Bosch CDi ignition box repair

I remember hearing (15 years ago now) about a company that would put a complete new system inside your old box.

The other possibility is to convert the dizzy to Pertronix and just clean up the old box to leave in place as a dummy?

 

Try these guys

Becker Autosound Website
They work on old radio's. They are familiar with resistors and transistors.

 

True but then it's still an ancient design. There must have been a reason Maserati had a bypass feature?

 

Those guys aren't all that far away from me!

 

Bosch was also original equipment for Porsche at this time...I would suggest the web pages here for some info on troubleshooting the systems and/or check out their Forum for contact info, from members...

Pelican Parts - 911 Technical Articles

1- Porsche Technical Forums - Pelican Parts Technical BBS

 

There's certainly not much in the circuit, but in electronics, 40 years is a geological age. My products are much newer than that, but I've still had to redesign some of them three times just due to parts going obsolete.

I see that salz63 beat me to the punch on the Pelican link. That thread was started years ago, but even then the main problem seemed to be parts obsolescence, especially of the thyristor. However, the first substitute mentioned in the posts is still available at Mouser (IRC 16RIA80). The transformer is unique, but the schematic gives the number of turns for the three windings, so it should be repairable by hand if it's been shorted. The passives would look different today, but should still be available. The PCB can be recreated if necessary. Of course, as Bob says, you can gut the box and stick more modern and much cheaper electronics in it. We did that for the old Sun tach boxes that used now-unavailable mercury batteries to get a stable supply voltage.

On a more general note, now that the definition of collector car includes some with electronics, what will the attitude be about restoration? I've read about the troubles QP3 owners have fixing TEDEL boxes (and nearly choked when I saw the cost). After 40 years of the stuff, I'm not very sentimental about electronics, but I know some people here go to great lengths to get the right weave for the carpet binding, so how will such folks feel about changing the internals of electronics boxes?

 

If it is neatly tucked inside the original "packaging" AND you don't need to modify the hook-ups/connections to make it work, it is "original" to me, for whatever it's worth. I know, it's not 100% "original" but it is an upgrade that would go unnoticed.

 

Ivan you always come up with interesting things on these cars. I don't know anything about electronics. But it seems that someone knowledgeable should be able to look up the existing component functions, study the connections and devise some suitable functional equivalent to fit inside the original box.

Good luck with it and keep us posted on your progress.

 

Here's the thing. For the late Bosch boxes used on Khamsins , late Boras and the QPIII it's the same as the one used on a Porsche 928. The dizzies used with those boxes were magnetic impulse generated so I could see keeping that intact. Besides it works well. But the earlier ignition boxes are still using points with a bypass option in case the box fails and for my money I'd just put a $70-$100 Pertronix kit in it. You can't see it's there unless you're a real eagle eye and then just leave the box as a pretty hollowed out decoration. I didn't need a CD ignition system in my Espada once I put the two Pertronix kits in it but you can still add a MSD box if you want. No more points or gaps just fun driving.

 

Ivan,

Can you direct us to some source of information as to what is so different about this ignition system? What is inside the coils, etc.? Is it all contemporary Porsche (as an earlier poster has stated)? So possibly looking at Porsche documentation will describe the guts?

Thanks,
Carmine

 

Not the same details of course but I was able to get a new set of Pertronix coils which once painted were indistinguishable from the original Marelli coils. As for performance, it's much better than the stock system on an early Espada. I'm unclear as to why I'd need to add a CD style unit though people do?

I'm using solid core 7mm wires though not Cavis. Perhaps I'm not as big a stickler for originality? Some of the vintage Lambo guys think I'm old fashioned though ... Several are using digital ignition and some even FI on those older V12s. I wanted the look of the distributor and all the wires which flow from it. You could still use Pertronix with a repaired old Bosch box.

Have you called Pertronix to discuss these issues? That assumes you get anyone knowledgeable on the phone ...

 

Hello Ivan,

After reading a lot about the CDI in the last days, i always came across this german Homepage:

Reparatur Bosch HKZ für Porsche 911 und 914/6

With google translator:

Google Übersetzer

I didn't had any contact with them, but they seem to have much knowledge about that bosch Ignition Boxes.

they are repairing the boxes for an overall of 250 Euros plus some extra money if you want in Sandblasted, new Stickers, a new conector plug or something else....

maybe you should contact them?

Best regards, Hendrik

 

I gotta say that based upon that description I would want to eject the unit from my car ASAP and just live with a coil that looks a bit different. It sounds way too finicky even when it does work correctly.

Yeah, the later Bosch box you describe is probably what's on the QPIII and late GT cars. Thank god. I can't imagine that working on a Ghibli with points though????

 

Perhaps the info in the attached link is applicable...don't know if the unit for the Maser is any different from the various units shown...

History of Bosch CDI ... toubleshooting info, parts list changes, and schematics ... - Pelican Parts Technical BBS

 

That does look very promising.

 

Believe it or not, the early Porsche 911's before 1976 I believe (it's been a while, so my dates may be off), used points...an electronic module replaced them in the mid-to-late-1970's.

 

Yes, early 911s used points. I replaced the points with a breakless system (name escapes me now of the maker). With the Porsche CDI, all parts can be replaced except the thyristor.

 

The breakerless system was likely a Pertronix unit

 

Thought it would be helpful!