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Is Crossfire An Issue?
Posted by: loud41 ()
Date: January 13, 2020 05:23PM

So, I've been experiencing a spark plug wire dilemma with my '95 F150 lately. Those trucks (the v8's) suffer quite a bit from spark plug wire crossfire because cylinders 5, 6, 7 and 8 fire next to each other in the firing order. This causes a lot of seemingly mysterious misfire problems.

This got me thinking. Are our Corvairs susceptible at all to crossfire? I mean, any more than usual? With our firing order it doesn't seem like it's anything beyond regular wire maintenance as far as changing the wires out every few years or whatever you guys are into. Are 8mm wires really helpful, or can one get by with 7mm (just asking the question. I have 8mm on mine personally)? Does one have to get high quality wires, or can one get by with cheapskate wires? I think most of us understand the consequences of going the cheapo route, but I wanna ask the question just to start a dialogue here.

Bare in mind, I'm only talking about a standard ignition system (nothing like a 40 million volt coil or whatever) on something like a daily driver or weekend warrior (ie. not a race car). Thoughts??

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Re: Is Crossfire An Issue?
Posted by: American Mel ()
Date: January 13, 2020 05:29PM

Welcome to CCF ! ! !
About time you posted.
Start an itro thread, and post some pictures of your Corvair! thumbs up

-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
WA. state, 1 mile south of the Canadian border,
I am not at the end of the world, but you can see it from here.
Have; '66 Monza Coupe - 140, 4-spd. Daily driver beater
'67 Monza Vert. - 140, 4-spd. Daily driver beater
'67 A/C Moredoor Monza
Have had; '61 Monza coupe, 80hp, PG
'62 Monza Wagon, 4spd.
'63 Spyder,
'65 Corsa
.
non-vair
'04 Dodge Cummins Quad Dually, approaching 400K
'03 Honda Del Sol
17'Terry

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Re: Is Crossfire An Issue?
Posted by: Timothy Shortle ()
Date: January 13, 2020 05:46PM

I don't know about it being an issue on Corvairs but most of us get our wires from Silicone Wire Systems in San Jose California.

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Re: Is Crossfire An Issue?
Posted by: 63turbo ()
Date: January 13, 2020 06:22PM

The short answer is that it can be, especially with high powered ignitions. The cure though is usually as easy as good wire routing and keep the wires from physically touching one another, using plug wire separators, and having the wires insulated from the shroud. Your Crossfire May Vary!!smiling smiley

------------------------------------

Kevin Nash
Friday Harbor Washington
63 Spyder, Daily driver, EFI read about my project here: [corvaircenter.com]
first test start on EFI here:[www.youtube.com]
first official EFI boost test here:[www.youtube.com]
My new fan! [corvaircenter.com]
engine less 62 Spyder
Canadian 64 Monza Parts car



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Re: Is Crossfire An Issue?
Posted by: JimBrandberg ()
Date: January 14, 2020 03:58AM

You can look at it running in the dark for visual traces. You can feel along the wires when it's running to see if you get a shock.

Jim Brandberg
Isanti, MN
CorvairRepair.com



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Re: Is Crossfire An Issue?
Posted by: joelsplace ()
Date: January 14, 2020 04:11AM

In addition to what Jim said use a spray bottle of water to mist the wires while you are checking them in the dark.

Joel
Northlake, TX
5 Ultravans, 114 Corvairs and counting...

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Re: Is Crossfire An Issue?
Posted by: vairmech ()
Date: January 14, 2020 04:41AM

Cross fire is not the same as bad wires that will arc out!

Yes it can happen on the Corvair if you bundle the wires together like the 2-4-6 wires under the belt. If the wires are kept in the wire loom that is prided there is no issues. Keep in mind that your F150 uses a little higher spark voltage than the Corvair does.

What difference does this make? It is the magnetic flux generated around the plug wire as it fires. If there is a wire next to it as the field collapses all of a sudden you have an impromptu secondary coil on the other wire and that could be enough to fire a different spark plug. Most time if you keep any separation of the plug wires the cross fire will not happen.

Ken Hand
Handy Car Care
248 613 8586

Vairmech@aol.com

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Re: Is Crossfire An Issue?
Posted by: vaporloc ()
Date: January 14, 2020 07:57AM

joelsplace Wrote:
-------------------------------------------------------
> In addition to what Jim said use a spray bottle of water to mist the wires while you are checking them in the dark.


Also remove your shoes and socks then wet the floor, if it has any spark leaking you will find it faster. LOL

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Re: Is Crossfire An Issue?
Posted by: jjohnsonjo ()
Date: January 14, 2020 08:18AM

A little OT, I've had more problems with carbon tracking in the distributor cap than actual wire issues. Keep in mind I'm running a turbo which stresses the system more.

J.O.

65 Corsa Turbo Vert
79 Honda XL 500S
69 Honda CL 160 D
2010 BMW F 650 GS
2003 Bounder 36D
2013 KIA Optima SX turbo-AKA ZIPPY (wife,s car)
69 Newport Holiday Sailboat
Baja 150 dune buggy cart
Coleman HS 500 UTV
2016 KIA Sorento SXL Turbo

Bethlehem,Pa


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Re: Is Crossfire An Issue?
Posted by: joelsplace ()
Date: January 14, 2020 08:58AM

>Cross fire is not the same as bad wires that will arc out!
True. I didn't stay on point at all with that.

> Also remove your shoes and socks then wet the floor, if it has any spark leaking you will find it faster. LOL
If you don't mind a little zap this might be a good check also. I've never been zapped using water mist and I wasn't kidding it works great. Might not be recommended if you have a pacemaker but getting zapped by ignition systems never bothered me much.

Joel
Northlake, TX
5 Ultravans, 114 Corvairs and counting...

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Re: Is Crossfire An Issue?
Posted by: Seth Emerson ()
Date: January 14, 2020 10:15AM

Just resist the urge to wire-tie the wires together when you route them. Ken Hand is correct about inducing another spark in an adjacent wire. If you use a clip or two to keep the wires apart, you won'r see any cross-fire with good wires. Don't be tempted to use solid core wires on a Corvair motor.

Seth Emerson

Check my new Performance Corvair Web site [www.perfvair.com]

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Re: Is Crossfire An Issue?
Posted by: 66vairman ()
Date: January 15, 2020 10:00AM

Seth Emerson Wrote:
-------------------------------------------------------
> Just resist the urge to wire-tie the wires together when you route them. Ken Hand is correct about inducing another spark in an adjacent wire. If you use a clip or two to keep the wires apart, you won'r see any cross-fire with good wires. Don't be tempted to use solid core wires on a Corvair motor.

Yes solid core wires are very prone to EMF cross talk and there is no advantage to using them versus good modern spark plug wire.

Most modern spark plug wires are constructed to minimize EMF cross talk and the thicker silicone insulation ensures there is no arcing between wires for many years of use.

I recall in the 60's the old spark plug wires would start arcing (great visuals at night with the hood up) after about five years.

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Re: Is Crossfire An Issue?
Posted by: hardcase ()
Date: January 15, 2020 12:34PM

vairmech Wrote:
-------------------------------------------------------
>
> What difference does this make? It is the magnetic flux generated around the plug wire as it fires. If there is a wire next to it as the field collapses all of a sudden you have an impromptu secondary coil on the other wire and that could be enough to fire a different spark plug. Most time if you keep any separation of the plug wires the cross fire will not happen.


Amplifying on Ken's excellent comment, the intensity of the magnetic flux decays with the square of the radius of the wire. In layman's terms, that means that it doesn't take a lot of separation to eliminate the effect of that changing magnetic field. It may not seem like the wire loom on the engine cover provides much separation, but if you're using, say, 8mm spark plug wires, every 4mm of separation reduces the magnetic field by a factor of 16.

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Re: Is Crossfire An Issue?
Posted by: solo2r ()
Date: January 15, 2020 09:00PM

I run an MSD Digital 7 ignition [that will knock One down into the Fetal position if hit!] through a stock brass Corvair cap and rotor and no issues.
With Seths wires of course as well.

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Re: Is Crossfire An Issue?
Posted by: irfgt ()
Date: January 16, 2020 09:15AM

in over 40 years of being a professional Automotive technician, I have never witnessed a condition of crossfire on any vehicle or ignition system no matter of how the wires were routed or bundled.Trust me I have seen some ugly stuff too!

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Re: Is Crossfire An Issue?
Posted by: Wagon Master ()
Date: January 16, 2020 09:32AM

irfgt Wrote:
-------------------------------------------------------
> in over 40 years of being a professional Automotive technician, I have never witnessed a condition of crossfire on any vehicle or ignition system no matter of how the wires were routed or bundled.Trust me I have seen some ugly stuff too!


irfgt. Off topic but I'm still waiting on your insight on the valve adjustment issue.
[corvaircenter.com]

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