MSD Wires

[Heo]

A question the wires from a MSD 6AL. Can i put all the wires in the
same harness or must the two wires from the distributor be in
a separate harness due to some magnetic interference or something?

[thatdarncat]

I think separate would be best, especially away from anything higher current. MSD does make a shielded magnetic pickup cable - part number 8862. 

[machoneman]

I've run my MSD's w/o any special shielding for years w/o any issues. Just be sure the plug wires (#7, #8) do not run in any long parallel stretch but I'm sure you know this already.

[Drew Pojedinec]

Haven't had any issues with running them together either.
I will say if you wire the distributor backwards the engine will run 1500rpms and super rough

[cjshaker]

What Kevin said. I think you'd want to run them separately just to be safe and not cause any potential issues. I run my distributor and coil wires on the opposite sides of the engine, and even have them running through different holes in the firewall (ignition box is in the interior). The magnetically shielded wire that Kevin mentioned would probably work good if you wanted to run them together.

[Heo]

I decided to run them separately. It looks better to go left with the wires from dist
under the expansion tank and along the  passenger valvecover and straight through
firewall and the coilwires with temp and oil press gauge wires to the mainharness
But thanks anyway

[jayb]

I have actually seen an engine miss at high RPM on the dyno, that was cured by moving the distributor pickup wires away from the wires that go to the coil on an MSD Digital 6.  Running them separate is the best approach, I think.

[Heo]

Yes i started to make a harnes with all the wires from coil and dist.
But i started to think mayby thats not a good idea  since they are
separated at the box. And to route the wires from dist with the other
wires you have to go around the dist 3/4. So it looks better with a separate
harnes for those two wires alongside the other valvecover and drill a
new hole in the firewall. I have the box under the loudspeaker grill

[Falcon67]

For any wires coming from the pickup to an ignition box I run shielded cable.  On cars I have also use shield braid on the wires from the box to the coil.  Those CD boxes hit the coil with big V so anything to shield against spikes would help.  I did not run coil shielded on the dragster but the wiring already included a pair twisted, which seems to work as well.  But the mag pickup to the 7AL3 is shielded wire.  Note on shields, you ground one end only. 

[Drew Pojedinec]

Ahh I was confused, I thought you meant the two wires going TO the distributor, meaning seperating those.

[Heo]

No separating those two from the rest

[Tobbemek]

I did not run coil shielded on the dragster but the wiring already included a pair twisted, which seems to work as well.

Back in the late80is early 90is when i was crewing on my friends -71 HEMI Cuda A/SA European record holder car, we ran in to an misfiring issue mowing the MSD box to the trunk with all the wiring going together in the same harness . You could see the tach needle shivering on the "playback" between 4000-6000 rpm ( when cylinder pressure is highest ) . You couldnt hear the misfiring ore see any potential time loss  on the ET slip. Any way it was cured with a "pair twisted " signal/trigger cable. 

[manofmerc]

It was recommended to me by MSDs tech. to keep the coil wires separated from the mag pickup wires .He went own to say that you want your coil ( blaster) to be straight up .Says it keeps the coil properly cooled by the oil inside .I have an issue with my comet drag car with a slight miss fire in the 1/4 so gave msd a call Doug