Bosch vs. MSD

[Ted_S]

It looks like I need to replace the ignition control unit on my 72 911S. I currently have what I believe is the original Bosch unit.

The mechanic's recommendation is moving to a MSD 6AL. I've done a bit of research and it seem like the 6AL/6AL-2 may perform better/last longer, and is potentially less expensive - which is the basis of his recommendation. On the other hand, there there are multiple places that look competent in rebuilding for not too much more.

My goal is to preserve originality where possible and where I don't materially compromise performance/reliability, and given that it looks like people have had good experience with rebuilt Bosch CDIs, I'm leaning that way.

I'm 95% a street driver, and put a couple thousand miles on it per year.

I'm still learning about the early 911s and so I'd appreciate the views of those of you who have experience on this topics:
1) Given my goals would you recommend going with the MSD or rebuilt Bosch?
2) Any experience with the different shops that offer rebuilding? As a default I"d probably go with Pelican given their commitment to pcars.

www.ottosvenice.com
www.ecudoctors.com
and pelican

Thanks Ted

[Flieger]

I would go with the Bosch. They have lasted 40 years or more on some cars and they put out a nice high power spark. MSD has an advantage with more power and more sparks at low revs to burn richer mixtures, but if you drive reasonably spiritedly and have the MFI in proper tune (particularly the thermostat) the Bosch should be just as good as the MSD, and it looks better.

[Mr9146]

It's been my experience that MSD boxes are fragile. Voltage spikes will kill them. Cross firing wires will kill them. Heat will kill them.

The Bosch units are FAR more durable and while they may give up a bit in the HP department, I would rather have a Bosch in my personal car.

The upswing to MSD is that they are cheap and readily available everywhere. I have used them in numerous applications with wonderful results, but if push comes to shove I prefer to stay with the factory hardware for continuity's sake.

As for the shops that rebuild them, we all use an outside vendor who has proven reliable and provides good, quality service at a fair price.

[classic]

Another option is a purmatune in a CD box with an optical pick up.

http://www.speed-components.de/index...id=2&Itemid=40

If your looking for originality looking engine bay with modern electronics.

If it was my car, I'd get the CD rebuilt.

[edmayo]

Go with the rebuilt Bosch. The MSD is not a bolt in, the plug wires should be changed, MSD does not like the stranded copper OEM wires. Then you have to find a way to mount that big red box, and run a wire with direct battery connection to the MSD. They also recommend their coil. Some of the wiring jobs I've seen are positively scary. As already stated, that OEM Bosch system worked fine for 40 years, plus you keep the originality, that will always be worth more.

[Tom F.]

Can anyone say who is a reliable rebuilder for the Bosch units?

[edmayo]

Systems Consulting at systemsc@systemsc.com We have used them several times.

[Ted_S]

Thanks everyone for the input. I decided to go the Bosch rebuild path with Specialized ECU Repair (ECU Doctors). They were credible on the phone, and got good reviews here and on Pelican. Expecting positive results - will let you know if there are any surprises...

[ajwans]

Does anybody have a source for the male part (harness side) of the 3-pin Bosch connector?

andy

[classic]

They come up on eBay or put a WTB up.

Also there's a guy breaking a 1970 911 on Pelican you could ask