Bosch CDI to MSD - Answers here!
 

Thanks to this great community, and many hours of data-mining, I have received a lot of help with most of my car projects. However, when I went to install my new MSD 6AL-2 (with built-in 2-Step rev control) I found information across several threads but nothing seemed to fit the variables of my install. So, after much research, some trick wiring, some design, and a pair of custom machined brackets, I put everything together in a packet to share with others in need. It's a .pdf that contains a bill of materials, wiring diagram of the entire system, and prints of the custom adapter brackets I needed in order to fit the MSD in the same spot as the CDI.

My install notes and diagrams can be downloaded here: http://www.switzerc.com/home/74911msdpdf.html


In the mean time, here's a before and after pic:

http://forums.pelicanparts.com/uploa...1233883040.jpg

Matt

P.S. Anyone interested in a Bosch CDI for a '74 911, complete with wiring harness, coil, and noise suppressor?

Nice PDF well thought out and nice adapter plates. Is the tach adapter needed with the new MSD unit? I was under the impression that it was only needed for the early models prior to 74.

An MSD tech told me that I would be very lucky if my tach would work without the adapter... he was right!

I don't know how to post a pdf, but I'd sure like a copy of it. This project is in my near future.

Thanks.

I tell guys to hit my user name, pelican e-mail, and put "something" in subject header. The guys e-mail me and I hit "reply" with the attachment.

In response to a PM question:
One adapter plate was needed because the MSD has a 4-hole mount pattern and my CDI had a 3-hole. Both hole patterns had to be arranged just right in order to cleanly fit the MSD in the OEM location. I've read many posts that say an adapter plate "might" be required, but was never able to get details on its configuration, so as soon as I had one that fit, I thought I'd share it.

The other adapter plate was required to shift my fuel accumulator and filter assembly 1" forward and .5" up to accommodate the larger MSD unit.

Both adapter plates were required, in my opinion, because I wanted to use the original mounting locations on the car for a professional looking install, and I did NOT want to drill holes in my car. If you don't mind drilling holes, then you might be able to get away without the adapters.

Matt

What spark plug wires did you install, and what plug gap did you adjust to?

For those with less skill, you can get a Perma-tune unit that simply plugs in, and mounts at the same points as the stock CDI unit. No extra wiring, etc, required. As my original CDI recently went bad, I made the switch, and the new unit seems just fine. My mechanic, who vintage races early 911's, highly recomended it, and says he's never had a failure. About $400 or so. I do miss the whistle a bit, though...

matt i would keep the original in the car, (glove box) sure give me piece of mind on long trips

permatune has issues it would be a good idea to get the skills to install the MSD.

I used the Magnecor wire set; PEL-MAGN65-83

I didn't have a baseline to work from for plug gap, so I went right in the middle of the recommended range, which for compression up to 10.5:1 is 0.050" to 0.060". I went with 0.055"
Matt

I checked with quite a few autocrossers, time trialers, racers, and mechanics before making my purchase, and an overwhelming majority of responses were for MSD. Several of the MSD respondents cited previously failed perma-tune units as well as performance gain as the reason(s) to go with MSD. The only reason(s) given for Perma-tune were ease of installation and good warranty response if/when it melts down. For me it was an easy decision.

anyone have the PDF? I am not getting a response from Fest 911.
I am stuck with a no start issue on my MSD install

If anyone has it please email to: JMALONE1@FERGUSON.COM

Thanks.

In-rotor resistor...

There are a few threads on here addressing the resistance inside the stock Bosch ignition rotors. I recently went through this, and the stock resistor registers about 5K ohms. This is true for both the 912 non-rev limiting rotor and the 911 rev limiting rotor. If it has black or red epoxy between the center contact and the outer contact, there is a resistor embedded in the epoxy. A simple check with a multi-meter on resistance (Ohms) setting will confirm this. I'm 99% sure the rotors from PP are all resistor type.

I attempted to locate older VW rotors that used a solid brass contact, but couldn't find one in the correct dimensions.

Following Jamie Novak's instructions, I used a Dremel tool to remove the epoxy out of the rotor. While removing the epoxy, I never did feel or see the resistor. The inner and outer brass contacts extend down into the epoxy cavity. When the epoxy is completely removed, the brass contacts have circular marks on them, resembling holes/dimples in the contacts of the fuse panel.

I then soldered in a piece of 12 gauge copper wire from the inner to outer contact. Continuity showed 2ohms from inner to out rotor contact. Original was 5000 ohms. I then mixed plastic epoxy and refilled the cavity. Sorry, no pics. Didn't have my camera when I did the project.

Spark plug gap:

Additionally, this info was on the MSD website. I'm running a Crane Ignition. The Crane techs actually recommended copper plugs and .042" gap for my 2.4E with 9.6:1. I have also read that anything wider than .045" is not effective. If at all concerned, contact MSD directly for their gap recommendation.

MSD: Spark Plug Gap
With a MSD Ignition you can run a wider spark plug gap than you would be able to with a stock ignition. The MSD Ignition has a higher voltage output and can jump the spark plug gap easier. As an example, if you normally would run a .028 inch gap on your spark plug with a stock ignition, you could run a .032-.034 inch gap with a MSD Ignition. There are variables that will affect the gap size: the higher the compression - the smaller the gap; the hotter the output of the ignition - the larger the gap, etc.

Steve Weiner posted a few times that .040" was the best for the MSD and our engines.

when one of the best tuners in the country says something all I can think of is "that's good enough for me"



and btw Fest 911... that's a very clean & sweet install

the wiring looks professional

The CDI to MSD pdf is now available for download, instead of via email, due to too many issues with my ISP. Please accept my apologies for delays in your receipt of this info. Download the CDI to MSD installation notes at: http://www.switzerc.com/home/74911msdpdf.html

Best regards,
Matt

Thanks Ronin! Nothing but the best for a Porsche! I always see installs for various electronic gadgets from other people (usually when the next owner calls for troubleshooting help) and the first thing they say is, "whoever installed this was a hack!" I spent a little extra time so I would never be remotely close to the hack category :)

Your MSD6-AL2 system doesn't have the mappable ignition curve function -- correct? So you're still using the distributor's advance mechanism to control the ignition advance -- right?

Definitely the best drawings and wire help I've seen. Thanks again for the info.

Fest 911, your guide is very well done. Thank you.

I do not understand your answer about the tach adapter. Did you need it and, if so, where did you mount it?

FWIW, I think that the answer on the need for a tach adapter can be found here: http://forums.pelicanparts.com/porsche-911-technical-forum/255151-msd-users-what-brand-tachometer-do-you-have.html.

What is not clear, to me, is where folks have mounted it, when needed.

Thank you in advance.

Tom