Spark plugs...

[streetlegends]

I just want to get opions about the way a spark plug is installed in the car. Do you think it matters what way a spark plug faces to get the most out of it? Like facing the intake manifold. Let me and everyone else know. Also wondering when a car comes from the factory which way are the plugs turned?

 

[Blitzeclips]

Yes it does matter. You need to check the spark plug gap in your owner's manual. Plugs don't have a set order of install, but if they're all symmetrical and set at the same gap, they SHOULD all be facing in the same direction, assuming all plugs are identical(brand, size, etc..)

 

[blcknspo0ln]

The gap is the only important part of a sparkplug. Using the NGK bprXes series will yield the most consistent results with spark. ONLY use NGK BPRxES plugs on your turbo setup. Gap to .028 using a roll gauge and tighten to 5-10 lb/ft of torque.

 

[DGajre777]

This is the first time I've heard about spark plugs having to be faced in the same direction.

 

[streetlegends]

Yes it does matter. You need to check the spark plug gap in your owner's manual. Plugs don't have a set order of install, but if they're all symmetrical and set at the same gap, they SHOULD all be facing in the same direction, assuming all plugs are identical(brand, size, etc..)

Thanks for the insight!

 

[a_scobel]

Thanks for the insight!

It screws in..there's no way to tell which way the plug's facing anyways. Since the threads are the same in each spark plug well, as well as the threads on the spark plug itself, they will pretty much be facing the same direction anyways, if they're all tightened to equal torque, i would assume.

From NGK's site:

4. Indexing

This is for racers only !!
Indexing refers to a process whereby auxiliary washers of varying thickness are placed under the spark plug's shoulder so that when the spark plug is tightened, the gap will point in the desired direction.

However, without running an engine on a dyno, it is impossible to gauge which type of indexing works best in your engine. While most engines like the spark plug's gap open to the intake valve, there are still other combinations that make more power with the gap pointed toward the exhaust valve.

In any case, engines with indexed spark plugs will typically make only a few more horsepower, typically less than 1% of total engine output. For a 500hp engine, you'd be lucky to get 5hp. While there are exceptions, the bottom line is that without a dyno, gauging success will be difficult.

 

[streetlegends]

It screws in..there's no way to tell which way the plug's facing anyways. Since the threads are the same in each spark plug well, as well as the threads on the spark plug itself, they will pretty much be facing the same direction anyways, if they're all tightened to equal torque, i would assume.

From NGK's site:

Yes you can if you marked it on the rachet extension like did but, I can see where you coming from about the NGK article. I changed mine to face the intake but like the ad said you need dyno testing to see what way works best the cars. Thanks for your help as well.

 

[steve]

Guys, Try a Google search in indexing spark plugs. That's what your talking about.

Steve