Learned about the plugs today

[Alec]

Well today in school I learned how Ford can use 2 different spark plugs in our trucks: one bank single plat, and one bank double plat.

I knew that half the plugs fired backwards, but didn't know why. Turns out the plugs work in pairs. The coil pack is actually 3 put together (on the OHV 6, slightly different on the 5.0). Each coil powers 2 cylinders. Thus, each plug fires not only on compression, but also on exhaust. The engine completes the circuit as a ground, so the complete circuit goes: coil > wire > plug > ground > plug > wire > coil. So thus on one bank the plugs fire normally, but reverse on the other bank.

It's called a waste spark system

This system doesn't wear any parts out faster, but newer coil-on-plug systems are more accurate and efficient.

I've learned lots more cool things since starting at UTI, but this was one of those Eureka moments.

 

[XplorerKid]

So, are we suppose to be running special plugs? and a certian one for the cylinders? Like 3 would be the sing, and 3 would be the double, and they would have to be on a certian Cylinder? or am i just reading to far into this, and confused like most of the time?.....

 

[spindlecone]

I do not think so, confusion here dude

 

[spindlecone]

whats the benifit of spark on the exhaust stroke?

 

[Alec]

Just run double plats in all cylinders.

There is no benefit to spark on the exhaust stroke, it's just how the system works.

But in case you're wondering, the "real" spark is stronger than the wasted spark due to the electrical resistance of the compressed fuel/air mixture.

 

[CodePoet]

That's pretty cool alec...i have actually considered going to UTI or lincoln tech in the future, just now finishing up my degree in cs though so got to take care of this hefty student load lol.

Later
CP