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New Owner - No Spark!

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SpitSix

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Hello all! I have finally come over to the MG side, after 33 years! Actually I am sure I will continue with my Triumphs as well, but I could not resist a very solid Texas MGB (77) I came across recently here in the Dallas area. At first I figured I could get it running and sell it, using proceeds gained for Triumph stuff... but then I sat in it.. and realized that it was roomier inside than my TR6! Then I started to read about engine conversions... where will it all end??

So, problem 1: No Spark.

The interim DPO said that he had it running when he picked it up from the primary DPO. The Car then sat for six months.

The car has a Pertronix Ignitor setup and Pertronix coil.

The Pertronix coil is labeled 3 ohms, and meter confirms 3 ohms resistance in the primary. Meter says around 80K ohms between primary and secondary. This is a 77 MGB and my readings on the web indicate that it should be a ballasted system. This would make a 3 ohm coil incorrect. Grime indicates that the coil has been in the car for a long time though.

There is power to the coil.

With ignition on the Pertronix Ignitor gets very hot to the touch after a couple of minutes. I realize this is not a good thing to do (ignition on for a long period) but wonder if this still might be an indicator of "good" or "bad" Ignitor.

No "in car" attempts to make the coil fire have been successful. These include disconnecting the Pertronics Ignitor and jumping the minus side of the coil to ground then removing jump.

All that said, Any ideas?
 
Not sure if this helps any but the Pertronix systems seem to respond badly to letting the key sit in the ignition, even with the ignition off. Some have claimed battery drain from this.
 
Please don't take this as insulting, but if t'were here it'd be getting a conventional iggy system first. Standard coil. Points and condensor, new plugs, cap and rotor, static time it and light it off.
 
Nothing insulting about that Doc, good thinking! I wonder if I still have the correct mounting plate for the points in there. Hopefully the Pertronics plate was an add in that did not require taking anything out first.

That still leaves the question of which coil is correct? That is, ballasted or non-ballasted system?

What does the ballast residtor look like?? Would like to put my finger on it to be sure. Is it the blue one almost in the harness?
 
All I recall of the '77 is that it has one in line on the coil power lead. I'd say that one HAS to be it. You should be able to just remove the Pertronics bits and reinstall the original points type bits in the dizzy to see if you get spark. Early Pertronics "smart boxes" were prone to self destruct if iggy was left energised and the engine wasn't running.
 
Thanks Doc, That is going to be the plan. Yes, reading the Pertronics site confirms that nothing gets tossed on installation of their stuff.

It would seem that the 3 ohm coil is incorrect. The resistor I am referring to is on the ground side of the coil though (sure - but going to go look again in just a minute).

Man -- your two cars ahead of me! I do have most parts of an airplane though!
 
Can't park an aeroplane onna curb an' walk home. /bcforum/images/%%GRAEMLIN_URL%%/wink.gif

...same applies to boats.

I've been pedalin' about in MG's, Lotus and Alfas for about forty years. Very few times have I had to concern myself with gettin' too close to the edges of the sky in one. /bcforum/images/%%GRAEMLIN_URL%%/devilgrin.gif
 
It sounds like you may have found the ballast resistor; it it's anything like my Midget then yes, the ballast resistor is actually a resistance wire built into the harness.

Pertronix units don't respond well to leaving the ignition on with the engine stopped. Only if the key is on though; leaving the key in is fine if you don't mind the door buzzer going off. If it's for a short time (maybe 10-15 seconds) then they are OK, but I wouldn't go for minutes.

One thing to check might be to get a 12 volt test light, connect it across the two coil terminals, and see if it blinks when you crank it. That's how I figured out my stock electronic ignition was shot and I put in a Pertronix to replace it.
 
Since you are new to the joys of MGs you might want to subscribe to the "University Motors" site on You Tube. John Twist has a series of videos on troubleshooting electrical problems and other things that are really very good.
 
Doc - I have pulled over to the curb a couple times in an airplane! Precautionary landings and overnight due to weather.
I once parked a rental Cessna in Denton and drove home too. Same reason. IMO small planes flown with good judgment are safer than a Spitfire in Dallas traffic :smile:

SparkyDave - Thanks for that tip! I had not tried that one. I am starting to think the Pertronix is shot. Garage I bought the car from probably left Ignition on until the battery ran down.

pwlester - Thanks, I will check it out (You Tube). Lots of neat MG stuff on there.

Hey guys - can I get this forum to send me an email when someone replies to the thread?
 
Go into your preferences & change the item:
"By default should anything added to your Watch Lists be emailed to you?" To yes.
Then add the thread to your watched topics list by clicking the "Topic Options" at the top.
 
SpitSix said:
IMO small planes flown with good judgment are safer than a Spitfire in Dallas traffic :smile:
Click to expand...


Too true. And about every other major metropolis I can think of. Civil aviation has a sterling record, particularly if compared to wheeled vehicles.
 
If you don't already have a wiring diagram for the B, visit Dan Master's web site, https://www.advanceautowire.com

On the left side of the screen you'll see links to wiring diagrams and there will be a link to "stock schematics" and there you will find a PDF compilation for the MGB.
 
SpitSix said:
Hey guys - can I get this forum to send me an email when someone replies to the thread?
Click to expand...
Yes, what you need to do is go to your "my preferences" page, and near the bottom of the page will be the question "By default should anything added to your Watch Lists be emailed to you?". Choose yes. Then, return to this thread or any other that you want email notifications for, and on the top left go to "topic options" and choose "Add topic to your watched topics".

EDIT: haha didn't see this had gone into a second page and this had been answered.
 
That's OK, it's info everybody needs to see as it seems to be hidden away and not incredibly obvious information. /bcforum/images/%%GRAEMLIN_URL%%/wink.gif
 
As I am a couple of days late reading this, I hope you have found your problem. However, I have never had any luck with pertronix. I'm not sure why but I havent. I too have a 77 B and had ignition problems. I tried different distributors but the best solution I found was to get the ultimate ignition kit from Brit-Tek. (I'm sure they are also available from other sources)The kit It features a euro curved points distributor that made a world of difference. Also you scrap the ballast hook up. Instructions are supplied and were very easy to follow. I have been running it for two years and no problems. Good Luck!
 
Call Jeff at Advanced Distributors.
He will set you up, real good! /bcforum/images/%%GRAEMLIN_URL%%/wink.gif
 
To clarify a few points:
The Pertronix MUST be run with a 3 Ohm coil, hence the change from stock. It should be supplied with 12V, fed direct from the relay or fuse panel, not ballasted.
The Pertronix canbe tested by installing a test light in series between the black Pertronix lead and the coil. Crank the engine and the light should flash. If it doesn't, then replace the module.

You probably have it installed in the factory distributor, which will not allow you to install points. It was an electrnoic distributor to begin with and doesn't have a points cam, no the holes to install the necessary points/condenser. Feel free to email me and I can send you details/pictures of what to look for. Email me a pic of your distributor and I can verify which one oyu have and help you get it fixed!
Jeff
jschlemmer1 *at* comcast.net
 
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