Plug Wires are crossfiring. Need help please
Abby Normal
Joined: Dec 2001
Posts: 53,462
Likes: 92
From: Press "2" for English
have you talked to any of the component manufacturers?
when i first installed my jacobs system, they recommended opening my plugs up to .065 and go up in .005 increments till i got detonation and then back off .005.
.045 is nothing for a high powered ignition. i've been to SEMA a couple times and both jacobs and MSD show their coils jumping a 1/2" (or more) gap. after all, that's the part of the reason you install a high output ignition, right? get more mixture between the electrodes. at least, that was my thinking.
open it up to .070 just for S&G. worst case scenario, it doesn't start.
hell just open up a couple and see if they cross fire. then you might have your answer.
when i first installed my jacobs system, they recommended opening my plugs up to .065 and go up in .005 increments till i got detonation and then back off .005.
.045 is nothing for a high powered ignition. i've been to SEMA a couple times and both jacobs and MSD show their coils jumping a 1/2" (or more) gap. after all, that's the part of the reason you install a high output ignition, right? get more mixture between the electrodes. at least, that was my thinking.
open it up to .070 just for S&G. worst case scenario, it doesn't start.
hell just open up a couple and see if they cross fire. then you might have your answer.
Le Mans Master
Joined: Jul 2005
Posts: 5,752
Likes: 4
From: Austin Texas
We're 
IMO. With a tighter gap,tlhere is LESS opportunity for the energy to dissapate in another area besides the spark gap. I think the "Light show" is static electricity. Prove it by touching the wires where you see the tiny spark. I am betting you won't feel a thing. (I hope)...lol. Ever play with one of those static generators in High School science class? It generates a good spark, but you don't get zapped. It's energy is too low. Like I said in an earlier post, I think the missing out is caused by something else. We see "cross-fires" on our shop 'scope, usually on C-4's with bad opti-spark distributors. You can see several extra spikes per engine revolution. 
IMO. With a tighter gap,tlhere is LESS opportunity for the energy to dissapate in another area besides the spark gap. I think the "Light show" is static electricity. Prove it by touching the wires where you see the tiny spark. I am betting you won't feel a thing. (I hope)...lol. Ever play with one of those static generators in High School science class? It generates a good spark, but you don't get zapped. It's energy is too low. Like I said in an earlier post, I think the missing out is caused by something else. We see "cross-fires" on our shop 'scope, usually on C-4's with bad opti-spark distributors. You can see several extra spikes per engine revolution.
Team Owner
Joined: Sep 2003
Posts: 88,393
Likes: 2
From: eville in
Originally Posted by clutchdust
have you talked to any of the component manufacturers?
when i first installed my jacobs system, they recommended opening my plugs up to .065 and go up in .005 increments till i got detonation and then back off .005.
.045 is nothing for a high powered ignition. i've been to SEMA a couple times and both jacobs and MSD show their coils jumping a 1/2" (or more) gap. after all, that's the part of the reason you install a high output ignition, right? get more mixture between the electrodes. at least, that was my thinking.
open it up to .070 just for S&G. worst case scenario, it doesn't start.
hell just open up a couple and see if they cross fire. then you might have your answer.
when i first installed my jacobs system, they recommended opening my plugs up to .065 and go up in .005 increments till i got detonation and then back off .005.
.045 is nothing for a high powered ignition. i've been to SEMA a couple times and both jacobs and MSD show their coils jumping a 1/2" (or more) gap. after all, that's the part of the reason you install a high output ignition, right? get more mixture between the electrodes. at least, that was my thinking.
open it up to .070 just for S&G. worst case scenario, it doesn't start.
hell just open up a couple and see if they cross fire. then you might have your answer.
Thread Starter
Instructor
Joined: Oct 2000
Posts: 226
Likes: 0
From: Lake Villa Illinois
Originally Posted by clutchdust
have you talked to any of the component manufacturers?
when i first installed my jacobs system, they recommended opening my plugs up to .065 and go up in .005 increments till i got detonation and then back off .005.
.045 is nothing for a high powered ignition. i've been to SEMA a couple times and both jacobs and MSD show their coils jumping a 1/2" (or more) gap. after all, that's the part of the reason you install a high output ignition, right? get more mixture between the electrodes. at least, that was my thinking.
open it up to .070 just for S&G. worst case scenario, it doesn't start.
hell just open up a couple and see if they cross fire. then you might have your answer.
when i first installed my jacobs system, they recommended opening my plugs up to .065 and go up in .005 increments till i got detonation and then back off .005.
.045 is nothing for a high powered ignition. i've been to SEMA a couple times and both jacobs and MSD show their coils jumping a 1/2" (or more) gap. after all, that's the part of the reason you install a high output ignition, right? get more mixture between the electrodes. at least, that was my thinking.
open it up to .070 just for S&G. worst case scenario, it doesn't start.
hell just open up a couple and see if they cross fire. then you might have your answer.
Thread Starter
Instructor
Joined: Oct 2000
Posts: 226
Likes: 0
From: Lake Villa Illinois
Originally Posted by clutchdust
do you know for sure it's crossfire? or could it be misfire? i would think that true crossfire, especially at high RPMs could result in new forms of crank case ventilation....
Burning Brakes
Joined: Aug 2005
Posts: 1,126
Likes: 0
From: Hudson Falls, N.Y. 76 Vette Modified L-48
Dave,
This may sound crazy, but maybe your arching problem is just a bad set of wires...that 2" section lighting up sounds damned suspicious to me...if you aren't in the poor house by now, I'd buy a set of copper core wires (if they still make them anymore) and substitue just one side of the engine, leaving the ceramic wires on the other side. If the copper wire side stops arching, it's the wires, which I now think is your problem..you may not like your radio reception after, but it shouldn't arch with copper core, all the arch should go straight to the plugs...as far as grabbing the 40k volt wire...it's the amps that'll kill ya, not the volts..you had to have one hand on a frame/engine ground to get a shock...not a fiberglass fender...you've tried just about everything else, gotta be the wires themselves....does this make sense to you?
This may sound crazy, but maybe your arching problem is just a bad set of wires...that 2" section lighting up sounds damned suspicious to me...if you aren't in the poor house by now, I'd buy a set of copper core wires (if they still make them anymore) and substitue just one side of the engine, leaving the ceramic wires on the other side. If the copper wire side stops arching, it's the wires, which I now think is your problem..you may not like your radio reception after, but it shouldn't arch with copper core, all the arch should go straight to the plugs...as far as grabbing the 40k volt wire...it's the amps that'll kill ya, not the volts..you had to have one hand on a frame/engine ground to get a shock...not a fiberglass fender...you've tried just about everything else, gotta be the wires themselves....does this make sense to you?
Thread Starter
Instructor
Joined: Oct 2000
Posts: 226
Likes: 0
From: Lake Villa Illinois
Originally Posted by kb2fzq
Dave,
This may sound crazy, but maybe your arching problem is just a bad set of wires...that 2" section lighting up sounds damned suspicious to me...if you aren't in the poor house by now, I'd buy a set of copper core wires (if they still make them anymore) and substitue just one side of the engine, leaving the ceramic wires on the other side. If the copper wire side stops arching, it's the wires, which I now think is your problem..you may not like your radio reception after, but it shouldn't arch with copper core, all the arch should go straight to the plugs...as far as grabbing the 40k volt wire...it's the amps that'll kill ya, not the volts..you had to have one hand on a frame/engine ground to get a shock...not a fiberglass fender...you've tried just about everything else, gotta be the wires themselves....does this make sense to you?
This may sound crazy, but maybe your arching problem is just a bad set of wires...that 2" section lighting up sounds damned suspicious to me...if you aren't in the poor house by now, I'd buy a set of copper core wires (if they still make them anymore) and substitue just one side of the engine, leaving the ceramic wires on the other side. If the copper wire side stops arching, it's the wires, which I now think is your problem..you may not like your radio reception after, but it shouldn't arch with copper core, all the arch should go straight to the plugs...as far as grabbing the 40k volt wire...it's the amps that'll kill ya, not the volts..you had to have one hand on a frame/engine ground to get a shock...not a fiberglass fender...you've tried just about everything else, gotta be the wires themselves....does this make sense to you?
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Racer
Joined: Dec 2005
Posts: 368
Likes: 4
From: . New Zealand
I once had a similar problem with a MSD Coil mounted horizontal, apparently they must be mounted vertically. This drove us crazy as we did a similar thing to you, trying everything. Mounting the coil vertically, it was fine.
Thread Starter
Instructor
Joined: Oct 2000
Posts: 226
Likes: 0
From: Lake Villa Illinois
Originally Posted by SwaveDave/1970 BB
REPLY: Makes darn good sense actually. I ordered a set of MSD Super Conductor copper core wires and will try them out . Dont care much about the radio as i enjoy the exhaust sound . I shall advise. Thanks, Dave
PROBLEM SOLVED ! I put on a set of MSD SUper Conductor copper core wires and no arching to ground or to one another . They were half the price of the Jacobs Ceramic wires too. Just for reference : The Jacobs wires will NOT work well with an MSD6 box and MSD-HVC2 high output Coil ; they cant handle the voltage. Thanks to all. Dave.
