Worn out spark plugs cause an engine to misfire and run badly. That is why you change them.
Bill Robertson
#5939
Printable View
How many times and how large do I have to write the word?
Increasing the gap WILL increase the voltage at the plug. It's a fact despite what Bill says. It's physics. The voltage at the plug will increase as you widen the gap until it's so wide that the coil can not produce enough to make it jump the gap. Haven't you ever pulled a coil wire an watched how far it will jump? Sure you have! Have you ever seen a (real) spark plug that you could gap anywhere near that wide? No.
You don't know what you are talking about. I installed a performance coil and increased my plug gap without increasing voltage (back when I had silly ideas like you).
Guess what happened? The damn thing started misfiring and many times it wouldn't even start. There was a really bad fuel smell back there.
I returned my plug gap back to stock specs and everything was fine.
When I got around to redoing my wiring I increased my voltage going into my performance coil, increased gap, and things were fine.
I am speaking from experience. You aren't.
They misfire and run bad because what's worn about them is the electrode is burn away creating a larger gap which increases the voltage which changes the curve which makes the max burn happen at the wrong time (to say the least) which causes it to run badly (which fowls the plug which causes a misfire).
No. From that, you should be guessing that since stock engines run with worn plugs and wide gaps, spark must be jumping across the worn/wider gaps.
So I ask you, "How the hell do you think spark is going to jump across a wider spark plug gap if you don't increase voltage?"
I never said it would. This is the question I keep asking you.
No one else on this thread is saying the crap you are saying. There is no debate saying you can or can't increase gap with it without the increased voltage.
The debate is whether or not the increased voltage and gap actually increase performance. I don't know what you are smoking but I really need some of it.
If you want to argue just say we are full of shit for believing we have increased performance because of our higher gapped plugs. At least then you would have someone on your side.
I don't think Ron or Martin has bothered to read the SAE paper posted earlier. For example, the engineer from Champion Spark Plugs on p. 62 said the same thing you are saying, and engineers from AC Delco concurred on p. 65.
From a historical perspective, wider plug gaps would never have been possible without:
- Breakerless ignition, which removed the inherent voltage limitations of breaker points
- New coil designs (General Motors adopted a coil mounted directly to the distributor cap)
Note that American manufacturers increased plug gaps on the same engines. For example, Ford's 250 inline 6 went from a .025" plug gap in 1969 to a .044" plug gap in 1980 on the same engine. What changed between 1969 and 1980? I'll give you a hint: it wasn't the engine.
Bill Robertson
#5939