JIM i may be way off here but i'll give it a go. I know on my msd stuff like 7al2 etc. it states Do Not use SOLID core spark plug wires!! I see in your pic the wires and don't they say SOLID on them? I am not sure if the digital msd can use them but it was worth a shot in saying my 2 cents

Just out of curiosity, what comprises a "sheilded" wire? Is it a special insulation? I have extended pickup wires before, I thought it was regular fine multistrand wire? Great post, BTW.

WOW Nice Job 440JIM

I have been lurking and waiting I dont think I would have ever figured that out. Nice Job sometimes its just little things that make the diff.

Good work Jim. Electrical gremlins can be a real PITA.

So how do pickup wires get classified that way? I have used plug wires (a while ago..I got them 'cause they looked cool..lol) that used a grounding strap like that, but pick-up dont. Or does the dist casing do it?

You need a special cable. They are not that way from the factory. That was why I was picking up the electrical noise from the alternator.

Ok, thanks Jim..didnt mean to sound "thick"..lol

way to go jim. i like how you fix it and not just throw a bunch of parts at it. hopeing to fix it.allso i am not trying to tell you what to do and you are a lot smarter than me.but next time try taking the wires comeing from your distributor. and twist them around each other.that way they act like a home made shielded cable.like you said two wires running right beside each other act like a little antina.thats what i had to do to a wheel speed sensor on a car when i worked at GM. i hope i said that to wear you can understand it.but any way good gob on fixing your car.mopar65

Wow!

That is great news Jim. That means for me, that i do not have to buy another set of sp wires.

Those wires as mentioned are the sames one that I have, but never used because.

I am glad that i asked, maybe it might help my msd box...

Thanks again Jim for clarifying that.


BP

Just to show I am not made of steel...
Revving the engine in the garage, in neutral to 6000 or 7000 rpm is a little un-nerving. But I did warm the engine before I did it, and that included both the water and the oil. Then I don't like "zinging" the RPM, but rather did a controlled steady increase in RPM. It started to sound a little like listening to NASCAR on TV as the engine passed 5000, 5500, 6000, 6500... After the first few times, it actually sounded nice. But a day later, thinking back, it was a little stressful! It was much worse when it would misfire at 5000 rpm, rather than the beautiful sound of the steady climb past 6000...

I'd like to drag this topic out of the archive because I'm having the same problem with my T-Bird. Last year, at the Keystone Natsionals, I noticed a misfire towards the end of the track (probably 7000-7600 rpm.). I suspected the RPM limiter might be the problem so I replaced the 8000 "chip" with an 8200 one and it seemed to fix it. This year it started to act up again, and I "fixed" the problem with a borrowed MSD box (7AL-2). I then put the original MSD box back in (was misfiring with a new box) and the problem came back. I reinstalled the borrowed box but this time it didn't help. I just bought a new pick up for the distributor (Old Chrysler Prestolite) which I hope will help. I also bought the newer type spark retard so that I can try the crank trigger again. I used to break starters with the old spark retard. This is really annoying me because I lost in the fifth round at the Div 1 race at Lebanon Valley by .002 seconds. I would have had a bye run into the final. I can't really test it without going to the track. I read your "fix" (sheilded leads) but was wondering if perhaps a weak magnet in the pick up might make the system more sensitive to noise. I also have a one wire GM alternator mounted close to the distributor, but ran this way for years without trouble. One other thing. The coil (MSD Pro Power) is mounted on the firewall. The car had a BB Chev. in it before I got it so the coil was close to the distributor. I checked the resistance of the plug wires and found that the MSD wires had about 100 ohms per foot. The coil wire was a Moroso wire which has about 1000 ohms per foot. That wire is about two feet long. I'm guessing I didn't have enough MSD wire for the coil wire so I used a wire from the Moroso set. I used to run Moroso wire all of the time and never had trouble. I did change the wire to a slightly shorter one at the track but it didn't help. Maybe I should mount the coil closer to the distributor.

B1Ken, are you running a Digital MSD (Digital 6,7)or are you running an Analog box (7AL2,3)?

Where can you get the shielded cable? Is this something MSD sells.

Summit part # MSD-8862 $18.88, got one last week ( to replace the one that I BARB- B - Q'd )

All I can say for sure, is it solved my problem. I modified my spare distributor now too. The new Power master 100 amp was worse than the old 63 amp alternator at the same amp draw.

Jim after reading this I went out and put a ground strap on the altinator. I wasen't having a problum but I guess it cant hurt. I use the pickup cable with the shield, but have a pigtail coming out of the MSD distributor old styel about 8" so maybe I will shorten that up too.
Thanks for keeping us up to dated.