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