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MG MGB Technical - Pertronix Ignition

Does anyone know about pertronix Ignition? It appears to be some setup that reuses the original distributor body.
Thanks, Dave
David Steverson

I've had one on my car for about 3 years without a hiccup and I'm a happy camper. Your results may
vary as I've read that other folks may have had different results.

It replaces the points and fits entirely inside the distributor. No external boxes.

You will have to re-time the engine after installation as the trigger is not positioned
exactly as the old points.
Daniel Wong

Hi Dave,

I put one in my 73B in about 15 minutes. Haven't had it in very long, but it isn't causing any problems either.

One note: If it does fail, without a replacement or replacement points/condenser, you are stuck with a capital S.

John
John Staub

David, you will find about 20 million comments on the pertronix in the archives.

I've had one for 3 years now. It does the job well and I no longer have to fool around with the tiny, stripped screw that holds down the points and readjusts them when you tighten it.

Go to their website!

Fred
Fred Horstmeyer

But always carry a set of points and a condenser as a spare ...
Paul Hunt

Paul's advice is worth heeding as the Pertronix unit is one of the very few that makes reverting to points a relative snap compared to most others. A nice feature when contemplating a dead unit at the edge of the road. FWIW.
Bob Muenchausen

It has been my observation that Pertronix systems come in two flavors - those that fail almost immediately (within hours or days), and those that last and work well a long time. Unfortunately, they are not identified as to which is which! If you can get past the infant mortality failure, you'll be very happy with it. If not, it has also been my observation that Pertronix is very good about replacing faulty units.

Let me emphasis the point made by John, Paul and Bob - carry a set of points/condenser, preset, so if the Pertronix fails you can pop it in and be on your way. This is not true only for Pertronix, but for all electronic ignition systems of that type. A points system usually fails gradually, giving you ample warning that trouble is ahead; an electronic system usualy just stops. And so does your car, regardless of how far away from home you are. There is no roadside repair possible with a failed electronic unit.
D Masters

My Pertronix Ignitor performed flawless up until the time it didn't. I got about 3 years of troublefree service and was delighted with it. One day this spring I was on my way to work and the car sputtered and died. I drifted to the side of the road and cranked it -- it fired right up. Drove a bit more, it sputtered and died. I stopped and checked things and quickly identified the Ignitor as the culprit, popped in the points I was carrying and was on my way.

I did a post mortem on it last weekend. Turns out it failed not because of a problem with the electronics but because the ground lead to the unit had fatigued and broken right at the point of entry into the plastic case. No way of reattaching the wire as the break is too close. I'm sure that electrically, the unit is fine. It is worth noting that Pertronix are currently shipping a slightly different style now than when I bought mine (the new ones are about a third smaller...)

The moral seems to be to pay very careful attention to the routing of the wires when you install it. Try to minimise the amount of movement of the wires as the advance moves the point plate. (And carry some points with you <grin!> )
Rob Edwards

Pertronix and others do mention in their installation instructions the need for a bit of slack AND also anchoring the leads to the movable breaker plate when installing these. This is to prevent the type of fatiguing of the wires noted by Rob.

A good installation will have a small bit of a loop on the unit side of the anchor (usually a small nylon wiring Ty-Wrap which can be cinched up snug)and then sufficient slack on the other side to allow full and free movement of the movable breaker plate.

Altho it is not mentioned in their instructions, I always "glue" the leads in place where they emerge from the distributor body with a dab of Silicone Sealant. This seals the hole and wires, and also acts also as a strain relief for the wires. You could go even further, and place another nylon wire tie at that point on the leads inside the dizzy where they just contact that hole. Anything you might do to control the jerking and tugging on those wires (like when I accidentally bump them or get them caught up in something else I am working on - doh!) will help extend their life and avoid what happened to Rob.
Bob Muenchausen

It is also _critical_ to have the correct coil ! Pertronix says to check the coil with an ohmmeter and for a 4 cylinder car use a coil with 30 ohms or greater resistance , this is (supposedly) why some of them fail and other's don't .

I have well over 40,000 happy troule free miles , it made the car run significantly smoother and start easier cold or hot but did _not_ increase power like an MSD setup
does .

-Nate
Nate

Nate, how much does an MSD increase HP on a dyno?? Tests I have seen seem to indicate that they burn the fuel/air charge more completely which results in some increase, but not a significant amount. What have you found to be true?? I ask because this is a consideration many folks wonder about when striving for a bit more performance and yet wonder whether that MSD is really going to net them anything they can feel at the seat of their pants vs. a simple electronic points substitution like the Pertronix unit.
Bob Muenchausen

30 ohms? Added a nought?. The 12v coil primary measures 3 ohms and the 6v coil 1.5. The secondaries are in the thousands of ohms.
Paul Hunt

Oops - my finger slpped , of course I meant to write 3.0 ohm primary resistance .

Be aware thet Ignitor II is a different unit the has variable dwell time and uses the low resitance coils 0 0.6 according to Pertronix .

Bob , I don't have dyno acess but I _gaurantee_ you'll feel the difference - my son is a very methodical hot rodder and only makes one change at a time then does extensive testing , the MD throws 2" long sparks (scared the sh*t out of me when testing it !) and I believe it does indeed promote better fuel charge burning .

Me , I don't like <magic> boxes that can fail and leave me walking but I do like the basic Ignitor .
-Nate
Nate

... but always carry points as a spare, I trust? ;)
Paul Hunt

Oh yes of course ! in a tiny ziplock baggie in the glovebox along with the original screws , just in case .

Never had to use them but my buddy is visiting his sister in Mn. and is having problems with coils dying - I cannot figure out why , told him to just pop in the points & motor on home .

-Nate
Nate

For the best prices I've found for Pertronix units I've found, go to:-
http://www.coupers-cars.com/

How about under $60 vs $100 from Moss.
Derek Nicholson

Does anybody know a company that sells them at decent prices in Europe?

Regards,

Alexander
Alexander M

As always, try Google. MGOC and others sell Lumenition Magnetronic which is much the same, as is the Aldon Ignitor, at much the same number in Sterling as dollars in the USA.
Paul Hunt

Try sending an eMail to Coupers Cars. I understand he's an ex-pat Brit, so he may be ready, willing and able to ship overseas. Worth the cost of an eMail to ask the question.
Derek Nicholson

instead of carrying a spare set of points, why not carry a spare Pertronix?
mark

Why invest the extra money for something that might not work when you need it most?
Paul Hunt

I carry a spare condenser and points to back up my pertronix, also. Consider test fitting the assembly to assure that it works, as I have had a condenser fail right out of the box. Test fitting will give you a little practice for the emergency road-side repair (and will quite possibly reimind you of why you went to Pertronix in the first place). Now that I think about it, if you purchase a spare Pertonix and trade it out for your current unit, you accomplish the same confidence in your back-up.

Dean
Dean Lake

... but if you'd stuck with points you wouldn't be changing them in an emergency roadside repair in the first place!
Paul Hunt

Why buy

I seem to recall a recent thread about using the original Lucas electronic system, which turned out to be a GM system in disguise. I believe everyone thought it was highly reliable.

If true, why not fit the GM system, save cash and get a well proven ignition.
Fred

One thing to remember about the Pertronix unit that has not been emphasized here is that it requires a full 12-volt input to the red wire in order to operate properly. Many people attempt to power the unit off the white wire to the distributor, which in later MGs is ballasted to ~6-volts. On my V-8 I had to run a new wire through the loom to the coil area, providing a 12-volt switched supply for the Pertronix module. If you try to run the unit on less than 12, you will get erratic operation and misfiring.

Also, the best backup for the Pertronix is to carry a fully set up point type distributor in the boot. That way, instead of fiddling with little points and condenser screws at the roadside, you can just "plonk and plug" the spare distributor in place and be on your way.

Cheers,
Paul Kile
Paul Kile

This thread was discussed between 27/09/2002 and 11/10/2002

MG MGB Technical index

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