Ignition issues365BB

This has been a very long road...having just completed a comprehensive engine overhaul. One would expect it would run well...after the "normal" tuning issues were addressed.

A lttle background...
New JE 11:1 pistons with 3-ring rings
New OE cams
Cases split...and line honed
All new bearings...
Rods rebuilt
New valves, intake and exhaust
New guides and viton type seals...
Engine rebalanced to 0.1 grams

And on and on...

The problem...
Idles well for a few minutes, with fresh plugs...then she'll foul a few. Usually the same 2-3 plugs will foul.

Carbs clean...and freshly rebuilt.

Ignition wires, plug extenders, cap and rotor - All new...
Plug gap at .030"
Old MSD 6AL-2 ignition system (been in the car for years...)

After a bit of head scratching...and doubting the integrity of my new motor, I did a leakdown test.

The engine has a hour of runtime and 30Km of driving....All cylinders have less than 2% leakage...Hmmm!

Pull plugs again...and inspect. Seems that three of the new plug extenders have carbon tracks on them...Can't be, 'cause they're new! So, I moved the "questionable" extenders to different cylinders...and low and behold the problem moved, as well.

Removed the tracking extender and covered with electrical tape, as a temporary move...to see if she would run smoothly. Hmmm, she'll idle now for about 15 minutes, whilst I recheck the carbs...and then she starts to pop thru the exhaust and run rich....

Re-pull the plugs and check. Number 9 cylinder fould for the nth time. Remove #9 wire from the cap and ohm check. Wire open...and visually burned at cap connector. Other wires on the same bank have the "correct resistance", but the connector at the cap appear to be starting to burn where that little u-clip is inserted in the center of the wire....

So, a whole lot of aggrevation for suspect quality OE wires and extenders.

Sooo, before I send back and attempt to warranty the OE ignition components, am I wasting my time, in that the problem is that the MSD unit is "smoking" these components...?

In the past, I rolled my own wires using MSD wires. No problems, though it wasn't stock!

Tempted to go with Magncore wires, and replace/circumvent the extenders...

Comments/thoughts?

Get rid of that old MSD asap.

suffice it say after looking at your list, that it's (MSD) the only piece of junk on there.

Throw that garbage (MSD) where it belongs.

I had a freakin missing, fouling, running condition from hell recently (last year), put a new MSD on (already had an old one installed) and instantly the problem went away.

If possible try a Perma Tune instead of an MSD.

http://www.perma-tune.com/Products/F...ari%201512.htm


http://www.perma-tune.com/New%20Prod...EC%20104-B.htm

www.perma-tune.com

That burning & carbon tracking sounds strange...could be caused by the MSD causing the plugs to load by a malfunction...then the insuing over amplified sparks have no where to go but out of the insulation, taking the path of least resistance..

Over the years I have had countless problems with the MSDs.

Others swear by them, I swear at them...

JRV,

This car, through the years has suffered with various errartic plug fouling issues that I've never been able to pinpoint, as to the exact cause...

Lots of burned wires ends, and arcing plug extenders...Candidly, I never suspected the MSD unit, though recently, while watching the spark with an HEI tester spark plug, things just didn't look right...inconsistent spark.

I respect your opinion and will take your advise and purchase a Permatune unit...In that the wires and extenders appear toasted, would you go down the Magnacore route to solve the ignition problem (s) once and for all??

Regards,
David

David,

I'm not so sure Magnacore wires are neccsary on the early ignition systems with old standard coils. I still use factory wires on the 70's cars like Daytonas & Espadas without problems, and both use CD boxes to enhance longivity.

Do you have a standard type coil or newer blaster type?

>>while watching the spark with an HEI tester spark plug, <<

approx. how much coil voltage were you seeing?

To burn up wires or extenders I would suspect too much..maybe over 80K....however, even if it is the normal 40K any type of arcing will burn up the leads...

It seems that as long as there is no arcing, caused by a broken spiral in a wire or excessive air gap in the cap that the stock wires should work fine.

It almost sounds like the coil has reversed polarity or excessive dwell time??? However that could be caused by the MSD unit?

I should add that in my experience MSDs were used to mask rich running carbs and not to enhance ignition system weakness's. The stock ignitions were plenty powerfull enough to work flawlessly when the carbs were tuned to the 2%-3% CO like they were supposed to be. Stock ignions even work fine up to about 4.5% CO...after that plug fouling does start to occur prematurely with the stock ignitions.

Part of the problem has been plugs however.

Copper core plugs with large wide electrode tips are very poor at self cleaning. Ferrari used the Champion Fine Wire Gold Plugs (and Porsche used the Fine Wire Platinums) because of their ability to clean themselves once sooted up. Because of the Gold or Platinum that soot does not bond to, and the fine tips so that the spark would be cleaning a tiny area those plugs are the most resilient to quick rich fouling, work over a much wider heat range and thermal shock conditions, and have the ability to come back once wet fouled and the mixture returns to normal. Analyze your plugs and see if an upgrade may be in order, especially with your compression boost .

JR,
As there are more than a few possibilities and/or variables here...

Here's what I know so far to be true, as of this morning:

11 plugs are firing...and look good for 20 minutes of idleing. I did not drive the car.
In that 11 are clean and firing,, can we for the moment rule out the MSD unit itself?

Spark plugs are NGK BP6ES. Gap at .030
Light tan and clean.
My HEI plug tester does tell voltage...only that their is ignition...I haven't put her on my ignition scope, as of yet..

The coil...HMMMM...This is new to this engine and it a MSD HEI mini coil per their recomendation. Past coil was a MSD Blaster 2 (over 15 years old, prior to change)

Year ago I made a connector that plugs the MSD unit directly into the BB wiring harness. Originally, at the new coil, there were three wires...Yellow, Red and Black. On the new coil, I have the Red wire connected to the "-" terminal, the Yellow to the "+" terminal...and the Black wire grounded at the coil base (chassis). Oddly, when I look at the BB wiring diagram, the Red wire is connected to the "B+" terminal on the OE coil...Presuming I didn't switch the leads at the MSD/OE connector (not visible from on top of the car), it would seem that the coil is hooked up backwards, as you suggested earlier. I'll get her upon the lift in the am to verify, for sure.

Either way, what is the ramification of having reversed polarity on the coil?

I still need to rectify the wires/extenders issue before going much further...

Appreciate your assistance!

Regards,
David

Reproduced HTH's:

Joking apart Champion the Plug Makers say that it does matter. I
reproduce below a section without diagrams etc. from


CHAMPION
Automotive Technical Service Manual




The subject of polarity often causes confusion and deserves a more
detailed discussion. Over the years car manufacturers have connected
either the positive or negative terminal of the battery to the chassis
but in recent years have adopted a negative earth as standard.


Most electrical components in the car have one of their leads connected
to the chassis, which acts as a common return path to the battery and
completes the electrical circuit of which the component is a part.


The ignition coil however is connected to the chassis only through the
closed contact breaker.


If the leads to SW and CB (or to terminals marked respective '+" and
"-") are reversed, the current flow through the coil primary is reversed
and this in turn reverses the polarity of the coil secondary voltage.
Coils are wound so that the output to the rotor arm is negative with
respect to the chassis but this depends on the correct primary
connections being made.


Spark plugs are sensitive to polarity and they will not function as
efficiently it the secondary coil voltage is of the wrong polarity.


The reason for this sensitivity is as follows. The centre electrode has
a higher temperature, normally, than the ground electrode so that more
electrons will be released from the hotter metal surface of the centre
electrode than from the ground electrode.


If the centre electrode polarity is more negative than the ground
electrode (which is connected to chassis) then the earth electrode will
attract electrons from the centre electrode; but if the coil secondary
voltage polarity is reversed, the voltage needed to cause electrons to
pass from the earth to the centre electrode (i.e. to make the gap
conductive) is increased.




Reversed coil polarity can be shown on an oscilloscope but a less
sophisticated test is to disconnect a plug lead with the engine running
and form an arc between the plug terminal and the end of the cable.


If the point of a soft lead pencil is placed in the path of the arc then
a shower at sparks will be created, either on the plug side (if polarity
is correct) or on the cable side (if the polarity is incorrect). The
condition of the plug will also indicate reversed coil polarity if this
situation has prevailed for some time. The use of the oscilloscope is a
more sophisticated means of determining the states of the engine,
ignition and fuel systems than the condition of the spark plug.








http://members.aol.com/bgahc/01_jwha...parkplugs.html

JR,

Interesting article...and confirms what I have found. The coil was indeed hooked up backwards (polarity reversed). I'm not sure how long it has been that way, but suspect it was done inadventently when the new coil was installed 100 miles ago. Further testing on the "bad" side of the engine has revealed yet another defective wire...with 12.5K ohm resistance. So now we had 3 plug extenders with carbon tracks...one open wire and one wire with high resistance. All the other wires on the "bad" side are approx. 1.2-1.7 ohms.

I'll be checking the resistance of the "good" side wires this morning.

I've got some work ahead of me...and will keep the board posted as I make progress.

Based on your previous comments, would I be better off with a needle electrode plug such as a NGK BP6EV to minimize any future plug fouling issues?

Appreciate your help..

Regards,
David

David, I believe the fine wire plugs would help you.

>>It almost sounds like the coil has reversed polarity or excessive dwell time??? <<

>>The coil was indeed hooked up backwards (polarity reversed). <<

Well at least we got to the bottom of frying wires &amp; plug connectors..{}...

In this venue it does take quality input though to surmise cause &amp; effects. The detailed nature of your input got my grey matter working {}