Ignition Crossfire on 302HO

Dan W

Supporter
Hi Guys, I got the engine fired up on my GT and am suffering little induction pops and sometimes in the exhaust. The engine is also surging as I'm sure it is sometimes firing at the wrong time on compression. I have tried routing of the wires as Ford calls for it. This seemed to help some but has not cured it. I am using wire seperators and trying to keep two wires running against each other.
I am running a msd 6AL and a Mallory distributer, Taylor street thunder silicon 8mm wires, the wires are not expensive ones. Things are pretty tight just above the distrib cap and wires with the fuel rails/braided lines. Would appreciate reccomendations,, experience with this,,,better wires,,, etc?
Trying not to go the coil pack and crank trigger route if I can avoid it since i aready bought the distrib and have everything nicley wired.
Thanks for your help. Dan
 
Hi Guys, I got the engine fired up on my GT and am suffering little induction pops and sometimes in the exhaust. The engine is also surging as I'm sure it is sometimes firing at the wrong time on compression. I have tried routing of the wires as Ford calls for it. This seemed to help some but has not cured it. I am using wire seperators and trying to keep two wires running against each other.
I am running a msd 6AL and a Mallory distributer, Taylor street thunder silicon 8mm wires, the wires are not expensive ones. Things are pretty tight just above the distrib cap and wires with the fuel rails/braided lines. Would appreciate reccomendations,, experience with this,,,better wires,,, etc?
Trying not to go the coil pack and crank trigger route if I can avoid it since i aready bought the distrib and have everything nicley wired.
Thanks for your help. Dan
Are you running the small cap dizzy? Multi spark msd and the small cap may be giving you spark scatter between the ht posts on the cap.

Bob
 

Dan W

Supporter
Hi Bob, it's a Mallory 5055101 distrib, It's the small cap. After rewiring to fords layout it ran the best ever , much smoother except for number 8, slight pop,, then I realized I had number 7 and 8 switched,, Oops,,,then it induction popped more often again after correcting that. Smoother than it originally started out but not there yet. So maybe it's not in the cap? Dont want to hurt the engine so i need to get this figured out. I guess i could rewire so as not to have the msd, and see what happens,, to do that,,, think i will have to add a ballast resistor.
 
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Hi Bob, it's a Mallory 5055101 distrib, It's the small cap. After rewiring to fords layout it ran the best ever , much smoother except for number 8, slight pop,, then I realized I had number 7 and 8 switched,, Oops,,,then it induction popped more often again after correcting that. Smoother than it originally started out but not there yet. So maybe it's not in the cap? Dont want to hurt the engine so i need to get this figured out. I guess i could rewire so as not to have the msd, and see what happens,, to do that,,, think i will have to add a ballast resistor.
Dan we had problems with the small caps and spark scatter when we last ran on a dyno. There are mods you can do which help, drilling holes between the HT posts at rotor height as suggested in here at the bottom of page three.
http://www.pim-engineering.com/tiedostot/MSD 6series.pdf

Bob
 
Two things I would do before trying anything else.
1. Do a leakdown check to ensure it has not clipped an intake valve due to all the backfire stuff going on.
2. Check the rotor to cap phasing to help with the potential crossfire issue, its not unknown for the upper part of a Mallory shaft to move in relation to the shaft which puts the rotor index to hell, also had instances where rotor has caught on cap due to high G forces after a prang and moved the rotor on shaft.
 

Dan W

Supporter
Hi Guys, Cam is a X303 roller , crane 1.6 rockers, a TWM stack injection on a 347 with performer rpm heads.
Thanks Bob on the tip on venting the cap etc.
 

Randy V

Admin
Lifetime Supporter
Might want to pull that distributor out and check the gear. If you have an iron gear, that steel cam will eat it up in short order...
Make sure that you have the 302HO/351 firing order wired into the cap as well..
 

Dan W

Supporter
Hi Randy, The engine is running the HO firing order. Today I seperated the wires as far as possible from each other,, running 2 on each side top of the valve cover and down and the other two under, but all as far away as possible starting from the cap. The Engine started better than ever, I heard 3 light pops come out of #7 trumpet right away then no more for about 5 mins, I balanced the left and right banks using a airflow meter and the air fuel ratio was looking pretty good. Once the engine hit 160 degrees is started poping again out of multiple cylinders. I tried to find the culprit by moving things around with a screw driver but could not find it and think I am hearing an arcing near the cap,, not sure. I may start it tonight once its dark and see if i can see it. I will order a better set of wires and go from there.

I looked at the mallory distributer on the web and could not find any info on the gear. I found the original box and it does not say what the gear is either. Will have to contact mallory tomorrow and see what they say. When i pull it all apart to change the wires, Ill pull the distrbuter and look it over.

Thanks, Dan
PS according to the summit website that distributer comes with a steel gear, but I cannot find that on the mallory site, nor on any other site,, wrote mallory,, will see their reply.
 
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Cliff Beer

Supporter
Dan, just a thought, but perhaps try the Nology Hotwires for your V8? They have grounding/shielding which helps to lead stray volts to ground rather than cross-wire.

I put in coils packs on an older V8 (ferrari) instead of the stock/OEM ignition and it looked like a light show at night under the engine cover due to all the wayward sparking (much hotter ignition). The nology plug wires did the trick as far as keeping the spark going where it should be going....

[ame]http://www.amazon.com/84-95-Mustang-Nology-HotWires-Ignition/dp/B006DNYIDI[/ame]
 
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