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MG MGB Technical - No Picture of my Dizzy? What kind??

Question? I have a MGB and I am trying to determine where I can get replacement parts for the distributor. It is a 1979, the "type" looks like the "Opus" in the MOSS (current book page 84).

When I took the cap off (inspect/clean) the center contact is very worn. Cap says it was made in Germany, but no parts number.

When I pulled off the Rotor Arm (looks like it has been arcing, edge very black). Note: this rotor must not have been off for a very long time... rust was on the top part of the dizzy shaft where this goes.

Now here is where I don't know what I have, because there isn't a cover anti-flash part...number 3 Moss book. The rest of the inside of the Distributor doesn't look like the Opus or the C.E.I. Instead there looks to be a very thin disk. There are 4 evenly spaced cuts in the disk, plus it looks like some kind of pickup unit on one side this spins under. Nothing even close is pictured in either Moss or Victoria British.

There is an amplifier (has a picture of a shark on it?) that is also part of the Dizzy set-up.

I cleaned up the inside of the cap. Cleaned the rotor to remove burnt edge, then stuck it back together... acutally runs better.

But, I would like to buy a new cap and rotor do you think the C.E.I. parts should be my choice?

And what about the part that looks like a small cd disk w/pick-up??? any ideas what this is and where to get replacement parts??

Note: could'nt find this in the Haynes manual either.

Any Help/ideas/suggestions please.

Pete
Pete

The metal body of the dizzy will be stamped with the model eg "45d4" and you can order the corresponding parts from there. The internals sound as if they have been replaced with an aftermarket optical system (maybe Piranha from the logo). If you can post pictures somewhere on the net others should be able to identify.
Steve Postins

For info on dizzy try www.aldonauto.co.uk
K Harris

Pete. Most of the Lucas 45DE4 distributors have failed in service, often early in the ownership of the new car. Mine did. Hence, most cars still running the Opus dizzy have had the internals replaced with one of the various aftermarket electronic triggers.

The Petronix unit is contained completely inside the distributor and does not have a power board associated with it. The Lumenition replacement, which was in my daughter's car when we purchased it, does have a power board associated with it. I believe the Crane (old Allison) system does also. It would be worthwhile for you to know what aftermarket system is currently installed in case you have problems with it in the future.

None of this, however, affects the rotor or distributor cap, all of which are generic to the Lucas 45D distributor series--i.e. each fit all of the various 45D models. As to the Made in Germany cap, probably a Bosch, which has always worked well for me. The various UniPart rotors and caps have also worked well, as do the Lucas brand parts. See what is available in your area. BAP used to carry parts for the various Lucas distributors at a very reasonable price.

Les
Les Bengtson

Great to hear from all of you! After I received your replies I double checked the Moss Catalog, all of the caps/rotors have the same stock number. Now that I feel comfortable, based on your info, that these parts are generic, I'll order these a.s.a.p.

I don't know how to post a picture, nor do I have a web site to display the internals of the Dizzy. So, Ill do a little research on the web site that K. Harris recommends.

Thanks,
Pete
Pete

Pete, but you a nickel it looks like this:-

http://www.triumphspitfire.com/images/ignition/insidedistrib.jpg

Let me know.

TTFN

Derek Nicholson

Does the kit logo look like the one on this?

http://www.citroentuning.de/ze_pira.htm

Piranha got bought by Newtronic but there are plenty of old kits around if needed.
Steve Postins

Derek.... I quess I owe you a nickel! I would say the picture of your unit is a lot better than what I saw in mine!

Steve.. That's what the unit looks like a "Piranha" not a shark as I had said earlier.

Now the question is this for everybody:

Should I try and search for the internal parts?? "Or" put my money into the package that Brit-Tech sells the "Ultimate Ignition System? (point system)

Do I have to "worry" about the disk/unit failing? I have NO idea how long it has been on the 79 MGB. I've had it for 7 years now. I have a Weber/Cannon Header (I installed last year)... so is the Piranha system still a good enough unit to run?

OK to just change the Cap/Rotor and leave the rest alone for now?

Hmmm, need some more repies please.

Pete
Pete

If the Piranha is working it is more than good enough so I'd leave well alone. What I would do however is get a base plate with points installed ready to go because aftermarket electronic systems run well when they work but have a habit of failing suddenly and irreparably, in my experience.
Steve Postins

Steve,
I was able to "pick-up" a 25D4 Distributor at a recent MG show. Has all of the internal parts (including base plate, old set of points/condensor/rotor). Would this base plate work if I purchase a new set of points/condensor inside this type of dizzy? Use as a "back-up"?

Looking forward to your response,
Pete
Pete

Pete, you can pay me next time I see you.

Not sure if they'll be useful to you, but you can get the installation instructions from here:-

http://www.triumphspitfire.com/piranha.html

The link to Newtronic doesn't work, but this one does:-

http://www.newtronic.co.uk/

What would I do? I'd make sure the 25D4 was working and carry it in the car as a spare on long trips. Anything further than the 100 mile radius that AAA will tow you for free! I don't know it the baseplate will fit.

TTFN

Derek Nicholson

Pete. I am not sure what you are asking.

You seem to have picked up a Lucas 25D4 distributor. But, that, in itself, means very little. The Lucas people made "a distributor" which fit "most British cars" of the period. The period, in this case, being about 1962 to 1974. However, there were quite a number of British cars made, using this distributor. There were even, horror of horrors, foreign cars using Lucas components. Some of them were rather expensive "exotic" cars.

Thus, "a Lucas 25D4" description tells us very little. They, when they were new, varied significantly in how they were set up. When they were new, they all performed to within the factory specification for their use. On the side of the distributor was a "specification number", something like the "40897" specification which was used on the early MGBs and seems near to be the ideal curve for general use. Under the specification number, you should also find some for of four digit marking like 13-65 which would indicate the part was made in the 13th week of 1965.

The Lucas 25D4 distributor specifications, as applicable to the various MGB models, varied, quite significantly over the years. Much of this was due to the varying US emissions requirements after the 1968 model year and the changes Lucas was required to make to allow the MGB to meet those requirements.

The same distributor, to different specification, was also used on the A-H Sprite and the MG midget, as well as other cars, of British manufacture, imported into the United States.

Thus, you need to know, exactly, what you have before you decide to install the distributor into your MGB. You also need to understand that what the distributor started out life as might not be what the distributor is today. I purchased an "Auto Zone" rebuilt distributor for my 1968 MGBGT. The investigation of this distributor was a "good learning experience". My dear friend, Bob Muenchausen, had obtained a Sun Distributor Test Machine for me, which allowed me to observe the mechanical advance at various rpms. A physical inspection of the distributor showed that it had an 18 degree mechanical advance stop. It should have been a ten degree stop. So, the distributor would allow 8 degrees of distributor advance (16 deg crankshaft advance) more than allowable. The dizzy test machine showed that the mechanical advance curve did not come in at the correct engine rpms. Thus, a distributor which had been rebuilt, was totally inappropriate for the engine under discussion, and would, have installed and used, have caused possible engine damage.

Much more information would be necessary before I would suggest you use you "new" distributor in your MGB.

Les
Les Bengtson

Les is right. Unless you can verify its even an MGB distributor, I'd stick with what you have. The points plate from the 25D will not fit in the 45D. If you want the 25D reworked for your car, drop me an email. Its your cheapest route to a performance igntion system!
Jeff
Jeff Schlemmer

Dereck, thanks for the link with the installation info. This will give me a better idea where the wires go, etc.

Steve, Since I cleaned up the inside, it's running great. But, I still think I'll order a new cap and rotor.

Les, I'll need to do a lot of home work about the 25D... may not in the end even do anything with it. I'm leaning toward changing the system to use the Ultimate Ignition Package from Brit-Tech. The intake/exhaust side of the engine is more up to date now (and easy for me to understand) with the Weber/Cannon Header. Now I want to update the ignition so I'll have less worries about using 1979 type equipment. Changing to a point system would be better for me anyway... I'm a few years over 60, and know / understand point system better than electornic system.

Anybody use the "Ultimate Ignition System Package" from Brit-Tech?? Is it as easy to install as the Weber/Header conversion?

Pete
Pete

The ultimate ignition system is a great option, but from my experience, the replacement 45D distributors aren't as long-lived as the factory 25Ds. I guess if you're not adding up 30k miles a year its no big deal. There's substantially less bearing surface on the 45Ds though, so they wear out faster.
Jeff Schlemmer

Pete. I am currently running that system on two of my cars and my daughter's car, all daily drivers. No problems noted.

They provide a Lucas Sports Coil and a new set of spark plug wires with the kit. If you use the Sports Coil, you will have to re-wire your current system to provide full time 12V input to the coil. Your current coil uses a resistance wire in the white wire circuit to drop the voltage to about 6-8V when the engine is running and you have a "6 volt coil" installed. I made this modification on my 79 and Theresa's 77 with no problems. Not sure the Sports Coil is really needed--the standard coil works fine in most operations except full out racing use. But, it comes as part of the package and a new coil should not hurt anything.

I have found no drawbacks to the Brit-Tek system and have had a lot of good information from Bob Ford over the years. He has, on the rare instances were there was a mistake in the order or the part was bad, quickly shipped the proper part and offered to pay for the return shipping on bad parts. One of the better people to deal with. I think you will be happy with the system.

Years ago, I recommended that people obtain a three ring binder and put useful articles off the internet, BBS threads, etc. into it as a form of ready reference. Doing that with the instruction sheet from the ignition kit is an excellent idea, along with any notes you make while doing the installation. As we get older, and I am only slightly younger than you, we tend to forget some things. The Book makes remembering what we have done over the years much easier. One of my friends is 80 and still driving his MG. Hence, both of us will need to be able to remember what we did 20 years ago, when we are his age and taking our MGs our for a drive.

Les
Les Bengtson

My "average miles per year" is less than 2,000 miles (now that I am retired it may go up a bit) Jeff so I don't think I'd wear out the bearing surface.

Les, thanks for the tip about making a notebook! I still have the instructions for the Weber/Cannon Header and they will be the first few pages in the book. I've made copies of the "Newtronic" (Piranha electornic system via the link) which will also get filed. And as soon as I can make the purchase for the "Ulitmate Ignition System"... that too will be added. I'm going to copy/print your last link so I can remember the tip about 12 volts.

20 years from now the book might be handy, to reference like you said.

Pete
Pete

The original 6v coil and starting HT boost system works very well, and there is no good reason for removing it. Whilst some electronic systems *require* you to remove it, they are unlikely to make much of a noticeable effect over a properly setup factory system.
Paul Hunt 2

Paul. You are perfectly correct and the points type system is not really affected by either running a 6V or a 12V coil. However, this system is sold as a package which includes the Sports Coil.

While I have heard rumor of the Sports Coil being available in the 6V configuration in the UK, all that I have seen in the US have been the older 12V model. Hence, I wanted to make very sure that the Sports Coil was either not installed (did it that way with my first installation), or is wired up according to the directions which Brit-Tek includes with the kit.

You are more competent than I to explain what happens when one runs a coil at one half of its intended voltage requirements. I suspect, however, that it is not a good thing.

Les
Les Bengtson

Hi Les. In fact running a coil at double its voltage (i.e. a 6v coil with the rubber bumper harness ballast bypassed or in a chrome bumper car) is more damaging to both coil and points/trigger as the current and hence heat is doubled. The other way round (12v coil in a rubber bumper car) just gives a weaker spark. I say 'just', but when that contributes to poor cold starting and one's better half is muttering under their breath ("It's got to go") it is still pretty serious. Not that I have done the coil thing, but there have been a couple of occasions of arms akimbo and foot tapping ...
Paul Hunt 2

Paul. Thanks. That is what I would have thought would happen. Especially with the wife, even though mine is quite understanding about most car related things. She says being stranded gives her time to catch up on her knitting.

Les
Les Bengtson

This thread was discussed between 05/10/2006 and 14/10/2006

MG MGB Technical index

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