CDI Showdown!

[BrokeMyCar]

Our host sells a host of ignition boxes, and I'm trying to figure out which one I may use to replace my possibly dying gold Perma-Tune box (I have an '82 SC that never sees the track). Here's what I've been able to learn by searching, please tell me if I'm wrong...

Bosch: Works great with my car, prohibitively expensive to buy new. Refurbished units cost ~$350.

Perma-Tune: $400-$550 for a plug/play identical unit. However, this unit has a bad history?

MSD-6200: Works great, some claims of marginal improvement with larger gaps. Will require some work to fit into my engine-bay. $180-220

Crane/Allison XR700 Fireball: Very little knowledge on the board about its longevity, but no bad news yet. It looks big so it will also require work to fit into my engine bay. The big upside: $130

Does that sound about right? Which would you pick? Are used units even worth considering?

I'm teetering towards MSD right now. But boy does Crane sound nice and cheap. On the other hand a cheap used perma-tune would be soooo easy. Maybe I could buy two, and carry one around for when the first one fails... decisions, decisions!

Babak

[304065]

Babak,

There has been a lively debate on this very topic running here for years, literally. For more information, search under the name, "Early_S_Man" and "Bosch CDI" and "Permatune" for the views of a genuine expert on the subject.

To summarize, you can't go wrong with the Bosch CDI. The higher initial cost is outweighed by reliability in the extreme, and the simplicity of wiring to the original harness can't be beat. That being said, the MSD 6AL can be had dirt cheap used and includes an integral electronic rev limiter that will allow you to ditch the expensive centrifugal rev-limiting rotor.

Of course the debate rages on, as to whether the other units have improved their reliability over the years, or the limitations of the short spark duration of a capacitor discharge system. Suffice it to say that Bosch CDIs have worked great for 911s since 1969.

There is also a tremendous amount of snake oil out there in the realm of ignitions, with outrageous claims that so-and-so's ignition box will make you three inches taller, enhance your portfolio returns and automatically make you a finalist for the Nobel Prize in Literature. Steer clear, also, of the giant add-on coils promising 50KV and the 10mm welding cable spark plug wires that require a come-a-long to bend into place when the temperature is lower than 20C. A good debunking of these and other myths can be found here: http://www.magnecor.com/magnecor1/main.htm

Good luck! Bosch CDIs come up in the classifieds from time to time.

[RoninLB]

MSD if you need it.


Bosch rebuilt otherwise.

Also I think Sherwood has Crane info.


all that said... all electronics eventually fail. If you can use distributor points a Kettering coil, resistor and points & condenser is a cheap back-up to stash in the smugglers box.

[azasadny]

I have 2 Bosch CDI units that I purchased here on the used parts forum. I don't believe I paid more than $150 for each one and they perform flawlessly. I keep one for a spare. I do not recommend the PermaTune as I had 2 units fail on me in 3 years.

[Early_S_Man]

Get a used/or refurbished Bosch ... they can be rebuilt indefinitely. A spare is a prudent option for confident, reliable travel in the future!

6-pin SC/Turbo CDI unit repair documentation

Every component in a Bosch CDI can be replaced ... even a burned-out transformer can be rewound with new magnet wire!