Spark Plug Wire "Crossfire" Issue? (SOHC 4.0)

swshawaii · Sep 9, 2011

Decided to do some engine cleaning, lot's of dust.

Looking at the crossed plug wires on the passenger side,

wanted to make them lay flat before reading about this.

Sounds like it's more of a problem on V-8 engines.

Does "crossfire" exist on the SOHC? Haven't driven it yet.

scott degroot · Sep 9, 2011

As the article states the crossfire issue is only really a problem IF you have two cylinders next to each other that fire right after each other and even then it depends on the integrity of the spark plug wires. This was really a problem on the Chrysler 5.2 and 5.9 Magnum engines, so much so that Chrysler issued a TSB on it. I don't think I have ever seen this problem on a 4 or 6 cylinder engine and have never seen it on the 4.0L.

swshawaii · Sep 9, 2011

Thanks l1tech. Just find it odd Ford would leave the 1-2-3 wires crossed, off the assembly line.

EddieS'04 · Sep 10, 2011

Steve,

I dont see a problem. If you notice ford has the wires on the distributor, crossing all over each other.

Also this is why I never buy the base cheap wires, from discount parts stores.. Im with Scott on wire integrity. Wire qaulity the last 20yrs. Is very good if you spend the $$ for qaulity.

swshawaii · Sep 10, 2011

Still on the fence between the Magnecor, Taylor, LiveWires, or even OEM Motorcraft's. Prices range from $45 to $100 w/ shipping.

Seems a very small price to pay considering their importance and life expectancy. Decisions, decisions. Thanks again guys!

Richard L · Sep 10, 2011

swshawaii,

As l1tech said it is not a real issue with Ford engines because the fireing order brings the two cylinders prone to cross-fire on different banks of the engine and less likely to have the sparkplug wires running parallel to each other.

It is not as common in a 4 or 6 cylinder engine because it's nearly impossible to have two cylinders firing within 90 degrees of crank rotation. 4 cylinders only have 2 cylinders firing on each rotation, V6 engines only have 3 cylinders firing and they are spaced 120 degrees apart

V8's are more prone to cross-fire damage when two cylinders firing within 90 degrees pick up the spark signal by induction and fire 90 degrees BTDC just when it's starting it's compression stroke. Also, most of the engines are older model V8's and did not have the high-tech sparkplug wires.

Crossing sparkplug wires at 90 degrees usually eliminates the cross fire, so it's important not to run sparkplug wires parallel to each other, especially on those engines with the 90 degree cylinders on the same bank, like GM, AMC and Chryslers with 5-7 cylinders. Ford has less of an issue since the 6-5 and 7-8 cylinders are on different sides of the engine, and less likely that the sparkplug wires will run parallel since they are going to opposite sides of the engine.

....Rich