MSD Ignition question/concern
 

I've been running an MSD ignition for three years now.
Six weeks ago I had to replace the coil because the spark ate through the wire cap and melted the coil top.
Last Fri. it happened again but this time it was the dizzy cap.
Anyone know why this is happening?

Thank you
Barclay
_____________
1981SC Coupe

what kind of coil? bosch/MSD. i have heard that mounting the coil upside down is bad.
do you have the rev limiter rotor? also, what type of plug wires?

Its an MSD coil,when I replaced the coil I also put on the coil a clamp that holds the coil wire down in place and a thicker cap that came with it, no issues yet.
No rev limiter rotor
Stainless braided wires except the coil, coil is a normal wire.

Was it a regular coil or MSD's High Vibration Coil? Regular coils are oil filled and should not be mounted upside down. The windings of the High Vibration Coil are encased in an epoxy making it possible to mount at any angle.

Yes, regular red Blaster coil.
I'll look for a longer wire and mount it upright
Is that whats causing the problem?

Moke81,

I see from your 1st post, you already replaced the coil - so that's probably not your problem. Mounting it upside down is not good for it, but since you replaced it and still have a problem, I'd keep looking.

Have you looked at your running engine in the dark to see if you have sparks running around where they're not supposed to be?

Been doing some looking - came up with this:
http://forums.pelicanparts.com/porsche-911-technical-forum/246885-my-911-fire-burning-msd-coil.html?highlight=melted+coil+cap

I guess it's possible that your coil could have been damaged by mounting it upside down. It's also possible that you didn't have the coil wire pushed in all the way - first to the coil, then to the distributor cap. Was your coil wire long enough?

Are you using any dielectric grease on the rotor?

Also are the wires you are using right for MSD?

I learned a while ago not to use dielectric grease on the rotor, it causes corrosion in the cap and can burn-up the rotor.

Just some thing to check...

Have you done the MSD Rotor mod?

http://forums.pelicanparts.com/porsche-911-technical-forum/472461-msd-rev-limit-set-3800-a.html?highlight=MSD

Need to have good solid contact or it makes it own spark that will burn out the sides after a while. Ask me how I know.

melting rotor/distributor caps/msd
 

This is copied from an MSD troubleshooting site.

regards,

al


77turbocarrera
03-29-2005, 10:43 PM
My Porsche 930 3.0 turbo keeps eating rotors ever since I installed the 6 digital and HVC 2 coil. Car runs & drives perfect until the center portion of the rotor (epoxy) melts away. Any obvious solutions? Bad ground? Too much voltage?

I'm using Bosch ignition parts FWIW.

Thanks,
Vince
msdtechsupport2
03-30-2005, 08:33 AM
This can be attributed to a couple of problems. If there is too much resistance in the secondary system such as cap, wires or plugs then it would make it easier for the spark to arc through the rotor to the distributor as opposed to traveling down through the plugs. This can also be a ground issue; double check motor grounds. Make sure the battery is grounded to the motor and the chassis and that the motor is grounded to the chassis as well.

77turbocarrera
03-30-2005, 08:50 AM
I will try the grounds today. As far as secondary resistance, what range of readings should I look for in the cap, rotor and wires ( all new parts btw - bosch cap & rotor, magnecor wires.)

Can the spark plugs be tested also?

Thanks
Vince

msdtechsupport2
03-30-2005, 09:39 AM
Your best bet is to check for resistance and if you see something obviously high then this will likely be your problem. Unfortunately I don't have the resistance reading on the MagnaCore spark plug wires however you may contact them to find out what they should read. How much boost are you running? If you are running high boost and the plug gap is too wide it would make it difficult for the ignition system to jump that gap.

mpdevelopment
04-01-2005, 03:58 PM
The Bosch rotor you are using has A 5k ohm current limiting resistor encapsulated in the black glyptal paint between the center and the distributor wiper end. With the 450 milliamp current provided by the Blaster HVC II coil the resultant peak power dissipated in the resistor is over 1000watts this will heat up and destroy the resistor. I have tested the 6plus with blaster hvc II on the bench and it will heat up a 1k ohm coil wire quite alot. You will have to solder in a fine jumper wire in place of the resistor.

mpdevelopment
04-01-2005, 04:21 PM
Just did a test with a 6AL + HVC II coil running through a Bosch 930 turbo rotor In less than 60 seconds the rotor was smoking and I could not pick it up (VERY HOT) This was at a simulated 4500 rpm. I have not tested a Bosch CDI system yet but I know the energy stored in the capacitor is approx 80 millijoules. I also believe the bosch system is designed for a fast rise time not for high current. I am currently experimenting with a twin plug Porsche 911 ignition using a Digital 7 Plus with two Blaster HVC coils in parallel this system will use less power than two 6AL boxs and will provide similar spark energy.

Mexican Rotor FIx
 

This rotor is manufactured in Mexico and purchased at a discount AP store that rhymes with Becker's.
After burning through about 7 million OEM rotors I tried this one and have had no issues, it is very sturdy.
As Al mentioned above the MSD kicks to much spark for the OEM rotor which frys the diode, once the circuit is fried the rotor shoots spark everywhere and can melt stuff.
This sturdier rotor puts the spark right where it needs to go and could probably handle a lightning strike or two.

http://forums.pelicanparts.com/uploa...1243394559.jpg

I believe your MSD Blaster coil was made to hang upside down.

That replacement coil takes an 8MM wire. Your stock cap and wires are 7MM. The 7MM wire will be loose in the aftermarket coil and could arc and eventually melt the coil.

As to why the cap would melt, can't help you there. Sympathy deal for the coil, maybe?

http://forums.pelicanparts.com/porsche-911-technical-forum/472461-msd-rev-limit-set-3800-a.html?highlight=MSD

Were did you get that rotor? Do you have a part number?

It took you guys a while to get going on this thread, but I'll have to say that I have learned a lot from the responses here - very interesting.

The red blaster 2 and red blaster 3 coils are oil filled and should not be mounted upside down.

i have a MSD 6AL with the hi-vibe coil mounted upside down. the wires are stock, non-braided pcar wires. my cap and rotor are also OEM. my car is even the same year as moke's. i dont have any issues. (knocking on wood, now).

been like this for years.. car runs great.

Just to avoid confusion, the windings of the High Vibration Coil are encased in an epoxy making it possible to mount at any angle.

I too have the hi-vibe coil mounted upside down, MSD-6A, and I'll have to look at my rotor as I didn't know there were differences - I also have Beru wires, and I have the stock plugs gaped at 0.035 and have not tried to open the gap as has been suggested. My car seems to run great at all RPMs, warm or cold.

I always use 6AL,I never use platnum plugs, Gap to 44, and always mount mine where orig sits.. NEVER, have had that issue..

Good luck..

Niehoff
 

It is a Niehoff (there is nothing better). I bought three at Checker's so if you cant find one let me know and I'll dig one up for you.

I cant find the box and there is no part # on the part, it might actually be a VW part.

I found out by chance that this happened to my rotor, my motor would run like crap and I kept going back to the store and buying rotors, it would run good for awhile and the the same thing, finally they ran out of OEM rotors and sold me the crappy aftermarket one which has worked great. I went back and bought two more, one is in my car and the other in my toolbox.

Bosch 04038 from pelican




http://forums.pelicanparts.com/uploa...1243489762.jpg

So what distributor does this rotor fit? 69-72? SC?

it fits my 1977

When I opened this post I did not have any issues with the MSD. But I think I'm going to put the high vibration coil on, and Bosch rotor.
I was also thinking that maybe its the stock wire to the coil that can't handle MSD.
Where can I get a heavier coil wire?

Thank you
Barclay
_____________
1981SC Coupe

Barclay,

The reason you are experiencing burning is due to high resistance in the HV circuit.

Make absolutely certain that all of the ignition wires are completely seated on the plugs, cap, and coil terminals. You need a non-resistor rotor, as above.

I prefer the 8mm Magnecor ignition wires (although they can be tricky to get them seated properly in the cap) but any good quality 7mm wire will work as long as get properly installed.

I've been using MSD ignition components since 1978 without a problem,.... :) :)

For the archives....That looks like AC Delco #F403:
While we find your parts, please enter your ZIP Code at CSK Auto

I'll tell you what makes me a little nervous about using the "ryhmes with Becker's" solid contact rotor. Look at the modest width of the contact at the tip, compared to the image of the Bosch rotor tip shown above. Remember that we have as much as 30 degrees of advance. Will the solid contact tip reach the distributor cap contact at full advance without requiring a very large spark jump, compared to the Bosch? I bought a solid contact rotor and I'm reluctant to use it for that reason. I think a better solution is to ream out the resistor on a Bosch rotor with a Dremel and solder in a jumper, as recommended many months and pages ago.

Interesting point. I couldn't find the solid one locally, so I'm going to mod my standard Bosch one. I think whatever is pictured by RoninLB is for a different year/kind of car.

I was buying a new rotor at the NAPA and got talking about what I was trying to do. The other counter guy overheard me and asked about what kind of German car I had. He said he makes/mods rotors for his hot rod dragster Beetle. He knew exactly what I was talking about. :)

I don't think you need to worry about the width of the rotor tip. Remember the timing advances because the inside of the distributor moves as it spins. The distributor doesn't move, the cap doesn't move so the connections for the plugs stay in the same place. The plates inside the distributor though moves and it will only discharge the spark that is built up as the rotor gets close to a conductor ( the plug connector). If anything, the smaller tip will make the timing more accurate as it has to get closer to the conductor before discharging the spark. I have done the Dremel thing and it is a PIA. Buy a couple of solid rotors and save some time.

jstobo, you've inspired me to think some more about my theory. You are correct, the rotor will fire at the same spot with respect to the distributor cap. At high RPM the internal distributor plates will move the rotor shaft to an advanced location with respect to the crankshaft...but the distributor cap contacts won't know the difference. So I CAN confidently use the "ryhmes with Beckers" rotor.

Hey Howard M, where'd you get that solid rotor? I just did the mod this evening on two rotors, my old melted one and a brand new one from NAPA. It was fun to twiddle in the garage, but I wouldn't want to make a practice of it. We don't have anything that rhymes with Deckers around here...are you referring to Checkers? Got a part number on that?

I got mine at Checkers O'riley. I cant find the box and there is no part # I'm going to go look for the box again now.

VA,

I couldnt find the box but It has to be the AC Delco part you mentioned above:

ACDelco Rotor, Distributor:

Part Number: F403


This product fits the following vehicles:

1978 Porsche 911
SC H6 3.0 Liter FI - VIN 2

1979 Porsche 911
SC H6 3.0 Liter FI - VIN 2

1980 Porsche 911
SC H6 3.0 Liter FI - SOHC

1981 Porsche 911
SC H6 3.0 Liter FI - VIN A

1982 Porsche 911
SC H6 3.0 Liter FI - VIN A

1983 Porsche 911
SC H6 3.0 Liter FI - VIN A

Shane

My information is for a 1976 911S (stock 2.7L). I found the Checkers web site ("CSK") to be very informative. For me, the Borg Warner D555 was the correct rotor. Somewhat confusingly there is also a D555P available. I called BW and they explained that the "P" products are a cheaper version (cheaper than an already cheap plastic rotor??). There is no Checkers near me either, so I purchased D555 by mail. The Bosch resistor rotor is a much more substantial piece than the BW D555, but the BW unit has the full solid contact.

I have had no problems with my conventional Bosch resistor rotor after more than five years with the MSD, so despite MSD's recommendation to use a non-resistor rotor, a burned rotor is probably an indication of some other issue.

Lots of good ideas for curing the problem here but feel compelled to throw out one more potential cause. Though the vacuum advance does not change rotor/cap alignment, the centrifigual does,you may want to check that.
Also possible that the vacuum unit has been changed and may not align correctly.

Apologies. Seems ive having distributor dyslexia------Vacuum advance changes the relative position not the other way around. anyway dizzy indexing is important when running MSDs lest one busrn things up.

Good point Howard !!!
 

I previously hadn't considered this point but you are right on target. This is a good point, the dozen or so rotors I had gone through were burnt because of the previous wires I had which arced really bad and were especially poor in the rain and that arcing is which I believe caused the rotor resistor to burn.

Now that I have changed to MSD wires I have had no problems with my rotor I just haven't changed back to the Bosch so I cant validate your point entirely.

Thanks, Shane

most excellent point although the Bosch dizzy doesn't seem to have major issues afai know



post the easiest method etc for the Bosch

thx




And my personal take on rpm rotors w/MSD is that it's a problem waiting to happen.
.. different strokes

http://forums.pelicanparts.com/uploa...1261982399.jpg






it fits mine

pelicanparts site will show which year span. Bosch dizzy, cap, & rotor is a great package.

I like blue


http://forums.pelicanparts.com/uploa...1261984854.jpg





MSD 6M-2
pn 6460

it's one of those units that can operate while spinning and banging inside an operating washing machine


those MSD rubber mounting feet work great

I have the MSD-6 on my 2.7 When I went to buy a coil for it the counter guy said here this is the one you need. It was a MSD but I do not remember which one. Reading his book their was something about that coil, possibly ohm rating that did not agree with my MSD-6 or possibly my pertronix. They did have another coil that looked identical that was the correct one. I have looked through everything I have and cannot find what the issue was though.

I'll keep looking