Indexing Spark Plugs

Just looking for some clarification regarding the ideal index when installing spark plugs. I do not have a good concept of the internals, regarding valves alignment, to know in which way the plugs should be facing.

 

Does anyone have any suggestions?

Just install them, and torque them correctly.

 

/thread.

Your opinion clearly... but that is not what the question was asking.

Does anyone have any suggestions?

 

Just install them, and torque them correctly.

 

I'm pretty sure I answered the question exactly as it was asked.

 

Plug index orientation does not matter at all.

let me find out you read some article or post over on NASIOC and now you have a little seed planted

actually it was from watching a show where they stated the orientation should be a certain way and to mark the plug to assist in getting that alignment. with the responses ive been getting i might have well asked it on NASIOC

All that really matters for plugs (albeit they should be the correct ones) is gap and proper torque. Orientation will not make a difference.

What responses did you want? Wrong ones?

Subaru DHOC cylinder chambers are Hemispherical, I don't see a need to index your plugs.

Plus getting to a certain index point could lead to father headaches by tightening them to much or to little. Just gap them and torque them to spec and enjoy.

Just looking for some clarification regarding the ideal index when installing spark plugs. I do not have a good concept of the internals, regarding valves alignment, to know in which way the plugs should be facing.

 

Does anyone have any suggestions?

You were most likely watching Powerblock tv and saw it on horsepower where they rebuilt the Vortec engine.

 

They did index the plugs and I believe it does warrant an increase in fuel efficiency due to the vortex of air that certain type of engine creates.

 

I had never heard of indexing spark plugs before seeing that.

Used to be a big thing back in the 70's in drag racing. Now day's it's not worth the effort and time.

 

We used to do it in the Small Block Chevy dragster.

I have to do it on the 511 c.i. BB in the hydroplane, CR of something approaching 16:1 the combustion chamber is very small and there is not enough clearance for the ground strap on the plug. We have to clock between 10-2 or we break or bend the ground strap, ask me how I know .

 

BAC is correct on this one.

You were most likely watching Powerblock tv and saw it on horsepower where they rebuilt the Vortec engine.

 

They did index the plugs and I believe it does warrant an increase in fuel efficiency due to the vortex of air that certain type of engine creates.

 

I had never heard of indexing spark plugs before seeing that.

 

Used to be a big thing back in the 70's in drag racing. Now day's it's not worth the effort and time.

 

We used to do it in the Small Block Chevy dragster.

 

Exactly. It was done back in the day when homogenous fuel injection was nearly non-existant. Where you were poorly atomizing fuel into the intake rush, and as such had uneven air/fuel density within the combustion chamber. That's when indexing the plugs became commonplace, and for a few reasons. The primary reason was to tailor flame-front propagation, I believe. I think the goal was to force burn rate to be consistent during a flame cycle, so power delivery would be smoother and ultimately improve efficiency by allowing more accurate timing and improving (decreasing) output ripple.

 

In modern engines, especially those that are fuel injected, atomization is fairly homogenous within the combustion volume, and ignition systems are significantly more powerful than their predecessors. As such, plug index makes no real difference. You'd notice just as much change if a fly happened to fart in the intake.

You were most likely watching Powerblock tv and saw it on horsepower where they rebuilt the Vortec engine.

 

They did index the plugs and I believe it does warrant an increase in fuel efficiency due to the vortex of air that certain type of engine creates.

 

I had never heard of indexing spark plugs before seeing that.

 

Thats where I saw it.

 

The more detailed explanations have been appreciated.