Couple of Coil Questions

[goodnigh]

Is there any way to test a coil for function?

There have been issues with the engine running

poorly and it does not seem to be a fuel delivery

problem. Bought new ignition wire set so I decided

to buy a new coil, why not. Everything from the coil

to the plugs is now new waiting to be installed.

What is the difference between oil filled and epoxy

as to application? The one I just got is epoxy filled.

mike

 

[Boss1Ray]

From the 'net:

Testing an Ignition Coil

The epoxy-filled ones allow better high heat, vibration or non-vertical installs.

Hope this helps.

Ray

 

[wwhite72]

Original points style coils are different than high output ignition coils. The pertronix I works with oem points coil. the blaster coils work wih pertronix II and III and MSD type ignitions and their magnetic pickups. They are not interchangable. The manufacturers are getting better at spelling out the differences.

 

[goodnigh]

From the 'net:

Testing an Ignition Coil

The epoxy-filled ones allow better high heat, vibration or non-vertical installs.

Hope this helps.

Ray

Yes, Thanks.

Tested the old coil and it tested fine.

Replaced it anyway.

The resistance between pos and neg poles

was 1.5 on both old and new. Resistance

from center post to either pole was 10k on both.

This was measured with a Fluke.

The car started

mike

 

[Boss1Ray]

From the 'net:

Testing an Ignition Coil

The epoxy-filled ones allow better high heat, vibration or non-vertical installs.

Hope this helps.

Ray

Yes, Thanks.

Tested the old coil and it tested fine.

Replaced it anyway.

The resistance between pos and neg poles

was 1.5 on both old and new. Resistance

from center post to either pole was 10k on both.

This was measured with a Fluke.

The car started

mike

So if it is still running poorly-

are you now thinking fuel issue?

Ray

 

[mityman]

This is interesting. I have my original oil filled coil and am using Pertronix II.

Am I doing some damage with this setup?

Original points style coils are different than high output ignition coils. The pertronix I works with oem points coil. the blaster coils work wih pertronix II and III and MSD type ignitions and their magnetic pickups. They are not interchangable. The manufacturers are getting better at spelling out the differences.

 

[goodnigh]

So if it is still running poorly-

are you now thinking fuel issue?

Ray

Not sure what is the next step.

Will be replacing the spark

plugs and wires. A couple of the

connectors we checked were green

and corroded.

mike

 

[wwhite72]

http://www.pertronix.com/prod/ig/flame/coils/chart.aspx This is the pertronix detail on coils and modules. I believe the reverse is what causes damage, putting higher output thru points or Ptrnx I, and you would expect. When i had personal experience with this problem Pertronix only had the one product on the market P II had not been introduced. You just popped in the module to replace the points and everythin worked great and you only paid $50 bucks. I stupidly installed a higher output coil 6 mos later and caused problems that resulted in a failed module and a blown power valve on the Holley. Im guessing you're fine with the original coil but the chart gives specs.

 

[goodnigh]

http://www.pertronix.com/prod/ig/flame/coils/chart.aspx This is the pertronix detail on coils and modules. I believe the reverse is what causes damage, putting higher output thru points or Ptrnx I, and you would expect. When i had personal experience with this problem Pertronix only had the one product on the market P II had not been introduced. You just popped in the module to replace the points and everythin worked great and you only paid $50 bucks. I stupidly installed a higher output coil 6 mos later and caused problems that resulted in a failed module and a blown power valve on the Holley. Im guessing you're fine with the original coil but the chart gives specs.

I hope the problems I am having are not because of a blown power

valve. The Holley is

fixed by Holley. What are the symptoms of a blown power valve?

We noticed corrosion on some of the spark plug wires which are 8mm

Taylor and three years old. Could a high energy coil (Pertronix) affect

wear and tear on the wires?

mike

 

[wwhite72]

there are some very experienced carb guys on this site who can offer opinions on yer holley. or you can check the holley site, they give details on checking the power valve on your carb. i tend not to think 3yr old 8mm wires would be the source of your poorly running engine, unless one or more got melted or something. of course 'green and corroded' doesnt sound good but connectors can be replaced on a lot of 8mm wires depending on the mfg. or even brushed up and dialectal greased for shot at inexpensive fix.

 

[Wolverine]

Need to be careful due to variety of ignitions.

1 thru 4 are valid regardless of ignition type.

1. Get a DWELL METER and make sure you have a good dwell. Points will give you consistent dwell at 26 +/= 3 or so regardless of RPM. Electronic(Pertronic, HEI, etc) should vary dwell as RPM changes. I believe the dwell is low at low RPM and hi at hi RPM.

2. Check your timing in 3 stages. Check it with the distributor vacuum hose connected...should be off the mark. Otherwise vacuum advance is toast or timing off.

3. Plug the vacuum hose, make sure your motor is at 600 rpm or less and check. Should be 6 degrees BTC. Otherwise adjust.

4. Push motor with vacuum hose plugged to 1500 RPM and again the timing should be off the mark, otherwise you have bad centrifugal springs or your distributor internals are stuck.

From here on down, your milage will vary based on ignition type:

- Points

- Pertronix Style(Not and HEI)

- HEI

Check this forum for more detailed and reliable information. I have posted some things with drawings and such. Basically:

5. Check the INPUT COIL VOLTAGE. Confirm it matches the input voltage of your coil.

For POINTS system:

6. FORD specific coils accept ONLY 6VDC in. 12VDC in will toast the coil.

7. Chevy specific coils take 12VDC in and have an internal ballast to knock the voltage down to 6VDC. 6VDC in will give crummy spark.

For Electronic Systems:

If you have Pertronix 6 or 7 above applies as Pertronix simply replaces points. However, Pertronix 1 or 2 MODULES NEED 12 VDC input to work properly(Confirm with Pertronix). In a Ford, Coil would generally still get 6VDC,

If you have an HEI, generally you would have a full 12VDC coil, meaning there is no ballast in the coil. This is not necessary, but provide the full power the HEI is capable of. Pert1 and Pert2 have low amp throughput to coil. HEI has high amp throughput, and can take advantage of the coil capabilities.

This is why you check your motor when it is running good, so you can benchmark it when you are running bad.

Good Luck.

 

[droptop73]

The Holley is

fixed by Holley. What are the symptoms of a blown power valve?

mike

The newer Holleys do have "blowout protection". The way to tell is if adjusting the idle mixture screws does nothing. If you can close the screws and it still runs, replace the power valve.

 

[goodnigh]

Need to be careful due to variety of ignitions.

If you have an HEI, generally you would have a full 12VDC coil, meaning there is no ballast in the coil. This is not necessary, but provide the full power the HEI is capable of. Pert1 and Pert2 have low amp throughput to coil. HEI has high amp throughput, and can take advantage of the coil capabilities.

This is why you check your motor when it is running good, so you can benchmark it when you are running bad.

Good Luck.

Too late to check how the motor "was" running now.

On a simple time line, the engine's performance changed

after we installed a tuned exhaust system purchased

from Don of OMS. The system is a copy of what came

on a Boss 351. Why would that effect the engines

performance? I don't think "bad" wires or plugs are causing

the problem. This is a great excuse to buy a scope, :angel:

We adjusted the idle screws to get 18 inches vacuum, and when

we gunned the engine the dial did what you would expect.

We have about 3000 miles on this engine and the only remaining

"original" part is the dizzy.. Hmmm

The coil is a new Flame Thrower with Ignitor "points", new cap

and rotor. I could run a series of diagnostics on the dizzy OR buy

a new one

mike

 

[Don C]

Changing to a free(er) flowing exhaust will usually cause the carburetor to lean out, may need to go up a jet size or two.

 

[goodnigh]

Changing to a free(er) flowing exhaust will usually cause the carburetor to lean out, may need to go up a jet size or two.

Don't know if it flows more freely.

There is some issue about back pressure.

The former exhaust was a straight pipe from

the H-pipe to the muffler with a couple bends

for body contour. The new pipe has bends where

they don't make sense unless you add back pressure

to your tuning specs.

mike

 

[Wolverine]

1. Make sure you are getting 12VDC to the Pertronix.

2. To save time/trouble, grab a spare spark plug and spare ignition wire. Ground the spark plug. Wire the spare ignition wire to the coil and spark plug. Do you get a GREAT spark?

3. Not sure what "boss" exhaust means. Boss had their own exhaust manifolds which were opened up at the piping end from 2.25" for the 4V's to 2.5" for the boss.

So, what type of manifold do you have 2v, 4v @ 2.25, 4v @2.50?

Seems to me you can follow the prior advice and try to run a little richer mixture.

It does not take much to take a smooth running engine and unbalance it.

You might also want to check you vacuum. If you don't have 17-20 pounds that could be an issue as well.

Good Luck.