Any reliable multiple spark CD units?

[Kevin G.]

Well, I killed my 3rd MSD 6A since August last nite. Admittedly, my second one lived a very short life, since I neglected to realize that the coil might be the culprit in the demise of the original one, and it gleefully murdered MSD #2 in short order.

MSD #3 was installed on August 9th, along with a brand new Blaster coil. 2.5 months of operating perfectly is not the kind of track record I am looking for.

The Permatune goes back in tonight. The car runs pretty poorly at low rpm commute type driving, but at least it runs. I am now trying to solicit views on alternatives to the permatune and MSD units.

Pelican can rebuild your own Bosch C/D for a very reasonable $275, but they do not offer rebuilt units off the shelf and my car came with the Permatune.

And, I am really going to miss the low-end smooth performance I got with the MSD multiple spark. Has anyone had any real time experience with a Reliable performance type ignition system that won't cost more than my first born? All opinions will be welcome!

[911pcars]

Well, since you've tried the others already, there's Crane. I've had good luck with XR700, then Hi-6S so far. Maybe they're not as fussy with the type of coil or I lucked out with my stock Bosch.



Sherwood Lee
http://members.rennlist.org/911pcars

[emcon5]

Did you use the high vibration blaster coil? As I understand it the standard blaster doesn't like being mounted upside-down.

Tom

[911pcars]

Not that it gets that warm inside the engine compartment and many, many folks mount the unit there, but MSD also recommends not mounting their units where it might get too warm. In addition, excessive vibration can kill electronic components really fast (or least the solder connections).

$.02
Sherwood

[Kevin G.]

I believe the MSD documentation refers to the excessive heat and vibration issues, and I tried to accomodate both of them in my install. Initially, I wanted to mount mine the same way that Sherwood mounted his Crane components, but the MSD was too large to fit where the old C/D unit was placed. Incidentally, I have the Crane optical trigger, mounted between the engine mounting bar and the rear of the compartment.

I even spent some time thinking about mounting the unit up front in the trunk with a feed off of one of the batteries, but didn't like the idea of such long wire feeds.

Incidentally, I like the performance of the MSD very much. The difference in low rpm response in my 2.2 S (w/MFI) motor is very, very evident and also shows when looking at the plugs when removed. Absolutely no trace of fouling.

As I mentioned before, I believe that the problem is with the coil, and that the coil is somehow creating a situation that is frying the MSD unit. Since I have only been using the MSD Blaster II coil since I switched from the Permatune, I am unawares of any other coil solutions for this setup. Are there any out there?

When I bought the first unit (from a local speed shop) I asked about the high-vibration version. The store owner said that the normal 6A was completely acceptable and that they only sold the high vibration units to off-road racers where the intense pounding was the norm.

[Eugene at Pelican Parts]

This isn't a solution but a suggestion. Since you've gone through 3 MSD boxes already, I think you should try the Crane HI-6. I just installed mine a few weeks ago so I can't speak for its reliability yet, but it seems to work just fine to me. After you resolve the issue at hand, shell out the $200 on a Crane (or other) and let us know what you think.

[emcon5]

Originally posted by Kevin G.
I
When I bought the first unit (from a local speed shop) I asked about the high-vibration version. The store owner said that the normal 6A was completely acceptable and that they only sold the high vibration units to off-road racers where the intense pounding was the norm.

He was wrong. I can't find the instructions on the MSD page, but the Summit Racing catalog says, regarding Blaster 2 coils

Do not mount this coil horizontally or upside down. The oil will not sufficiently cover the windings for cooling purposes and the coil may overheat.

For the High vibration blaster coils

The coil can be mounted in any position.

If you were mounting the blaster 2 in the stock top-down position, that may have be the problem.

Tom

[Early_S_Man]

Kevin,

Sure, Porsche started putting an exceptionally reliable system on 906E's in 1967 ... called BOSCH! Dual ignition equates to multiple sparks, right?

You aren't the only person on this board who questions MSD relibility ... besides myself!

John Walker does NOT recommend MSD on SC engines ... says he has a whole box of failed units removed from problem cars! Bosch units fixed the MSD problems.

I have personally never seen any difference in performance between working Permatune and Bosch CDI-units with 'clean' wiring and connectors! So, with that said, why not clean up your Permatune installation and return your ignition to original factory performance ... which I assume was fully satisfactory, 30 years or so ago???

Is your Permatune box blue or natural anodized aluminum finish?

For any owners of cars with marginal or misbehaving Bosch CDI-units ... the following will ALSO serve as an electrical 'tune-up for YOUR CDI!

To assure proper operation of your Permatune unit, I recommend the following steps be taken:

1. Clean the braided ground straps at the coil, distributor, and relay/fuse/regulator/CDI-unit panel. Run an additional ground strap -- at least 12 ga. wire -- from the upper left mounting bolt of the Permatune unit to the leftmost mounting bolt for the MFI filter mounting bracket ... clean the body panel and corner of the Permatune box where the strap will attach! Apply Dow Corning 4, 11, or 112 to the strap connections.

2. Clean all four 1/4" Faston tabs on the Permatune box ... shiny-bright!

3. Clean the Red 12 Volt supply wire to terminal 'B' of the CDI-unit plug at the fuse block ... loosen, remove, and clean set screw. Then, remove wire end and clean. Reassemble with a coating of silicone grease.

4. Clean the FOUR individual female Faston connectors that connect to the Permatune box. The three wires in the rubber/plastic boot can be carefully slipped out an inch or so to work on them ... dip, spray, or brush on a bit of vinegar onto the female Faston and let sit for three-four minutes. Rinse off with distilled water, then isopropyl alcohol and let dry. Test for the presence of 12.5+ Volts at the CDI-end connector of the Red wire with the ignition switched on!!! Test for a snug & secure fit onto a new 1/4" tab. If loose or marginal ... crimp the siodes of the female connector slightly to increase the tension, but DON'T close the gap entirely!!! Test the fit on the new tab again. If snug and satisfactory ... proceed to the next connector ... when all three 'captive' connectors are clean, pull back down into the rubber boot. Apply silicone grease to all four and re-attach to Permatune unit.

5. Clean the 1/4" tab and connector on the Black/Violet wire at the distributor!

6. BE SURE that you are using the proper & correct Bosch 0.221.121.001 or 0.221.121.006 coil for the CDI-system, and that the terminals and connectors are clean and snug! Test the coil for primary side resistance of 0.4 to 0.6 Ohms, and secondary resistance of 650 - 780 Ohms at room temperature.

Test your system by starting the engine and doing a test drive ... I believe you will find full power performance again at your disposal!

[Superman]

Grounding is a common problem. Last weekend the daughter's boyfriend's alternator started making 18-19 volts. We tried to chase the ground, but the engine block connection is hidden, so we just created another ground conductor to the block. Solved the problem.

If the unit is grounded through its base, and if the attachement method does not connect that base with the grounded body of the car, then that is likely your problem.

And what the heck is wrong with Permatune? They seem to be at least as reliable as MSD, and if the gasoline is ignited, how can you ignite it again? If MSD makes ten sparks, can you improve performance by getting a unit that makes a hundred sparks, instead of one. In my mind, either the gasoline ignites, or it does not.

[Kevin G.]

Thanks, Warren.

My Permatune unit is blue. What is the difference?

[Randy Webb]

try to find an old Bosch unti and get it rebuilt

[Early_S_Man]

Kevin,

The Blue-anodized Permatune units are the older version from the '70s and '80s, and far more reliable, according to all reports!

Also, as a bonus ... the blue units aren't potted in epoxy like current production models, hence they can be repaired just like the Bosch CDI-units! The layout internally is quite simple and straightforward, easy to troubleshoot! A definite boon to those lucky owners who might be non-electronics-impaired ...

[911pcars]

"If MSD makes ten sparks, can you improve performance by getting a unit that makes a hundred sparks, instead of one. In my mind, either the gasoline ignites, or it does not."

Mercedes Benz for one, uses an ignition system (probably Bosch) that fires two plugs/cylinder a few crankshaft degrees apart - probably for emissions reduction. So yes, if a second spark in a MB engine works, then maybe the several hundred produced by MSD, Crane et al provides some benefit as well (well, maybe only the second or third spark). I don't think MB would go to the R&D expense to install a second plug if it didn't work or to sell twice as many spark plugs.

The MSD/Crane type ignition boxes only produce multiple sparks below 3k rpm or so. So they claim no HP/torque benefits as a result.

But questions remain: Does the engine start faster? Does it run smoother at idle? Does it tend to reduce plug fouling at cruise and low speed? In my case, the answer is yes, it seems to.

Sherwood
http://members.rennlist.org/911pcars

[David]

I have a friend that worked at MSD, and he said they had bad ones returned all the time. With that said, I had one on my Datsun and never had any problems. It also solved a detonation problem I had after bumping the compression from 8.3 to 9.8 and it seemed to help the low end power.

[lateapex911]

True, it is hard to debate the advantages of multiple sparks, whether by multiple plugs or electronic units.

Mazda has been using that technique for 30 years on the rotary. The "combustion chamber" is very long, and complete combustion is improved with multiple sparks, from multiple plugs.

Also, we all know that older distributor based cars can't provide perfect ignition timing at all revs for all ambient conditions. Modern computers are constanly adjusting timing and fuel injection and can therefore create an engine that runs really well, in spite of some high compression and hot cams.

So, think of the MSD as a cheap soultion to on the fly timing adjustment! The shotgun approach, as it were! Not ideal, but better than nothing.