msd ignition

[randywebb]

If you open up the plug gaps, do you need to alter timing, or reset (or even rejet) the carbs to get any perf. benefit?

or is it 'free'?

[kwm]

Superman...I wanted to remain stock and looked far and wide last May to find a rebuilt Bosch unit and never found any close to $100 price point so I would really like to know where you are finding them for that price. I don't know very much about the rebuilding process but I am pretty sure they do not replace everything with new components so what is to say something else in the 25 year old rebuild unit isn't set to go out as well. The reality of my search not even a year ago after several calls, emails, online searches and talking to local independent shops etc... was this:

Used unit off of a running car from a German car auto dismantler in GA was $400 w/o shipping

Used rebuilt was $400 w/ shipping from a company I found online who rebuilds many types of auto elect. components

Used but working from DC Motors he had about 2 or at that time wanted $325 for the best one which I took that to mean the best "LOOKING" one

Brand new unit that I was still able to get from the dealer was $1400

$175 MSD unit x 8 is $1400 or 8 times the cost

[DaveE]

Originally posted by jluetjen
DaveE -- BTW, what sort of gap were you running on the plugs prior to the MSD failing?

John, it's been a few years since I disconnected it. I followed the recommendations in the manual. I believe it was somewhere around 0.45 maybe? Or a little more?

I spent a bit of time at the track, where it started failing, trying to find the problem. It started failing by cutting out over 5000 rpm so I switched back to the stock ignition. I had the wiring arranged so I could do that easily enough if I had to. I played with it a little after that but finally the thing just gave out. There's one wire that has a 12V output all the time, maybe to the coil (I don't remember too much about it now)? It had no output anymore.

[Lorenfb]

"I wanted to remain stock and looked far and wide last May to find a rebuilt Bosch unit"

Obviously did look in the right places, i.e. Pelican Parts.

MSD Negatives:

1. Must make wiring changes - hookup time, i.e. Remember labor has value.
2. The MSD produces higher voltage (NOT ENERGY) which stresses the ignition
system, i.e. ignition wires, cap & rotor.
3. Has less overall reliability because of the circuit complexity. i.e. Reliability is inversely
related to the component count.
4. The MSD requires mounting hole mods and looks unsightly in the 911 engine
compartment, i.e. a 911 waiting for a Chevy engine convertion.
5. The MSD radiates and causes more "noise" on the electrical system
affecting other electronics, e.g. voltage regulators, radios, & etc.

[Superman]

$100 is the swap meet/garage sale price. Actually, I called out for these things a year ago or so and picked several up. $100 was the highest price. One was fifty and one was free. They all worked. Indeed, Bosch units are darned near as reliable as a hammer. MSD and Permatune, not so much.

There are guys who know how to rebuild these things so they are at least as reliable as a brand new stock unit. MSD and Permatune like to encase their electronics in epoxy, which makes them impossible to repair.

[carsngolf]

Compared to most of you contributors, I'm barely out of the crib but I'm pleased with the MSD6AL I installed in my 2.0L '66 with the MSD coil but the only problem I encountered was the tachometer reading 3 times the actual RPM up to 3,000. I was told it was due to the MSD producting 3 sparks at low RPM. I purchased and installed the MSD part that was supposed to overcome the problem but it wasn't any better so I just live with it. My unit is now 10 yrs. old and still works fine although I only drive it 1 - 2,000 miles a year.

[Brad01mc]

Hi!

I just added an MSD to my 911 and I like the results. I have the old unit as a spare and I found out that my problem was a bad green dizzy wire.

I was able to install everything on the Al plate and it looks very clean. I had to remove the rear window defrost relay, but the PO cut all the wires to the window, so it was just extra weight in the first place.

Anyway, my car starts better and idles/drives smoother when cold. It seems to behave a little different, but I can't put my finger on it. I also don't have any electrical noise through the radio. My tach works fine without anything added too.

Since I live in CA, I have to get my car smoged, so I figured that the multiple spark will help with the emissions, if anything.

I set the gap at 0.055 and seems to be OK. The manual says 0.05-0.06.

Oh, if you find that you have a bad green wire, go to your local pick-a-part and look for an old 70's Mercedes S class, or any of the old v-8's. They have the exact same plug on the dizzy! $2 fix.

Brad

[Steve@Rennsport]

Originally posted by Lorenfb
MSD Negatives:

1. Must make wiring changes - hookup time, i.e. Remember labor has value.
2. The MSD produces higher voltage (NOT ENERGY) which stresses the ignition
system, i.e. ignition wires, cap & rotor.
3. Has less overall reliability because of the circuit complexity. i.e. Reliability is inversely
related to the component count.
4. The MSD requires mounting hole mods and looks unsightly in the 911 engine
compartment, i.e. a 911 waiting for a Chevy engine convertion.
5. The MSD radiates and causes more "noise" on the electrical system
affecting other electronics, e.g. voltage regulators, radios, & etc.

Hey Loren:

Another opinion:

1) Labor does have value but its really easy to make the necessary connections. Properly done, one can swap back and forth without issues.

2) MSD 6 series produce 120mj and thats more than the Bosch CDI's from memory. If one's cap, rotor and wires/connectors are all in excellent health, the added current flow is not a big issue. If one maintains stock plug gaps, there is NO further erosion inside the caps and rotors.

3) Reliability is excellent IF,...IF its properly installed. Thats all about Human Factors, not componentry. I have a LOT of MSD's in service for over 25 years with no issues. One could make a good argument that 25-35 yr old electronics are not as reliable as when they were new and I think you know that, too.

4) MSD's do mount differently but appearance judgements are totally subjective and all in the eyes's of the beholder. I've made MSD's look very much like Bosch units by removing the red paint and carefully refinishing the case.

5) RFI & EMI issues are all related to the quality of the installation. Once again, IF,......IF these are installed correctly with proper grounding, they are every bit as quiet as the OEM Bosch ignitions. Don't blame the components when Human Factors are at work.


Just my opinion of course so consider the source,.....

[Lorenfb]

Failed to understand the points:

"1) Labor does have value but its really easy to make the necessary connections. Properly done, one can swap back and forth without issues."

Wiring mods are required which takes time versus a direct replacement.
Also, just read many of the MSD posts where installations have problems.

"2) MSD 6 series produce 120mj and thats more than the Bosch CDI's from memory. If one's cap, rotor and wires/connectors are all in excellent health, the added current flow is not a big issue. If one maintains stock plug gaps, there is NO further erosion inside the caps and rotors."

As I said it's NOT the peak energy nor the peak current (~60-80ma), but the peak
voltage of 50-60KV versus 35-40KV for the Bosch CD. This higher voltage is what
stresses the system.

"3) Reliability is excellent IF,...IF its properly installed. Thats all about Human Factors, not componentry. I have a LOT of MSD's in service for over 25 years with no issues. One could make a good argument that 25-35 yr old electronics are not as reliable as when they were new and I think you know that, too."

Another missed point!. It's not how the unit is installed that's key, although it's a factor.
It's the NUMBER of components used to implement any system which reduces its reliability.
The MSD has more than twice as many components as the Bosch unit. Also remember
that ALL electronics go thru an "infant mortality phase" where components are MORE
likely to fail when new versus a mechanical system where the failures increase with time.

"5) RFI & EMI issues are all related to the quality of the installation. Once again, IF,......IF these are installed correctly with proper grounding, they are every bit as quiet as the OEM Bosch ignitions. Don't blame the components when Human Factors are at work."

Installation does affect radiation, but with the MSD it's the high freq & high current
pulses which are problematic which is not the case for the Bosch unit.

[RoninLB]

Different strokes for different folks.

The worst that can be said is that it's a simple adapter build for an MSD back-up to toss in the trunk.

IMO MSD is a must w/carbs and a maybe without. Personally, separate hd wiring for msd, dizzy and coil is uncomplicated to build. I also needed the msd noise suppressor for $30.

Also if memory serves the msd has longer spark duration than Bosch.

I bought some tempertaure strips, for entertainment, to mount on the msd to see how hot it gets when mounted out of the elec panel cover. I figure 110F high deserts at 3.6-4k for a few hours will give me a decent idea. It won't be running max voltage loads on the plugs but it'll be good enough to see what happens. I think if i ever had to run peak msd voltages the cap /rotor would probably crossfire.

[Steve W]

Originally posted by Lorenfb
Failed to understand the points:

"1) Labor does have value but its really easy to make the necessary connections. Properly done, one can swap back and forth without issues."

Wiring mods are required which takes time versus a direct replacement.
Also, just read many of the MSD posts where installations have problems.

"2) MSD 6 series produce 120mj and thats more than the Bosch CDI's from memory. If one's cap, rotor and wires/connectors are all in excellent health, the added current flow is not a big issue. If one maintains stock plug gaps, there is NO further erosion inside the caps and rotors."

As I said it's NOT the peak energy nor the peak current (~60-80ma), but the peak
voltage of 50-60KV versus 35-40KV for the Bosch CD. This higher voltage is what
stresses the system.

"3) Reliability is excellent IF,...IF its properly installed. Thats all about Human Factors, not componentry. I have a LOT of MSD's in service for over 25 years with no issues. One could make a good argument that 25-35 yr old electronics are not as reliable as when they were new and I think you know that, too."

Another missed point!. It's not how the unit is installed that's key, although it's a factor.
It's the NUMBER of components used to implement any system which reduces its reliability.
The MSD has more than twice as many components as the Bosch unit. Also remember
that ALL electronics go thru an "infant mortality phase" where components are MORE
likely to fail when new versus a mechanical system where the failures increase with time.

"5) RFI & EMI issues are all related to the quality of the installation. Once again, IF,......IF these are installed correctly with proper grounding, they are every bit as quiet as the OEM Bosch ignitions. Don't blame the components when Human Factors are at work."

Installation does affect radiation, but with the MSD it's the high freq & high current
pulses which are problematic which is not the case for the Bosch unit.

And, once again, the point is don't buy MSDs because Loren makes a living rebuilding old Bosch CD units, and each MSD purchased means less dollars in his pocket.

[RoninLB]

I guess an argument can be made for journalism?

Bosch is a great system that has performed reliably for many cars and ditto for msd. The mid 1970s 8-pin Bosch is a failed knock off of the original Porsche race car 8-pin Permatune.

unnecessary entertainment pic
I just removed hot rod shop corrugated split loom wire covering for a change to www.waytekwire.com double wall shrink tube. Big difference in appearance and more space being available. Old corrugated pic has been posted before so this is brand new. I don't recommend this install as it's "different strokes..."

[RoninLB]

i think this wire covering is great.

[johndglynn]

The Bosch unit on my SC failed on the morning of a track day last year, as the car was warming up ready to leave home. A replacement was not available from stock anywhere, so I lost a day on track and had to do the trip in my 4runner instead. Used six pins are minimum £150 here (just about $300), that is not for rebuilt guaranteed, that is just second hand, which of course could fail any time. I bought another one and stuck it on the car, dropped the dud into my local Bosch place and it is not an economic repair.

I have three pin on the C3 and got a spare box when I bought the car also, but am going MSD for sure. The Bosch boxes are silly money for what they are, I can buy two new MSDs for the price of one Bosch so it's a no-brainer. Install/wiring is easy, don't see that as an issue. If I wasn't gearing up to sell the Cabrio that would now have MSD also.

A 930-owning buddy had his Bosch go on the road to Classic Le mans last year, same thing with no replacement available easily. He ended up borrowing a unit to get him home but imagine the cost had that not been available. Thing that bugs me most about the Bosch is that there's no warning, no indication that something might be going wrong, there's just *phut* followed by a £500 bill if you replace like with like.

[fred cook]

To Loren, et. al.,

I installed an MSD6A unit in my 911SC about 3 years ago. I did so because the Bosch CDI was failing and for the cost of a rebuilt Bosch unit I was able to purchase both the MSD unit and a set of Magnecor wires.

Not wanting to alter the stock wiring harness, I simply put crimp on male terminals on the MSD wires and plugged them into the 6 pin master plug. No cutting requred and if desired, it can be put back to stock in just a few minutes. By rotating the rear window defrost relay 90 degrees, I was able to mount it on the existing aluminum bracket that the Bosch unit had mounted on.

Once the MSD was installed, the car fired up immediately and ran smoothly, much more smoothly than it ever did with the Bosch. After warming up, I had to lower the idle speed by about 500 rpm! That indicates to me that the MSD was providing a better spark. With this system installed, the engine will pull very strongly up to redline (and beyond if not careful). As installed, the stock cover for the electrics still fits in place and covers all of the MSD unit except for a couple of inches on the forward end.

Would I do this swap again? Certainly. Would I ever go back to using a Bosch CDI? Only if I could buy a NEW one for the same price as the NEW MSD. The only change I might make in the future is to rob a 6 pin plug off a Bosch unit so that I will have a truly "plug and play" system.

[Alan Cottrill]

I found that the MSD helped with the seasonal starting issues I had with my cis car. this may have just been because of a dying permatune box but I was able to stop fighting with the car every time the weather changed.

just my $.02... keep the change.

[Lorenfb]

"I had to lower the idle speed by about 500 rpm!"

Please!!!!!!!!!!! You had another problem.

"£500 bill if you replace like with like."

What??????

Another one who hasn't fully checked the Pelican Parts catalog.
Pelican Parts has many sources for Porsche parts and can provide
just about anything your Porsche may need at reasonable prices.

So what's the problem?

[johndglynn]

Originally posted by Lorenfb
"£500 bill if you replace like with like."

What??????

Another one who hasn't fully checked the Pelican Parts catalog.
Pelican Parts has many sources for Porsche parts and can provide
just about anything your Porsche may need at reasonable prices.

A friend of mine's C3 recently fell foul of a failed CDI, so he took it to his local independent specialist to be repaired. They gave him two options.

1. A new Bosch three pin unit, only through Porsche for approx £400 but a 10 wk waiting list.

2. Get the parts from the 'States in 10 days for approx £500.

We discussed these options plus 3: buy an MSD from Pelican (dearer than some other US suppliers but support the forum). Option 3 was chosen, parts as ever arrived no probs a couple of days later and the car now runs perfectly. It was a very straightforward fit and even with the labour to fit came in cheaper than straight supply of a CDI unit.

Pelican do new CDIs for an SC for $1600, whereas new MSD's are under $300, plus $60 for a coil. So I can buy two MSDs and a coil for about $600, $1000 less than buying a new CDI.

Put that into our money: £400 for a new CDI, or £170 for a new MSD (replacement part + spare ) and the proper coil, hmmm.

I will post a pic of mine when it's in. Steve, I like your idea of taking off the red, nice one

[Lorenfb]

"Pelican do new CDIs for an SC for $1600"

So??????????????

As posted before, they HAVE rebuilts also or can get them!

Remember, if you can't find it in the Pelican Parts catalog CALL and talk to
a salesman, e.g. John, Jason, Scott, & etc. This not only applies to this part,
but any Porsche part. The internet hasn't obsoleted the telephone yet!

[johndglynn]

Originally posted by Lorenfb
"Pelican do new CDIs for an SC for $1600"

So??????????????

As posted before, they HAVE rebuilts also or can get them!

The SC rebuilt units are priced at $370 from Pelican, C3 3-pins not currently available.

Add a bit for shipping, import duty and VAT on top of all that and the £400 for a new unit here is the better buy, especially considering new is probably good for another 15/20 years whereas recon/rebuilt has a year's guarantee.

There are very few people in the UK rebuilding these units, most people just replace with new, though the wait can be a pain in the rear if you go looking for one at the wrong time. I don't know of a Porsche specialist here who recommends buying a rebuilt CDI over a new one, but I guess there might be one out there somewhere.