Spark plug - which way do they face?

I have read conflicting suggestions about how to face your spark plugs when installing. What I mean by this is the direction the opening is supposed to face.

Some people say that it should be to the right. Others say that it really doesn't matter. Anyone have an opinion?

Well it depends on the head design and it will make a difference. You may not feel it on a stock bike, but it helps.

What head ya got?

Its a stock head, and I agree that it probably won't make a difference, but I know some people with the same setup that swear by it.

Its a stock head, and I agree that it probably won't make a difference, but I know some people with the same setup that swear by it.


Do you ride a harley v-twin? If so then the opening in the electrod should face the right side of the bike if the plug is on the left side of the round cylinder.

Big yes on the harley!

Perhaps I'm confused a little but....If you thread a sparkplug in and tighten to the aloted torque, the plug will always be facing the same way no matter where you started to thread it in. To change the position of the opening you would either have to over or under tighten the plug OR change the starting points of the threads on either the plug or the head.

Perhaps I'm confused a little but....If you thread a sparkplug in and tighten to the aloted torque, the plug will always be facing the same way no matter where you started to thread it in. To change the position of the opening you would either have to over or under tighten the plug OR change the starting points of the threads on either the plug or the head.

Racers have been indexing plugs as long as I can remember. I don't necessarily know that every plug is threaded so that it can be put in with the electrode facing the same direction.

We use the spacers to make sure that when the plug is inserted, tightening it made the electrod face a particular way.

Racers have been indexing plugs as long as I can remember. I don't necessarily know that every plug is threaded so that it can be put in with the electrode facing the same direction.

We use the spacers to make sure that when the plug is inserted, tightening it made the electrod face a particular way.
....but ofcourse ;)

This is going too far...

A Harley Davidson engine in any form of extreme modification will see no appreciable effect from spark plug electrode position in the firing chamber. The flame front in the chamber will not be experienced any sooner nor will it take its course of travel in any other direction as a result of the spark plug electrode position. These are occurances that are ordinary laws of strict physical nature. The speed of piston travel has more effect on flame front than any other physical occurance but the fuel/air mix can only burn at a given speed. The RPMs where a physical change in the flame front occurs is far beyond the ability of an engine design such as the Harley Davidson V twin, even the high RPM twin cam engine.

Sorry, no sale. Besides, why not purchase circular fire spark plugs that have no protruding electrode? These have been around since the frist outboard marine engine. "Surface Gap" spark plugs were designed to decrease the frequency of oil fouling in a two cycle, fuel/oil mixed engine. These little spacers to position the electrode are basically similar to the cell phone paste on antenna enhancer - bunk, with no sound scientific evidence or proof.

Just install your spark plugs to the proper torque and forget about reving your engine in an attempt to see the difference where the electrode happens to be. The electrode gap will have more effect...

My question about these spacers is simple; why are you trying to sell people on this idea? The answer to that question is also simple - greed.

BClem

This is going too far...

A Harley Davidson engine in any form of extreme modification will see no appreciable effect from spark plug electrode position in the firing chamber. The flame front in the chamber will not be experienced any sooner nor will it take its course of travel in any other direction as a result of the spark plug electrode position. These are occurances that are ordinary laws of strict physical nature. The speed of piston travel has more effect on flame front than any other physical occurance but the fuel/air mix can only burn at a given speed. The RPMs where a physical change in the flame front occurs is far beyond the ability of an engine design such as the Harley Davidson V twin, even the high RPM twin cam engine.

Sorry, no sale. Besides, why not purchase circular fire spark plugs that have no protruding electrode? These have been around since the frist outboard marine engine. "Surface Gap" spark plugs were designed to decrease the frequency of oil fouling in a two cycle, fuel/oil mixed engine. These little spacers to position the electrode are basically similar to the cell phone paste on antenna enhancer - bunk, with no sound scientific evidence or proof.

Just install your spark plugs to the proper torque and forget about reving your engine in an attempt to see the difference where the electrode happens to be. The electrode gap will have more effect...

My question about these spacers is simple; why are you trying to sell people on this idea? The answer to that question is also simple - greed.

BClem


WOW, nice rant, but you missed the part where I said you won't feel it.

As for the greed and spacers, I think I get a handful of them for free whenever I buy spark plugs. Who's getting rich on these?

If a tech wants a plug installed a certain way to read it, good for him.

And you can call bullshit all you want, I'm no expert and I can see a different burn/wear pattern on a plug that has been installed facing one way or the other in a cylinder.

http://www.nightrider.com/biketech/hdsparkplugs_indexing.htm

http://www.ngksparkplugs.com/techinfo/spark_plugs/installation.asp?nav=31300&country=US

http://racingsecrets.com/spark_plug_reading.shtml

http://pw1.netcom.com/~pow/sparkplugs.html

Those links should be enough to show it's not snake oil.

Nice job smeg! Sent that "Lurker" back into hiding! Heres what I found from a guy on another site who is a tech. If you feel you need to do it then this is how to do it. You will need spark plug shims. The opening of the electrodes need to face the intake valves. Mark where the opening is on the plug somewhere you will see it when the plug is in the head. Screw it in and see where the mark is in relation to the intake valves. Shim it until they line up and there you go. The idea is that as the fuel enters the cylinder, and the spark arc is facing the fuel with nothing in the way (meaning the ground electrode which is the "L" shaped one) you get a better burn. I got a stock Harley and don't believe for 1 minute that my bike is gonna turn into a rocket by doing this. But for the guys out there who do look for little things to increase performance, I thought that this would be helpful, so thats why I started the thread.

No bullshit here! Your links don't say much about indexing that doesn't explain away my points of no gain. As a matter of fact, the resistance measuring artical is totally from left field. The 'resistance' you are being told to measure is impossible with a conventional ohm meter available to the avarage shop. You must measure that resistance under the load and voltage that the spark plug 'resistor' will receive in use - as much as 60,000 volts. The matching of resistance between plugs is more bunk.

You're quick to lable what someone offers here as bullshit. Is this how this forum works?

BClem

Nice job SMEG? What is that all about? Last time I checked, this was a free country and ideas and comments were welcomed. Not here? This a cult?

BClem

P.S. There is No Gain from indexing spark plugs in a street run engine. Why waste the time?

Nice job SMEG? What is that all about? Last time I checked, this was a free country and ideas and comments were welcomed. Not here? This a cult?

BClem

P.S. There is No Gain from indexing spark plugs in a street run engine. Why waste the time?

Exactly, we all agree on this, but you seem hell bent on dismissing the whole proceedure it seems.

As for resistance and voltage, ohms law is very "Real" math and is set in stone physics. That was exactly what I was schooled in and know it cold. When you dismiss something like ohms law, it's hard to listen to the rest of the story.

We're not a cult, but we aint exaclty gonna lie down and worship one opinion. So far the one thing we agree with you on you are still argueing about and the one thing that is finate math, you dismiss.

Some of us do want to ride beyond the street and some of us do and have done it. Don't be so quick to assume this conversation will stay at the street level.

I've been to the track with top gas and nitro. Those guys do the math and use the tips and tricks and win doing it. I won't dismiss this as snake oil.

If you want people to "welcome your ideas and comments" then practice what you preach. I started a friendly discussion and you "jumped" all over us with "This is going too far..." & "Sorry, no sale."! And then like Bclem said you just decided you were gonna "dismiss" the whole topic. I really don't spend my day trying to decide if I am gonna "index" my plugs, get real. I spend more time trying to figure out ways to get people to open up and contribute to the forum in a friendly manner. Thats all!

Doesn't appear to be much being said to argue the topic point, did you two just give up or get on your high horses (together).

SMEG, I expected a bit more of you; you are narrow minded! I have a degree in electronics and work with it every day. You jumped to a conclusion again, didn't you? I build IC engines as a hobby in my home machine shop, I have experience with all sorts of engines including the engines on the four HD's that I own from '56 to '04. I may come on a bit harsh but I know what I'm talking about.

I see that you are definitely cultish here, too bad.

No need to respond, I'll continue with what I was doing. I received an email from this forum (I thought)and it said something about being welcomed to join in. I see that it was sent in error.

You guys should really get a life!

B.C.

Attaboy! Been a member since November & could only come up with 7 posts in that timeframe. 4 wasted on this thread. Anyway, let em fade back to "Lurker" land. Smeg. Who gives out the spacers, motorcycle shops, or dealers? I have managed several Auto Parts stores, Autozone, Checker, etc. and have never seen them before.

Doesn't appear to be much being said to argue the topic point, did you two just give up or get on your high horses (together).

SMEG, I expected a bit more of you; you are narrow minded! I have a degree in electronics and work with it every day. You jumped to a conclusion again, didn't you? I build IC engines as a hobby in my home machine shop, I have experience with all sorts of engines including the engines on the four HD's that I own from '56 to '04. I may come on a bit harsh but I know what I'm talking about.

I see that you are definitely cultish here, too bad.

No need to respond, I'll continue with what I was doing. I received an email from this forum (I thought)and it said something about being welcomed to join in. I see that it was sent in error.

You guys should really get a life!

B.C.


Nobody said you don't know. We all agree that for the average rider that indexing is of no great importance. However there is an industry of products for doing so. Someone feels it's a worthwhile effort at some level.

Can we move on now?

Attaboy! Been a member since November & could only come up with 7 posts in that timeframe. 4 wasted on this thread. Anyway, let em fade back to "Lurker" land. Smeg. Who gives out the spacers, motorcycle shops, or dealers? I have managed several Auto Parts stores, Autozone, Checker, etc. and have never seen them before.

Perhaps I exergerated, they come with plugs and any busy garage has extras it seems.(At least where I hang out)

Extra rings should not be hard to get for free though is my point. If you are racing and need them, I'm sure you would source them in different thicknesses and pay for um.

Damn, I have looked at three different threads where everyone got pissy. All opinions are welcomed. If One says something disagreeable he is not getting dismissed, he is given another's viewpoint. There are almost 500 members on here and I am sure you would get 500 different opinions and 500 different "fixes" Can't we all just get along?