Technical INDEX SPARK PLUGS ( anyone else do it )

allways read good reports on mikuni carbs,but ran a super b then a shorty super e.sounds like a good combo to me.

 

i just like to have a motor running nice to its potential.on the street no racing for me.

 

Hey Boodlum. Those Hardly Ableson's need all the help they can get.

 

I had a 12.5 302 chevy that I had to to clear the piston dome. Only engine I ever did it on.

 

Why all the consternation? If all you are doing is changing the plugs anyway the only extra step is looking at which direction you place the new plug into the socket which takes a nanosecond.

EXCEPT if you are working on a Chevrolet or other GM product. On GM products you may need to add a shim to make the electrode end up in the correct orientation BUT since most plugs a manufactured to pretty good tolerances after the first time the next time you do it the same shims can be applied.

Like someone pointed out it's for competitors. I still do it on customers cars just out of habit (used to change plugs in the race engine once a week) but they wouldn't notice or care if I didn't.

This is why I used to love Class Drag Racing (not bracket racing) when you were trying to beat a supposedly "Equal" car. Everything being equal except for preparation, every little thing you did better than the other guy increased your chances of winning. Striving for excellence was a worthy goal not just "Good enough".

 

Never done it. I've lost races by snoozing on the line or buggering up a gear change. Plugs have been in for the last couple of events.

 

you have let the cat out of the bag now.!

 

How many things do we do because somebody thought it was the way to go and it has become a tradition and there is no repeatable horse hp gain on a dyno. I understand small gains on a dyno are hard to pinpoint. No two runs are exactly the same numbers even with no changes made. I have indexed plugs because physical damage to the plug.

 

Playing with ignition timing, seems to have far more effect on how fast my car runs, than playing with which way the plugs point. And, as a bonus, there is a plausible reason for it.

 

Think of it this way.... when the explosive mixture enters the combustion chamber, and the ignition fires, The plug puts out a source to ignite the fire so to speak.

If the electrode strap has been positioned with the open end toward the mixture the flame kernel ignites the mixture SOONER (yea I know a matter of nanoseconds) so the flame front has that much MORE time to travel across the combustion chamber combusting MORE of the mixture than if the combustion started LATER with an electrode ground strap hidden on the other side of the plug. And we should all know that a more efficient burning of the mixture produces MORE POWER.

Yes all these things happen EXTREMELY RAPIDLY. Think about it at 6000 RPM how many times is the ignition firing and burning the mixture, if I am figuring right 2 revolutions for a firing cycle 2 into 6000 is 3000 per minute 60 seconds in a minute so 50 times A SECOND.

So at the rate of 50 times per second anything that you can do to extend the minuscule amount of burning time HAS to produce more power. It could be proven by a dyno if you could get one accurate enough or resort to just plan old laws of physics.

 

There must be some reason that my Gen III Hemi has dual plugs?

 

Same reason more complete combustion

 

could the top plug do with being turned anticlockwise 90 degrees.if 1 plug is good,then more must be better !

 

Could be for emissions purposes.

 

I remember Street Rod or R&C doing some sort of test and they basically said that for a street driven car it was a waste of time. Everyone that did it will tell you they got 10 mph faster though. If you have that much time on your hand's try it.

 

if Henry Ford had his way we would all be driving model T s.fine job in its day but a little innovation goes a long way.my friend had a twin plugged shovel head.if you disconnected one plug the idle dropped off.that had high volt coils as well and electronic ignition.all together it made for a sweet running motor.i dont ever remember it breaking down either. back to the indexing

 

its only 8 plugs and the plugs dont wear out that quickly.if you make the special tool to aid finding the best plug for a given cylinder it wont take too long second time round.

 

The fire slot took the place in part of the indexed plugs. part of the idea behind indexing was to regulate the fire trail, at least that is the theory on it. The fire groove was for the same purpose to make the flame cover the top of the piston equally.

My father-in-law (RIP Norman) was a Navy aircraft mechanic in the South Pacific Theater, a Master Chief. He said that when they got a new motor they indexed the plugs, I never questioned him, no reason to lie about it.

 

I understand the argument but there are so many variables as difference between cylinders as a SBC has mirrored chambers If we are talking nano seconds are distributors that accurate from one cylinder to the next? Some times I feel we overthink things.

 

I think that the idea is that if the ground wire gap is facing the same way on all cylinders then in theory the flame will travel the same way on all cylinders.

I also think that a lot of the stuff that we do is kind of like witch craft. it works because we think it does.

 

You mean you can't spare the 3 seconds to look and see in which position you put the plug in the plug socket???

 

So...what fraction of a degree would you have to advance the ignition timing, to achieve the same amount of "SOONER" ignition?

 

id think you would have the most to gain or lose in a single cylinder engine say a motorcycle from the 50s with basic combustion chamber design.in a v8 from the same era the most to gain if all were indexed correctly but in most cases where random plugs were fitted in random cylinders some 2-3 maybe are likley to be fitted in benefical positions while 8 still have to be checked to get the benefit in 5-6 cylinders.not a big deal to someone determined to get the most benefit..if you are one of the slobs who dont see the benefit in changing oil and filter or setting your valve clearances you wont be changing your plugs either

 

There are things to change that make a difference, and things to change that don't. I don't change oil more than is necessary, but I do change it as often as is necessary.

If you want to index your plugs, by all means, go ahead and do it. No need to ask permission. Have fun!

 

Back in 1960, my Brother had a set of chrome, Lodge, Tri-Gappers. I suppose the theory was to have the spark scattered around, to ignite all of the fuel in the chamber.

 

True story: 1963, my bud Jack's Dad bought him a new 426 Plymouth. 3 speed stick, the car was a Fury, deluxe interior... from Purdue Plymouth, Redwood City.
Not competitive...
I tore a customer's 330 Dodge 426 apart to see what happened when the local wiseass drove it. (spun #3 rod brg)
The owner was distraught, high repair estimate, he offered me the car if I'd take over payments. Sure!
I repaired the engine, and we (buddy Jack and I) pulled into Fremont Drag strip. Yes, we're gonna run.
I was in the pits, indexing my plugs. Jack was laughing. "Think that'll get you a low E.T.?"
"Can't hurt..." I was going thru 2 boxes of plugs, marking the ceramic with a #2 soft lead pencil. Jack was laughing as he walked to get us some food...I went over his fender and ran my pencil down the ceramics of 3 of his plugs, then put the boots back on...
He couldn't figure for the life of him why the engine missed so bad...
I said "Index your plugs..."

 

I always index my E3 Diamond fire plugs. John force says they are better than sliced bread. What are you running in your engine ?

 

I don’t get 16 free ones for each 1/4 mile....

 

I did on drag cars or engines with lots of compression, dont on dailys, it really doesnt take too long.

 

A millidegree would START it sooner BUT you wouldn't achieve the same more complete burning because the spark would END sooner also.