must have been a dandy, it was RED and it was on the car when I bought it. Bill W.

Carbroke · 07-29-2013, 12:21 PM

I know this is an older thread, but some might find this info useful.

In the early days of two way radio, we used mostly low band, around 30 to 50 MHz radios.

We constantly fought ignition noise in the cars and trucks we installed the old tube gear in.

We took several measures to manage the noise, as follows:

1. Bond the hood to the firewall and the firewall to the fenders with braided ground strap. Copper is best, but there is a silver plated copper version most use. This essentially puts all of the metal surrounding the engine at the same potential and aids in stopping the RF spraying from the ignition system from getting to your antenna. On the older cars, it probably isn't as useful as on say a 50's or 60's to modern cars.

There used to be a sintered bronze clip that had teeth and which screwed down to the cowl area under the rear lip of the hood. When the hood closed, the teeth dug in through the paint and bonded the hood when it was closed.

2. Absolutely MUST use resistive spark plug wires. These wires attenuate the spark noise greatly, also attenuating the RF generated. Also use resitive plugs. Don't forget the common wire from the coil to the distributor cap (if present) as well. We bought resistive spark plug wire in bulk on a spool and made our own wires, swaging the plug ends on with a crimping tool.

3. Add a coaxial capacitor in the generator output wire to filter any RF that is impressed into the generator wiring. Usually RF filter capacitors are .001 microfarad. There is a version available that comes with a screw stud for connecting wire lugs to the capacitor.

4. Find some pure silicone dielectric grease and LIGHTLY coat each of the spark wire electrodes in your distributor. Don't glob it on, the rotor will just spray it all over the inside. A light coating increases the voltage buildup required to arc the gap, resulting in a single clean arc rather than a long noisy drawn out arc. This is probably one of the most effective steps to do.

There is also a RF filter capacitor that is added to the source side of the ignition coil, but I don't recall its value. Probably any of the factory caps used on later cars would be proper for this.

Another bit of information. It is extremely easy to have ground loops in a vehicle. The best way to eliminate these is by making sure the battery and engine and charging system are all bonded to a common point. Usually this is the frame. Then the panel that the antenna is mounted on must be bonded to the system as well.

Ground loops are essentially multiple paths to ground, but each path has different resistance, and any current flowing drops varying voltages across the resistance. This heightens the noise. Usually this is a generator whine that follows the RPM of the engine.

The best way to tell if you are dealing with ground loops is to install a whine filter in the hot lead of your electronic unit. If the noise is only attenuated a slight bit, you probably have a ground loop issue.

If you do all of this and still have a problem, you are always going to have a problem, so start looking at other sources, such as a bad generator/alternator, bad coil, etc that is exascerbating the problem.

PC/SR · 07-29-2013, 06:43 PM

You have interference coming through the power wires and the antenna. It is not the antenna connector leaking, that is shielded by the coax connector, its just that when you disconnect the antenna, that interference is eliminated.
Mount the antenna on the back bumper, as far away from the engine as possible. Wire the power cables directly to the battery, which is in effect a large capacitor. Put fuses on both leads. A separate battery for the radio would eliminate interference from the engine, as noted above.
Separately ground the radio chassis if there is a connection for that. Run the wire back to the battery, with a fuse in it.
Try resistance wire, carbon or otherwise, from the coil.
These things may help. As noted above, AM is susceptible to interferance.

Pat Martone · 07-29-2013, 07:09 PM

Thank you for the recent and amazingly informative comments on how to minimize ignition noise to our CB radios used for touring in large groups. I continue to be amazed by the expertise on this site and the willingness to share it with others.
Since I do not want to replace the original type brass spark plug leads and I am also running a high-output Pertronix coil, I have decided to live with the ignition noise. However, I was wondering if a well-shielded but original looking coil wire might reduce ignition noise.

Buz · 07-30-2013, 08:33 AM

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Quote:

Originally Posted by walt jones

I use a seperate small 12volt rechargable sealed lead-acid battery rated at 7.2 amp hours. I have used this on tours lasting several days with no problems. There is not near as much noise as if the radio were connected to the car battery. It will need charging from time to time. A small 12v charger can be used for this.

This is exactly what I did, radio worked great with no noise and no modifications had to be made to the car at all.

BrianM · 07-30-2013, 08:53 AM

jmeckel has nailed this one. Pitch the CB's and use the fm family radios. No more having to mount a non-period radio and antenna, and no power leads to connect. The family radios are cheap, compact, and effective.

BrianM (retired electrical engineer/ham radio operator for over 50 years)

Pete · 07-30-2013, 11:29 AM

Quote:

Originally Posted by BILL WILLIAMSON

Pat,
Just an afterthought, resistor wires causes spark voltage to increase in order to overcome the resitance, which will result in the plugs burning cleaner. This is a PROVEN fact! When modern cars changed to electronic ignition, black, sooty plugs were almost non existant!
Some of my local chaps say a Model A won't run with resistor wires!!! (Poor chaps!)
On my'30, with 6 volt system, stock distributor, I ran it for 2 weeks with NO ground electrodes on the plugs!! I don't know what brand the coil was, but it must have been a dandy, it was RED and it was on the car when I bought it. Bill W.

I'm sorry to inform you that you can not create matter.
Spark voltage does NOT increase with resistor wires unless you increase the input voltage to the system or change to a hotter coil.
Resistor wires will cut the current at the plugs by as much as 5 milliamps. Since the automotive ignition system is NOT a constant current type of system, the voltage will drop with higher resistance.
Your "proven facts" are wrong.
As a retired auto technician, you should have been exposed to Ohm's law somewhere along the line in order to service electrical equipment.

BILL WILLIAMSON · 07-30-2013, 01:38 PM

Quote:

Originally Posted by Pete

I'm sorry to inform you that you can not create matter.
Spark voltage does NOT increase with resistor wires unless you increase the input voltage to the system or change to a hotter coil.
Resistor wires will cut the current at the plugs by as much as 5 milliamps. Since the automotive ignition system is NOT a constant current type of system, the voltage will drop with higher resistance.
Your "proven facts" are wrong.
As a retired auto technician, you should have been exposed to Ohm's law somewhere along the line in order to service electrical equipment.

Then why can you "clean" ugly sooted plugs by gapping the coil wire 1/2" or so & run the engine at higher RPM's for a couple of minutes?
An engine that's completely drowned in raw fuel can be started in the same manner & run a couple of minutes at higher RPM's to clear everything out.
1 crusty, oil fouled plug can be made to fire by gapping it's plug wire, in the same manner. SO??
Whatever the explanation, resistance wiring DOES result in better/more efficient plug firing. How did you measure the 5 milliamp loss at the plug, you're pretty TRICKY! 5 milliamps is only about a GNAT'S eyebrow!! Bill W.
(S A, Yes, I KNOW about OHM's law.! I'm NOT a DUMB ASS & I DO know what works in PRACTICAL applications!!!!)

Tom Wesenberg · 07-30-2013, 02:21 PM

Quote:

Originally Posted by BILL WILLIAMSON

Then why can you "clean" ugly sooted plugs by gapping the coil wire 1/2" or so & run the engine at higher RPM's for a couple of minutes?
An engine that's completely drowned in raw fuel can be started in the same manner & run a couple of minutes at higher RPM's to clear everything out.
1 crusty, oil fouled plug can be made to fire by gapping it's plug wire, in the same manner. SO??
Whatever the explanation, resistance wiring DOES result in better/more efficient plug firing. How did you measure the 5 milliamp loss at the plug, you're pretty TRICKY! 5 milliamps is only about a GNAT'S eyebrow!! Bill W.
(S A, Yes, I KNOW about OHM's law.! I'm NOT a DUMB ASS & I DO know what works in PRACTICAL applications!!!!)

This is true that by putting a gap in the system the coil needs to build to a higher voltage before it jumps the gaps. This higher voltage can then jump the spark plug gap before it has time to bleed off through the wet or dirty insulator. I learned about this when I was in 11th grade and went to a car show. The snake oil salesman was showing how his magic spark intensifier could soup up an engine. I looked and looked for some fine wires shorting out the plugs, or some such gimmic, but I didn't see anything amiss. I bought one and stuck it in my distributor cap, and of course there was no improvement because I didn't have any fouled plugs. I broke the plastic case to see what was inside, and it was simply about a 1/8" gap that the spark had to jump.

I've helped many fouled plugs by holding the coil wire up a little until the plug heats up and burns clean.

28ACoupe · 07-30-2013, 03:53 PM

There are a couple of ways to deal with this:

1) As you probably have a bunch of excess antenna wire, take the excess and make up a smallish(6" diameter) coil with the coax such that the coils are close together and wrap with black tape to hold it. This will help cancel out the noise. This is what it should look like when you have it done:

2) Secondarily, you can contact a company such as Ham Radio Outlet and ask for ferrite magnets to go on your coax which, along with the above coil, will also cancel out a lot of the noise. If you don't have enough coax to form the coil, the magnets may still help. Here are what the magnets look like and yes they do actually work:

I hope this helps

BILL WILLIAMSON · 07-30-2013, 05:54 PM

Quote:

Originally Posted by Tom Wesenberg

This is true that by putting a gap in the system the coil needs to build to a higher voltage before it jumps the gaps. This higher voltage can then jump the spark plug gap before it has time to bleed off through the wet or dirty insulator. I learned about this when I was in 11th grade and went to a car show. The snake oil salesman was showing how his magic spark intensifier could soup up an engine. I looked and looked for some fine wires shorting out the plugs, or some such gimmic, but I didn't see anything amiss. I bought one and stuck it in my distributor cap, and of course there was no improvement because I didn't have any fouled plugs. I broke the plastic case to see what was inside, and it was simply about a 1/8" gap that the spark had to jump.

I've helped many fouled plugs by holding the coil wire up a little until the plug heats up and burns clean.

Thank you, Sir, for backing me up.
I NEVER post helps, procedures, or advice, unless it has WORKED for ME! Sometimes I'll say something "MIGHT" work, or you "MIGHT" try this or that to get a better idea on the diagnosis of a problem. Bill W.

Pete · 07-30-2013, 09:12 PM

"How did you measure the 5 milliamp loss at the plug?"

With an oscilloscope.

The typical stock points type 12v ignition coil draws about 4 amps under load.
The coil turns ratio between the primary and secondary is usually around
100 to 1.
This equates to around 12 kilovolts at 40 milliamps on the secondary.
Losing 4 to 5 milliamps to resistor wire is about a 10% loss in current.
That is why everything in the secondary circuit has to be in the best condition possible when running resistor wire.

The reason a wide gap or secondary gap cleans plugs is that the spark temperature increases (to a point) as the gap increases.
While increasing the gap may show a slight improvement at low rpm, as
you increase load and speed performance will fall off dramatically.

The plug gap needs to match the design of the rest of the ignition system for a given engine and use.

Pete · 07-30-2013, 09:37 PM

To get back to the original question.
Most of the previous suggestions will decrease ignition noise to some degree.
The problem being, you can completely eliminate all noise from your car but when you get it to a very low level, you begin hearing passing cars and cars in front and behind you and this can be as bad as yours was to start with.
Modern diesel cars have electronic timed injectors and they are extremely noisy.

A good example that can be viewed almost anywhere is to look at a Corvette. Tinware and shields everywhere around the ignition. Fiberglass body so no shielding help there.
Take a look at the ignition on a small plane. Plug wires completely shielded with braid type wire and fully shielded spark plugs.
Expensive to duplicate in automotive applications but possible.
I used to work in the 2 way radio industry and any problem is solvable if you throw enough money at it.

The cheapest way to solve the problem for model A tours is get FRS (family radio service) or GMRS (general mobile radio service) FM radios. These can be had used cheaper than old AM CB's now
and mobiles only require an antenna 5 inches long.
Hand helds are the size of a cigarette pack or cell phone.

08-04-2012, 12:07 PM	#21
Pat Martone Senior Member Join Date: Jul 2011 Posts: 495	Re: Is there a "cure" for ingition noise overpowering a CB radio? Purdy and others, Thank you for the informative responses!

07-29-2013, 12:21 PM	#23
Carbroke Member Join Date: Sep 2012 Location: Western WA. Posts: 86	Re: Is there a "cure" for ingition noise overpowering a CB radio? I know this is an older thread, but some might find this info useful. In the early days of two way radio, we used mostly low band, around 30 to 50 MHz radios. We constantly fought ignition noise in the cars and trucks we installed the old tube gear in. We took several measures to manage the noise, as follows: 1. Bond the hood to the firewall and the firewall to the fenders with braided ground strap. Copper is best, but there is a silver plated copper version most use. This essentially puts all of the metal surrounding the engine at the same potential and aids in stopping the RF spraying from the ignition system from getting to your antenna. On the older cars, it probably isn't as useful as on say a 50's or 60's to modern cars. There used to be a sintered bronze clip that had teeth and which screwed down to the cowl area under the rear lip of the hood. When the hood closed, the teeth dug in through the paint and bonded the hood when it was closed. 2. Absolutely MUST use resistive spark plug wires. These wires attenuate the spark noise greatly, also attenuating the RF generated. Also use resitive plugs. Don't forget the common wire from the coil to the distributor cap (if present) as well. We bought resistive spark plug wire in bulk on a spool and made our own wires, swaging the plug ends on with a crimping tool. 3. Add a coaxial capacitor in the generator output wire to filter any RF that is impressed into the generator wiring. Usually RF filter capacitors are .001 microfarad. There is a version available that comes with a screw stud for connecting wire lugs to the capacitor. 4. Find some pure silicone dielectric grease and LIGHTLY coat each of the spark wire electrodes in your distributor. Don't glob it on, the rotor will just spray it all over the inside. A light coating increases the voltage buildup required to arc the gap, resulting in a single clean arc rather than a long noisy drawn out arc. This is probably one of the most effective steps to do. There is also a RF filter capacitor that is added to the source side of the ignition coil, but I don't recall its value. Probably any of the factory caps used on later cars would be proper for this. Another bit of information. It is extremely easy to have ground loops in a vehicle. The best way to eliminate these is by making sure the battery and engine and charging system are all bonded to a common point. Usually this is the frame. Then the panel that the antenna is mounted on must be bonded to the system as well. Ground loops are essentially multiple paths to ground, but each path has different resistance, and any current flowing drops varying voltages across the resistance. This heightens the noise. Usually this is a generator whine that follows the RPM of the engine. The best way to tell if you are dealing with ground loops is to install a whine filter in the hot lead of your electronic unit. If the noise is only attenuated a slight bit, you probably have a ground loop issue. If you do all of this and still have a problem, you are always going to have a problem, so start looking at other sources, such as a bad generator/alternator, bad coil, etc that is exascerbating the problem.

07-29-2013, 06:43 PM	#24
PC/SR Senior Member Join Date: May 2010 Location: Santa Rosa, CA Posts: 1,280	Re: Is there a "cure" for ingition noise overpowering a CB radio? You have interference coming through the power wires and the antenna. It is not the antenna connector leaking, that is shielded by the coax connector, its just that when you disconnect the antenna, that interference is eliminated. Mount the antenna on the back bumper, as far away from the engine as possible. Wire the power cables directly to the battery, which is in effect a large capacitor. Put fuses on both leads. A separate battery for the radio would eliminate interference from the engine, as noted above. Separately ground the radio chassis if there is a connection for that. Run the wire back to the battery, with a fuse in it. Try resistance wire, carbon or otherwise, from the coil. These things may help. As noted above, AM is susceptible to interferance.

07-29-2013, 07:09 PM	#25
Pat Martone Senior Member Join Date: Jul 2011 Posts: 495	Re: Is there a "cure" for ingition noise overpowering a CB radio? Thank you for the recent and amazingly informative comments on how to minimize ignition noise to our CB radios used for touring in large groups. I continue to be amazed by the expertise on this site and the willingness to share it with others. Since I do not want to replace the original type brass spark plug leads and I am also running a high-output Pertronix coil, I have decided to live with the ignition noise. However, I was wondering if a well-shielded but original looking coil wire might reduce ignition noise.

07-30-2013, 08:53 AM	#27
BrianM Member Join Date: Aug 2012 Location: Gwinn, MI Posts: 46	Re: Is there a "cure" for ingition noise overpowering a CB radio? jmeckel has nailed this one. Pitch the CB's and use the fm family radios. No more having to mount a non-period radio and antenna, and no power leads to connect. The family radios are cheap, compact, and effective. BrianM (retired electrical engineer/ham radio operator for over 50 years)

07-30-2013, 03:53 PM	#31
28ACoupe Senior Member Join Date: Jun 2012 Posts: 559	Re: Is there a "cure" for ingition noise overpowering a CB radio? There are a couple of ways to deal with this: 1) As you probably have a bunch of excess antenna wire, take the excess and make up a smallish(6" diameter) coil with the coax such that the coils are close together and wrap with black tape to hold it. This will help cancel out the noise. This is what it should look like when you have it done: 2) Secondarily, you can contact a company such as Ham Radio Outlet and ask for ferrite magnets to go on your coax which, along with the above coil, will also cancel out a lot of the noise. If you don't have enough coax to form the coil, the magnets may still help. Here are what the magnets look like and yes they do actually work: I hope this helps __________________ 1928 Model A Business Coupe Rebuild picture gallery here The light at the end of the tunnel has been turned off due to budget cuts. Last edited by 28ACoupe; 07-30-2013 at 04:04 PM.

07-30-2013, 09:12 PM	#33
Pete Senior Member Join Date: May 2010 Location: Wa. Posts: 5,410	Re: Is there a "cure" for ingition noise overpowering a CB radio? "How did you measure the 5 milliamp loss at the plug?" With an oscilloscope. The typical stock points type 12v ignition coil draws about 4 amps under load. The coil turns ratio between the primary and secondary is usually around 100 to 1. This equates to around 12 kilovolts at 40 milliamps on the secondary. Losing 4 to 5 milliamps to resistor wire is about a 10% loss in current. That is why everything in the secondary circuit has to be in the best condition possible when running resistor wire. The reason a wide gap or secondary gap cleans plugs is that the spark temperature increases (to a point) as the gap increases. While increasing the gap may show a slight improvement at low rpm, as you increase load and speed performance will fall off dramatically. The plug gap needs to match the design of the rest of the ignition system for a given engine and use.

07-30-2013, 09:37 PM	#34
Pete Senior Member Join Date: May 2010 Location: Wa. Posts: 5,410	Re: Is there a "cure" for ingition noise overpowering a CB radio? To get back to the original question. Most of the previous suggestions will decrease ignition noise to some degree. The problem being, you can completely eliminate all noise from your car but when you get it to a very low level, you begin hearing passing cars and cars in front and behind you and this can be as bad as yours was to start with. Modern diesel cars have electronic timed injectors and they are extremely noisy. A good example that can be viewed almost anywhere is to look at a Corvette. Tinware and shields everywhere around the ignition. Fiberglass body so no shielding help there. Take a look at the ignition on a small plane. Plug wires completely shielded with braid type wire and fully shielded spark plugs. Expensive to duplicate in automotive applications but possible. I used to work in the 2 way radio industry and any problem is solvable if you throw enough money at it. The cheapest way to solve the problem for model A tours is get FRS (family radio service) or GMRS (general mobile radio service) FM radios. These can be had used cheaper than old AM CB's now and mobiles only require an antenna 5 inches long. Hand helds are the size of a cigarette pack or cell phone.